We investigated 13940 (6735 male, 7250 female) adult head and facial physical attributes from 19 different Han ethnic groups in 10 southern-China provinces, and calculated 12 head and facial indexes. Indexes were used...We investigated 13940 (6735 male, 7250 female) adult head and facial physical attributes from 19 different Han ethnic groups in 10 southern-China provinces, and calculated 12 head and facial indexes. Indexes were used to analyze the variation of head and facial morphological characteristics with increased age. Results showed that as age increases: (1) Head breadth, minimum frontal breadth, face breadth, interocular breadth, external biocular breadth, lip height, lip thickness, head circumference, auricular height, length-breadth head index, length-height head index, and lip-index values decline significantly in a linear fashion. (2) Nose breadth, mouth breadth, morphological facial height, upper-lip height, physiognomic ear length, physiognomic ear breadth, visor skin-fold, and vertical head-facial index values significantly increase in a linear fashion.展开更多
Soil erosion is a major environmental problem in China.Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information.The aim of this article is to present the methods and r...Soil erosion is a major environmental problem in China.Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information.The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011.A multi-stage,unequal probability,systematic area sampling method was employed.A total of 32,948 sample units,which were either 0.2-3 km2 small catchments or 1 km2 grids,were investigated on site.Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit,along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units.Maps were created by using a spatial interpolation method at national,river basin,and provincial scales.Results showed that the calculated average soil erosion rate was 5 t ha-1 yr-1 in China,and was 18.2 t ha-1 yr-1 for sloped,cultivated cropland.Intensive soil erosion occurred on cropland,overgrazing grassland,and sparsely forested land.The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids.The national average ratio was 13.5%,which represents the area of land in China that requires the implementation of soil conservation practices.These survey results and the maps provide the basic information for national conservation planning and policymaking.展开更多
This paper presents a study on the use of best management practices(BMPs)for controlling nonpoint pollution in the Xikeng Reservoir watershed located in Shenzhen,China.A BMP treatment train design,including a pond,a w...This paper presents a study on the use of best management practices(BMPs)for controlling nonpoint pollution in the Xikeng Reservoir watershed located in Shenzhen,China.A BMP treatment train design,including a pond,a wetland,and a buffer strip placed in series was implemented at the reservoir location.A separate grass swale was also constructed at the site.Low impact development(LID)BMPs,namely a planter box and bioboxes,were used at the parking lot of the reservoir’s Administration Building.Samples were collected during storm events and were analyzed for total suspended solids(TSS),biochemical oxygen demand(BOD5),ammonia nitrogen(NH3-N),and total phosphorus(TP).The removal efficiencies of both BMP systems were evaluated using the Efficiency Ratio(ER)method based on the event mean concentration(EMC)data.In summary,the pond/wetland treatment train removed 70%–90%of TSS,20%–50%of BOD5,and 30%–70%of TP and NH3-N.The swale removed 50%–90%of TSS,30%–55%of BOD5,–10%–35%of NH3-N,and 25%–70%of TP.For the planter box and biobox,the ranges of removal rates were 70%–90%,20%–50%,and 30%–70%for TSS,BOD5,and ammonia and phosphorus,respectively.展开更多
A direct synthesis of methyl levulinate from cellulose alcoholysis in methanol medium under mild condition(180 210 C)catalyzed by extremely low concentration sulfuric acid(0.01 mol/L)and the product isolation were dev...A direct synthesis of methyl levulinate from cellulose alcoholysis in methanol medium under mild condition(180 210 C)catalyzed by extremely low concentration sulfuric acid(0.01 mol/L)and the product isolation were developed in this study.Effects of different process variables towards the catalytic performance were performed as a function of reaction time.The results indicated that sulfuric acid concentration,temperature and initial cellulose concentration had significant effects on the synthesis of methyl levulinate.An optimized yield of around 50%was achieved at 210 C for 120 min with sulfuric acid concentration of 0.01 mol/L and initial cellulose concentration below 100 g/L.The resulting product mixture was isolated by a distillation technique that combines an atmospheric distillation with a vacuum distillation where n-dodecane was added to help distill the heavy fraction.The light fraction including mainly methanol could be reused as the reaction medium without any substantial change in the yield of methyl levulinate.The chemical composition and structural of lower heavy fraction were characterized by GC/MS,FTIR,1H-NMR and13C-NMR techniques.Methyl levulinate was found to be a major ingredient of lower heavy fraction with the content over 96%.This pathway is efficient,environmentally benign and economical for the production of pure levulinate esters from cellulose.展开更多
Alkaline earth benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR, X ray powder diffraction. All of them are monoclinic and have layered structure. The ...Alkaline earth benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR, X ray powder diffraction. All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of alkaline earth benzoates was studied by using TG, DTA, IR and gas chromatography mass spectrometry. The thermal decomposition of alkaline earth benzoates in nitrogen proceeded in one or two stages: they decomposed to form MCO 3 (M=Ca,Sr,Ba) or MgO and organic compounds, respectively. The organic compounds obtained from decomposition reaction are mainly benzophenone, triphenylmethane and so on.展开更多
As one of the major concerns of climate change,identifying a proper eco‐friendly insulation gas for replacing sulphur hexafluoride(SF_(6))becomes a prominent research topic in recent years.c-C_(4)F_(8),CF_(3)I,C_(5)F...As one of the major concerns of climate change,identifying a proper eco‐friendly insulation gas for replacing sulphur hexafluoride(SF_(6))becomes a prominent research topic in recent years.c-C_(4)F_(8),CF_(3)I,C_(5)F_(10O),C_(6)F_(12O)and C4F7N are some potential al-ternatives that are proved to have excellent characteristics,including high insulation strengths and low Global Warming Potentials(GWPs).Beyond these key factors,the decomposition products of these alternatives are closely related to the gases'insulation performance,as well as the safety of operators and the compatibility with other materials.In addition,the type and content of decomposition products can be used for fault diagnosis.Therefore,a number of studies were carried out to reveal the decomposition mechanism of these alternative gases,and then to explore the gases'application feasibility and strategy.The recent advances obtained in these studies,including theoretical calcu-lation methods,detection of gas decomposition products,decomposition mechanism are reviewed,and some perspectives for future works are proposed.It is concluded that the phenomenon of solid matter precipitation in c-C_(4)F_(8)and CF_(3)I gas decomposition cannot be ignored and that more research is needed to reveal the influence of buffer gases,micro‐aerobic,micro‐water and other impurities on the gas decomposition process.展开更多
Introduction:In the early stages of the coronavirus disease 2019(COVID-19)epidemic in China,the highest level of public health emergency response(Level 1 Response)was launched in all province-level administrative divi...Introduction:In the early stages of the coronavirus disease 2019(COVID-19)epidemic in China,the highest level of public health emergency response(Level 1 Response)was launched in all province-level administrative divisions(PLADs)across the country.Provision of vaccination services was selectively suspended due to the physical distancing and gathering restrictions required of Level 1 Response.The purpose of this paper is to evaluate the impact of COVID-19 on vaccination services and the effectiveness of selective vaccination service suspension and catch-up vaccinations in China.Methods:Vaccine doses administered,routine vaccination coverage levels,catch-up vaccine doses administered,and coverage levels after the catch-up campaign were determined from individual vaccination records in sampled clinics,standard routine immunization administrative coverage reports,and catch-up vaccination activity reports submitted by PLADs between October 2019 and October 2020.Results:National Immunization Program(NIP)and non-NIP vaccine doses administered in sampled clinics decreased by 80% and 90%,respectively,compared with doses administered before the COVID-19 pandemic.Coverage with the birth dose of hepatitis B vaccine(HepB1)and the Bacillus Calmette-Guérin vaccine(BCG)—two vaccinations recommended to continue throughout the epidemic due to their timecritical nature—were maintained at over 85%,while coverage of other NIP vaccines decreased to below 60%by February 2020.Catch-up vaccination coverage of the 29 PLADs,excluding Xinjiang and Xizang(Tibet),began in April 2020 and exceeded 90%;Hubei catch-up coverage was 95% by October 2020.Conclusions and Implications for Public Health Practice:The COVID-19 pandemic had a great impact on China’s vaccination services.During the epidemic and time of local transmission of the coronavirus,HepB1,BCG,rabies vaccine for postexposure prophylaxis,and tetanus antitoxin(TAT)for wound prophylaxis were maintained at high levels.Of the 69 million vaccine doses postponed during the time of loc展开更多
The correlation between mean surface air temperature and altitude is analyzed in this paper based on the annual and monthly mean surface air temperature data from 106 weather stations over the period 1961-2003 across ...The correlation between mean surface air temperature and altitude is analyzed in this paper based on the annual and monthly mean surface air temperature data from 106 weather stations over the period 1961-2003 across the Qinghai-Tibet Plateau. The results show that temperature variations not only depend on altitude but also latitude, and there is a gradual decrease in temperature with the increasing altitude and latitude. The overall trend for the vertical temperature lapse rate for the whole plateau is approximately linear. Three methods, namely multivariate composite analysis, simple correlation and traditional stepwise regression, were applied to analyze these three correlations. The results assessed with the first method are well matched to those with the latter two methods. The apparent mean annual near-surface lapse rate is -4.8 ℃ /km and the latitudinal effect is -0.87 ℃ /°latitude. In summer, the altitude influences the temperature variations more significantly with a July lapse rate of -4.3℃/km and the effect of latitude is only -0.28℃ /°latitude. In winter, the reverse happens. The temperature decrease is mainly due to the increase in latitude. The mean January lapse rate is -5.0℃/km, while the effect of latitude is -1.51℃ /°latitude. Comparative analysis for pairs of adjacent stations shows that at a small spatial scale the difference in altitude is the dominant factor affecting differences in mean annual near-surface air temperature, aided to some extent bydifferences of latitude. In contrast, the lapse rate in a small area is greater than the overall mean value for the Qinghai-Tibet Plateau （5 to 13℃ /km）. An increasing trend has been detected for the surface lapse rate with increases in altitude. The temperature difference has obvious seasonal variations, and the trends for the southern group of stations （south of 33 o latitude） and for the more northerly group are opposite, mainly because of the differences in seasonal variation at low altitudes. For yearly changes, the tem展开更多
Space-deployable mechanisms can be used as supporting structures for large-diameter antennas in space engineering.This study proposes a novel method for constructing the surface design of space reflector antennas base...Space-deployable mechanisms can be used as supporting structures for large-diameter antennas in space engineering.This study proposes a novel method for constructing the surface design of space reflector antennas based on polar scissor units.The concurrency and deployability equations of the space scissor unit with definite surface constraints are derived using the rod and vector methods.Constraint equations of the spatial transformation for space n-edge polar scissor units are summarized.A new closed-loop deployable structure,called the polar scissor deployable antenna(PSDA),is designed by combining planar polar scissor units with spatial polar scissor units.The overconstrained problem is solved by releasing the curve constraint that locates at the end-point of the planar scissor mechanism.Kinematics simulation and error analysis are performed.The results show that the PSDA can effectively fit the paraboloid of revolution.Finally,deployment experiments verify the validity and feasibility of the proposed design method,which provides a new idea for the construction of large space-reflector antennas.展开更多
Introduction:The current study aims to assess the performance of data mining techniques in detecting safety signals for adverse events following immunization(AEFI)using routinely obtained data in China.Four different ...Introduction:The current study aims to assess the performance of data mining techniques in detecting safety signals for adverse events following immunization(AEFI)using routinely obtained data in China.Four different methods for detecting vaccine safety signals were evaluated.Methods:The AEFI data from 2011 to 2015 was collected for our study.We analyzed the data using four different methods to detect signals:the proportional reporting ratio(PRR),reporting odds ratio(ROR),Bayesian confidence propagation neural network(BCPNN),and multi-item gamma Poisson shrinker(MGPS).Each method was evaluated at 1–3 thresholds for positivity.To assess the performance of these methods,we used the published signal rates as gold standards to determine the sensitivity and specificity.Results:The number of identified signals varied from 602 for PRR1(with a threshold of 1)to 127 for MGPS1.When considering the common reactions as the reference standard,the sensitivity ranged from 0.9%for MGPS1/2 to 38.2%for PRR1/2,and the specificity ranged from 85.2%for PRR1 and ROR1 to 96.7%for MGPS1.When considering the rare reactions as the reference standard,PRR1,PRR2,ROR1,ROR2,and BCPNN exhibited the highest sensitivity(73.3%),while MGPS1 exhibited the highest specificity(96.9%).Discussion:For common reactions,the sensitivities were modest and the specificities were high.For rare reactions,both the sensitivities and specificities were high.Our study provides valuable insights into the selection of signal detection methods and thresholds for AEFI data in China.展开更多
Emerging two-dimensional(2D)materials have stimulated tremendous scientific and industrial interests due to their diverse and tunable physical,chemical,and mechanical properties.The scalable production of high-quality...Emerging two-dimensional(2D)materials have stimulated tremendous scientific and industrial interests due to their diverse and tunable physical,chemical,and mechanical properties.The scalable production of high-quality wafer-scale 2D materials has become significantly essential to bring us closer to practical industrial applications,particularly in electronic devices.Vapor-phase growth provides attractive opportunities for the synthesis of large-area and high-quality 2D materials.In this review,we will emphasize vapor-phase growth strategies from three aspects,including suppressing nucleation,seamless stitching,and evolutionary selection growth.We discuss the general understanding of the related fundamental mechanism and specific parameter optimization from precursors and substrate design to the adjusting of growth parameters(temperature and pressure).Meanwhile,we present other strategies to produce various kinds of wafer-scale 2D materials.Finally,we conclude the current challenges and future directions in this developing field.This work may inspire researchers to better design routes in the synthesis of wafer-scale 2D materials with high quality.展开更多
The westerly fluctuation and the atmospheric water vapor transport over the Qilian-Heihe valley are analyzed and the results show that, in the water vapor transport stream field from Jun to September, this valley is i...The westerly fluctuation and the atmospheric water vapor transport over the Qilian-Heihe valley are analyzed and the results show that, in the water vapor transport stream field from Jun to September, this valley is in the westerly stream and the water vapor comes from westerlies water transport via the Black Sea and the Caspian Sea. The net water vapor transport is less net import and different from most areas of the northwest China. The interannual changes in water vapor transport over the valley arise from the westerly fluctuation, and have a positive relationship to the interannual changes in westerly wind speed. The cold air actions from the Mongol low pressure are the primary system that controls the westerly water vapor transport. Its action chain is that, the Mongol low pressure is strengthened → the circulation meridionality will be increased → the cold air will move southwards → the westerly will be stronger → the wind convergence of direction and speed will be stronger → the water vapor convergence transport will be increased → the local water vapor content will be increased. The interannual changes in atmospheric water vapor transport over the valley rely mainly on the convergence transport, but the effect of advection transport is less. The interannual changes of strong or weak westerly affect mainly the convergence transport, and then make the atmospheric water vapor net transport increase or decrease over the Qilian-Heihe valley.展开更多
[Objectives]The extraction conditions of formula oolong tea were investigated by an orthogonal experiment.[Methods]The technical conditions were optimized by the 4C method,and the application of formula oolong tea ext...[Objectives]The extraction conditions of formula oolong tea were investigated by an orthogonal experiment.[Methods]The technical conditions were optimized by the 4C method,and the application of formula oolong tea extract in cigarettes was studied.[Results]①In the experimental range,the best sensory evaluation effect of formula oolong tea extract was obtained with extraction conditions of 70%ethanol as extraction solvent,extraction time h,extraction temperature 25℃,and ultrasonic frequency 80 kHz,and follow-up low-temperature concentration,low-temperature sedimentation and low-temperature centrifugation.②The effects of different centrifugal speeds on the quality of formula oolong tea extract were explored.The formula oolong tea extract obtained under the conditions of 3000 r/min and centrifugal time of 10 min showed the best evaluation effect with soft and delicate smoke,rich smoke fragrance,good comfort and refreshing mouthfeel.③The effective aroma components in the formula oolong tea extract were qualitatively analyzed by GC-MS.[Conclusions]This study provides high-quality raw materials and a theoretical basis for the research of independent flavor blending in cigarette industry enterprises.展开更多
Autoimmune diseases are characterized by an imbalance between regulatory T cells and effector T-cell subsets, such as Thl and Th17 cells. Studies have confirmed that natural CD4＋Foxp3＋ Tregs were unstable and dysfun...Autoimmune diseases are characterized by an imbalance between regulatory T cells and effector T-cell subsets, such as Thl and Th17 cells. Studies have confirmed that natural CD4＋Foxp3＋ Tregs were unstable and dysfunctional in the presence of pro-inflammatory cytokines. In the current study, human CD39hi Tregs and CD39low Tregs were sorted from Tregs in vitro after 7 days of expansion. The functions of both Treg subsets were investigated under inflammatory conditions in vitro and in vivo. In the presence of IL-1β and IL-6, cultured CD4＋CD39hi Tregs maintained stable forkhead box protein 3 expression, whereas CD4＋CD39low Tregs lost Foxp3 expression and trans-differentiated into Thl or Th17 cells. Decreased IL-1βR and IL-6R expression on the CD39hi Tregs was the primary mechanism responsible for Treg stability. In addition, reduced activation of downstream molecules, such as STAT1 and STAT3, through the modulation of CpG demethylation played an important role. Finally, human CD4＋CD39hi Tregs but not CD4＋CD39low Tregs protected against xenograft versus host disease in model mice. These results strongly implied the physiological importance of CD39 expression and suggested that manipulation of CD39hi Tregs might represent a novel strategy for the treatment of autoimmune diseases.展开更多
Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.He...Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites:Cs2AgBi1-xInxCl6(0<x<1).The Cs2AgBi0.125In0.875Cl6breaks the parity-forbidden transition and retains direct band gap structure,having warm-white light emission,with photoluminescence quantum efficiency(PLQE)of 70.3%,much higher than the PLQE of reported lead perovskite materials.Its exciton self-trapping dynamics is investigated.Meanwhile,the Cs2AgBi0.125In0.875Cl6nanocrystals and Cs2AgBi0.125In0.875Cl6microcrystals can be synthesized by modified hot injection and rapid cooling crystallization,respectively.The size effect of Cs2AgBi0.125In0.875Cl6is studied on the photoluminescence(PL)property.Additionally,the bulk material exhibits excellent stability on exposure to light,humidity and air for more than 3 months.It is a promising candidate as highly efficient warm white-light emitting material for road lighting.展开更多
Introduction The Haemophilus influenzae type b(Hib)conjugate vaccine is widely administered in China.Methods We extracted data on Hib vaccine doses administered and adverse events following immunization(AEFI)reported ...Introduction The Haemophilus influenzae type b(Hib)conjugate vaccine is widely administered in China.Methods We extracted data on Hib vaccine doses administered and adverse events following immunization(AEFI)reported between 2010 and 2021 from the Chinese National Immunization Information System(CNIIS).A descriptive analysis was conducted to examine the characteristics and incidence rates of AEFI with the Hib vaccine.Results In China,between 2010 and 2021,a total of 52,910 AEFIs with the Hib vaccine were reported,resulting in an overall AEFI reporting rate of 38.10 per 100,000 doses.Common(typically minor)and rare(potentially serious)vaccine reactions occurred at rates of 34.71 and 2.78 per 100,000 doses,respectively.Among the common vaccine reactions,the incidences of fever(axillary temperature≥38.6℃),injection site redness and swelling(>2.5 cm in diameter),and injection site induration(>2.5 cm in diameter)were 11.93,9.69,and 3.38 per 100,000 doses,respectively.Rare vaccine reactions included anaphylactic rash,angioedema,and febrile convulsion with reported incidences of 2.42,0.10,and 0.05 per 100,000 doses,respectively.The incidence of serious rare vaccine reactions was 0.16 per 100,000 doses.Conclusions The reported incidence of AEFI with the Hib vaccine was low,with the occurrence of serious rare adverse reactions also being markedly low throughout the period 2010–2021 in China.展开更多
The biodistribution of gold nanoparticles （AuNPs） is closely related to toxicological effects and is of great concern because of their potential application in diverse biomedical areas. However, with the discovery o...The biodistribution of gold nanoparticles （AuNPs） is closely related to toxicological effects and is of great concern because of their potential application in diverse biomedical areas. However, with the discovery of novel anatomic and histological structures for fluid transport, the underlying mechanisms involved in the in vivo transport and biodistribution of AuNPs require further in-depth investigations. In the current study, we investigated the biodistribution of 10-nm AuNPs in rats after intervaginal space injection （ISI） in the tarsal tunnel, where a focal point of tendons, vessels, and nerve fibers may optimally connect to other remote connective tissues. The intravenous injection （IVI） of AuNPs served as a control. The blood and organs were collected at 5, 15, and 30 min and at 1, 4, 12, and 24 h after injection for quantitative analysis of Au distribution with inductively coupled plasma mass spectrometry （ICP-MS）. IVI and ISI yielded significantly different results： The AuNP content in the blood after ISI was much lower than that after IVI; was similar in the lungs, heart, and intestines; and was higher in the skin and muscle. These findings were supported by the ratios of AuNP content and relative organ AuNP distribution proportions. Our results demonstrated a fast, direct, and the circulation-independent AuNP-organ transport pathway, which may improve our understanding of physiological and pathological biodistribution processes in biological systems. Furthermore, these results provide novel insights into the in vivo transport and biodistribution of AuNPs, which may lead to novel and efficient therapeutic and administration strategies.展开更多
Intrinsic broadband photoluminescence(PL)of self-trapped excitons(STEs)are systematically studied in lead-free double perovskite nanocrystals(NCs).It is clarified that bandgap(direct/indirect)has important influence o...Intrinsic broadband photoluminescence(PL)of self-trapped excitons(STEs)are systematically studied in lead-free double perovskite nanocrystals(NCs).It is clarified that bandgap(direct/indirect)has important influence on the PL properties of STEs:indirect bandgap NCs exhibit strong exciton-phonon coupling which results in non-radiative STEs,while direct bandgap NCs exhibit moderate exciton-phonon coupling,inducing bright STE PL.Furthermore,by alloying K+and Li+ions in Cs2AgInCl6 NCs,the NCs exhibit broadband white-light emission.Charge-carrier dynamics study indicates that the efficient white-light emission originates from the further suppressed non-radiative processes of the STEs in the direct bandgap structure.This work may deepen the understanding of STEs and guide the design of highperformance lead-free perovskites.展开更多
Haynaldia villosa （L.） Schur （syn. Dasypyrurn villosum （L.） Can- dargy） （2n - 14, genome VV）, a wild relative of wheat, is an impor- tant gene pool for improving wheat quality and disease resistance. Several g...Haynaldia villosa （L.） Schur （syn. Dasypyrurn villosum （L.） Can- dargy） （2n - 14, genome VV）, a wild relative of wheat, is an impor- tant gene pool for improving wheat quality and disease resistance. Several genes found in H. villosa have been transferred into wheat to improve wheat resistance by the development of alien transloca- tion lines. The seed storage protein loci on chromosome 1V contribute to grain quality （Zhang et al., 2014）.展开更多
Large-scale solar sails can provide power to spacecraft for deep space exploration.A new type of telescopic tubular mast(TTM)driven by a bistable carbon fiber-reinforced polymer tube was designed in this study to solv...Large-scale solar sails can provide power to spacecraft for deep space exploration.A new type of telescopic tubular mast(TTM)driven by a bistable carbon fiber-reinforced polymer tube was designed in this study to solve the problem of contact between the sail membrane and the spacecraft under light pressure.Compared with the traditional TTM,it has a small size,light weight,high extension ratio,and simple structure.The anti-blossoming and self-unlocking structure of the proposed TTM was described.We aimed to simplify the TTM with a complex structure into a beam model with equal linear mass density,and the simulation results showed good consistency.The dynamic equation was derived based on the equivalent model,and the effects of different factors on the vibration characteristics of the TTM were analyzed.The performance parameters were optimized based on a multiobjective genetic algorithm,and prototype production and load experiments were conducted.The results show that the advantages of the new TTM can complete the deployment of large-scale solar sails,which is valuable for future deep space exploration.展开更多
基金supported by the National Natural Science Foundation of China (30830062)
文摘We investigated 13940 (6735 male, 7250 female) adult head and facial physical attributes from 19 different Han ethnic groups in 10 southern-China provinces, and calculated 12 head and facial indexes. Indexes were used to analyze the variation of head and facial morphological characteristics with increased age. Results showed that as age increases: (1) Head breadth, minimum frontal breadth, face breadth, interocular breadth, external biocular breadth, lip height, lip thickness, head circumference, auricular height, length-breadth head index, length-height head index, and lip-index values decline significantly in a linear fashion. (2) Nose breadth, mouth breadth, morphological facial height, upper-lip height, physiognomic ear length, physiognomic ear breadth, visor skin-fold, and vertical head-facial index values significantly increase in a linear fashion.
文摘Soil erosion is a major environmental problem in China.Planning for soil erosion control requires accurate soil erosion rate and spatial distribution information.The aim of this article is to present the methods and results of the national soil erosion survey of China completed in 2011.A multi-stage,unequal probability,systematic area sampling method was employed.A total of 32,948 sample units,which were either 0.2-3 km2 small catchments or 1 km2 grids,were investigated on site.Soil erosion rates were calculated with the Chinese Soil Loss Equation in 10 m by 10 m grids for each sample unit,along with the area of soil loss exceeding the soil loss tolerance and the proportion of area in excess of soil loss tolerance relative to the total land area of the sample units.Maps were created by using a spatial interpolation method at national,river basin,and provincial scales.Results showed that the calculated average soil erosion rate was 5 t ha-1 yr-1 in China,and was 18.2 t ha-1 yr-1 for sloped,cultivated cropland.Intensive soil erosion occurred on cropland,overgrazing grassland,and sparsely forested land.The proportions of soil loss tolerance exceedance areas of sample units were interpolated through the country in 250 m grids.The national average ratio was 13.5%,which represents the area of land in China that requires the implementation of soil conservation practices.These survey results and the maps provide the basic information for national conservation planning and policymaking.
基金the US Environmental Protection Agency,National Risk Management Research Laboratory,and Urban Watershed Management Branch(H00562)。
文摘This paper presents a study on the use of best management practices(BMPs)for controlling nonpoint pollution in the Xikeng Reservoir watershed located in Shenzhen,China.A BMP treatment train design,including a pond,a wetland,and a buffer strip placed in series was implemented at the reservoir location.A separate grass swale was also constructed at the site.Low impact development(LID)BMPs,namely a planter box and bioboxes,were used at the parking lot of the reservoir’s Administration Building.Samples were collected during storm events and were analyzed for total suspended solids(TSS),biochemical oxygen demand(BOD5),ammonia nitrogen(NH3-N),and total phosphorus(TP).The removal efficiencies of both BMP systems were evaluated using the Efficiency Ratio(ER)method based on the event mean concentration(EMC)data.In summary,the pond/wetland treatment train removed 70%–90%of TSS,20%–50%of BOD5,and 30%–70%of TP and NH3-N.The swale removed 50%–90%of TSS,30%–55%of BOD5,–10%–35%of NH3-N,and 25%–70%of TP.For the planter box and biobox,the ranges of removal rates were 70%–90%,20%–50%,and 30%–70%for TSS,BOD5,and ammonia and phosphorus,respectively.
基金supported by the National Key Basic Research Program (2010CB732201) from the Ministry of Science and Technology of Chinathe State Key Laboratory Open Foundation of Pulp and Paper Engineering of China (201225)
文摘A direct synthesis of methyl levulinate from cellulose alcoholysis in methanol medium under mild condition(180 210 C)catalyzed by extremely low concentration sulfuric acid(0.01 mol/L)and the product isolation were developed in this study.Effects of different process variables towards the catalytic performance were performed as a function of reaction time.The results indicated that sulfuric acid concentration,temperature and initial cellulose concentration had significant effects on the synthesis of methyl levulinate.An optimized yield of around 50%was achieved at 210 C for 120 min with sulfuric acid concentration of 0.01 mol/L and initial cellulose concentration below 100 g/L.The resulting product mixture was isolated by a distillation technique that combines an atmospheric distillation with a vacuum distillation where n-dodecane was added to help distill the heavy fraction.The light fraction including mainly methanol could be reused as the reaction medium without any substantial change in the yield of methyl levulinate.The chemical composition and structural of lower heavy fraction were characterized by GC/MS,FTIR,1H-NMR and13C-NMR techniques.Methyl levulinate was found to be a major ingredient of lower heavy fraction with the content over 96%.This pathway is efficient,environmentally benign and economical for the production of pure levulinate esters from cellulose.
文摘Alkaline earth benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR, X ray powder diffraction. All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of alkaline earth benzoates was studied by using TG, DTA, IR and gas chromatography mass spectrometry. The thermal decomposition of alkaline earth benzoates in nitrogen proceeded in one or two stages: they decomposed to form MCO 3 (M=Ca,Sr,Ba) or MgO and organic compounds, respectively. The organic compounds obtained from decomposition reaction are mainly benzophenone, triphenylmethane and so on.
基金supported by the National Key R&D Pro-gramme under Grant No.2017YFB0902500the Tech-nology Programme of State Grid Corporation of China under Grant No.5500-202,055,292A-0-0-00.
文摘As one of the major concerns of climate change,identifying a proper eco‐friendly insulation gas for replacing sulphur hexafluoride(SF_(6))becomes a prominent research topic in recent years.c-C_(4)F_(8),CF_(3)I,C_(5)F_(10O),C_(6)F_(12O)and C4F7N are some potential al-ternatives that are proved to have excellent characteristics,including high insulation strengths and low Global Warming Potentials(GWPs).Beyond these key factors,the decomposition products of these alternatives are closely related to the gases'insulation performance,as well as the safety of operators and the compatibility with other materials.In addition,the type and content of decomposition products can be used for fault diagnosis.Therefore,a number of studies were carried out to reveal the decomposition mechanism of these alternative gases,and then to explore the gases'application feasibility and strategy.The recent advances obtained in these studies,including theoretical calcu-lation methods,detection of gas decomposition products,decomposition mechanism are reviewed,and some perspectives for future works are proposed.It is concluded that the phenomenon of solid matter precipitation in c-C_(4)F_(8)and CF_(3)I gas decomposition cannot be ignored and that more research is needed to reveal the influence of buffer gases,micro‐aerobic,micro‐water and other impurities on the gas decomposition process.
基金funded by grants from the Vaccine Preventable Diseases and Immunization(VDI)of World Health Organization Office in China(No.2020/1017283-0).
文摘Introduction:In the early stages of the coronavirus disease 2019(COVID-19)epidemic in China,the highest level of public health emergency response(Level 1 Response)was launched in all province-level administrative divisions(PLADs)across the country.Provision of vaccination services was selectively suspended due to the physical distancing and gathering restrictions required of Level 1 Response.The purpose of this paper is to evaluate the impact of COVID-19 on vaccination services and the effectiveness of selective vaccination service suspension and catch-up vaccinations in China.Methods:Vaccine doses administered,routine vaccination coverage levels,catch-up vaccine doses administered,and coverage levels after the catch-up campaign were determined from individual vaccination records in sampled clinics,standard routine immunization administrative coverage reports,and catch-up vaccination activity reports submitted by PLADs between October 2019 and October 2020.Results:National Immunization Program(NIP)and non-NIP vaccine doses administered in sampled clinics decreased by 80% and 90%,respectively,compared with doses administered before the COVID-19 pandemic.Coverage with the birth dose of hepatitis B vaccine(HepB1)and the Bacillus Calmette-Guérin vaccine(BCG)—two vaccinations recommended to continue throughout the epidemic due to their timecritical nature—were maintained at over 85%,while coverage of other NIP vaccines decreased to below 60%by February 2020.Catch-up vaccination coverage of the 29 PLADs,excluding Xinjiang and Xizang(Tibet),began in April 2020 and exceeded 90%;Hubei catch-up coverage was 95% by October 2020.Conclusions and Implications for Public Health Practice:The COVID-19 pandemic had a great impact on China’s vaccination services.During the epidemic and time of local transmission of the coronavirus,HepB1,BCG,rabies vaccine for postexposure prophylaxis,and tetanus antitoxin(TAT)for wound prophylaxis were maintained at high levels.Of the 69 million vaccine doses postponed during the time of loc
基金financially supported by the National Natural Science Foundation of China (Grant No.40640420072 and No.40771006)
文摘The correlation between mean surface air temperature and altitude is analyzed in this paper based on the annual and monthly mean surface air temperature data from 106 weather stations over the period 1961-2003 across the Qinghai-Tibet Plateau. The results show that temperature variations not only depend on altitude but also latitude, and there is a gradual decrease in temperature with the increasing altitude and latitude. The overall trend for the vertical temperature lapse rate for the whole plateau is approximately linear. Three methods, namely multivariate composite analysis, simple correlation and traditional stepwise regression, were applied to analyze these three correlations. The results assessed with the first method are well matched to those with the latter two methods. The apparent mean annual near-surface lapse rate is -4.8 ℃ /km and the latitudinal effect is -0.87 ℃ /°latitude. In summer, the altitude influences the temperature variations more significantly with a July lapse rate of -4.3℃/km and the effect of latitude is only -0.28℃ /°latitude. In winter, the reverse happens. The temperature decrease is mainly due to the increase in latitude. The mean January lapse rate is -5.0℃/km, while the effect of latitude is -1.51℃ /°latitude. Comparative analysis for pairs of adjacent stations shows that at a small spatial scale the difference in altitude is the dominant factor affecting differences in mean annual near-surface air temperature, aided to some extent bydifferences of latitude. In contrast, the lapse rate in a small area is greater than the overall mean value for the Qinghai-Tibet Plateau （5 to 13℃ /km）. An increasing trend has been detected for the surface lapse rate with increases in altitude. The temperature difference has obvious seasonal variations, and the trends for the southern group of stations （south of 33 o latitude） and for the more northerly group are opposite, mainly because of the differences in seasonal variation at low altitudes. For yearly changes, the tem
基金Supported by National Key R&D Program of China(Grant No.2018YFB1304600)National Natural Science Foundation of China(Grant No.51775541)+1 种基金CAS Interdisciplinary Innovation Team of China(Grant No.JCTD-2018-11)Hundred-Talent Program(Chinese Academy of Sciences)(Grant No.Y8A3210304).
文摘Space-deployable mechanisms can be used as supporting structures for large-diameter antennas in space engineering.This study proposes a novel method for constructing the surface design of space reflector antennas based on polar scissor units.The concurrency and deployability equations of the space scissor unit with definite surface constraints are derived using the rod and vector methods.Constraint equations of the spatial transformation for space n-edge polar scissor units are summarized.A new closed-loop deployable structure,called the polar scissor deployable antenna(PSDA),is designed by combining planar polar scissor units with spatial polar scissor units.The overconstrained problem is solved by releasing the curve constraint that locates at the end-point of the planar scissor mechanism.Kinematics simulation and error analysis are performed.The results show that the PSDA can effectively fit the paraboloid of revolution.Finally,deployment experiments verify the validity and feasibility of the proposed design method,which provides a new idea for the construction of large space-reflector antennas.
基金Supported by the Beijing Natural Science Foundation(L212058).
文摘Introduction:The current study aims to assess the performance of data mining techniques in detecting safety signals for adverse events following immunization(AEFI)using routinely obtained data in China.Four different methods for detecting vaccine safety signals were evaluated.Methods:The AEFI data from 2011 to 2015 was collected for our study.We analyzed the data using four different methods to detect signals:the proportional reporting ratio(PRR),reporting odds ratio(ROR),Bayesian confidence propagation neural network(BCPNN),and multi-item gamma Poisson shrinker(MGPS).Each method was evaluated at 1–3 thresholds for positivity.To assess the performance of these methods,we used the published signal rates as gold standards to determine the sensitivity and specificity.Results:The number of identified signals varied from 602 for PRR1(with a threshold of 1)to 127 for MGPS1.When considering the common reactions as the reference standard,the sensitivity ranged from 0.9%for MGPS1/2 to 38.2%for PRR1/2,and the specificity ranged from 85.2%for PRR1 and ROR1 to 96.7%for MGPS1.When considering the rare reactions as the reference standard,PRR1,PRR2,ROR1,ROR2,and BCPNN exhibited the highest sensitivity(73.3%),while MGPS1 exhibited the highest specificity(96.9%).Discussion:For common reactions,the sensitivities were modest and the specificities were high.For rare reactions,both the sensitivities and specificities were high.Our study provides valuable insights into the selection of signal detection methods and thresholds for AEFI data in China.
基金The research was supported by the National Natural Science Foundation of China(grants 21673161)the Science and Technology Department of Hubei Province(grant 2017AAA114)+1 种基金the Postdoctoral Innovation Talent Support Program of China(BX20180224)the Sino-German Center for Research Promotion(grant 1400).
文摘Emerging two-dimensional(2D)materials have stimulated tremendous scientific and industrial interests due to their diverse and tunable physical,chemical,and mechanical properties.The scalable production of high-quality wafer-scale 2D materials has become significantly essential to bring us closer to practical industrial applications,particularly in electronic devices.Vapor-phase growth provides attractive opportunities for the synthesis of large-area and high-quality 2D materials.In this review,we will emphasize vapor-phase growth strategies from three aspects,including suppressing nucleation,seamless stitching,and evolutionary selection growth.We discuss the general understanding of the related fundamental mechanism and specific parameter optimization from precursors and substrate design to the adjusting of growth parameters(temperature and pressure).Meanwhile,we present other strategies to produce various kinds of wafer-scale 2D materials.Finally,we conclude the current challenges and future directions in this developing field.This work may inspire researchers to better design routes in the synthesis of wafer-scale 2D materials with high quality.
文摘The westerly fluctuation and the atmospheric water vapor transport over the Qilian-Heihe valley are analyzed and the results show that, in the water vapor transport stream field from Jun to September, this valley is in the westerly stream and the water vapor comes from westerlies water transport via the Black Sea and the Caspian Sea. The net water vapor transport is less net import and different from most areas of the northwest China. The interannual changes in water vapor transport over the valley arise from the westerly fluctuation, and have a positive relationship to the interannual changes in westerly wind speed. The cold air actions from the Mongol low pressure are the primary system that controls the westerly water vapor transport. Its action chain is that, the Mongol low pressure is strengthened → the circulation meridionality will be increased → the cold air will move southwards → the westerly will be stronger → the wind convergence of direction and speed will be stronger → the water vapor convergence transport will be increased → the local water vapor content will be increased. The interannual changes in atmospheric water vapor transport over the valley rely mainly on the convergence transport, but the effect of advection transport is less. The interannual changes of strong or weak westerly affect mainly the convergence transport, and then make the atmospheric water vapor net transport increase or decrease over the Qilian-Heihe valley.
文摘[Objectives]The extraction conditions of formula oolong tea were investigated by an orthogonal experiment.[Methods]The technical conditions were optimized by the 4C method,and the application of formula oolong tea extract in cigarettes was studied.[Results]①In the experimental range,the best sensory evaluation effect of formula oolong tea extract was obtained with extraction conditions of 70%ethanol as extraction solvent,extraction time h,extraction temperature 25℃,and ultrasonic frequency 80 kHz,and follow-up low-temperature concentration,low-temperature sedimentation and low-temperature centrifugation.②The effects of different centrifugal speeds on the quality of formula oolong tea extract were explored.The formula oolong tea extract obtained under the conditions of 3000 r/min and centrifugal time of 10 min showed the best evaluation effect with soft and delicate smoke,rich smoke fragrance,good comfort and refreshing mouthfeel.③The effective aroma components in the formula oolong tea extract were qualitatively analyzed by GC-MS.[Conclusions]This study provides high-quality raw materials and a theoretical basis for the research of independent flavor blending in cigarette industry enterprises.
文摘Autoimmune diseases are characterized by an imbalance between regulatory T cells and effector T-cell subsets, such as Thl and Th17 cells. Studies have confirmed that natural CD4＋Foxp3＋ Tregs were unstable and dysfunctional in the presence of pro-inflammatory cytokines. In the current study, human CD39hi Tregs and CD39low Tregs were sorted from Tregs in vitro after 7 days of expansion. The functions of both Treg subsets were investigated under inflammatory conditions in vitro and in vivo. In the presence of IL-1β and IL-6, cultured CD4＋CD39hi Tregs maintained stable forkhead box protein 3 expression, whereas CD4＋CD39low Tregs lost Foxp3 expression and trans-differentiated into Thl or Th17 cells. Decreased IL-1βR and IL-6R expression on the CD39hi Tregs was the primary mechanism responsible for Treg stability. In addition, reduced activation of downstream molecules, such as STAT1 and STAT3, through the modulation of CpG demethylation played an important role. Finally, human CD4＋CD39hi Tregs but not CD4＋CD39low Tregs protected against xenograft versus host disease in model mice. These results strongly implied the physiological importance of CD39 expression and suggested that manipulation of CD39hi Tregs might represent a novel strategy for the treatment of autoimmune diseases.
基金supported by the National Natural Science Foundation of China (21533010, 21525315)the National Key Research and Development Program of China (2017YFA0204800)+2 种基金DICP DMTO201601DICP ZZBS201703the Science Challenging Program (JCKY2016212A501)
文摘Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites:Cs2AgBi1-xInxCl6(0<x<1).The Cs2AgBi0.125In0.875Cl6breaks the parity-forbidden transition and retains direct band gap structure,having warm-white light emission,with photoluminescence quantum efficiency(PLQE)of 70.3%,much higher than the PLQE of reported lead perovskite materials.Its exciton self-trapping dynamics is investigated.Meanwhile,the Cs2AgBi0.125In0.875Cl6nanocrystals and Cs2AgBi0.125In0.875Cl6microcrystals can be synthesized by modified hot injection and rapid cooling crystallization,respectively.The size effect of Cs2AgBi0.125In0.875Cl6is studied on the photoluminescence(PL)property.Additionally,the bulk material exhibits excellent stability on exposure to light,humidity and air for more than 3 months.It is a promising candidate as highly efficient warm white-light emitting material for road lighting.
基金Supported by the Emergency Response Mechanism Operation Programme of China CDC(102393220020010000017)。
文摘Introduction The Haemophilus influenzae type b(Hib)conjugate vaccine is widely administered in China.Methods We extracted data on Hib vaccine doses administered and adverse events following immunization(AEFI)reported between 2010 and 2021 from the Chinese National Immunization Information System(CNIIS).A descriptive analysis was conducted to examine the characteristics and incidence rates of AEFI with the Hib vaccine.Results In China,between 2010 and 2021,a total of 52,910 AEFIs with the Hib vaccine were reported,resulting in an overall AEFI reporting rate of 38.10 per 100,000 doses.Common(typically minor)and rare(potentially serious)vaccine reactions occurred at rates of 34.71 and 2.78 per 100,000 doses,respectively.Among the common vaccine reactions,the incidences of fever(axillary temperature≥38.6℃),injection site redness and swelling(>2.5 cm in diameter),and injection site induration(>2.5 cm in diameter)were 11.93,9.69,and 3.38 per 100,000 doses,respectively.Rare vaccine reactions included anaphylactic rash,angioedema,and febrile convulsion with reported incidences of 2.42,0.10,and 0.05 per 100,000 doses,respectively.The incidence of serious rare vaccine reactions was 0.16 per 100,000 doses.Conclusions The reported incidence of AEFI with the Hib vaccine was low,with the occurrence of serious rare adverse reactions also being markedly low throughout the period 2010–2021 in China.
基金This work was supported by the National Basic Research Program of China （Nos. 2015CB5545507 and 2013CB933700） and the National Natural Science Foundation of China （No. 21305024）.
文摘The biodistribution of gold nanoparticles （AuNPs） is closely related to toxicological effects and is of great concern because of their potential application in diverse biomedical areas. However, with the discovery of novel anatomic and histological structures for fluid transport, the underlying mechanisms involved in the in vivo transport and biodistribution of AuNPs require further in-depth investigations. In the current study, we investigated the biodistribution of 10-nm AuNPs in rats after intervaginal space injection （ISI） in the tarsal tunnel, where a focal point of tendons, vessels, and nerve fibers may optimally connect to other remote connective tissues. The intravenous injection （IVI） of AuNPs served as a control. The blood and organs were collected at 5, 15, and 30 min and at 1, 4, 12, and 24 h after injection for quantitative analysis of Au distribution with inductively coupled plasma mass spectrometry （ICP-MS）. IVI and ISI yielded significantly different results： The AuNP content in the blood after ISI was much lower than that after IVI; was similar in the lungs, heart, and intestines; and was higher in the skin and muscle. These findings were supported by the ratios of AuNP content and relative organ AuNP distribution proportions. Our results demonstrated a fast, direct, and the circulation-independent AuNP-organ transport pathway, which may improve our understanding of physiological and pathological biodistribution processes in biological systems. Furthermore, these results provide novel insights into the in vivo transport and biodistribution of AuNPs, which may lead to novel and efficient therapeutic and administration strategies.
基金supported by the National Natural Science Foundation of China(21533010,21525315)the National Key Research and Development Program of China(2017YFA0204800)DICP DMTO201601,DICP ZZBS201703,and the Science Challenging Program(JCKY2016212A501).
文摘Intrinsic broadband photoluminescence(PL)of self-trapped excitons(STEs)are systematically studied in lead-free double perovskite nanocrystals(NCs).It is clarified that bandgap(direct/indirect)has important influence on the PL properties of STEs:indirect bandgap NCs exhibit strong exciton-phonon coupling which results in non-radiative STEs,while direct bandgap NCs exhibit moderate exciton-phonon coupling,inducing bright STE PL.Furthermore,by alloying K+and Li+ions in Cs2AgInCl6 NCs,the NCs exhibit broadband white-light emission.Charge-carrier dynamics study indicates that the efficient white-light emission originates from the further suppressed non-radiative processes of the STEs in the direct bandgap structure.This work may deepen the understanding of STEs and guide the design of highperformance lead-free perovskites.
基金supported by the grants from the National Key Research and Development Program (2016YFD0102001)the National Natural Science Foundation of China (Nos.31571653,31771782,31201204,and 31501305)+6 种基金the International Cooperation and Exchange of the National Natural Science Foundation of China (No.31661143005)the ‘948’ Project of Ministry of Agriculture (2015-Z41)the Fundamental Research Funds for the Central Universities (KYZ201403 and KJ2013003)the Technology Support Program of Jiangsu Province (BE2015352-2)the special fund of Jiangsu Province for the transformation of scientific and technological achievements (BA2017138)the Program of Introducing Talents of Discipline to Universities (B08025)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Haynaldia villosa （L.） Schur （syn. Dasypyrurn villosum （L.） Can- dargy） （2n - 14, genome VV）, a wild relative of wheat, is an impor- tant gene pool for improving wheat quality and disease resistance. Several genes found in H. villosa have been transferred into wheat to improve wheat resistance by the development of alien transloca- tion lines. The seed storage protein loci on chromosome 1V contribute to grain quality （Zhang et al., 2014）.
基金Supported by National Key R&D Program of China (Grant No.2018YFB1304600)National Natural Science Foundation of China (Grant No.51905527)+1 种基金CAS Interdisciplinary Innovation Team of China (Grant No.JCTD-2018-11)State Key Laboratory of Robotics Foundation of China (Grant No.Y91Z0303)。
文摘Large-scale solar sails can provide power to spacecraft for deep space exploration.A new type of telescopic tubular mast(TTM)driven by a bistable carbon fiber-reinforced polymer tube was designed in this study to solve the problem of contact between the sail membrane and the spacecraft under light pressure.Compared with the traditional TTM,it has a small size,light weight,high extension ratio,and simple structure.The anti-blossoming and self-unlocking structure of the proposed TTM was described.We aimed to simplify the TTM with a complex structure into a beam model with equal linear mass density,and the simulation results showed good consistency.The dynamic equation was derived based on the equivalent model,and the effects of different factors on the vibration characteristics of the TTM were analyzed.The performance parameters were optimized based on a multiobjective genetic algorithm,and prototype production and load experiments were conducted.The results show that the advantages of the new TTM can complete the deployment of large-scale solar sails,which is valuable for future deep space exploration.
