With the development of network technology and cloud computing, data sharing is becoming increasingly popular, and many scholars have conducted in-depth research to promote its flourish. As the scale of data sharing e...With the development of network technology and cloud computing, data sharing is becoming increasingly popular, and many scholars have conducted in-depth research to promote its flourish. As the scale of data sharing expands, its privacy protection has become a hot issue in research. Moreover, in data sharing, the data is usually maintained in multiple parties, which brings new challenges to protect the privacy of these multi-party data. In this paper, we propose a trusted data sharing scheme using blockchain. We use blockchain to prevent the shared data from being tampered, and use the Paillier cryptosystem to realize the confidentiality of the shared data. In the proposed scheme, the shared data can be traded, and the transaction information is protected by using the （p, t）-threshold Paillier cryptosystem. We conduct experiments in cloud storage scenarios and the experimental results demonstrate the efficiency and effectiveness of the proposed scheme.展开更多
Background:The ongoing new coronavirus pneumonia(Corona Virus Disease 2019,COVID-19)outbreak is spreading in China,but it has not yet reached its peak.Five million people emigrated from Wuhan before lockdown,potential...Background:The ongoing new coronavirus pneumonia(Corona Virus Disease 2019,COVID-19)outbreak is spreading in China,but it has not yet reached its peak.Five million people emigrated from Wuhan before lockdown,potentially representing a source of virus infection.Determining case distribution and its correlation with population emigration from Wuhan in the early stage of the epidemic is of great importance for early warning and for the prevention of future outbreaks.Methods:The official case report on the COVID-19 epidemic was collected as of January 30,2020.Time and location information on COVID-19 cases was extracted and analyzed using ArcGIS and WinBUGS software.Data on population migration from Wuhan city and Hubei province were extracted from Baidu Qianxi,and their correlation with the number of cases was analyzed.Results:The COVID-19 confirmed and death cases in Hubei province accounted for 59.91%(5806/9692)and 95.77%(204/213)of the total cases in China,respectively.Hot spot provinces included Sichuan and Yunnan,which are adjacent to Hubei.The time risk of Hubei province on the following day was 1.960 times that on the previous day.The number of cases in some cities was relatively low,but the time risk appeared to be continuously rising.The correlation coefficient between the provincial number of cases and emigration from Wuhan was up to 0.943.The lockdown of 17 cities in Hubei province and the implementation of nationwide control measures efficiently prevented an exponential growth in the number of cases.Conclusions:The population that emigrated from Wuhan was the main infection source in other cities and provinces.Some cities with a low number of cases showed a rapid increase in case load.Owing to the upcoming Spring Festival return wave,understanding the risk trends in different regions is crucial to ensure preparedness at both the individual and organization levels and to prevent new outbreaks.展开更多
In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this pa...In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this paper,numerical simulation was carried out on the separating cleaning process of flax threshing material based on CFD-DEM method.Simulation results showed that the components of flax threshing material were separated and cleaned under the influence of airflow field,meanwhile,variation curves of quantity and mean velocity of flax seeds in the separating cleaning system were obtained.By referring to streamline distribution of gas-solid coupling,the quantity variation law of components of flax threshing material with time was explored and their motion curves and variation tendency of average velocity were studied.Verification test results showed that the cleaning rate of separating cleaning device for flax threshing material was 92.66%with 1.58%of total separation loss.Compared with simulation results,the test results were 1.34%and 0.93%lower,showing that it is feasible to apply the gas-solid coupling theory and method to simulate the separating and cleaning operation of flax threshing material.展开更多
This paper first constructed a system to evaluate the innovation efficiency of industrial companies within China's Mainland.Then,a principal component analysis(PCA) was performed to these indicators for dimensiona...This paper first constructed a system to evaluate the innovation efficiency of industrial companies within China's Mainland.Then,a principal component analysis(PCA) was performed to these indicators for dimensionality reduction,so as to figure out the technology innovation efficiency in these two phases,respectively.Finally,the overall efficiency of industrial companies in different regions was estimated and factorized via data envelopment analysis(DEA).The results showed that:(1)the efficiency of green technology innovation of industrial companies in China was relatively low as a whole,which mainly resulted from pure technical efficiency(PTE).Further,this huge gap continues to expand in these regions.And both PTE and scale efficiency(SE) in central and western regions leave much to be expected.(2)In the first phase of green technology development,when environmental factors were concerned,the efficiency was much lower than that without environmental considerations.Besides,the central and western regions were facing increasingly severe environmental problems,and there was a wide disparity in technology development efficiency among eastern,central,and western regions.(3)In the second phase of green technology commercialization,there were still more rooms for improvement in raising the efficiency of green technology innovation,and the efficiency in eastern,central,and western regions was ranked from highest to lowest.(4)Liaoning,Hebei,Heilongjiang,Xinjiang,Shanxi,Inner Mongolia,Yunnan,and Qinghai should focus on improving their technology;Jilin,Jiangxi,Anhui,and Guangxi should make their efforts to reduce resource redundancy;whereas Ningxia and Gansu should try to solve the above two issues.展开更多
Internet use has become an indispensable part of people’s daily lives,and the relationship between Internet use and residents’subjective well-being is receiving increasing attention from researchers.However,the exis...Internet use has become an indispensable part of people’s daily lives,and the relationship between Internet use and residents’subjective well-being is receiving increasing attention from researchers.However,the existing literature on the relationship between Internet use and residents’subjective well-being is still controversial and inconclusive,and there has been relatively little discussion of the mechanisms by which Internet use affects well-being.On the basis of data from the China General Social Survey 2015(CGSS2015),this paper provides an empirical analysis of the impact of Internet usage on residents’subjective wellbeing.The study finds that while Internet use had no significant impact on the well-being of residents compared to non-use,frequency of Internet usage did significantly improve subjective well-being.On this basis,we tested the mechanisms by which Internet use affects residents’well-being through the three channels of the personal income effect,the human capital effect and the social capital effect.The findings partially verify the hypothesis of the mediating effect of social capital between Internet use and residents’subjective wellbeing,but do not verify the hypothesis of the moderating effect of personal income and human capital.Compared with previous studies,this paper is innovative in the following three ways:it uses the latest available representative national microdata,which is better able to reflect recent Internet usage and its impact on residents’subjective well-being;on the basis of existing research on the impact of Internet usage on residents’well-being,it analyzes the specific mechanisms through which Internet use affects well-being,using the moderating effect model and the mediating effect model to make up for the shortcomings of existing research on the impact mechanism;and it applies the Bioprobit model to deal with the potential endogeneity of key explanatory variables,using a variety of model estimation methods to obtain more robust estimation results.展开更多
Rapid and accurate access to large-scale,high-resolution crop-type distribution maps is important for agricultural management and sustainable agricultural development.Due to the limitations of remote sensing image qua...Rapid and accurate access to large-scale,high-resolution crop-type distribution maps is important for agricultural management and sustainable agricultural development.Due to the limitations of remote sensing image quality and data processing capabilities,large-scale crop classification is still challenging.This study aimed to map the distribution of crops in Heilongjiang Province using Google Earth Engine(GEE)and Sentinel-1 and Sentinel-2 images.We obtained Sentinel-1 and Sentinel-2 images from all the covered study areas in the critical period for crop growth in 2018(May to September),combined monthly composite images of reflectance bands,vegetation indices and polarization bands as input features,and then performed crop classification using a Random Forest(RF)classifier.The results show that the Sentinel-1 and Sentinel-2 monthly composite images combined with the RF classifier can accurately generate the crop distribution map of the study area,and the overall accuracy(OA)reached 89.75%.Through experiments,we also found that the classification performance using time-series images is significantly better than that using single-period images.Compared with the use of traditional bands only(i.e.,the visible and near-infrared bands),the addition of shortwave infrared bands can improve the accuracy of crop classification most significantly,followed by the addition of red-edge bands.Adding common vegetation indices and Sentinel-1 data to the crop classification improved the overall classification accuracy and the OA by 0.2 and 0.6%,respectively,compared to using only the Sentinel-2 reflectance bands.The analysis of timeliness revealed that when the July image is available,the increase in the accuracy of crop classification is the highest.When the Sentinel-1 and Sentinel-2 images for May,June,and July are available,an OA greater than 80%can be achieved.The results of this study are applicable to large-scale,high-resolution crop classification and provide key technologies for remote sensing-based crop classification in s展开更多
Humans deeply influence the urbanizing of earth’s surface system in an exacerbating manner across space and time[1].Around the globe,urban land-use/cover changes reflect the intensities of human activities and land s...Humans deeply influence the urbanizing of earth’s surface system in an exacerbating manner across space and time[1].Around the globe,urban land-use/cover changes reflect the intensities of human activities and land shifts from nature or semi-nature lands to man-made–dominated surfaces[2].展开更多
Size-resolved aerosols were continuously collected by a Nano Sampler for 13 days at an urban site in Beijing during winter 2012 to measure the chemical composition of ambient aerosol particles. Data collected by the N...Size-resolved aerosols were continuously collected by a Nano Sampler for 13 days at an urban site in Beijing during winter 2012 to measure the chemical composition of ambient aerosol particles. Data collected by the Nano Sampler and an ACSM（Aerodyne Aerosol Chemical Speciation Monitor） were compared. Between the data sets,similar trends and strong correlations were observed,demonstrating the validity of the Nano Sampler. PM10 and PM2.5concentrations during the measurement were 150.5 ± 96.0 μg/m3（mean ± standard variation）and 106.9 ± 71.6 μg/m3,respectively. The PM2.5/PM10 ratio was 0.70 ± 0.10,indicating that PM2.5dominated PM10. The aerosol size distributions showed that three size bins of 0.5–1,1–2.5 and 2.5–10 μm contributed 21.8%,23.3% and 26.0% to the total mass concentration（TMC）,respectively. OM（organic matter） and SIA（secondary ionic aerosol,mainly SO42-,NO3-and NH4＋） were major components of PM2.5. Secondary compounds（SIA and secondary organic carbon） accounted for half of TMC（about 49.8%） in PM2.5,and suggested that secondary aerosols significantly contributed to the serious particulate matter pollution observed in winter. Coal burning,biomass combustion,vehicle emissions and SIA were found to be the main sources of PM2.5. Mass concentrations of water-soluble ions and undetected materials,as well as their fractions in TMC,strikingly increased with deteriorating particle pollution conditions,while OM and EC（elemental carbon） exhibited different variations,with mass concentrations slightly increasing but fractions in TMC decreasing.展开更多
The Baiyin serial murders,or called Gan-Meng 8.05 serial murders,has been considered to be the most infamous among the major criminal cases since 1949.Between May26,1988 and February 9,2002,11 women including an8-year...The Baiyin serial murders,or called Gan-Meng 8.05 serial murders,has been considered to be the most infamous among the major criminal cases since 1949.Between May26,1988 and February 9,2002,11 women including an8-year-old girl were found gagged,raped,and murdered,often by slitting their throats,and some of their bodies were mutilated brutally,resembling the infamous‘‘Jack the Ripper’’killings that occurred in London more than one hundred years ago.Nine of these 11 murders took place展开更多
To reduce the communication among processors and improve the computing time for solving linear complementarity problems, we present a two-step modulus-based syn- chronous multisplitting iteration method and the corres...To reduce the communication among processors and improve the computing time for solving linear complementarity problems, we present a two-step modulus-based syn- chronous multisplitting iteration method and the corresponding symmetric modulus-based multisplitting relaxation methods. The convergence theorems are established when the system matrix is an H＋-matrix, which improve the existing convergence theory. Numeri- cal results show that the symmetric modulus-based multisplitting relaxation methods are effective in actual implementation.展开更多
The helical structures possess unique physical and chemical properties,such as superelasticity,high specific strength,chirality,and electromagnetic cross-polarization characteristics.With the development of nanoscienc...The helical structures possess unique physical and chemical properties,such as superelasticity,high specific strength,chirality,and electromagnetic cross-polarization characteristics.With the development of nanoscience and nanotechnology,helical structures with various scales have been discovered or synthesized artificially.Among them,the helical carbon materials receive much attention around the world.Herein,we present a brief review of the development of helical carbon materials in terms of structures,synthesis techniques and mechanisms,and applications.The controllable designing of catalysts,carbon sources and reaction parameters plays a key role to optimize the properties of the helical carbon materials.At the same time,the applications in microwave absorption devices,sensors,catalysts,energy conversions and storage devices,and solar cell are also presented.For the good chemical and physical properties,helical carbon materials have a good application prospect in many fields.The potential issues and future opportunities of the helical carbon materials are also proposed.展开更多
In order to realize seedbed mechanization of whole plastic-film mulching on double ridges and to overcome the difficulty in crosswise belt type soil covering by whole plastic-film,a kind of crosswise belt type whole p...In order to realize seedbed mechanization of whole plastic-film mulching on double ridges and to overcome the difficulty in crosswise belt type soil covering by whole plastic-film,a kind of crosswise belt type whole plastic-film ridging-mulching corn seeder on double ridges was designed in this study.The key components of the sample machine was designed and its working parameters of seedbed soil covering device,crosswise-belt soil covering mechanism and profiling sowing depth adjustment device were determined.After numerical simulation on the film edge and crosswise soil covering by whole plastic-film on double ridges by discrete element method,the velocity and displacement of the oscillating plate,and the variation rule of amount of covered soil with time were explored.Field test results show that,when the advancing velocity of the machine was 0.50 m/s,the qualified rate of soil width covered on film edge of the seedbed reached 96.1%,qualified rate of crosswise soil belt width was 94.5%,qualified rate of soil thickness on seedbed was 95.3%,qualified rate of sowing depth was 89.3%,qualified rate of spacing between crosswise soil belts reached 93.6%,which all met related standards in China and satisfied design requirements,and could realize seedbed mechanization of whole plastic-film mulching on double ridges.Comparison tests on working performances of practical soil covering show a basic consistence with the seedbed soil covering simulation,and verified the effectiveness of the soil covering model built by using discrete element method.展开更多
Let(Z_n) be a supercritical branching process with immigration in a random environment. Firstly, we prove that under a simple log moment condition on the offspring and immigration distributions, the naturally normaliz...Let(Z_n) be a supercritical branching process with immigration in a random environment. Firstly, we prove that under a simple log moment condition on the offspring and immigration distributions, the naturally normalized population size W_n converges almost surely to a finite random variable W. Secondly, we show criterions for the non-degeneracy and for the existence of moments of the limit random variable W. Finally, we establish a central limit theorem, a large deviation principle and a moderate deviation principle about log Z_n.展开更多
Brain-derived neurotrophic factor(BDNF)regulates a variety of biological processes predominantly via binding to the transmembrane receptor tyrosine kinase TrkB.It is a potential therapeutic target in numerous neurolog...Brain-derived neurotrophic factor(BDNF)regulates a variety of biological processes predominantly via binding to the transmembrane receptor tyrosine kinase TrkB.It is a potential therapeutic target in numerous neurological,mental and metabolic disorders.However,the lack of efficient means to deliver BDNF into the body imposes an insurmountable hurdle to its clinical application.To address this challenge,we initiated a cell-based drug screening to search for small molecules that act as the TrkB agonist.7,8-Dihydroxyflavone(7,8-DHF)is our first reported small molecular TrkB agonist,which has now been extensively validated in various biochemical and cellular systems.Though binding to the extracellular domain of TrkB,7,8-DHF triggers TrkB dimerization to induce the downstream signaling.Notably,7,8-DHF is orally bioactive that can penetrate the brain blood barrier(BBB)to exert its neurotrophic activities in the central nervous system.Numerous reports suggest 7,8-DHF processes promising therapeutic efficacy in various animal disease models that are related to deficient BDNF signaling.In this review,we summarize our current knowledge on the binding activity and specificity,structure-activity relationship,pharmacokinetic and metabolism,and the pre-clinical efficacy of 7,8-DHF against some human diseases.展开更多
There is little fundamental research in civil law theory on the relationship between computer data and goods(objects)and property under civil law.Existing judgments on online civil disputes and current theoretical res...There is little fundamental research in civil law theory on the relationship between computer data and goods(objects)and property under civil law.Existing judgments on online civil disputes and current theoretical research have tended to process electronic data as an object or property in isolation.But electronic data is not specific and independent;it does not fall under intangibles,nor can it be classified as an object with civil rights content.It has no independent economic value,and trading in data is constrained by its information content.Moreover,the realization of its value is dependent for protection on data security and self-control,so it cannot easily be regarded as property.Since electronic data is not an object,contracts for big data transactions can readily be defined as data service contracts,but given the uncertainty of the entity in question,the problem of externalities and the lack of a monopoly,it is not easy to realize data rights.Electronic data has the essential character of instrumental neutrality,and there are limits to the law’s imposition on it of regulatory functions.Online civil disputes can be divided into the instrumental and the virtual,used respectively as general tort remedy and as tort remedy for infringement of laws protecting others.展开更多
The existing homomorphie eneryption scheme is based on ring of the integer, and the possible operators are restricted to addition and multiplication only. In this paper, a new operation is defined Similar Modul. Base ...The existing homomorphie eneryption scheme is based on ring of the integer, and the possible operators are restricted to addition and multiplication only. In this paper, a new operation is defined Similar Modul. Base on the Similar Modul, the number sets of the homomorphic encryption scheme is extended to real number, and the possible operators are extended to addition, subtraction, multiplication and division. Our new approach provides a practical ways of implementation because of the extension of the operators and the number sets.展开更多
This article is the ninth in the series of Fungal Diversity Notes,where 107 taxa distributed in three phyla,nine classes,31 orders and 57 families are described and illustrated.Taxa described in the present study incl...This article is the ninth in the series of Fungal Diversity Notes,where 107 taxa distributed in three phyla,nine classes,31 orders and 57 families are described and illustrated.Taxa described in the present study include 12 new genera,74 new species,three new combinations,two reference specimens,a re-circumscription of the epitype,and 15 records of sexualasexual morph connections,new hosts and new geographical distributions.Twelve new genera comprise Brunneofusispora,Brunneomurispora,Liua,Lonicericola,Neoeutypella,Paratrimmatostroma,Parazalerion,Proliferophorum,Pseudoastrosphaeriellopsis,Septomelanconiella,Velebitea and Vicosamyces.Seventy-four new species are Agaricus memnonius,A.langensis,Aleurodiscus patagonicus,Amanita flavoalba,A.subtropicana,Amphisphaeria mangrovei,Baorangia major,Bartalinia kunmingensis,Brunneofusispora sinensis,Brunneomurispora lonicerae,Capronia camelliaeyunnanensis,Clavulina thindii,Coniochaeta simbalensis,Conlarium thailandense,Coprinus trigonosporus,Liua muriformis,Cyphellophora filicis,Cytospora ulmicola,Dacrymyces invisibilis,Dictyocheirospora metroxylonis,Distoseptispora thysanolaenae,Emericellopsis koreana,Galiicola baoshanensis,Hygrocybe lucida,Hypoxylon teeravasati,Hyweljonesia indica,Keissleriella caraganae,Lactarius olivaceopallidus,Lactifluus midnapurensis,Lembosia brigadeirensis,Leptosphaeria urticae,Lonicericola hyaloseptispora,Lophiotrema mucilaginosis,Marasmiellus bicoloripes,Marasmius indojasminodorus,Micropeltis phetchaburiensis,Mucor orantomantidis,Murilentithecium lonicerae,Neobambusicola brunnea,Neoeutypella baoshanensis,Neoroussoella heveae,Neosetophoma lonicerae,Ophiobolus malleolus,Parabambusicola thysanolaenae,Paratrimmatostroma kunmingensis,Parazalerion indica,Penicillium dokdoense,Peroneutypa mangrovei,Phaeosphaeria cycadis,Phanerochaete australosanguinea,Plectosphaerella kunmingensis,Plenodomus artemisiae,P.lijiangensis,Proliferophorum thailandicum,Pseudoastrosphaeriellopsis kaveriana,Pseudohelicomyces menglunicus,Pseudoplagiostoma mangiferae,Robillarda mangif展开更多
A study was conducted with Hy-Line Brown laying hens to examine the effects of reduced protein diet,deficiency of arginine(Arg),and addition of crystalline Arg,citrulline(Cit)and guanidinoacetic acid(GAA)as substitute...A study was conducted with Hy-Line Brown laying hens to examine the effects of reduced protein diet,deficiency of arginine(Arg),and addition of crystalline Arg,citrulline(Cit)and guanidinoacetic acid(GAA)as substitutes for Arg.Hen performance,egg quality,serum uric acid,liver and reproductive organ weights,and energy and protein digestibility were measured using a completely randomized design with 5 treatments.Treatments were a standard diet(17%protein diet;SP),a reduced diet(13%protein diet deficient in Arg;RP)and RP with added Arg(0.35%,RP-Arg),GAA(0.46%equivalent to 0.35%Arg,RP-GAA)or Cit(0.35%,RP-Cit)to the level of SP.It was hypothesized that performance would decrease with Arg deficient RP diet and the addition of GAA or Cit in RP would allow birds to perform similar or greater than Arg-added RP treatment.The experiment was conducted from 20 to 39 wk of age but the treatment effect was seen only after 29 wk of age.The birds offered RP had reduced egg and albumin weights(P<0.01),lower yolk color score(P<0.01),lower protein intake and excretion(P<0.01)than those offered SP.When Arg or Cit were added to RP to make them equivalent to SP,feed intake(FI)and egg production were not different than those of RP(P>0.05).The birds offered RP-GAA decreased FI and egg production(P<0.01)compared to those offered RP.The addition ofArg,Cit or GAA to the RP had no effect on egg quality parameters,protein and energy digestibilities(P>0.05).However,birds offered the RP-Cit diet tended to have higher Haugh unit(P=0.095)and lower shell breaking strength(P=0.088)compared to all other treatments while those offered RP-GAA had higher energy digestibility(P<0.05)than all other groups but RP.The limited performance response of hens fed RP with added Arg,GAA,or Cit may be due to deficiency of some other nutrients in RP such as phenylalanine,potassium or non-essential amino acids and other components of soybean meal in the diet.展开更多
文摘With the development of network technology and cloud computing, data sharing is becoming increasingly popular, and many scholars have conducted in-depth research to promote its flourish. As the scale of data sharing expands, its privacy protection has become a hot issue in research. Moreover, in data sharing, the data is usually maintained in multiple parties, which brings new challenges to protect the privacy of these multi-party data. In this paper, we propose a trusted data sharing scheme using blockchain. We use blockchain to prevent the shared data from being tampered, and use the Paillier cryptosystem to realize the confidentiality of the shared data. In the proposed scheme, the shared data can be traded, and the transaction information is protected by using the （p, t）-threshold Paillier cryptosystem. We conduct experiments in cloud storage scenarios and the experimental results demonstrate the efficiency and effectiveness of the proposed scheme.
基金This work was supported by grants from the National Science and Technology Major Project(No.2018ZX10101002-001-001)National Key Research and Development Program Projects of China(No.2017YFD0500305)+3 种基金the State Key Program of National Natural Science of China(No.U1808202)NSFC International(regional)cooperation and exchange program(No.31961143024)the Key-Area Research and Development Program of Guangdong province(No.2018B020241002)the Guangdong Provincial Science and Technology Project(No.2018B020207013)。
文摘Background:The ongoing new coronavirus pneumonia(Corona Virus Disease 2019,COVID-19)outbreak is spreading in China,but it has not yet reached its peak.Five million people emigrated from Wuhan before lockdown,potentially representing a source of virus infection.Determining case distribution and its correlation with population emigration from Wuhan in the early stage of the epidemic is of great importance for early warning and for the prevention of future outbreaks.Methods:The official case report on the COVID-19 epidemic was collected as of January 30,2020.Time and location information on COVID-19 cases was extracted and analyzed using ArcGIS and WinBUGS software.Data on population migration from Wuhan city and Hubei province were extracted from Baidu Qianxi,and their correlation with the number of cases was analyzed.Results:The COVID-19 confirmed and death cases in Hubei province accounted for 59.91%(5806/9692)and 95.77%(204/213)of the total cases in China,respectively.Hot spot provinces included Sichuan and Yunnan,which are adjacent to Hubei.The time risk of Hubei province on the following day was 1.960 times that on the previous day.The number of cases in some cities was relatively low,but the time risk appeared to be continuously rising.The correlation coefficient between the provincial number of cases and emigration from Wuhan was up to 0.943.The lockdown of 17 cities in Hubei province and the implementation of nationwide control measures efficiently prevented an exponential growth in the number of cases.Conclusions:The population that emigrated from Wuhan was the main infection source in other cities and provinces.Some cities with a low number of cases showed a rapid increase in case load.Owing to the upcoming Spring Festival return wave,understanding the risk trends in different regions is crucial to ensure preparedness at both the individual and organization levels and to prevent new outbreaks.
基金The authors acknowledge that this work was financially supported by China Agriculture Research System(CARS-14-1-28)Discipline construction fund project of Gansu Agricultural University(GAU-XKJS-2018-189).
文摘In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this paper,numerical simulation was carried out on the separating cleaning process of flax threshing material based on CFD-DEM method.Simulation results showed that the components of flax threshing material were separated and cleaned under the influence of airflow field,meanwhile,variation curves of quantity and mean velocity of flax seeds in the separating cleaning system were obtained.By referring to streamline distribution of gas-solid coupling,the quantity variation law of components of flax threshing material with time was explored and their motion curves and variation tendency of average velocity were studied.Verification test results showed that the cleaning rate of separating cleaning device for flax threshing material was 92.66%with 1.58%of total separation loss.Compared with simulation results,the test results were 1.34%and 0.93%lower,showing that it is feasible to apply the gas-solid coupling theory and method to simulate the separating and cleaning operation of flax threshing material.
基金supported by the Humanities and Social Science project of Ministry of Education of China[Grant Number:16YJA790036]the National Natural Science Foundation of China[Grant Number:71503272]
文摘This paper first constructed a system to evaluate the innovation efficiency of industrial companies within China's Mainland.Then,a principal component analysis(PCA) was performed to these indicators for dimensionality reduction,so as to figure out the technology innovation efficiency in these two phases,respectively.Finally,the overall efficiency of industrial companies in different regions was estimated and factorized via data envelopment analysis(DEA).The results showed that:(1)the efficiency of green technology innovation of industrial companies in China was relatively low as a whole,which mainly resulted from pure technical efficiency(PTE).Further,this huge gap continues to expand in these regions.And both PTE and scale efficiency(SE) in central and western regions leave much to be expected.(2)In the first phase of green technology development,when environmental factors were concerned,the efficiency was much lower than that without environmental considerations.Besides,the central and western regions were facing increasingly severe environmental problems,and there was a wide disparity in technology development efficiency among eastern,central,and western regions.(3)In the second phase of green technology commercialization,there were still more rooms for improvement in raising the efficiency of green technology innovation,and the efficiency in eastern,central,and western regions was ranked from highest to lowest.(4)Liaoning,Hebei,Heilongjiang,Xinjiang,Shanxi,Inner Mongolia,Yunnan,and Qinghai should focus on improving their technology;Jilin,Jiangxi,Anhui,and Guangxi should make their efforts to reduce resource redundancy;whereas Ningxia and Gansu should try to solve the above two issues.
文摘Internet use has become an indispensable part of people’s daily lives,and the relationship between Internet use and residents’subjective well-being is receiving increasing attention from researchers.However,the existing literature on the relationship between Internet use and residents’subjective well-being is still controversial and inconclusive,and there has been relatively little discussion of the mechanisms by which Internet use affects well-being.On the basis of data from the China General Social Survey 2015(CGSS2015),this paper provides an empirical analysis of the impact of Internet usage on residents’subjective wellbeing.The study finds that while Internet use had no significant impact on the well-being of residents compared to non-use,frequency of Internet usage did significantly improve subjective well-being.On this basis,we tested the mechanisms by which Internet use affects residents’well-being through the three channels of the personal income effect,the human capital effect and the social capital effect.The findings partially verify the hypothesis of the mediating effect of social capital between Internet use and residents’subjective wellbeing,but do not verify the hypothesis of the moderating effect of personal income and human capital.Compared with previous studies,this paper is innovative in the following three ways:it uses the latest available representative national microdata,which is better able to reflect recent Internet usage and its impact on residents’subjective well-being;on the basis of existing research on the impact of Internet usage on residents’well-being,it analyzes the specific mechanisms through which Internet use affects well-being,using the moderating effect model and the mediating effect model to make up for the shortcomings of existing research on the impact mechanism;and it applies the Bioprobit model to deal with the potential endogeneity of key explanatory variables,using a variety of model estimation methods to obtain more robust estimation results.
基金funded by the National Key R&D Program of China(2017YFD0201803)the Talent Recruitment Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences.
文摘Rapid and accurate access to large-scale,high-resolution crop-type distribution maps is important for agricultural management and sustainable agricultural development.Due to the limitations of remote sensing image quality and data processing capabilities,large-scale crop classification is still challenging.This study aimed to map the distribution of crops in Heilongjiang Province using Google Earth Engine(GEE)and Sentinel-1 and Sentinel-2 images.We obtained Sentinel-1 and Sentinel-2 images from all the covered study areas in the critical period for crop growth in 2018(May to September),combined monthly composite images of reflectance bands,vegetation indices and polarization bands as input features,and then performed crop classification using a Random Forest(RF)classifier.The results show that the Sentinel-1 and Sentinel-2 monthly composite images combined with the RF classifier can accurately generate the crop distribution map of the study area,and the overall accuracy(OA)reached 89.75%.Through experiments,we also found that the classification performance using time-series images is significantly better than that using single-period images.Compared with the use of traditional bands only(i.e.,the visible and near-infrared bands),the addition of shortwave infrared bands can improve the accuracy of crop classification most significantly,followed by the addition of red-edge bands.Adding common vegetation indices and Sentinel-1 data to the crop classification improved the overall classification accuracy and the OA by 0.2 and 0.6%,respectively,compared to using only the Sentinel-2 reflectance bands.The analysis of timeliness revealed that when the July image is available,the increase in the accuracy of crop classification is the highest.When the Sentinel-1 and Sentinel-2 images for May,June,and July are available,an OA greater than 80%can be achieved.The results of this study are applicable to large-scale,high-resolution crop classification and provide key technologies for remote sensing-based crop classification in s
基金supported by the Special Project of Global Space Remote Sensing Information Submission and Annual Report from the Ministry of Science and Technology(1061302600001)the National Natural Science Foundation of China(41871343)+1 种基金the Strategic Priority Research Program(A)of the Chinese Academy of Sciences(XDA23100201)the Second Tibetan Plateau Scientific Expedition(2019QZKK0608)。
文摘Humans deeply influence the urbanizing of earth’s surface system in an exacerbating manner across space and time[1].Around the globe,urban land-use/cover changes reflect the intensities of human activities and land shifts from nature or semi-nature lands to man-made–dominated surfaces[2].
基金supported by the National Natural Science Foundation of China (No.41175018)the Ministry of Science and Technology of China (No.2013CB955804)the special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control (Nos.13Z02ESPCP and 13K04ESPCP)
文摘Size-resolved aerosols were continuously collected by a Nano Sampler for 13 days at an urban site in Beijing during winter 2012 to measure the chemical composition of ambient aerosol particles. Data collected by the Nano Sampler and an ACSM（Aerodyne Aerosol Chemical Speciation Monitor） were compared. Between the data sets,similar trends and strong correlations were observed,demonstrating the validity of the Nano Sampler. PM10 and PM2.5concentrations during the measurement were 150.5 ± 96.0 μg/m3（mean ± standard variation）and 106.9 ± 71.6 μg/m3,respectively. The PM2.5/PM10 ratio was 0.70 ± 0.10,indicating that PM2.5dominated PM10. The aerosol size distributions showed that three size bins of 0.5–1,1–2.5 and 2.5–10 μm contributed 21.8%,23.3% and 26.0% to the total mass concentration（TMC）,respectively. OM（organic matter） and SIA（secondary ionic aerosol,mainly SO42-,NO3-and NH4＋） were major components of PM2.5. Secondary compounds（SIA and secondary organic carbon） accounted for half of TMC（about 49.8%） in PM2.5,and suggested that secondary aerosols significantly contributed to the serious particulate matter pollution observed in winter. Coal burning,biomass combustion,vehicle emissions and SIA were found to be the main sources of PM2.5. Mass concentrations of water-soluble ions and undetected materials,as well as their fractions in TMC,strikingly increased with deteriorating particle pollution conditions,while OM and EC（elemental carbon） exhibited different variations,with mass concentrations slightly increasing but fractions in TMC decreasing.
基金supported by the National Natural Science Foundation of China (31671297, 81671874)NSFC for Excellent Young Scholar (31222030)+4 种基金MOE Scientific Research Project (113022A)Shanghai Shuguang Project (14SG05), Natural Science Foundation of Gansu Province (1308RJZA190)Scientific Research Project for Colleges of Gansu Province (2014A-085)Evidence Science, Technology and Application for Key Laboratory Foundation of Gansu Province (ZDSYS-Y20)Gansu Institute of Political Science and Law Foundation Project (GZF2011XQNLW45)
文摘The Baiyin serial murders,or called Gan-Meng 8.05 serial murders,has been considered to be the most infamous among the major criminal cases since 1949.Between May26,1988 and February 9,2002,11 women including an8-year-old girl were found gagged,raped,and murdered,often by slitting their throats,and some of their bodies were mutilated brutally,resembling the infamous‘‘Jack the Ripper’’killings that occurred in London more than one hundred years ago.Nine of these 11 murders took place
文摘To reduce the communication among processors and improve the computing time for solving linear complementarity problems, we present a two-step modulus-based syn- chronous multisplitting iteration method and the corresponding symmetric modulus-based multisplitting relaxation methods. The convergence theorems are established when the system matrix is an H＋-matrix, which improve the existing convergence theory. Numeri- cal results show that the symmetric modulus-based multisplitting relaxation methods are effective in actual implementation.
基金financially supported by National Natural Science Foundation of China(No.51972045)the Fundamental Research Funds for the Central Universities of China(No.ZYGX2019J025)the Sichuan Science and Technology Program(Nos.2020JDRC0015 and 2020JDRC0045)。
文摘The helical structures possess unique physical and chemical properties,such as superelasticity,high specific strength,chirality,and electromagnetic cross-polarization characteristics.With the development of nanoscience and nanotechnology,helical structures with various scales have been discovered or synthesized artificially.Among them,the helical carbon materials receive much attention around the world.Herein,we present a brief review of the development of helical carbon materials in terms of structures,synthesis techniques and mechanisms,and applications.The controllable designing of catalysts,carbon sources and reaction parameters plays a key role to optimize the properties of the helical carbon materials.At the same time,the applications in microwave absorption devices,sensors,catalysts,energy conversions and storage devices,and solar cell are also presented.For the good chemical and physical properties,helical carbon materials have a good application prospect in many fields.The potential issues and future opportunities of the helical carbon materials are also proposed.
基金The authors acknowledge that this work was financially supported by National Natural Science Foundation of China(Grant No.51775115No.51405086)China Agriculture Research System(CARS-14-1-28).
文摘In order to realize seedbed mechanization of whole plastic-film mulching on double ridges and to overcome the difficulty in crosswise belt type soil covering by whole plastic-film,a kind of crosswise belt type whole plastic-film ridging-mulching corn seeder on double ridges was designed in this study.The key components of the sample machine was designed and its working parameters of seedbed soil covering device,crosswise-belt soil covering mechanism and profiling sowing depth adjustment device were determined.After numerical simulation on the film edge and crosswise soil covering by whole plastic-film on double ridges by discrete element method,the velocity and displacement of the oscillating plate,and the variation rule of amount of covered soil with time were explored.Field test results show that,when the advancing velocity of the machine was 0.50 m/s,the qualified rate of soil width covered on film edge of the seedbed reached 96.1%,qualified rate of crosswise soil belt width was 94.5%,qualified rate of soil thickness on seedbed was 95.3%,qualified rate of sowing depth was 89.3%,qualified rate of spacing between crosswise soil belts reached 93.6%,which all met related standards in China and satisfied design requirements,and could realize seedbed mechanization of whole plastic-film mulching on double ridges.Comparison tests on working performances of practical soil covering show a basic consistence with the seedbed soil covering simulation,and verified the effectiveness of the soil covering model built by using discrete element method.
基金supported by National Natural Science Foundation of China (Grants Nos. 11401590 and 11571052)
文摘Let(Z_n) be a supercritical branching process with immigration in a random environment. Firstly, we prove that under a simple log moment condition on the offspring and immigration distributions, the naturally normalized population size W_n converges almost surely to a finite random variable W. Secondly, we show criterions for the non-degeneracy and for the existence of moments of the limit random variable W. Finally, we establish a central limit theorem, a large deviation principle and a moderate deviation principle about log Z_n.
基金This work is supported by grant from National Institute of Health(NS045627)to KYe.
文摘Brain-derived neurotrophic factor(BDNF)regulates a variety of biological processes predominantly via binding to the transmembrane receptor tyrosine kinase TrkB.It is a potential therapeutic target in numerous neurological,mental and metabolic disorders.However,the lack of efficient means to deliver BDNF into the body imposes an insurmountable hurdle to its clinical application.To address this challenge,we initiated a cell-based drug screening to search for small molecules that act as the TrkB agonist.7,8-Dihydroxyflavone(7,8-DHF)is our first reported small molecular TrkB agonist,which has now been extensively validated in various biochemical and cellular systems.Though binding to the extracellular domain of TrkB,7,8-DHF triggers TrkB dimerization to induce the downstream signaling.Notably,7,8-DHF is orally bioactive that can penetrate the brain blood barrier(BBB)to exert its neurotrophic activities in the central nervous system.Numerous reports suggest 7,8-DHF processes promising therapeutic efficacy in various animal disease models that are related to deficient BDNF signaling.In this review,we summarize our current knowledge on the binding activity and specificity,structure-activity relationship,pharmacokinetic and metabolism,and the pre-clinical efficacy of 7,8-DHF against some human diseases.
基金a phased result of the University of International Business and Economics Phase Ⅲ Key Project for the 211 Project,"A Solution to the Dilemma of Private Rights Theory in the Internet Age"(8110060402)the Ministry of Education’s Humanities and Social Sciences Key Research Base,Research Centre of Civil and Commercial Jurisprudence of Renmin University of China Key Project "Research on Major Issues in Property Law"(11JJD820012)
文摘There is little fundamental research in civil law theory on the relationship between computer data and goods(objects)and property under civil law.Existing judgments on online civil disputes and current theoretical research have tended to process electronic data as an object or property in isolation.But electronic data is not specific and independent;it does not fall under intangibles,nor can it be classified as an object with civil rights content.It has no independent economic value,and trading in data is constrained by its information content.Moreover,the realization of its value is dependent for protection on data security and self-control,so it cannot easily be regarded as property.Since electronic data is not an object,contracts for big data transactions can readily be defined as data service contracts,but given the uncertainty of the entity in question,the problem of externalities and the lack of a monopoly,it is not easy to realize data rights.Electronic data has the essential character of instrumental neutrality,and there are limits to the law’s imposition on it of regulatory functions.Online civil disputes can be divided into the instrumental and the virtual,used respectively as general tort remedy and as tort remedy for infringement of laws protecting others.
基金Supported by the National Natural Science Foun-dation of China (90104005)
文摘The existing homomorphie eneryption scheme is based on ring of the integer, and the possible operators are restricted to addition and multiplication only. In this paper, a new operation is defined Similar Modul. Base on the Similar Modul, the number sets of the homomorphic encryption scheme is extended to real number, and the possible operators are extended to addition, subtraction, multiplication and division. Our new approach provides a practical ways of implementation because of the extension of the operators and the number sets.
基金CAS President’s International Fellowship Initiative(PIFI)for Young Staff 2019-2021(grant number 2019FY0003)the Research Fund from China Postdoctoral Science Foundation(Grant No.Y71B283261)+15 种基金the Yunnan Provincial Department of Human Resources and Social Security(Grant No.Y836181261)National Science Foundation of China(NSFC)project code 31850410489 for financial research supportthe Foreign Experts Bureau of Yunnan Province,Foreign Talents Program(2018,Grant No.YNZ2018002)Thailand Research grants entitled Biodiversity,phylogeny and role of fungal endophytes on above parts of Rhizophora apiculata and Nypa fruticans(Grant No:RSA5980068)the future of specialist fungi in a changing climate:baseline data for generalist and specialist fungi associated with ants,Rhododendron species and Dracaena species(Grant No:DBG6080013)Impact of climate change on fungal diversity and biogeography in the Greater Mekong Subregion(Grant No:RDG6130001)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant No.QYZDY-SSW-SMC014)the National Science Foundation of China and the Chinese Academy of Sciences for financial support under the following grants:41761144055,41771063 and Y4ZK111B01the Fonds de la Recherche Scientifique-FNRS(Belgium)for travel grantsCAS President’s International Fellowship Initiative(PIFI)for funding his postdoctoral research(Grant No.2018PC0006)the National Science Foundation of China(NSFC,project code 31750110478)CAS President’s International Fellowship Initiative(PIFI)for funding his postdoctoral research(Grant No.2019PC0008)supported under the Distinguished Scientist Fellowship Program(DSFP),King Saud University,Kingdom of Saudi Arabia.the Kerala State Council for Science,Technology and Environment(KSCSTE)in the form of a PhD fellowship(Grant No.001/FSHP/2011/CSTE)the Principal Chief Conservator of forests,Kerala State,for granting permission(No.WL10-4937/2012,dated 03-10-2013)to collect agarics from the forests of Keralathe Council of Scientific&Industrial Research
文摘This article is the ninth in the series of Fungal Diversity Notes,where 107 taxa distributed in three phyla,nine classes,31 orders and 57 families are described and illustrated.Taxa described in the present study include 12 new genera,74 new species,three new combinations,two reference specimens,a re-circumscription of the epitype,and 15 records of sexualasexual morph connections,new hosts and new geographical distributions.Twelve new genera comprise Brunneofusispora,Brunneomurispora,Liua,Lonicericola,Neoeutypella,Paratrimmatostroma,Parazalerion,Proliferophorum,Pseudoastrosphaeriellopsis,Septomelanconiella,Velebitea and Vicosamyces.Seventy-four new species are Agaricus memnonius,A.langensis,Aleurodiscus patagonicus,Amanita flavoalba,A.subtropicana,Amphisphaeria mangrovei,Baorangia major,Bartalinia kunmingensis,Brunneofusispora sinensis,Brunneomurispora lonicerae,Capronia camelliaeyunnanensis,Clavulina thindii,Coniochaeta simbalensis,Conlarium thailandense,Coprinus trigonosporus,Liua muriformis,Cyphellophora filicis,Cytospora ulmicola,Dacrymyces invisibilis,Dictyocheirospora metroxylonis,Distoseptispora thysanolaenae,Emericellopsis koreana,Galiicola baoshanensis,Hygrocybe lucida,Hypoxylon teeravasati,Hyweljonesia indica,Keissleriella caraganae,Lactarius olivaceopallidus,Lactifluus midnapurensis,Lembosia brigadeirensis,Leptosphaeria urticae,Lonicericola hyaloseptispora,Lophiotrema mucilaginosis,Marasmiellus bicoloripes,Marasmius indojasminodorus,Micropeltis phetchaburiensis,Mucor orantomantidis,Murilentithecium lonicerae,Neobambusicola brunnea,Neoeutypella baoshanensis,Neoroussoella heveae,Neosetophoma lonicerae,Ophiobolus malleolus,Parabambusicola thysanolaenae,Paratrimmatostroma kunmingensis,Parazalerion indica,Penicillium dokdoense,Peroneutypa mangrovei,Phaeosphaeria cycadis,Phanerochaete australosanguinea,Plectosphaerella kunmingensis,Plenodomus artemisiae,P.lijiangensis,Proliferophorum thailandicum,Pseudoastrosphaeriellopsis kaveriana,Pseudohelicomyces menglunicus,Pseudoplagiostoma mangiferae,Robillarda mangif
基金The authors would like to acknowledge and thank Australian Egg Corporation Limited for their financial support for this study.
文摘A study was conducted with Hy-Line Brown laying hens to examine the effects of reduced protein diet,deficiency of arginine(Arg),and addition of crystalline Arg,citrulline(Cit)and guanidinoacetic acid(GAA)as substitutes for Arg.Hen performance,egg quality,serum uric acid,liver and reproductive organ weights,and energy and protein digestibility were measured using a completely randomized design with 5 treatments.Treatments were a standard diet(17%protein diet;SP),a reduced diet(13%protein diet deficient in Arg;RP)and RP with added Arg(0.35%,RP-Arg),GAA(0.46%equivalent to 0.35%Arg,RP-GAA)or Cit(0.35%,RP-Cit)to the level of SP.It was hypothesized that performance would decrease with Arg deficient RP diet and the addition of GAA or Cit in RP would allow birds to perform similar or greater than Arg-added RP treatment.The experiment was conducted from 20 to 39 wk of age but the treatment effect was seen only after 29 wk of age.The birds offered RP had reduced egg and albumin weights(P<0.01),lower yolk color score(P<0.01),lower protein intake and excretion(P<0.01)than those offered SP.When Arg or Cit were added to RP to make them equivalent to SP,feed intake(FI)and egg production were not different than those of RP(P>0.05).The birds offered RP-GAA decreased FI and egg production(P<0.01)compared to those offered RP.The addition ofArg,Cit or GAA to the RP had no effect on egg quality parameters,protein and energy digestibilities(P>0.05).However,birds offered the RP-Cit diet tended to have higher Haugh unit(P=0.095)and lower shell breaking strength(P=0.088)compared to all other treatments while those offered RP-GAA had higher energy digestibility(P<0.05)than all other groups but RP.The limited performance response of hens fed RP with added Arg,GAA,or Cit may be due to deficiency of some other nutrients in RP such as phenylalanine,potassium or non-essential amino acids and other components of soybean meal in the diet.
