Lithium batteries have always played a key role in the field of new energy sources.However,non-controllable lithium dendrites and volume dilatation of metallic lithium in batteries with lithium metal as anodes have li...Lithium batteries have always played a key role in the field of new energy sources.However,non-controllable lithium dendrites and volume dilatation of metallic lithium in batteries with lithium metal as anodes have limited their development.Recently,a large number of studies have shown that the electrochemical performances of lithium batteries can be enhanced through the regulation of external physical fields.Especially,it significantly hinders the growth of lithium dendrites and promoting the reaction kinetics.This review summarizes recent innovations in the investigation of various physical fields of lithium batteries.The application of magnetic field in the synthesis of lithium battery electrode materials is introduced.The influence factors and regulation mechanism of various physical fields on the electrochemical performance of lithium batteries are reviewed emphatically.In addition,the current research status and existing challenges,along with future directions for the evolution of lithium batteries,are minutely discussed and prospected.New strategies for the further evolution of lithium batteries have also been provided.展开更多
Shading in greenhouses is a simple and cheap method usually used to reduce the intensity of solar radiation and air temperature.Moreover,combining Photovoltaic(PV)panels and crops on the same cropland could alleviate ...Shading in greenhouses is a simple and cheap method usually used to reduce the intensity of solar radiation and air temperature.Moreover,combining Photovoltaic(PV)panels and crops on the same cropland could alleviate the increasing competition for the agricultural land between food and energy production.In addition,the integration of PV with greenhouses could reduce,or partially replace the energy consumption for greenhouse crop production.Therefore,the aim of this study was to investigate the shading effect of semi-transparent mono-crystalline silicon double glazing photovoltaic panels(STPV),mounted on top of an agricultural greenhouse,which occupied 20%of the roof area,on the microclimate conditions and the growth of lettuce plants inside a greenhouse.Results showed that the combination of STPV and polyethylene cover decreased the solar radiation by 35%to 40%compared to the use of polyethylene cover only for clear days which was in the acceptable range of photosynthetically active radiation for lettuce plants.Moreover,STPV shading decreases the air temperature by 1℃-3℃ and had no effect in the relative humidity under natural ventilation.Furthermore,there were no significant differences(p<0.05)in the growth of lettuce plants between the shaded greenhouse by the STPV and the unshaded.Shading insignificantly increased the fresh weight,leaf area and the chlorophyll contents(p<0.05).In conclusion,the integration of STPV modules can decrease the solar irradiation and the internal air temperatures as well as generate electric energy for environmental control systems without significant influence on the growth of lettuce plants.Meanwhile,it can decrease the water consumption by decreasing the evapotranspiration rate.展开更多
Strain engineering,as a cutting-edge method for modulating the electronic structure of catalysts,plays a crucial role in regulating the interaction between the catalytic surface and the adsorbed molecules.The electroc...Strain engineering,as a cutting-edge method for modulating the electronic structure of catalysts,plays a crucial role in regulating the interaction between the catalytic surface and the adsorbed molecules.The electrocatalytic performance is influenced by the electronic structure,which can be achieved by introducing the external forces or stresses to adjust interatomic spacing between surface atoms.The challenges in strain engineering research lie in accurately understanding the mechanical impact of strain on performance.This paper first introduces the basic strategy for generating the strain,summarizes the different strain generation forms and their advantages and disadvantages.The progress in researching the characterization means for the lattice strains and their applications in the field of electrocatalysis is also emphasized.Finally,the challenges of strain engineering are introduced,and an outlook on the future research directions is provided.展开更多
运用太阳能热泵系统为草莓温室供暖,能有效提升草莓的产量和品质。为探究温室内立体栽培的供暖特性,以及相匹配的太阳能热泵系统的供暖系数(coefficient of performance,COP),该文设计并搭建了太阳能热泵阶梯式供暖系统。以"京藏香...运用太阳能热泵系统为草莓温室供暖,能有效提升草莓的产量和品质。为探究温室内立体栽培的供暖特性,以及相匹配的太阳能热泵系统的供暖系数(coefficient of performance,COP),该文设计并搭建了太阳能热泵阶梯式供暖系统。以"京藏香"草莓为试材,分析了距离地面0.5、1.0、1.5及2.0 m不同阶梯高度的空间温度,对比了阶梯式供暖的太阳能温室和未供暖的普通温室内的草莓品质及产量。结果表明,在北亚热带低纬高原山地季风气候地区,冬季采用太阳能热泵系统为温室供暖的COP值在3.02~5.15之间。在太阳能温室内种植的草莓产量是普通温室产量的1.56倍,可溶性固形物含量的平均值达10.5%。在太阳能热泵系统阶梯式供暖的温室中,距离地面1.0~1.5 m高度范围内的供暖效果较好,且放置于1.0 m阶梯上的草莓与其他高度的草莓相比,产量最高品质最优,其单果最大值为32.3 g,可溶性固形物含量为12.5%,因此,采用阶梯式供暖的温室中,距离地面1.0 m高度的温度更适宜草莓生长需求。展开更多
Yttrium(Ⅲ)oxide or so-called diyttrium trioxide(Y_2O_3)is an excellent candidate ceramic material for optoelectronic applications.Structural,electrical conductivity,and dielectric relaxation properties of bulk yttri...Yttrium(Ⅲ)oxide or so-called diyttrium trioxide(Y_2O_3)is an excellent candidate ceramic material for optoelectronic applications.Structural,electrical conductivity,and dielectric relaxation properties of bulk yttrium(Ⅲ)oxide were studied.X-ray diffraction(XRD)results indicate that the yttrium(Ⅲ)oxide compound has a crystalline cubic phase.Fourier transform infrared(FTIR)technique was used to ascertain the chemical structure of the yttrium(Ⅲ)oxide compound.Impedance spectroscopy was used to analyze frequency-dependent electrical properties as a function of temperature in the range of 303-423 K and frequency range of 0.1 Hz-2 MHz.Impedance spectroscopy parameters such as dielectric constant,dielectric loss,loss factor,electric modulus,and complex impedance of the yttrium(Ⅲ)oxide compound were studied.The Nyquist plot describes the complex impedance of the yttrium(Ⅲ)oxide for different temperatures.The universal Jonscher's power law was used for the analysis of the complex electrical conductivity of the yttrium(Ⅲ)oxide compound.It is found that the real(σ')and imaginary(σ")parts of the complex conductivity increase with increasing frequency.The exponent frequency(s)equals unity,which confirms that the predominant conduction mechanism is a nearly constant loss(NCL)mechanism.DFT/TD-DFT studies using B3LYP/LanL2DZ level of theory were used to provide comparable theoretical data and electronic energy gap of HOMO→LUMO.展开更多
Hydrogen is a popular clean high-energy-density fuel.However,its utilization is limited by the challenges toward low-cost hydrogen production and safe hydrogen storage.Fortunately,these issues can be addressed using p...Hydrogen is a popular clean high-energy-density fuel.However,its utilization is limited by the challenges toward low-cost hydrogen production and safe hydrogen storage.Fortunately,these issues can be addressed using promising hydrogen storage materials such as B–H compounds.Hydrogen stored in B–H compounds can be released by hydrolysis at room temperature,which requires catalysts to increase the rate of the reaction.Recently,several effective approaches have been developed for hydrogen generation by catalyzing the hydrolysis of B–H compounds.This review summarizes the existing research on the use of nanoparticles loaded on hydrogels as catalysts for the hydrolysis of B–H compounds.First,the factors affecting the hydrolysis rate,such as temperature,p H,reactant concentration,and type of nano particles,were investigated.Further,the preparation methods(in situ reduction,one-pot method,template adsorption,etc.)for the hydrogel catalysts and the types of loaded catalysts were determined.Additionally,the hydrogel catalysts that can respond to magnetic fields,ultrasound fields,optical fields,and other physical fields are introduced.Finally,the issues and future developments of hydrogel-based catalysts are discussed.This review can inspire deeper investigations and provide guidance for the study of hydrogel catalysts in the field of hydrogen production via hydrolysis.展开更多
Coronavirus causes an outbreak of viral pneumonia that spread throughout the world. Liver injury is becoming more widely recognized as a component of the clinical picture of COVID-19 infection. We aimed to review this...Coronavirus causes an outbreak of viral pneumonia that spread throughout the world. Liver injury is becoming more widely recognized as a component of the clinical picture of COVID-19 infection. We aimed to review this relation in a concise way. This review article includes a large number of patients from both western and eastern countries with no clear difference of liver affection. The more severe and frequent liver injury, the more severe COVID-19 infection. Up to half of patients developed hepatitis with serum ALT elevation. Both hepatocellular and/or ductular injury were observed as evidenced by alkaline phosphatase elevation. Increase incidence of morbidity and mortality had been recorded in patients with CLD. Cirrhosis mortality extended in line with the Child-Turcotte-Pugh class. The incidence of ACLF in CLD patients with COVID 19 is not clear. There are no significant associations with the etiology of liver disease and death in cirrhosis. COVID-19 hinders HCV elimination by 2030. Patients should continue their medications if already receiving treatment. Patients with occult or resolved HBV and COVID-19 who are receiving immunosuppressive agents should use antiviral therapy to prevent viral flare-ups.展开更多
2-(pyridine-2-yl)-N-p-chlorohydrazinecarbothioamide (HCPTS) was synthesized, characterized and successfully applied for the preconcentration of Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II) in wat...2-(pyridine-2-yl)-N-p-chlorohydrazinecarbothioamide (HCPTS) was synthesized, characterized and successfully applied for the preconcentration of Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II) in water, blood, and urine samples prior to graphite furnace atomic absorption determination (GFAAS);Hg was determined by cold vapor technique. Under the optimum experimental conditions (i.e. pH = 8, 10–4 M of HCPTS, 0.05% w/v of Triton X-114), calibration graphs were linear in the range of 0.02 to 200 ng?mL–1 for Co(II), Cd(II), Pb(II) and Ni(II);0.03 to 200 ng?mL–1 for Cu(II);0.07 to 200 ng?mL–1 for Fe(II) and Zn(II) and 0.02 to 150 ng?mL–1 for Hg(II). The enrichment factors were 43, 51, 41, 46, 54, 40, 45 and 52 for Cu(II), Ni(II),Zn (II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II), respectively. The limit of detection were found to be 0.019, 0.094, 0.0514, 0.052, 0.0165, 0.047, 0.068 and 0.041 ng?mL–1 for Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II), respectively. The developed method was applied to the determination of these metal ions in water, blood and urine samples with satisfactory results.展开更多
Currently,COVID-19 is spreading all over the world and profoundly impacting people’s lives and economic activities.In this paper,a novel approach called the COVID-19 Quantum Neural Network(CQNN)for predicting the sev...Currently,COVID-19 is spreading all over the world and profoundly impacting people’s lives and economic activities.In this paper,a novel approach called the COVID-19 Quantum Neural Network(CQNN)for predicting the severity of COVID-19 in patients is proposed.It consists of two phases:In the first,the most distinct subset of features in a dataset is identified using a Quick Reduct Feature Selection(QRFS)method to improve its classification performance;and,in the second,machine learning is used to train the quantum neural network to classify the risk.It is found that patients’serial blood counts(their numbers of lymphocytes from days 1 to 15 after admission to hospital)are associated with relapse rates and evaluations of COVID-19 infections.Accordingly,the severity of COVID-19 is classified in two categories,serious and non-serious.The experimental results indicate that the proposed CQNN’s prediction approach outperforms those of other classification algorithms and its high accuracy confirms its effectiveness.展开更多
Steel connection design using pre-tensioned bolts depends significantly on the value of the Prying forces exerted from the end plate. The Egyptian Code ECP （205） suggested a formula that can determine the Prying for...Steel connection design using pre-tensioned bolts depends significantly on the value of the Prying forces exerted from the end plate. The Egyptian Code ECP （205） suggested a formula that can determine the Prying force value. In this research, the Prying force is numerically computed in a T-Stub connection using nonlinear finite element techniques. The model uses plane stress four node elements with two degrees of freedom per node to simulate the flange of the T-Stub. The bolts are simulated using a truss element with large deformation capability to allow modeling of the pretension force. Surface to surface gap elements are used in order to simulate the contact between the T-Stub and the supporting element. Parametric study on the end plate thickness, bolt size, bolt arrangement and pretension forces is performed in order to calibrate the Code formula. The parametric study covers all the practical ranges of the variables. The study revealed that the Code formula, inaccurately, determines the Prying force in a certain range. Moreover, a new equation for the prying force is developed using regression analysis on the finite element results.展开更多
Medical image enhancement is an essential process for superior disease diagnosis as well as for detection of pathological lesion accurately. Computed Tomography (CT) is considered a vital medical imaging modality to e...Medical image enhancement is an essential process for superior disease diagnosis as well as for detection of pathological lesion accurately. Computed Tomography (CT) is considered a vital medical imaging modality to evaluate numerous diseases such as tumors and vascular lesions. However, speckle noise corrupts the CT images and makes the clinical data analysis ambiguous. Therefore, for accurate diagnosis, medical image enhancement is a must for noise removal and sharp/clear images. In this work, a medical image enhancement algorithm has been proposed using log transform in an optimization framework. In order to achieve optimization, a well-known meta-heuristic algorithm, namely: Cuckoo search (CS) algorithm is used to determine the optimal parameter settings for log transform. The performance of the proposed technique is studied on a low contrast CT image dataset. Besides this, the results clearly show that the CS based approach has superior convergence and fitness values compared to PSO as the CS converge faster that proves the efficacy of the CS based technique. Finally, Image Quality Analysis (IQA) justifies the robustness of the proposed enhancement technique.展开更多
In this study,CdS/ZnO(2:3 mol%)thin films are successfully deposited on quartz substrates by using the sputtering technique.Good images on the structural and optical characteristic features of CdS/ZnO thin films befor...In this study,CdS/ZnO(2:3 mol%)thin films are successfully deposited on quartz substrates by using the sputtering technique.Good images on the structural and optical characteristic features of CdS/ZnO thin films before and after annealing are obtained.The CdS/ZnO thin films are annealed respectively at temperatures of 373 K,473 K,and 573 K and the structural features are examined by XRD,ATR-FTIR,and FESEM.The optical properties of CdS/ZnO thin films such as refractive indices,absorption coefficients,optical band gap energy values,Urbach energy values,lattice dielectric constants,and high frequency dielectric constants are determined from spectrophotometer data recorded over the spectral range of 300 nm-2500 nm.Dispersion parameters are investigated by using a single-oscillator model.Photoluminescence spectra of CdS/ZnO thin films show an overall decrease in their intensity peaks after annealing.The third-order nonlinear optical parameter,and nonlinear refractive index are also estimated.展开更多
Identity verification using authenticity evaluation of handwritten signatures is an important issue.There have been several approaches for the verification of signatures using dynamics of the signing process.Most of t...Identity verification using authenticity evaluation of handwritten signatures is an important issue.There have been several approaches for the verification of signatures using dynamics of the signing process.Most of these approaches extract only global characteristics.With the aim of capturing both dynamic global and local features,this paper introduces a novel model for verifying handwritten dynamic signatures using neutrosophic rule-based verification system(NRVS)and Genetic NRVS(GNRVS)models.The neutrosophic Logic is structured to reflect multiple types of knowledge and relations among all features using three values:truth,indeterminacy,and falsity.These three values are determined by neutrosophic membership functions.The proposed model also is able to deal with all features without the need to select from them.In the GNRVS model,the neutrosophic rules are automatically chosen by Genetic Algorithms.The performance of the proposed system is tested on the MCYT-Signature-100 dataset.In terms of the accuracy,average error rate,false acceptance rate,and false rejection rate,the experimental results indicate that the proposed model has a significant advantage compared to different well-known models.展开更多
The aim of this paper is to study the thermal radiation effects on the flow and heat transfer of an unsteady magnetohydrodynamic （MHD） micropolar fluid over a vertical heated nonisothermal stretching surface in the ...The aim of this paper is to study the thermal radiation effects on the flow and heat transfer of an unsteady magnetohydrodynamic （MHD） micropolar fluid over a vertical heated nonisothermal stretching surface in the presence of a strong nonuniform magnetic field. The symmetries of the governing partial differential equations are de- termined by the two-parameter group method. One of the resulting systems of reduced nonlinear ordinary differential equations are solved numerically by the Chebyshev spec- tral method. The effects of various parameters on the velocity, the angular velocity, and the temperature profiles as well as the skin-friction coefficient, the wall couple stress co- efficient, and the Nusselt number are studied.展开更多
The lateral torsional buckling phenomenon often governs design of steel I-beams. Although web opening is often used to accommodate the required mechanical and piping works in buildings, its effect on the buckling inst...The lateral torsional buckling phenomenon often governs design of steel I-beams. Although web opening is often used to accommodate the required mechanical and piping works in buildings, its effect on the buckling instability is not considered in the design codes. In this paper, the effect of web opening on both lateral torsional buckling and local buckling behaviors has been investigated. A simply supported steel I-beam has been studied under uniform bending moment around the major axis. Buckling analysis has been performed using the finite element method. Linear regression analysis has been conducted for output data to formulate an equation for the critical moment including web opening effect. The results have shown a limited reduction in the lateral torsional buckling capacity and a significant reduction in the local buckling capacity.展开更多
Microwave photonics,a field that crosscuts microwave/millimeter-wave engineering with optoelectronics,has sparked great interest from research and commercial sectors. This multidisciplinary fusion can achieve ultrawid...Microwave photonics,a field that crosscuts microwave/millimeter-wave engineering with optoelectronics,has sparked great interest from research and commercial sectors. This multidisciplinary fusion can achieve ultrawide bandwidth and ultrafast speed that were considered impossible in conventional chip-scale microwave/millimeterwave systems. Conventional microwave-to-photonic converters,based on resonant acousto-optic modulation,produce highly efficient modulation but sacrifice bandwidth and limit their applicability for most real-world microwave signal-processing applications. In this paper,we build highly efficient and wideband microwaveto-photonic modulators using the acousto-optic effect on suspended lithium niobate thin films. A wideband microwave signal is first piezoelectrically transduced using interdigitated electrodes into Lamb acoustic waves,which directly propagates across an optical waveguide and causes refractive index pertp urbation through the photoelastic effect. This approach is power-efficient,with phase shifts up to 0.0166 rad∕m W over a 45μm modulation length and with a bandwidth up to 140 MHz at a center frequency of 1.9 GHz. Compared to the state-ofthe-art,a 9×more efficient modulation has been achieved by optimizing the acoustic and optical modes and their interactions.展开更多
Sound waves technology has been applied to different plants. It has been found that sound waves were at different frequencies, sound pressure levels （SPLs）, exposure periods, and distances from the source of sound i...Sound waves technology has been applied to different plants. It has been found that sound waves were at different frequencies, sound pressure levels （SPLs）, exposure periods, and distances from the source of sound influence plant growth. Experiments have been conducted in the open field and under greenhouse growing conditions with different levels of audible sound frequencies and sound pressure levels. Sound waves at 1 kHz and 100 dB for 1 h within a distance of 0.20 m could significantly promote the division and cell wall fluidity of callus cells and also significantly enhance the activity of protective enzymes and endogenous hormones. Sound waves stimulation could increase the plant plasma-membrane IT-ATPase activity, the contents of soluble sugar, soluble protein, and amylase activity of callus. Moreover, sound waves could increase the content of RNA and the level of transcription. Stress-induced genes could switch on under sound stimulation. Sound waves at 0.1-1 kHz and SPL of （70＋5） dB for 3 h from plant acoustic frequency technology （PAFT） generator within a distance ranged from 30 to 60 m every other day significantly increased the yield of sweet pepper, cucumber and tomato by 30.05, 37.1 and 13.2%, respectively. Furthermore, the yield of lettuce, spinach, cotton, rice, and wheat were increased by 19.6, 22.7, 11.4, 5.7, and 17.0%, respectively. Sound waves may also strengthen plant immune systems. It has been proved that spider mite, aphids, gray mold, late blight and virus disease of tomatoes in the greenhouses decreased by 6.0, 8.0, 9.0, 11.0, and 8.0%, respectively, and the sheath blight office was reduced by 50%. This paper provides an overview of literature for the effects of sound waves on various growth parameters of plant at different growth stages.展开更多
People started posting textual tweets on Twitter as soon as the novel coronavirus(COVID-19)emerged.Analyzing these tweets can assist institutions in better decision-making and prioritizing their tasks.Therefore,this s...People started posting textual tweets on Twitter as soon as the novel coronavirus(COVID-19)emerged.Analyzing these tweets can assist institutions in better decision-making and prioritizing their tasks.Therefore,this study aimed to analyze 43 million tweets collected between March 22 and March 30,2020 and describe the trend of public attention given to the topics related to the COVID-19 epidemic using evolutionary clustering analysis.The results indicated that unigram terms were trended more frequently than bigram and trigram terms.A large number of tweets about the COVID-19 were disseminated and received widespread public attention during the epidemic.The high-frequency words such as“death”,“test”,“spread”,and“lockdown”suggest that people fear of being infected,and those who got infection are afraid of death.The results also showed that people agreed to stay at home due to the fear of the spread,and they were calling for social distancing since they become aware of the COVID-19.It can be suggested that social media posts may affect human psychology and behavior.These results may help governments and health organizations to better understand the psychology of the public,and thereby,better communicate with them to prevent and manage the panic.展开更多
基金financially supported by the National Natural Science Fund of China(Nos.12172118 and 12172205)the Research Program of Local Science Research Development under the Guidance of Central(No.216Z4402G)+1 种基金Science Research Project of Hebei Education Department(No.JZX2023004)support from"Yuanguang"Scholar Program of Hebei University of Technology。
文摘Lithium batteries have always played a key role in the field of new energy sources.However,non-controllable lithium dendrites and volume dilatation of metallic lithium in batteries with lithium metal as anodes have limited their development.Recently,a large number of studies have shown that the electrochemical performances of lithium batteries can be enhanced through the regulation of external physical fields.Especially,it significantly hinders the growth of lithium dendrites and promoting the reaction kinetics.This review summarizes recent innovations in the investigation of various physical fields of lithium batteries.The application of magnetic field in the synthesis of lithium battery electrode materials is introduced.The influence factors and regulation mechanism of various physical fields on the electrochemical performance of lithium batteries are reviewed emphatically.In addition,the current research status and existing challenges,along with future directions for the evolution of lithium batteries,are minutely discussed and prospected.New strategies for the further evolution of lithium batteries have also been provided.
基金The authors acknowledge the financial support of the Collaborative Innovation Center of Research and Development of Renewable Energy in the Southwest Area in China(No.05300205020516009)the International Scientific and Technological Cooperation Projects of China(No.2011DFA62380).
文摘Shading in greenhouses is a simple and cheap method usually used to reduce the intensity of solar radiation and air temperature.Moreover,combining Photovoltaic(PV)panels and crops on the same cropland could alleviate the increasing competition for the agricultural land between food and energy production.In addition,the integration of PV with greenhouses could reduce,or partially replace the energy consumption for greenhouse crop production.Therefore,the aim of this study was to investigate the shading effect of semi-transparent mono-crystalline silicon double glazing photovoltaic panels(STPV),mounted on top of an agricultural greenhouse,which occupied 20%of the roof area,on the microclimate conditions and the growth of lettuce plants inside a greenhouse.Results showed that the combination of STPV and polyethylene cover decreased the solar radiation by 35%to 40%compared to the use of polyethylene cover only for clear days which was in the acceptable range of photosynthetically active radiation for lettuce plants.Moreover,STPV shading decreases the air temperature by 1℃-3℃ and had no effect in the relative humidity under natural ventilation.Furthermore,there were no significant differences(p<0.05)in the growth of lettuce plants between the shaded greenhouse by the STPV and the unshaded.Shading insignificantly increased the fresh weight,leaf area and the chlorophyll contents(p<0.05).In conclusion,the integration of STPV modules can decrease the solar irradiation and the internal air temperatures as well as generate electric energy for environmental control systems without significant influence on the growth of lettuce plants.Meanwhile,it can decrease the water consumption by decreasing the evapotranspiration rate.
基金supported by the National Natural Science Foundation of China(Nos.12172118,52071125,12227801)the Research Program of Local Science and Technology Development under the Guidance of Central(No.216Z4402G)+2 种基金Science Research Project of Hebei Education Department(No.JZX2023004)Opening fund of State Key Laboratory of Nonlinear Mechanics(LNM)National Key Research and Development Program of China(No.2019YFC0840709)。
文摘Strain engineering,as a cutting-edge method for modulating the electronic structure of catalysts,plays a crucial role in regulating the interaction between the catalytic surface and the adsorbed molecules.The electrocatalytic performance is influenced by the electronic structure,which can be achieved by introducing the external forces or stresses to adjust interatomic spacing between surface atoms.The challenges in strain engineering research lie in accurately understanding the mechanical impact of strain on performance.This paper first introduces the basic strategy for generating the strain,summarizes the different strain generation forms and their advantages and disadvantages.The progress in researching the characterization means for the lattice strains and their applications in the field of electrocatalysis is also emphasized.Finally,the challenges of strain engineering are introduced,and an outlook on the future research directions is provided.
基金supported by Taif University Researchers,Taif University,Taif,Saudi Arabia(grant numbers TURSP-2020/22)。
文摘Yttrium(Ⅲ)oxide or so-called diyttrium trioxide(Y_2O_3)is an excellent candidate ceramic material for optoelectronic applications.Structural,electrical conductivity,and dielectric relaxation properties of bulk yttrium(Ⅲ)oxide were studied.X-ray diffraction(XRD)results indicate that the yttrium(Ⅲ)oxide compound has a crystalline cubic phase.Fourier transform infrared(FTIR)technique was used to ascertain the chemical structure of the yttrium(Ⅲ)oxide compound.Impedance spectroscopy was used to analyze frequency-dependent electrical properties as a function of temperature in the range of 303-423 K and frequency range of 0.1 Hz-2 MHz.Impedance spectroscopy parameters such as dielectric constant,dielectric loss,loss factor,electric modulus,and complex impedance of the yttrium(Ⅲ)oxide compound were studied.The Nyquist plot describes the complex impedance of the yttrium(Ⅲ)oxide for different temperatures.The universal Jonscher's power law was used for the analysis of the complex electrical conductivity of the yttrium(Ⅲ)oxide compound.It is found that the real(σ')and imaginary(σ")parts of the complex conductivity increase with increasing frequency.The exponent frequency(s)equals unity,which confirms that the predominant conduction mechanism is a nearly constant loss(NCL)mechanism.DFT/TD-DFT studies using B3LYP/LanL2DZ level of theory were used to provide comparable theoretical data and electronic energy gap of HOMO→LUMO.
基金supported by National Natural Science Fund of China(Grant No.12172118,52071125)the Research Program of Local Science and Technology Development under the Guidance of Central(216Z4402G)+1 种基金Science and Technology Project of Hebei Education Department(BJK2022015)support from“Yuanguang”Scholar Program of Hebei University of Technology。
文摘Hydrogen is a popular clean high-energy-density fuel.However,its utilization is limited by the challenges toward low-cost hydrogen production and safe hydrogen storage.Fortunately,these issues can be addressed using promising hydrogen storage materials such as B–H compounds.Hydrogen stored in B–H compounds can be released by hydrolysis at room temperature,which requires catalysts to increase the rate of the reaction.Recently,several effective approaches have been developed for hydrogen generation by catalyzing the hydrolysis of B–H compounds.This review summarizes the existing research on the use of nanoparticles loaded on hydrogels as catalysts for the hydrolysis of B–H compounds.First,the factors affecting the hydrolysis rate,such as temperature,p H,reactant concentration,and type of nano particles,were investigated.Further,the preparation methods(in situ reduction,one-pot method,template adsorption,etc.)for the hydrogel catalysts and the types of loaded catalysts were determined.Additionally,the hydrogel catalysts that can respond to magnetic fields,ultrasound fields,optical fields,and other physical fields are introduced.Finally,the issues and future developments of hydrogel-based catalysts are discussed.This review can inspire deeper investigations and provide guidance for the study of hydrogel catalysts in the field of hydrogen production via hydrolysis.
文摘Coronavirus causes an outbreak of viral pneumonia that spread throughout the world. Liver injury is becoming more widely recognized as a component of the clinical picture of COVID-19 infection. We aimed to review this relation in a concise way. This review article includes a large number of patients from both western and eastern countries with no clear difference of liver affection. The more severe and frequent liver injury, the more severe COVID-19 infection. Up to half of patients developed hepatitis with serum ALT elevation. Both hepatocellular and/or ductular injury were observed as evidenced by alkaline phosphatase elevation. Increase incidence of morbidity and mortality had been recorded in patients with CLD. Cirrhosis mortality extended in line with the Child-Turcotte-Pugh class. The incidence of ACLF in CLD patients with COVID 19 is not clear. There are no significant associations with the etiology of liver disease and death in cirrhosis. COVID-19 hinders HCV elimination by 2030. Patients should continue their medications if already receiving treatment. Patients with occult or resolved HBV and COVID-19 who are receiving immunosuppressive agents should use antiviral therapy to prevent viral flare-ups.
文摘2-(pyridine-2-yl)-N-p-chlorohydrazinecarbothioamide (HCPTS) was synthesized, characterized and successfully applied for the preconcentration of Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II) in water, blood, and urine samples prior to graphite furnace atomic absorption determination (GFAAS);Hg was determined by cold vapor technique. Under the optimum experimental conditions (i.e. pH = 8, 10–4 M of HCPTS, 0.05% w/v of Triton X-114), calibration graphs were linear in the range of 0.02 to 200 ng?mL–1 for Co(II), Cd(II), Pb(II) and Ni(II);0.03 to 200 ng?mL–1 for Cu(II);0.07 to 200 ng?mL–1 for Fe(II) and Zn(II) and 0.02 to 150 ng?mL–1 for Hg(II). The enrichment factors were 43, 51, 41, 46, 54, 40, 45 and 52 for Cu(II), Ni(II),Zn (II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II), respectively. The limit of detection were found to be 0.019, 0.094, 0.0514, 0.052, 0.0165, 0.047, 0.068 and 0.041 ng?mL–1 for Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II), respectively. The developed method was applied to the determination of these metal ions in water, blood and urine samples with satisfactory results.
文摘Currently,COVID-19 is spreading all over the world and profoundly impacting people’s lives and economic activities.In this paper,a novel approach called the COVID-19 Quantum Neural Network(CQNN)for predicting the severity of COVID-19 in patients is proposed.It consists of two phases:In the first,the most distinct subset of features in a dataset is identified using a Quick Reduct Feature Selection(QRFS)method to improve its classification performance;and,in the second,machine learning is used to train the quantum neural network to classify the risk.It is found that patients’serial blood counts(their numbers of lymphocytes from days 1 to 15 after admission to hospital)are associated with relapse rates and evaluations of COVID-19 infections.Accordingly,the severity of COVID-19 is classified in two categories,serious and non-serious.The experimental results indicate that the proposed CQNN’s prediction approach outperforms those of other classification algorithms and its high accuracy confirms its effectiveness.
文摘Steel connection design using pre-tensioned bolts depends significantly on the value of the Prying forces exerted from the end plate. The Egyptian Code ECP （205） suggested a formula that can determine the Prying force value. In this research, the Prying force is numerically computed in a T-Stub connection using nonlinear finite element techniques. The model uses plane stress four node elements with two degrees of freedom per node to simulate the flange of the T-Stub. The bolts are simulated using a truss element with large deformation capability to allow modeling of the pretension force. Surface to surface gap elements are used in order to simulate the contact between the T-Stub and the supporting element. Parametric study on the end plate thickness, bolt size, bolt arrangement and pretension forces is performed in order to calibrate the Code formula. The parametric study covers all the practical ranges of the variables. The study revealed that the Code formula, inaccurately, determines the Prying force in a certain range. Moreover, a new equation for the prying force is developed using regression analysis on the finite element results.
文摘Medical image enhancement is an essential process for superior disease diagnosis as well as for detection of pathological lesion accurately. Computed Tomography (CT) is considered a vital medical imaging modality to evaluate numerous diseases such as tumors and vascular lesions. However, speckle noise corrupts the CT images and makes the clinical data analysis ambiguous. Therefore, for accurate diagnosis, medical image enhancement is a must for noise removal and sharp/clear images. In this work, a medical image enhancement algorithm has been proposed using log transform in an optimization framework. In order to achieve optimization, a well-known meta-heuristic algorithm, namely: Cuckoo search (CS) algorithm is used to determine the optimal parameter settings for log transform. The performance of the proposed technique is studied on a low contrast CT image dataset. Besides this, the results clearly show that the CS based approach has superior convergence and fitness values compared to PSO as the CS converge faster that proves the efficacy of the CS based technique. Finally, Image Quality Analysis (IQA) justifies the robustness of the proposed enhancement technique.
基金the Deanship of Scientific Research,Taif University,Kingdom of Saudi Arabia(Grant No.1-440-6136).
文摘In this study,CdS/ZnO(2:3 mol%)thin films are successfully deposited on quartz substrates by using the sputtering technique.Good images on the structural and optical characteristic features of CdS/ZnO thin films before and after annealing are obtained.The CdS/ZnO thin films are annealed respectively at temperatures of 373 K,473 K,and 573 K and the structural features are examined by XRD,ATR-FTIR,and FESEM.The optical properties of CdS/ZnO thin films such as refractive indices,absorption coefficients,optical band gap energy values,Urbach energy values,lattice dielectric constants,and high frequency dielectric constants are determined from spectrophotometer data recorded over the spectral range of 300 nm-2500 nm.Dispersion parameters are investigated by using a single-oscillator model.Photoluminescence spectra of CdS/ZnO thin films show an overall decrease in their intensity peaks after annealing.The third-order nonlinear optical parameter,and nonlinear refractive index are also estimated.
文摘Identity verification using authenticity evaluation of handwritten signatures is an important issue.There have been several approaches for the verification of signatures using dynamics of the signing process.Most of these approaches extract only global characteristics.With the aim of capturing both dynamic global and local features,this paper introduces a novel model for verifying handwritten dynamic signatures using neutrosophic rule-based verification system(NRVS)and Genetic NRVS(GNRVS)models.The neutrosophic Logic is structured to reflect multiple types of knowledge and relations among all features using three values:truth,indeterminacy,and falsity.These three values are determined by neutrosophic membership functions.The proposed model also is able to deal with all features without the need to select from them.In the GNRVS model,the neutrosophic rules are automatically chosen by Genetic Algorithms.The performance of the proposed system is tested on the MCYT-Signature-100 dataset.In terms of the accuracy,average error rate,false acceptance rate,and false rejection rate,the experimental results indicate that the proposed model has a significant advantage compared to different well-known models.
文摘The aim of this paper is to study the thermal radiation effects on the flow and heat transfer of an unsteady magnetohydrodynamic （MHD） micropolar fluid over a vertical heated nonisothermal stretching surface in the presence of a strong nonuniform magnetic field. The symmetries of the governing partial differential equations are de- termined by the two-parameter group method. One of the resulting systems of reduced nonlinear ordinary differential equations are solved numerically by the Chebyshev spec- tral method. The effects of various parameters on the velocity, the angular velocity, and the temperature profiles as well as the skin-friction coefficient, the wall couple stress co- efficient, and the Nusselt number are studied.
文摘The lateral torsional buckling phenomenon often governs design of steel I-beams. Although web opening is often used to accommodate the required mechanical and piping works in buildings, its effect on the buckling instability is not considered in the design codes. In this paper, the effect of web opening on both lateral torsional buckling and local buckling behaviors has been investigated. A simply supported steel I-beam has been studied under uniform bending moment around the major axis. Buckling analysis has been performed using the finite element method. Linear regression analysis has been conducted for output data to formulate an equation for the critical moment including web opening effect. The results have shown a limited reduction in the lateral torsional buckling capacity and a significant reduction in the local buckling capacity.
文摘Microwave photonics,a field that crosscuts microwave/millimeter-wave engineering with optoelectronics,has sparked great interest from research and commercial sectors. This multidisciplinary fusion can achieve ultrawide bandwidth and ultrafast speed that were considered impossible in conventional chip-scale microwave/millimeterwave systems. Conventional microwave-to-photonic converters,based on resonant acousto-optic modulation,produce highly efficient modulation but sacrifice bandwidth and limit their applicability for most real-world microwave signal-processing applications. In this paper,we build highly efficient and wideband microwaveto-photonic modulators using the acousto-optic effect on suspended lithium niobate thin films. A wideband microwave signal is first piezoelectrically transduced using interdigitated electrodes into Lamb acoustic waves,which directly propagates across an optical waveguide and causes refractive index pertp urbation through the photoelastic effect. This approach is power-efficient,with phase shifts up to 0.0166 rad∕m W over a 45μm modulation length and with a bandwidth up to 140 MHz at a center frequency of 1.9 GHz. Compared to the state-ofthe-art,a 9×more efficient modulation has been achieved by optimizing the acoustic and optical modes and their interactions.
基金funded by the Chinese Government Doctorate Scholarship Particularly China Scholarship Council (CSC)the Urban Agriculture from Education Committee of Beijing,China
文摘Sound waves technology has been applied to different plants. It has been found that sound waves were at different frequencies, sound pressure levels （SPLs）, exposure periods, and distances from the source of sound influence plant growth. Experiments have been conducted in the open field and under greenhouse growing conditions with different levels of audible sound frequencies and sound pressure levels. Sound waves at 1 kHz and 100 dB for 1 h within a distance of 0.20 m could significantly promote the division and cell wall fluidity of callus cells and also significantly enhance the activity of protective enzymes and endogenous hormones. Sound waves stimulation could increase the plant plasma-membrane IT-ATPase activity, the contents of soluble sugar, soluble protein, and amylase activity of callus. Moreover, sound waves could increase the content of RNA and the level of transcription. Stress-induced genes could switch on under sound stimulation. Sound waves at 0.1-1 kHz and SPL of （70＋5） dB for 3 h from plant acoustic frequency technology （PAFT） generator within a distance ranged from 30 to 60 m every other day significantly increased the yield of sweet pepper, cucumber and tomato by 30.05, 37.1 and 13.2%, respectively. Furthermore, the yield of lettuce, spinach, cotton, rice, and wheat were increased by 19.6, 22.7, 11.4, 5.7, and 17.0%, respectively. Sound waves may also strengthen plant immune systems. It has been proved that spider mite, aphids, gray mold, late blight and virus disease of tomatoes in the greenhouses decreased by 6.0, 8.0, 9.0, 11.0, and 8.0%, respectively, and the sheath blight office was reduced by 50%. This paper provides an overview of literature for the effects of sound waves on various growth parameters of plant at different growth stages.
文摘People started posting textual tweets on Twitter as soon as the novel coronavirus(COVID-19)emerged.Analyzing these tweets can assist institutions in better decision-making and prioritizing their tasks.Therefore,this study aimed to analyze 43 million tweets collected between March 22 and March 30,2020 and describe the trend of public attention given to the topics related to the COVID-19 epidemic using evolutionary clustering analysis.The results indicated that unigram terms were trended more frequently than bigram and trigram terms.A large number of tweets about the COVID-19 were disseminated and received widespread public attention during the epidemic.The high-frequency words such as“death”,“test”,“spread”,and“lockdown”suggest that people fear of being infected,and those who got infection are afraid of death.The results also showed that people agreed to stay at home due to the fear of the spread,and they were calling for social distancing since they become aware of the COVID-19.It can be suggested that social media posts may affect human psychology and behavior.These results may help governments and health organizations to better understand the psychology of the public,and thereby,better communicate with them to prevent and manage the panic.
