Climate variability modes, usually known as primary climate phenomena, are well recognized as the most impor- tant predictability sources in subseasonal-interarmual climate prediction. This paper begins by reviewing t...Climate variability modes, usually known as primary climate phenomena, are well recognized as the most impor- tant predictability sources in subseasonal-interarmual climate prediction. This paper begins by reviewing the re- search and development carried out, and the recent progress made, at the Beijing Climate Center （BCC） in predicting some primary climate variability modes. These include the El Nifio-Southern Oscillation （ENSO）, Madden-Julian Oscillation （MJO）, and Arctic Oscillation （AO）, on global scales, as well as the sea surface temperature （SST） modes in the Indian Ocean and North Atlantic, western Pacific subtropical high （WPSH）, and the East Asian winter and summer monsoons （EAWM and EASM, respectively）, on regional scales. Based on its latest climate and statistical models, the BCC has established a climate phenomenon prediction system （CPPS） and completed a hindcast experi- ment for the period 1991-2014. The performance of the CPPS in predicting such climate variability modes is system- atically evaluated. The results show that skillful predictions have been made for ENSO, MJO, the Indian Ocean basin mode, the WPSH, and partly for the EASM, whereas less skillful predictions were made for the Indian Ocean Dipole （IOD） and North Atlantic SST Tripole, and no clear skill at all for the AO, subtropical IOD, and EAWM. Improve- ments in the prediction of these climate variability modes with low skill need to be achieved by improving the BCC＇s climate models, developing physically based statistical models as well as correction methods for model predictions. Some of the monitoring/prediction products of the BCC-CPPS are also introduced in this paper.展开更多
To describe the real world which is a harmonious unification world with both de- terminism and randomness, we propose a harmonious unifying hybrid preferential model (HUHPM) of a certain class of complex dynamical net...To describe the real world which is a harmonious unification world with both de- terminism and randomness, we propose a harmonious unifying hybrid preferential model (HUHPM) of a certain class of complex dynamical networks. HUHPM is gov- erned only by the total hybrid ratio d/r according to the practical need. As some typical examples, the concepts and methods of the HUHPM are applied to the un-weighted BA model proposed by Barabási et al., the weighted BBV model pro- posed by Barat et al. and the weighted TDE model proposed by Wang et al. to get the so-called HUHPM-BA network, HUHPM-BBV network and HUHPM-TDE network. These HUHPM networks are investigated both analytically and numerically. It is found that the HUHPM reveals several universal properties, which more approach to the real-world networks for both un-weighted and weighted networks and have potential for applications.展开更多
Three approaches, i.e., the harmonic analysis （HA） technique, the thermal diffusion equation and correction （TDEC） method, and the calorimetric method used to estimate ground heat flux, are evaluated by using obse...Three approaches, i.e., the harmonic analysis （HA） technique, the thermal diffusion equation and correction （TDEC） method, and the calorimetric method used to estimate ground heat flux, are evaluated by using observations from the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL） in July, 2008. The calorimetric method, which involves soil heat flux measurement with an HFP01SC self-calibrating heat flux plate buried at a depth of 5 cm and heat storage in the soil between the plate and the surface, is here called the ITHP approach. The results show good linear relationships between the soil heat fluxes measured with the HFP01SC heat flux plate and those calculated with the HA technique and the TDEC method, respectively, at a depth of 5 cm. The soil heat fluxes calculated with the latter two methods well follow the phase measured with the HFP01SC heat flux plate. The magnitudes of the soil heat flux calculated with the HA technique and the TDEC method are close to each other, and they are about 2 percent and 6 percent larger than the measured soil heat flux, respectively, which mainly occur during the nighttime. Moreover, the ground heat fluxes calculated with the TDEC method and the HA technique are highly correlated with each other （R2= 0.97）, and their difference is only about 1 percent. The TDEC-calculated ground heat flux also has a good linear relationship with the ITttP-calculated ground heat flux （R2 = 0.99）, but their difference is larger （about 9 percent）. Furthermore, compared to the HFP01SC direct measurements at a depth of 5 cm, the ground heat flux calculated with the HA technique, the TDEC method, and the ITHP approach can improve the surface energy budget closure by about 6 percent, 7 percent, and 6 percent at SACOL site, respectively. Therefore, the contribution of ground heat flux to the surface energy budget is very important for the semi-arid grassland over the Loess Plateau in China. Using turbulent heat fluxes with common corrections, soil heat 展开更多
Buildings contribute to almost 30%of total energy consumption worldwide.Developing building energy modeling programs is of great significance for lifecycle building performance assessment and optimization.Advances in ...Buildings contribute to almost 30%of total energy consumption worldwide.Developing building energy modeling programs is of great significance for lifecycle building performance assessment and optimization.Advances in novel building technologies,the requirements of high-performance computation,and the demands for multi-objective models have brought new challenges for building energy modeling software and platforms.To meet the increasing simulation demands,DeST 3.0,a new-generation building performance simulation platform,was developed and released.The structure of DeST 3.0 incorporates four simulation engines,including building analysis and simulation(BAS)engine,HVAC system engine,combined plant simulation(CPS)engine,and energy system(ES)engine,connected by air loop and water loop balancing iterations.DeST 3.0 offers numerous new simulation features,such as advanced simulation modules for building envelopes,occupant behavior and energy systems,cross-platform and compatible simulation kernel,FMI/FMU-based co-simulation functionalities,and high-performance parallel simulation architecture.DeST 3.0 has been thoroughly evaluated and validated using code verification,inter-program comparison,and case-study calibration.DeST 3.0 has been applied in various aspects throughout the building lifecycle,supporting building design,operation,retrofit analysis,code appliance,technology adaptability evaluation as well as research and education.The new generation building simulation platform DeST 3.0 provides an efficient tool and comprehensive simulation platform for lifecycle building performance analysis and optimization.展开更多
Northeast Asian cut-off lows are crucial cyclonic systems that can bring temperature and precipitation extremes over large areas.Skillful subseasonal forecasting of Northeast Asian cut-off lows is of great importance....Northeast Asian cut-off lows are crucial cyclonic systems that can bring temperature and precipitation extremes over large areas.Skillful subseasonal forecasting of Northeast Asian cut-off lows is of great importance.Using two dynamical forecasting systems,one from the Beijing Climate Center(BCC-CSM2-HR)and the other from the Met Office(GloSea5),this study assesses simulation ability and subseasonal prediction skill for early-summer Northeast Asian cut-off lows.Both models are shown to have good ability in representing the spatial structure of cut-off lows,but they underestimate the intensity.The skillful prediction time scales for cut-off low intensity are about 10.2 days for BCC-CSM2-HR and 11.4 days for GloSea5 in advance.Further examination shows that both models can essentially capture the initial Rossby wave train,rapid growth and decay processes responsible for the evolution of cut-off lows,but the models show weaker amplitudes for the three-stage processes.The underestimated simulated strength of both the Eurasian midlatitude and East Asian subtropical jets may lead to the weaker local eddy-mean flow interaction responsible for the cut-off low evolution.展开更多
The majority of topology optimization of compliant mechanisms uses linear finite element models to find the structure responses.Because the displacements of compliant mechanisms are intrinsically large,the topological...The majority of topology optimization of compliant mechanisms uses linear finite element models to find the structure responses.Because the displacements of compliant mechanisms are intrinsically large,the topological design can not provide quantitatively accurate result.Thus,topological design of these mechanisms considering geometrical nonlinearities is essential.A new methodology for geometrical nonlinear topology optimization of compliant mechanisms under displacement loading is presented.Frame elements are chosen to represent the design domain because they are capable of capturing the bending modes.Geometrically nonlinear structural response is obtained by using the co-rotational total Lagrange finite element formulation,and the equilibrium is solved by using the incremental scheme combined with Newton-Raphson iteration.The multi-objective function is developed by the minimum strain energy and maximum geometric advantage to design the mechanism which meets both stiffness and flexibility requirements, respectively.The adjoint method and the direct differentiation method are applied to obtain the sensitivities of the objective functions. The method of moving asymptotes（MMA） is employed as optimizer.The numerical example is simulated to show that the optimal mechanism based on geometrically nonlinear formulation not only has more flexibility and stiffness than that based on linear formulation,but also has better stress distribution than the one.It is necessary to design compliant mechanisms using geometrically nonlinear topology optimization.Compared with linear formulation,the formulation for geometrically nonlinear topology optimization of compliant mechanisms can give the compliant mechanism that has better mechanical performance.A new method is provided for topological design of large displacement compliant mechanisms.展开更多
The aim of this paper is to study the 3x + 1 problem based on the Collatz iterative formula. It can be seen from the iterative formula that the necessary condition for the Collatz iteration convergence is that its slo...The aim of this paper is to study the 3x + 1 problem based on the Collatz iterative formula. It can be seen from the iterative formula that the necessary condition for the Collatz iteration convergence is that its slope being less than 1. An odd number N that satisfies the condition of a slope less than 1 after n<sup>th</sup> Collatz iterations is defined as an n-step odd number. Through statistical analysis, it is found that after n<sup>th</sup> Collatz iterations, the iterative value of any n-step odd number N that is greater than 1 is less than N, which proves that the slope less than 1 is a sufficient and necessary condition for Collatz iteration convergence.展开更多
Aims:Multiple genes and environmental factors are known to be involved in congenital heart disease(CHD),but epigenetic variation has received little attention.Monozygotic(MZ)twins with CHD provide a unique model for e...Aims:Multiple genes and environmental factors are known to be involved in congenital heart disease(CHD),but epigenetic variation has received little attention.Monozygotic(MZ)twins with CHD provide a unique model for exploring this phenomenon.In order to investigate the potential role of Deoxyribonucleic Acid(DNA)methyla-tion in CHD pathogenesis,the present study examined DNA methylation variation in MZ twins discordant for CHD,especially ventricular septal defect(VSD).Methods and Results:Using genome-wide DNA methylation profiles,we identified 4004 differentially methylated regions(DMRs)in 18 MZ twin pairs discordant for CHD,and 2826 genes were identified.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis revealed a list of CHD-associated pathways.To further investigate the role of DNA methylation in VSD,data from 7 pairs of MZ twins with VSD were analyzed.We identified 1614 DMRs corresponding to 1443 genes associated with arrhythmogenic right ventricular cardiomyopathy,cyclic guanosine monopho-sphate-protein kinase G(cGMP-PKG)signaling pathway by KEGG analysis,and cell-cell adhesion,calcium ion transmembrane transport by GO analysis.A proportion of DMR-associated genes were involved in calcium signaling pathways.The methylation changes of calcium signaling genes might be related to VSD pathogenesis.Conclusion:CHD is associated with differential DNA methylation in MZ twins.CHD may be etiologically linked to DNA methylation,and methylation of calcium signaling genes may be involved in the development of VSD.展开更多
CircRNAs,a novel type of endogenous non-coding RNAs(ncRNAs),are typically produced by back-splicing from exons of protein-coding genes,which are characterized by a covalently closed structure with neither 5'to 3&#...CircRNAs,a novel type of endogenous non-coding RNAs(ncRNAs),are typically produced by back-splicing from exons of protein-coding genes,which are characterized by a covalently closed structure with neither 5'to 3'polarity nor a poly(A)tail.'On the one hand,circRNAs are involved in the regulation of a variety of important biological processes,such as apoptosis,proliferation,migration,and inflammatory responses.'On the other hand,the relationship between circRNAs and several fibrotic diseases has been reported.2 However.展开更多
Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years.To further improve the processing efficiency,a newly designed rotary kiln with three-section ...Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years.To further improve the processing efficiency,a newly designed rotary kiln with three-section structure is proposed,and the behaviours of particle motion and heat transfer are investigated.Firstly,a lab-scale rotary kiln is manufactured,and experiments are carried out.Verified by experimental data,a CFD-DEM numerical model is developed to analyze the particle motion and heat transfer characteristics with the effects of inlet flue gas temperature,feeding rate and rotating speed.The results show that the outlet temperature increases linearly with the flue gas temperature,while it is negatively correlated with the feeding rate and rotating speed.In addition,the volumetric heat transfer coefficient in this complex rotary kiln is analyzed,the overall heat transfer coefficient is between 200 and 700 W/(m^(3)K).展开更多
As the“emission peak and carbon neutrality peak”are proceeding all over the world,CO_(2) electroreduction is studied extensively as it is a powerful way to transform CO_(2)into value-added products.The earthabundant...As the“emission peak and carbon neutrality peak”are proceeding all over the world,CO_(2) electroreduction is studied extensively as it is a powerful way to transform CO_(2)into value-added products.The earthabundant Sn-based materials and copper sulfides as electrochemical catalysts have shown activity for generating formate from CO_(2) electroreduction.Herein,the composite of CuS and S-doped SnO_(2)(CuS/SnO_(2)-S)was synthesized by a redox reaction under room temperature.The unique structural reconstruction of CuS/SnO_(2)-S nanoparticles to Cu/Sn/Cu_(6.26)Sn_(5) nanowires decreases the energy barrier of the adsorption of CO_(2),and increases the adsorption of^(*)H,primarily suppressing the competing reaction of hydrogen evolution reaction(HER).As a result,at-0.8 V vs.RHE,it reaches an electrochemical CO_(2)-to-formate conversion with a Faradaic efficiency(FE)of 84.9%at a yield of 8860μmol h-1cm^(-2) under a partial current density of~18.8 mA cm^(-2) in an H-type reactor.This study provides significant insight into the structural evolution of the CuSn sulfides and the mechanism of formate formation.展开更多
Background:Risk assessment and treatment stratification for three-vessel coronary disease(TVD)remain challenging.This study aimed to investigate the prognostic value of left atrial volume index(LAVI)with the Synergy B...Background:Risk assessment and treatment stratification for three-vessel coronary disease(TVD)remain challenging.This study aimed to investigate the prognostic value of left atrial volume index(LAVI)with the Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery(SYNTAX)score II,and its association with the long-term prognosis after three strategies(percutaneous coronary intervention[PCI],coronary artery bypass grafting[CABG],and medical therapy[MT])in patients with TVD.Methods:This study was a post hoc analysis of a large,prospective cohort of patients with TVD in China,that aimed to determine the long-term outcomes after PCI,CABG,or optimal MT alone.A total of 8943 patients with TVD were consecutively enrolled between 2004 and 2011 at Fuwai Hospital.A total of 7818 patients with available baseline LAVI data were included in the study.Baseline,procedural,and follow-up data were collected.The primary endpoint was major adverse cardiac and cerebrovascular events(MACCE),which was a composite of all-cause death,myocardial infarction(MI),and stroke.Secondary endpoints included all-cause death,cardiac death,MI,revascularization,and stroke.Long-term outcomes were evaluated among LAVI quartile groups.Results:During a median follow-up of 6.6 years,a higher LAVI was strongly associated with increased risk of MACCE(Q3:hazard ratio[HR]1.20,95%confidence interval[CI]1.06-1.37,P=0.005;Q4:HR 1.85,95%CI 1.64-2.09,P<0.001),all-cause death(Q3:HR 1.41,95%CI 1.17-1.69,P<0.001;Q4:HR 2.54,95%CI 2.16-3.00,P<0.001),and cardiac death(Q3:HR 1.81,95%CI 1.39-2.37,P<0.001;Q4:HR 3.47,95%CI 2.71-4.43,P<0.001).Moreover,LAVI significantly improved discrimination and reclassification of the SYNTAX score II.Notably,there was a significant interaction between LAVI quartiles and treatment strategies for MACCE.CABG was associated with lower risk of MACCE than MT alone,regardless of LAVI quartiles.Among patients in the fourth quartile,PCI was associated with significantly increased risk of cardiac death compared with CABG(HR展开更多
The Shanghai Tianma 65 m radio telescope(TMRT)is a large,fully rotatable radio telescope with multiple scientific purposes.The main body of the telescope and four low-frequency receiving systems,including L,C,and S/X ...The Shanghai Tianma 65 m radio telescope(TMRT)is a large,fully rotatable radio telescope with multiple scientific purposes.The main body of the telescope and four low-frequency receiving systems,including L,C,and S/X bands,were completed between 2008 and 2012.From 2013 to 2017,four high-frequency receiving systems,including Ku,K,Ka,and Q bands,were constructed and their performance was comprehensively tested.There are three main innovations.(1)A fully movable large radio telescope system with advanced performance and complete functions has been built.(2)An advanced,reliable main reflector adjustment system has been completed,overcoming gravity deformation and creating a large antenna with a main reflective surface accuracy of 0.28 mm(root mean square)for any elevation.(3)Five innovative technologies have been developed to achieve high-precision pointing in any direction within 3″.The TMRT has made a crucial contribution to the orbital measurement and positioning of China’s lunar and deep space probes.Significantly enhancing China's ability to participate in international VLBI observations and radio astronomy,this has facilitated a series of achievements in observational radio astronomical research,in areas such as VLBI,spectral lines,and pulsars.展开更多
The Tianma 65 m radio telescope(TMRT)at Shanghai is a fully steerable single-dish radio telescope in China,operating at centimeter to millimeter wavelengths(1.25 GHz to 50 GHz).This paper presents details on the main ...The Tianma 65 m radio telescope(TMRT)at Shanghai is a fully steerable single-dish radio telescope in China,operating at centimeter to millimeter wavelengths(1.25 GHz to 50 GHz).This paper presents details on the main specifications,design,performance analysis,testing,and construction of the telescope antenna.The measured total efficiency is better than 50%over the whole elevation angle range,first sidelobe levels are less than−20 dB,antenna system noise temperatures are less than 70 K at 30°elevation angle,and pointing accuracy is less than 3″.The measured and calculated results are in good agreement,verifying the effectiveness of the design and analysis.展开更多
The surface accuracy of a radio telescope is directly related to its operational efficiency and detection sensitivity.This is crucial under high-frequency observation conditions,where surface shape errors need to be c...The surface accuracy of a radio telescope is directly related to its operational efficiency and detection sensitivity.This is crucial under high-frequency observation conditions,where surface shape errors need to be controlled to within 1/16 of the working wavelength.In addition,the primary reflector of large radio telescopes is subject to dynamic deformation,caused by factors such as gravity and thermal effects.This paper presents a method for detecting the surface shape of radio telescopes using radio interferometry techniques combined with active reflector adjustment technology.This enables accurate assessment and correction of surface errors,ensuring the electrical performance of the radio telescope.This study investigates the practical applications of high-precision measurement techniques,such as microwave holography,out-of-focus holography,and wavefront distortion methods at the Tianma 65 m radio telescope(TMRT).Furthermore,the study presents the construction method of gravity models at different elevation angles and demonstrates the efficacy of the active reflector model.The results of the measurements indicate that the application of these methods to the TMRT has led to a notable enhancement of the accuracy of the primary reflector and a substantial improvement in efficiency in the Q-band.Through a process of iterative measurements and adjustments,the surface shape error is ultimately reduced to 0.28 mm root mean square(RMS).展开更多
Heavy metal pollution in landfill humus can cause serious environmental problems and may endanger soil ecosystems and human health.The biological toxicity of heavy metals is not only related to their total amount but ...Heavy metal pollution in landfill humus can cause serious environmental problems and may endanger soil ecosystems and human health.The biological toxicity of heavy metals is not only related to their total amount but also influenced to a greater extent by the distribution of their chemical speciation.Exploring the different chemical speciation and proportions of heavy metals can provide a more comprehensive and accurate understanding of the pollution characteristics and biological toxic-ity of heavy metals in landfill soil.Based on a review of the relevant literature,this paper systematically summarizes the recent research status of typical heavy metal chemical speciation in landfill humus.This chemical speciation is diverse and complex.For instance,heavy metals in residual states and organically bound states have little impact on organisms,while heavy metals in exchangeable states and Fe-Mn oxide states can easily migrate and transform.The chemical speciation of heavy metals is affected by many factors,among which the soil pH and organic matter content are some of the most important factors.Finally,the existing gaps in the current research on the chemical speciation of heavy metals in landfills are described and future research directions are proposed.This work provides a theoretical reference for researching the restoration of heavy metal-contaminated humus soil and the resource utilization of humus soil.展开更多
Acute myocardial infarction (AMI) has been associated with poor prognosis,even after revascularization with percutaneous coronary intervention (PCI),likely due to coronary endothelial cell dysfunction and injury.^([1,...Acute myocardial infarction (AMI) has been associated with poor prognosis,even after revascularization with percutaneous coronary intervention (PCI),likely due to coronary endothelial cell dysfunction and injury.^([1,2])Endothelin-1 (ET-1),a peptide that serves as a vasoconstrictor of smooth muscle cell proliferation,can reflect endothelial cell functional states.Due to low circulation levels and short plasma half-life time,measuring plasma ET-1 levels is difficult.In contrast,big ET-1.展开更多
To the Editor:It has been eighteen years since telocytes(TCs)were first categorized by Popescu et al^([1])in 2005.TCs were classified into interstitial cells of the Cajal(ICC)type based on their ultrastructure and imm...To the Editor:It has been eighteen years since telocytes(TCs)were first categorized by Popescu et al^([1])in 2005.TCs were classified into interstitial cells of the Cajal(ICC)type based on their ultrastructure and immunohistochemical features,which are similar to mesenchymal cells.^([2])In the following ten years,TCs were found to have their own distinctive characteristics in terms of three-dimensional structure,immunological biomarkers,genomics,and multiple functions.Interestingly,TCs are definitely distinct from fibroblasts,mesenchymal stem cells,and endothelial cells in multiple organs of human beings and animals.^([3])展开更多
Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,...Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,and solar energy harvesting for glazed facades.In this study,we addressed these conflicts by introducing a new dynamic and vertical photovoltaic integrated building envelope(dvPVBE)that offers extraordinary flexibility with weather-responsive slat angles and blind positions,superior architectural aesthetics,and notable energy-saving potential.Three hierarchical control strategies were proposed for different scenarios of the dvPVBE:power generation priority(PGP),natural daylight priority(NDP),and energy-saving priority(ESP).Moreover,the PGP and ESP strategies were further analyzed in the simulation of a dvPVBE.An office room integrated with a dvPVBE was modeled using EnergyPlus.The influence of the dvPVBE in improving the building energy efficiency and corresponding optimal slat angles was investigated under the PGP and ESP control strategies.The results indicate that the application of dvPVBEs in Beijing can provide up to 131%of the annual energy demand of office rooms and significantly increase the annual net energy output by at least 226%compared with static photovoltaic(PV)blinds.The concept of this novel dvPVBE offers a viable approach by which the thermal load,daylight penetration,and energy generation can be effectively regulated.展开更多
Paper-based electronics offer a simple and cost-effective means to fabricate reconfigurable devices. In response to the problem of fixed shape and single function of most antennas, which limits their applications, a r...Paper-based electronics offer a simple and cost-effective means to fabricate reconfigurable devices. In response to the problem of fixed shape and single function of most antennas, which limits their applications, a reconfigurable paper-based metamaterial antenna with 2D and 3D forms is presented for tunable operating frequency. The proposed antenna consists of two square split resonant rings fed by a coplanar waveguide. The working frequency of the 2D antenna is adjusted by the length, width, and opening size of the internal open resonant ring. While the folding angle of the antenna turns from 0° to 90°, the operating frequency of the paper-based metamaterial antenna changes from 2.759 to 4.223 GHz. In terms of 3D form, an additional resonant peak is generated by bending the paper-based metamaterial antenna, thus further realizing dual-band antenna design.After a simple process flow, a series of proposed antennas are fabricated and evaluated. The simulated and measured results both demonstrate that the proposed antenna has a good performance in turning the working band. The environment-friendly nature and pliability of paper, as well as simple fabrication procedures, make paper-based metamaterial promising candidates for future green electronics.展开更多
基金Supported by the National(Key)Basic Research and Development(973)Program of China(2015CB453203)China Meteorological Administration Special Public Welfare Research Fund(GYHY201506013 and GYHY201406022)+3 种基金National Natural Science Foundation of China(41205058,41375062,41405080,41505065,41606019,and 41605116)US National Science Foundation(AGS-1406601)US Department of Energy(DOE)(DE-SC000511)the UK–China Research&Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP) China as part of the Newton Fund
文摘Climate variability modes, usually known as primary climate phenomena, are well recognized as the most impor- tant predictability sources in subseasonal-interarmual climate prediction. This paper begins by reviewing the re- search and development carried out, and the recent progress made, at the Beijing Climate Center （BCC） in predicting some primary climate variability modes. These include the El Nifio-Southern Oscillation （ENSO）, Madden-Julian Oscillation （MJO）, and Arctic Oscillation （AO）, on global scales, as well as the sea surface temperature （SST） modes in the Indian Ocean and North Atlantic, western Pacific subtropical high （WPSH）, and the East Asian winter and summer monsoons （EAWM and EASM, respectively）, on regional scales. Based on its latest climate and statistical models, the BCC has established a climate phenomenon prediction system （CPPS） and completed a hindcast experi- ment for the period 1991-2014. The performance of the CPPS in predicting such climate variability modes is system- atically evaluated. The results show that skillful predictions have been made for ENSO, MJO, the Indian Ocean basin mode, the WPSH, and partly for the EASM, whereas less skillful predictions were made for the Indian Ocean Dipole （IOD） and North Atlantic SST Tripole, and no clear skill at all for the AO, subtropical IOD, and EAWM. Improve- ments in the prediction of these climate variability modes with low skill need to be achieved by improving the BCC＇s climate models, developing physically based statistical models as well as correction methods for model predictions. Some of the monitoring/prediction products of the BCC-CPPS are also introduced in this paper.
基金Supported by the Key Project of the National Natural Science Foundation of China (Grand No. 70431002)the National Natural Science Foundation of China (Grand No. 70371068)
文摘To describe the real world which is a harmonious unification world with both de- terminism and randomness, we propose a harmonious unifying hybrid preferential model (HUHPM) of a certain class of complex dynamical networks. HUHPM is gov- erned only by the total hybrid ratio d/r according to the practical need. As some typical examples, the concepts and methods of the HUHPM are applied to the un-weighted BA model proposed by Barabási et al., the weighted BBV model pro- posed by Barat et al. and the weighted TDE model proposed by Wang et al. to get the so-called HUHPM-BA network, HUHPM-BBV network and HUHPM-TDE network. These HUHPM networks are investigated both analytically and numerically. It is found that the HUHPM reveals several universal properties, which more approach to the real-world networks for both un-weighted and weighted networks and have potential for applications.
基金supported by the National Natural Science Foundation of China (GrantNo. 40725015)
文摘Three approaches, i.e., the harmonic analysis （HA） technique, the thermal diffusion equation and correction （TDEC） method, and the calorimetric method used to estimate ground heat flux, are evaluated by using observations from the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL） in July, 2008. The calorimetric method, which involves soil heat flux measurement with an HFP01SC self-calibrating heat flux plate buried at a depth of 5 cm and heat storage in the soil between the plate and the surface, is here called the ITHP approach. The results show good linear relationships between the soil heat fluxes measured with the HFP01SC heat flux plate and those calculated with the HA technique and the TDEC method, respectively, at a depth of 5 cm. The soil heat fluxes calculated with the latter two methods well follow the phase measured with the HFP01SC heat flux plate. The magnitudes of the soil heat flux calculated with the HA technique and the TDEC method are close to each other, and they are about 2 percent and 6 percent larger than the measured soil heat flux, respectively, which mainly occur during the nighttime. Moreover, the ground heat fluxes calculated with the TDEC method and the HA technique are highly correlated with each other （R2= 0.97）, and their difference is only about 1 percent. The TDEC-calculated ground heat flux also has a good linear relationship with the ITttP-calculated ground heat flux （R2 = 0.99）, but their difference is larger （about 9 percent）. Furthermore, compared to the HFP01SC direct measurements at a depth of 5 cm, the ground heat flux calculated with the HA technique, the TDEC method, and the ITHP approach can improve the surface energy budget closure by about 6 percent, 7 percent, and 6 percent at SACOL site, respectively. Therefore, the contribution of ground heat flux to the surface energy budget is very important for the semi-arid grassland over the Loess Plateau in China. Using turbulent heat fluxes with common corrections, soil heat
基金supported by the“13th Five-Year”National Key R&D Program of China(No.2017YFC0702200)。
文摘Buildings contribute to almost 30%of total energy consumption worldwide.Developing building energy modeling programs is of great significance for lifecycle building performance assessment and optimization.Advances in novel building technologies,the requirements of high-performance computation,and the demands for multi-objective models have brought new challenges for building energy modeling software and platforms.To meet the increasing simulation demands,DeST 3.0,a new-generation building performance simulation platform,was developed and released.The structure of DeST 3.0 incorporates four simulation engines,including building analysis and simulation(BAS)engine,HVAC system engine,combined plant simulation(CPS)engine,and energy system(ES)engine,connected by air loop and water loop balancing iterations.DeST 3.0 offers numerous new simulation features,such as advanced simulation modules for building envelopes,occupant behavior and energy systems,cross-platform and compatible simulation kernel,FMI/FMU-based co-simulation functionalities,and high-performance parallel simulation architecture.DeST 3.0 has been thoroughly evaluated and validated using code verification,inter-program comparison,and case-study calibration.DeST 3.0 has been applied in various aspects throughout the building lifecycle,supporting building design,operation,retrofit analysis,code appliance,technology adaptability evaluation as well as research and education.The new generation building simulation platform DeST 3.0 provides an efficient tool and comprehensive simulation platform for lifecycle building performance analysis and optimization.
基金supported by the National Key Research and Development Program of China(2021YFA0718000)NSF of China under Grant No.42175075the UK-China Research&Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP)China as part of the Newton Fund.
文摘Northeast Asian cut-off lows are crucial cyclonic systems that can bring temperature and precipitation extremes over large areas.Skillful subseasonal forecasting of Northeast Asian cut-off lows is of great importance.Using two dynamical forecasting systems,one from the Beijing Climate Center(BCC-CSM2-HR)and the other from the Met Office(GloSea5),this study assesses simulation ability and subseasonal prediction skill for early-summer Northeast Asian cut-off lows.Both models are shown to have good ability in representing the spatial structure of cut-off lows,but they underestimate the intensity.The skillful prediction time scales for cut-off low intensity are about 10.2 days for BCC-CSM2-HR and 11.4 days for GloSea5 in advance.Further examination shows that both models can essentially capture the initial Rossby wave train,rapid growth and decay processes responsible for the evolution of cut-off lows,but the models show weaker amplitudes for the three-stage processes.The underestimated simulated strength of both the Eurasian midlatitude and East Asian subtropical jets may lead to the weaker local eddy-mean flow interaction responsible for the cut-off low evolution.
基金supported by National Science Foundation for Distinguished Young Scholars of China(Grant No.50825504)National Natural Science Foundation of China(Grant No.50775073)United Fund of Natural Science Foundation of China and Guangdong Province (Grant No.U0934004)
文摘The majority of topology optimization of compliant mechanisms uses linear finite element models to find the structure responses.Because the displacements of compliant mechanisms are intrinsically large,the topological design can not provide quantitatively accurate result.Thus,topological design of these mechanisms considering geometrical nonlinearities is essential.A new methodology for geometrical nonlinear topology optimization of compliant mechanisms under displacement loading is presented.Frame elements are chosen to represent the design domain because they are capable of capturing the bending modes.Geometrically nonlinear structural response is obtained by using the co-rotational total Lagrange finite element formulation,and the equilibrium is solved by using the incremental scheme combined with Newton-Raphson iteration.The multi-objective function is developed by the minimum strain energy and maximum geometric advantage to design the mechanism which meets both stiffness and flexibility requirements, respectively.The adjoint method and the direct differentiation method are applied to obtain the sensitivities of the objective functions. The method of moving asymptotes（MMA） is employed as optimizer.The numerical example is simulated to show that the optimal mechanism based on geometrically nonlinear formulation not only has more flexibility and stiffness than that based on linear formulation,but also has better stress distribution than the one.It is necessary to design compliant mechanisms using geometrically nonlinear topology optimization.Compared with linear formulation,the formulation for geometrically nonlinear topology optimization of compliant mechanisms can give the compliant mechanism that has better mechanical performance.A new method is provided for topological design of large displacement compliant mechanisms.
文摘The aim of this paper is to study the 3x + 1 problem based on the Collatz iterative formula. It can be seen from the iterative formula that the necessary condition for the Collatz iteration convergence is that its slope being less than 1. An odd number N that satisfies the condition of a slope less than 1 after n<sup>th</sup> Collatz iterations is defined as an n-step odd number. Through statistical analysis, it is found that after n<sup>th</sup> Collatz iterations, the iterative value of any n-step odd number N that is greater than 1 is less than N, which proves that the slope less than 1 is a sufficient and necessary condition for Collatz iteration convergence.
基金China’s National Natural Science Foundation provided funding for this study(81900222)Guangzhou Science and Technology Program(SL2022A04J01269,202201020646)Guangzhou Health Science and Technology Program(20211A010026).
文摘Aims:Multiple genes and environmental factors are known to be involved in congenital heart disease(CHD),but epigenetic variation has received little attention.Monozygotic(MZ)twins with CHD provide a unique model for exploring this phenomenon.In order to investigate the potential role of Deoxyribonucleic Acid(DNA)methyla-tion in CHD pathogenesis,the present study examined DNA methylation variation in MZ twins discordant for CHD,especially ventricular septal defect(VSD).Methods and Results:Using genome-wide DNA methylation profiles,we identified 4004 differentially methylated regions(DMRs)in 18 MZ twin pairs discordant for CHD,and 2826 genes were identified.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis revealed a list of CHD-associated pathways.To further investigate the role of DNA methylation in VSD,data from 7 pairs of MZ twins with VSD were analyzed.We identified 1614 DMRs corresponding to 1443 genes associated with arrhythmogenic right ventricular cardiomyopathy,cyclic guanosine monopho-sphate-protein kinase G(cGMP-PKG)signaling pathway by KEGG analysis,and cell-cell adhesion,calcium ion transmembrane transport by GO analysis.A proportion of DMR-associated genes were involved in calcium signaling pathways.The methylation changes of calcium signaling genes might be related to VSD pathogenesis.Conclusion:CHD is associated with differential DNA methylation in MZ twins.CHD may be etiologically linked to DNA methylation,and methylation of calcium signaling genes may be involved in the development of VSD.
基金supported by grants from the National Nature Science Foundation of China(No.82070791,81670690,81470991,81200492 to N.L.No.82070700,81830021 to S.Z.)+7 种基金the Shanghai Scientific Committee of China(No.20ZR1445800,23ZR1452200,13PJ1406900to N.L.)the Outstanding Leaders Training Program of Pudong Health Bureau of Shanghai,China(No.PWR12021-02 to N.L.)the Shanghai Health Bureau and Shanghai Administration of Traditional Chinese Medicine of China(No.ZHYY-ZXYJHZX-202114 to N.L.)the Project of Pudong Health Bureau of Shanghai,China(No.PW2021D-04,PWZxk2022-05,PWZxk2017-05 to N.L.)the Clinical Investigation Grant of Shanghai East Hospital,Shanghai,China(No.DFLC2022016 to N.L.)the Shanghai Sailing Program(China)(No.23YF1434700 to Y.s.)the China Postdoctoral Science Foundation(No.2021M692436 to Y.S.)the Branch Grantof NationaKl ey R&D Programof China(No.2018YFA0108802 to S.Z.).
文摘CircRNAs,a novel type of endogenous non-coding RNAs(ncRNAs),are typically produced by back-splicing from exons of protein-coding genes,which are characterized by a covalently closed structure with neither 5'to 3'polarity nor a poly(A)tail.'On the one hand,circRNAs are involved in the regulation of a variety of important biological processes,such as apoptosis,proliferation,migration,and inflammatory responses.'On the other hand,the relationship between circRNAs and several fibrotic diseases has been reported.2 However.
基金the National Natural Science Foundation of China(grant No.52306207)the Key R&D Program of Zhejiang province(grant No.2022c03056)+1 种基金the“Leading Goose”R&D Program of Zhejiang province(grant No.2023C03157)the National Key R&D Program of China(grant No.2018YFC1802102).
文摘Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years.To further improve the processing efficiency,a newly designed rotary kiln with three-section structure is proposed,and the behaviours of particle motion and heat transfer are investigated.Firstly,a lab-scale rotary kiln is manufactured,and experiments are carried out.Verified by experimental data,a CFD-DEM numerical model is developed to analyze the particle motion and heat transfer characteristics with the effects of inlet flue gas temperature,feeding rate and rotating speed.The results show that the outlet temperature increases linearly with the flue gas temperature,while it is negatively correlated with the feeding rate and rotating speed.In addition,the volumetric heat transfer coefficient in this complex rotary kiln is analyzed,the overall heat transfer coefficient is between 200 and 700 W/(m^(3)K).
基金supported by the National Natural Science Foundation of China(Grant Nos.22278020,2177060378)the Program for Changjiang Scholars,Innovative Research Teams in Universities of China(Grant No.IRT1205)the Fundamental Research Funds for the Central Universities of China(Grant Nos.12060093063,XK1803-05)。
文摘As the“emission peak and carbon neutrality peak”are proceeding all over the world,CO_(2) electroreduction is studied extensively as it is a powerful way to transform CO_(2)into value-added products.The earthabundant Sn-based materials and copper sulfides as electrochemical catalysts have shown activity for generating formate from CO_(2) electroreduction.Herein,the composite of CuS and S-doped SnO_(2)(CuS/SnO_(2)-S)was synthesized by a redox reaction under room temperature.The unique structural reconstruction of CuS/SnO_(2)-S nanoparticles to Cu/Sn/Cu_(6.26)Sn_(5) nanowires decreases the energy barrier of the adsorption of CO_(2),and increases the adsorption of^(*)H,primarily suppressing the competing reaction of hydrogen evolution reaction(HER).As a result,at-0.8 V vs.RHE,it reaches an electrochemical CO_(2)-to-formate conversion with a Faradaic efficiency(FE)of 84.9%at a yield of 8860μmol h-1cm^(-2) under a partial current density of~18.8 mA cm^(-2) in an H-type reactor.This study provides significant insight into the structural evolution of the CuSn sulfides and the mechanism of formate formation.
基金supported by National Program on Key Basic Research Project(973 Program,No.2010CB732601)National High-Tech Research and Development Program of China(863 Program,No.2015AA020407)+5 种基金Beijing Municipal Science&Technology Commission(No.Z191100006619106)National Natural Science Foundation of China(Nos.81470380 and 81770365)National Key Research and Development Program of the Ministry of Science and Technology of China during the"13^(th)Five-Year Plan"(No.2016YFC1301301)National Clinical Research Center for Cardiovascular Diseases,Fuwai Hospital,Chinese Academy of Medical Sciences(No.NCRC2020013)Key Project of Yunnan National Regional Medical Center for Cardiovascular Diseases(No.202002AA310100-14)Beijing United Heart Foundation(No.BJUHFCSOARF201901-19)
文摘Background:Risk assessment and treatment stratification for three-vessel coronary disease(TVD)remain challenging.This study aimed to investigate the prognostic value of left atrial volume index(LAVI)with the Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery(SYNTAX)score II,and its association with the long-term prognosis after three strategies(percutaneous coronary intervention[PCI],coronary artery bypass grafting[CABG],and medical therapy[MT])in patients with TVD.Methods:This study was a post hoc analysis of a large,prospective cohort of patients with TVD in China,that aimed to determine the long-term outcomes after PCI,CABG,or optimal MT alone.A total of 8943 patients with TVD were consecutively enrolled between 2004 and 2011 at Fuwai Hospital.A total of 7818 patients with available baseline LAVI data were included in the study.Baseline,procedural,and follow-up data were collected.The primary endpoint was major adverse cardiac and cerebrovascular events(MACCE),which was a composite of all-cause death,myocardial infarction(MI),and stroke.Secondary endpoints included all-cause death,cardiac death,MI,revascularization,and stroke.Long-term outcomes were evaluated among LAVI quartile groups.Results:During a median follow-up of 6.6 years,a higher LAVI was strongly associated with increased risk of MACCE(Q3:hazard ratio[HR]1.20,95%confidence interval[CI]1.06-1.37,P=0.005;Q4:HR 1.85,95%CI 1.64-2.09,P<0.001),all-cause death(Q3:HR 1.41,95%CI 1.17-1.69,P<0.001;Q4:HR 2.54,95%CI 2.16-3.00,P<0.001),and cardiac death(Q3:HR 1.81,95%CI 1.39-2.37,P<0.001;Q4:HR 3.47,95%CI 2.71-4.43,P<0.001).Moreover,LAVI significantly improved discrimination and reclassification of the SYNTAX score II.Notably,there was a significant interaction between LAVI quartiles and treatment strategies for MACCE.CABG was associated with lower risk of MACCE than MT alone,regardless of LAVI quartiles.Among patients in the fourth quartile,PCI was associated with significantly increased risk of cardiac death compared with CABG(HR
基金supported by National Natural Science Foundation of China(12273098).
文摘The Shanghai Tianma 65 m radio telescope(TMRT)is a large,fully rotatable radio telescope with multiple scientific purposes.The main body of the telescope and four low-frequency receiving systems,including L,C,and S/X bands,were completed between 2008 and 2012.From 2013 to 2017,four high-frequency receiving systems,including Ku,K,Ka,and Q bands,were constructed and their performance was comprehensively tested.There are three main innovations.(1)A fully movable large radio telescope system with advanced performance and complete functions has been built.(2)An advanced,reliable main reflector adjustment system has been completed,overcoming gravity deformation and creating a large antenna with a main reflective surface accuracy of 0.28 mm(root mean square)for any elevation.(3)Five innovative technologies have been developed to achieve high-precision pointing in any direction within 3″.The TMRT has made a crucial contribution to the orbital measurement and positioning of China’s lunar and deep space probes.Significantly enhancing China's ability to participate in international VLBI observations and radio astronomy,this has facilitated a series of achievements in observational radio astronomical research,in areas such as VLBI,spectral lines,and pulsars.
文摘The Tianma 65 m radio telescope(TMRT)at Shanghai is a fully steerable single-dish radio telescope in China,operating at centimeter to millimeter wavelengths(1.25 GHz to 50 GHz).This paper presents details on the main specifications,design,performance analysis,testing,and construction of the telescope antenna.The measured total efficiency is better than 50%over the whole elevation angle range,first sidelobe levels are less than−20 dB,antenna system noise temperatures are less than 70 K at 30°elevation angle,and pointing accuracy is less than 3″.The measured and calculated results are in good agreement,verifying the effectiveness of the design and analysis.
基金supported by the National Key R&D Program of China(2018YFA0404702,2019YFA0708904,2021YFC2203501)Shanghai Key Laboratory of Space Navigation and Positioning Techniques,the National Natural Science Foundation of China(12273097,11903068).
文摘The surface accuracy of a radio telescope is directly related to its operational efficiency and detection sensitivity.This is crucial under high-frequency observation conditions,where surface shape errors need to be controlled to within 1/16 of the working wavelength.In addition,the primary reflector of large radio telescopes is subject to dynamic deformation,caused by factors such as gravity and thermal effects.This paper presents a method for detecting the surface shape of radio telescopes using radio interferometry techniques combined with active reflector adjustment technology.This enables accurate assessment and correction of surface errors,ensuring the electrical performance of the radio telescope.This study investigates the practical applications of high-precision measurement techniques,such as microwave holography,out-of-focus holography,and wavefront distortion methods at the Tianma 65 m radio telescope(TMRT).Furthermore,the study presents the construction method of gravity models at different elevation angles and demonstrates the efficacy of the active reflector model.The results of the measurements indicate that the application of these methods to the TMRT has led to a notable enhancement of the accuracy of the primary reflector and a substantial improvement in efficiency in the Q-band.Through a process of iterative measurements and adjustments,the surface shape error is ultimately reduced to 0.28 mm root mean square(RMS).
基金the Zhejiang Provincial Science and Technology Plan Project(No.2022C03082).
文摘Heavy metal pollution in landfill humus can cause serious environmental problems and may endanger soil ecosystems and human health.The biological toxicity of heavy metals is not only related to their total amount but also influenced to a greater extent by the distribution of their chemical speciation.Exploring the different chemical speciation and proportions of heavy metals can provide a more comprehensive and accurate understanding of the pollution characteristics and biological toxic-ity of heavy metals in landfill soil.Based on a review of the relevant literature,this paper systematically summarizes the recent research status of typical heavy metal chemical speciation in landfill humus.This chemical speciation is diverse and complex.For instance,heavy metals in residual states and organically bound states have little impact on organisms,while heavy metals in exchangeable states and Fe-Mn oxide states can easily migrate and transform.The chemical speciation of heavy metals is affected by many factors,among which the soil pH and organic matter content are some of the most important factors.Finally,the existing gaps in the current research on the chemical speciation of heavy metals in landfills are described and future research directions are proposed.This work provides a theoretical reference for researching the restoration of heavy metal-contaminated humus soil and the resource utilization of humus soil.
基金National Clinical Research Center for Cardiovascular Diseases,Fuwai Hospital,Chinese Academy of Medical Sciences(NCRC2020013)CAMS Innovation Fund for Medical Sciences(2020-I2M-C&T-B-049)。
文摘Acute myocardial infarction (AMI) has been associated with poor prognosis,even after revascularization with percutaneous coronary intervention (PCI),likely due to coronary endothelial cell dysfunction and injury.^([1,2])Endothelin-1 (ET-1),a peptide that serves as a vasoconstrictor of smooth muscle cell proliferation,can reflect endothelial cell functional states.Due to low circulation levels and short plasma half-life time,measuring plasma ET-1 levels is difficult.In contrast,big ET-1.
基金supported by found from Shandong Postdoctoral Innovation Project(No.SDCX-ZG-202203046)Natural Science Foundation of Shandong Province(No.ZR2022QH066)Medical and Health Science and Technology Development of Shandong(No.202104080599)
文摘To the Editor:It has been eighteen years since telocytes(TCs)were first categorized by Popescu et al^([1])in 2005.TCs were classified into interstitial cells of the Cajal(ICC)type based on their ultrastructure and immunohistochemical features,which are similar to mesenchymal cells.^([2])In the following ten years,TCs were found to have their own distinctive characteristics in terms of three-dimensional structure,immunological biomarkers,genomics,and multiple functions.Interestingly,TCs are definitely distinct from fibroblasts,mesenchymal stem cells,and endothelial cells in multiple organs of human beings and animals.^([3])
基金supported by the National Natural Science Foundation of China(52078269 and 52325801).
文摘Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,and solar energy harvesting for glazed facades.In this study,we addressed these conflicts by introducing a new dynamic and vertical photovoltaic integrated building envelope(dvPVBE)that offers extraordinary flexibility with weather-responsive slat angles and blind positions,superior architectural aesthetics,and notable energy-saving potential.Three hierarchical control strategies were proposed for different scenarios of the dvPVBE:power generation priority(PGP),natural daylight priority(NDP),and energy-saving priority(ESP).Moreover,the PGP and ESP strategies were further analyzed in the simulation of a dvPVBE.An office room integrated with a dvPVBE was modeled using EnergyPlus.The influence of the dvPVBE in improving the building energy efficiency and corresponding optimal slat angles was investigated under the PGP and ESP control strategies.The results indicate that the application of dvPVBEs in Beijing can provide up to 131%of the annual energy demand of office rooms and significantly increase the annual net energy output by at least 226%compared with static photovoltaic(PV)blinds.The concept of this novel dvPVBE offers a viable approach by which the thermal load,daylight penetration,and energy generation can be effectively regulated.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2241243, 52102061 and 52372101)the Fundamental Research Funds for the Central Universities(Grant No.2023ZCJH03)。
文摘Paper-based electronics offer a simple and cost-effective means to fabricate reconfigurable devices. In response to the problem of fixed shape and single function of most antennas, which limits their applications, a reconfigurable paper-based metamaterial antenna with 2D and 3D forms is presented for tunable operating frequency. The proposed antenna consists of two square split resonant rings fed by a coplanar waveguide. The working frequency of the 2D antenna is adjusted by the length, width, and opening size of the internal open resonant ring. While the folding angle of the antenna turns from 0° to 90°, the operating frequency of the paper-based metamaterial antenna changes from 2.759 to 4.223 GHz. In terms of 3D form, an additional resonant peak is generated by bending the paper-based metamaterial antenna, thus further realizing dual-band antenna design.After a simple process flow, a series of proposed antennas are fabricated and evaluated. The simulated and measured results both demonstrate that the proposed antenna has a good performance in turning the working band. The environment-friendly nature and pliability of paper, as well as simple fabrication procedures, make paper-based metamaterial promising candidates for future green electronics.
