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Future changes in thermal comfort conditions over China based on multi-RegCM4 simulations 被引量:43
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作者 GAO Xue-Jie WU Jie +7 位作者 SHI Ying WU Jia HAN Zhen-Yu ZHANG Dong-Feng TONG Yao LI Rou-Ke XU Ying GIORGI Filippo 《Atmospheric and Oceanic Science Letters》 CSCD 2018年第4期291-299,共9页
A set of high resolution(25 km)21st century climate change projections using the regional climate model RegCM4 driven by four global model simulations were conducted over East Asia under the mid-range RCP4.5 scenario.... A set of high resolution(25 km)21st century climate change projections using the regional climate model RegCM4 driven by four global model simulations were conducted over East Asia under the mid-range RCP4.5 scenario.In the present paper,the authors investigate the change in thermal comfort conditions over china based on an ensemble of the projections,using the index of effective temperature(ET),which considers the aggregate effects of temperature,relative humidity,and wind on human thermal perception.The analysis also accounts for exposure as measured by distributed population amount scenarios.The authors find that the general increase in ET leads to a large increase in population exposure to very hot days(a China-aggregated sixfold increase in‘person-days’by the end of the 21st century.There is a decrease in cool,cold,and very cold person-days.Meanwhile,a decrease in comfortable day conditions by 22%person-days is found despite an increase in climate-based comfortable days.Analysis of the different contributions to the changes(climate,population,and interactions between the two)show that climate effects play a more important role in the hot end of the thermal comfort categories,while the population effects tend to be dominant in the cold categories.Thus,overall,even a mid-level warming scenario is found to increase the thermal stress over China,although there is a strong geographical dependence.The inclusion of population exposure strongly modulates the climateonly signal,which highlights the need for including socioeconomic factors in the assessment of risks associated with climate change. 展开更多
关键词 Thermal COMFORT conditions REGCM CLIMATE CHANGE POPULATION
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Law Professor: Changes "Substantial" in China's Human Rights Conditions
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作者 STAFF REPORTER 《The Journal of Human Rights》 2005年第3期10-10,共1页
"Substantial" changes have taken place in China’s human rights conditions, according to Professor Xu Xianming, president of the China University of Law and Political Sciences. As a member of the Law Committ... "Substantial" changes have taken place in China’s human rights conditions, according to Professor Xu Xianming, president of the China University of Law and Political Sciences. As a member of the Law Committee of the Standing Committee of the National People’s Congress, China’s highest legislature, he is known for his contributions to improvements in the country’s legal system. In an interview with Human Rights magazine, Professor Xu Xianming listed what he chose to call the "five most important changes" in China’s human rights conditions: 展开更多
关键词 in China’s Human Rights conditions changes Law Professor Substantial
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A Witness's Account of Changes in Tibet's Human Rights Conditions
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作者 LIN TIAN 《The Journal of Human Rights》 2009年第4期30-33,共4页
After riots that occurred on March 14, 2008 in Lhasa, Tibet, the China Central Television Station broadcast a documentary film titled Tibet's Past shot years ago by the Central Newsreel & Documentary Film Studio abo... After riots that occurred on March 14, 2008 in Lhasa, Tibet, the China Central Television Station broadcast a documentary film titled Tibet's Past shot years ago by the Central Newsreel & Documentary Film Studio about the miserable life of serfs under Tibet's feudal serf system before a democratic reform was carried out in the region. The documentary stunned many people. It helps people see through the reactionary and corrupt nature of the Dalai clique. 展开更多
关键词 than more A Witness’s Account of changes in Tibet’s Human Rights conditions WITNESS
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Developmental and Condition-Related Changes in the Prefrontal Cortex Activity during Rest 被引量:1
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作者 Ling-Yin Liang Jia-Jin Jason Chen +1 位作者 Patricia A. Shewokis Nancy Getchell 《Journal of Behavioral and Brain Science》 2016年第12期485-497,共13页
The prefrontal cortex (PFC) plays an important role in cognitive process related to executive function, but is also active during resting states. Quantifying prefrontal cortex activity during resting states provides a... The prefrontal cortex (PFC) plays an important role in cognitive process related to executive function, but is also active during resting states. Quantifying prefrontal cortex activity during resting states provides a baseline for interpreting task-induced brain activity. Researchers commonly use resting conditions where participants are prompted to stare at a screen (eyes open) or close their eyes (eyes closed). Are these two conditions equivalent representations of a baseline resting state? Further, does prefrontal cortex activity during these conditions change as a function of development? The aim of this study was to examine differences in prefrontal cortex activity between eyes open and eyes closed conditions during resting states in children and adults to provide a rationale of proper selection of baseline condition in future research. Thirty-six participants in 3 age groups were recruited in this study including twenty-four adults, five 12 - 15 years old children, and seven 8 - 11 years old children. Relative changes in concentrations of oxygenated hemoglobin (Δoxy-Hb) and deoxygenated hemoglobin (Δdeoxy-Hb) were obtained by using functional Near-Infrared Spectroscopy (fNIRS) in eyes closed (EC) and eyes open (EO) conditions, 3 minutes each. Contrasts were tested to compare the differences of Δoxy-Hb and Δdeoxy-Hb between eyes open and eyes closed conditions. The EC condition had significantly higher Δoxy-Hb than EO when all groups were combined (t (17.268) = 3.021, p = .008, Cohen’s d = –0.72). When comparing Δoxy-Hb between eyes conditions within each group, the younger group had significantly higher Δoxy-Hb in EC than EO (t (9.459) = 2.734, p = 0.022, Cohen’s d = –1.46). Based on these results, the EO condition may be a better baseline condition, particularly in studies with younger children, since it has less activity in the PFC that could interfere with interpretations of task-induced activity. 展开更多
关键词 Functional Near-infrared Spectroscopy (fNIRS) Developmental changes Resting conditions Eyes Open (EO) Eyes Closed (EC)
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The Spatial Variation Characteristics of Physical Conditions of College Students in Jiangsu Province
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作者 Bo Chen Dongjin Xian Yuhao Gu 《Applied Mathematics》 2017年第6期868-877,共10页
As an important component of national talent resources, the physical conditions of college students appear to be particularly important. Based on geographic information system platform of ArcGIS, this paper builds dat... As an important component of national talent resources, the physical conditions of college students appear to be particularly important. Based on geographic information system platform of ArcGIS, this paper builds database to make a statistical analysis on the physical conditions of college students in Jiangsu province in the years of 2012 to 2016, using the analysis function and graphics. The conclusions: 1) The students’ physique conditions in Jiangsu province is in an overall downward trend;2) There are differences between the male and female college students’ physical changes;3) In view of the college students’ physical deterioration degree of agglomeration, different areas should adopt effective measures to strengthen students’ physique. 展开更多
关键词 PHYSICAL HEALTH PHYSICAL CHANGE conditions Global AUTOCORRELATION COEFFICIENT
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Stress relaxation of warm frozen soil under drained or undrained conditions
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作者 SongHe Wang JiLin Qi 《Research in Cold and Arid Regions》 2011年第6期468-472,共5页
To investigate the influence of drainage conditions on stress relaxation characteristics of warm frozen soil, a series of laboratory tests were carried out under drained and undrained conditions. The results indicate ... To investigate the influence of drainage conditions on stress relaxation characteristics of warm frozen soil, a series of laboratory tests were carried out under drained and undrained conditions. The results indicate that confining pressure obviously influences the relaxation process of warm frozen soil. Under undrained condition, with increase in confining pressure, the critical relaxation du- ration tends to grow as well as instantaneous relaxation. But the relaxation rate is sensitive to confining pressure in the initial stage, and with further development, the effect tends to diminish. Under drained condition, the relaxation rate is greater than that under tmdrained condition in the initial stage but with the development of relaxation, the difference decreases. The volumetric defor- mation of warm frozen clay under drained condition is much larger than that under undrained condition. 展开更多
关键词 warm frozen soil stress relaxation confining pressure drained and undrained conditions volumetric change
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Forecasting Methods of Agrometeorological Conditions in the Northern Zone of the Republic of Kazakhstan
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作者 Bakytkan Dauletbakov Lyazzat Seidakhmetovna Sultangaliyeva Zhadra Dnimova 《Agricultural Sciences》 2018年第9期1205-1214,共10页
This work presents the forecast of quality indicators of wheat from weather conditions in the Northern zone of the Republic of Kazakhstan, obtained on the basis of the correlation of protein and gluten content of grai... This work presents the forecast of quality indicators of wheat from weather conditions in the Northern zone of the Republic of Kazakhstan, obtained on the basis of the correlation of protein and gluten content of grain with an average monthly air temperature and precipitation. The equation obtained by the authors allows estimating the quality of grain with the monthly advance, which is important in the organization of harvesting of grain crops. 展开更多
关键词 Natural and CLIMATIC conditions AGRICULTURAL METEOROLOGICAL changes GRAin YIELD Regression Analysis Forecasting
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CONVERGENCE RESULTS FOR NON-OVERLAP SCHWARZ WAVEFORM RELAXATION ALGORITHM WITH CHANGING TRANSMISSION CONDITIONS
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作者 Minh-Phuong TRAN Thanh-Nhan NGUYEN +3 位作者 Phuoc-Toan HUYNH Nhu-Binh LY Minh-Dang NGUYEN Quoc-Anh HO 《Acta Mathematica Scientia》 SCIE CSCD 2022年第1期105-126,共22页
In this paper,we establish a new algorithm to the non-overlapping Schwarz domain decomposition methods with changing transmission conditions for solving one dimensional advection reaction diffusion problem.More precis... In this paper,we establish a new algorithm to the non-overlapping Schwarz domain decomposition methods with changing transmission conditions for solving one dimensional advection reaction diffusion problem.More precisely,we first describe the new algorithm and prove the convergence results under several natural assumptions on the sequences of parameters which determine the transmission conditions.Then we give a simple method to estimate the new value of parameters in each iteration.The interesting advantage of our method is that one may update the better parameters in each iteration to save the computational cost for optimizing the parameters after many steps.Finally some numerical experiments are performed to show the behavior of the convergence rate for the new method. 展开更多
关键词 domain decomposition method Schwarz waveform relaxation algorithm advection reaction diffusion changing transmission conditions
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Magneto-Caloric Effect of Gd5Si2Ge2Compounds under Different Processing Conditions
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作者 Zeng Hong Yue Ming +1 位作者 Niu Peili Zhang Jiuxing 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第z1期76-78,共3页
The magneto-caloric effect of Gd5 Si2Ge2 compounds produced by various techniques is investigated in terms of their magnetization behaviors in the magnetic field from 0 to 2.0 T.The studied materials include arc-melte... The magneto-caloric effect of Gd5 Si2Ge2 compounds produced by various techniques is investigated in terms of their magnetization behaviors in the magnetic field from 0 to 2.0 T.The studied materials include arc-melted, annealed and sintered alloys.The results demonstrate that the Gd5Si2Ge2 alloys obtained under different processing conditions possess distinct magneto-caloric effect due to their various microstructures.Proper annealing treatment can enhance the magneto-caloric effect of the alloy remarkably.While the sintered alloy bears relatively lower value of magnetic entropy change ( △ SM) than arc-melted one.The magnetic entropy change of the annealed Gd5 Si2Ge2 alloy arrives the arrives the maximum value of - △SM = 15.29 J· kg-1· K-1 for magnetic field change under 2.0 T in the present work. 展开更多
关键词 magneto-caloric effect processing conditions Gd5Si2Ge2 magnetic entropy change
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Analysis of tight oil accumulation conditions and prediction of sweet spots in Ordos Basin: A case study
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作者 Ying Tang Shihao Tan +3 位作者 Ruifei Wang Hao Wang Chunming Xia Kaiyun Chen 《Energy Geoscience》 2022年第4期417-426,共10页
Tight sandstone reservoirs are widely developed in the Mesozoic Yanchang Formation of the Ordos Basin,China.There is a lack of understanding on the sedimentary setting,source-reservoir relationship and oil accumulatio... Tight sandstone reservoirs are widely developed in the Mesozoic Yanchang Formation of the Ordos Basin,China.There is a lack of understanding on the sedimentary setting,source-reservoir relationship and oil accumulation conditions in this area.In this study,through the comprehensive analysis of the distri-bution of tight oil,we evaluated the properties and petrological features of reservoir,geochemical characteristics of source rocks,the source-reservoir relationship,as well as the trapping,preservation and accumulation conditions of tight oil in the Chang 7 Member,and predicted the sweet spots of tight oil in the study area.The results show that the Chang 7 Member is a typical low-porosity and ultra-low permeability reservoir with great tightness,small pore throat and high capillary pressure,and must have been of near-source accumulation.The source rocks are mainly developed in the Chang 7_(3) submember,and the reservoirs mainly occur in the Chang 7_(1) and Chang 7_(2) submembers,forming a combination mode of“lower source rock and upper reservoir”.Sandbodies with good connectivity and fractures being well developed in local areas are the main hydrocarbon transport systems.The abnormal high pressure caused by hydrocarbon generation and pressurization is the main driving force of tight oil accumulation.The mode of hydrocarbon transportation is dominated by the vertical or lateral migration from under-lying source rocks or adjacent source rocks to reservoirs within a short distance.Following the integrated evaluation of lithology,physical properties and oil saturation of reservoirs and geochemical character-istics of source rocks,we grouped the sweet spots of Chang 7 Member into three types:Type I,Type II and Type III.Among others,the Type I sweet spots are the best in terms of porosity,permeability and source rock thickness and hydrocarbon enrichment which should be the focus of oilfield development.This study lays an important foundation for the economic and efficient development of tight oil in the Chang 7 Member of Heshui area,and has important implications on tight sandstone reservoirs in other regions of Ordos Basin in China. 展开更多
关键词 Tight oil Accumulation condition Sweet spot Chang 7 Member Ordos Basin
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Global Reporting Format (GRF) Application Automation for Runway Surface Conditions in West Africa
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作者 Dieudonné Sama Doua Allain Gnabahou +3 位作者 Frédéric Ouattara Marie Zidouemba Oboulbiga Diassibo Sibri Alphonse Sandwidi 《Advances in Aerospace Science and Technology》 2022年第3期135-145,共11页
This paper aims to design an automated Global Reporting Format’s (GRF) application in order to reduce time of manual application (on a runway) of the Global Reporting Format developed by International Civil Aviation ... This paper aims to design an automated Global Reporting Format’s (GRF) application in order to reduce time of manual application (on a runway) of the Global Reporting Format developed by International Civil Aviation Organization (ICAO). A method has been used to measure and generate Runway Condition Report (RCR) automatically. The developed computing model is an autonomous and automatic application implemented specially for West Africa (and can be extended to any rainy area). It uses Arduino materials and computing code developed by the authors. Results obtained show that using that method to retrieve the Runway Condition Report (RCR) is fast, so human presence on the runway is reduced. Even though the results obtained using this model are slightly different from those expected, the actual runway conditions are not too much affected. 展开更多
关键词 Climate Change Global Reporting Format Runway Surface Condition Measurements Duration West Africa ICAO
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Monitoring vegetation drought in the nine major river basins of China based on a new developed Vegetation Drought Condition Index
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作者 ZHAO Lili LI Lusheng +4 位作者 LI Yanbin ZHONG Huayu ZHANG Fang ZHU Junzhen DING Yibo 《Journal of Arid Land》 SCIE CSCD 2023年第12期1421-1438,共18页
The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecolo... The effect of global climate change on vegetation growth is variable.Timely and effective monitoring of vegetation drought is crucial for understanding its dynamics and mitigation,and even regional protection of ecological environments.In this study,we constructed a new drought index(i.e.,Vegetation Drought Condition Index(VDCI))based on precipitation,potential evapotranspiration,soil moisture and Normalized Difference Vegetation Index(NDVI)data,to monitor vegetation drought in the nine major river basins(including the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin,Yangtze River Basin,Southeast River Basin,Pearl River Basin,Southwest River Basin and Continental River Basin)in China at 1-month–12-month(T1–T12)time scales.We used the Pearson's correlation coefficients to assess the relationships between the drought indices(the developed VDCI and traditional drought indices including the Standardized Precipitation Evapotranspiration Index(SPEI),Standardized Soil Moisture Index(SSMI)and Self-calibrating Palmer Drought Severity Index(scPDSI))and the NDVI at T1–T12 time scales,and to estimate and compare the lag times of vegetation response to drought among different drought indices.The results showed that precipitation and potential evapotranspiration have positive and major influences on vegetation in the nine major river basins at T1–T6 time scales.Soil moisture shows a lower degree of negative influence on vegetation in different river basins at multiple time scales.Potential evapotranspiration shows a higher degree of positive influence on vegetation,and it acts as the primary influencing factor with higher area proportion at multiple time scales in different river basins.The VDCI has a stronger relationship with the NDVI in the Songhua River and Liaohe River Basin,Haihe River Basin,Yellow River Basin,Huaihe River Basin and Yangtze River Basin at T1–T4 time scales.In general,the VDCI is more sensitive(with shorter lag time of vegetation response to drought)than the traditional drought indices(SPEI,scPDSI and SSMI)in monitoring vegetation drought,and thus it could be applied to monitor short-term vegetation drought.The VDCI developed in the study can reveal the law of unclear mechanisms between vegetation and climate,and can be applied in other fields of vegetation drought monitoring with complex mechanisms. 展开更多
关键词 vegetation drought Vegetation Drought Condition index(VDCI) Normalized Difference Vegetation index(NDVI) vegetation dynamics climate change China
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Organic matter transformation ratio, hydrocarbon expulsion efficiency and shale oil enrichment type in Chang 7_(3) shale of Upper Triassic Yanchang Formation in Ordos Basin, NW China
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作者 ZHAO Wenzhi BIAN Congsheng +4 位作者 LI Yongxin LIU Wei DONG Jin WANG Kun ZENG Xu 《Petroleum Exploration and Development》 2023年第1期14-26,共13页
The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion effi... The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion efficiency and roof/floor sealing conditions of the Chang 7_(3) shale,and evaluates the major enrichment type of shale oil in this interval.The average organic matter transformation ratio of the Chang 7_(3) shale is about 45%;in other words,more than 50%of the organic matters have not transformed to hydrocarbons,and the lower the maturity,the greater the proportion of untransformed organic matters.The cumulative hydrocarbon expulsion efficiency of the transformed hydrocarbon is 27.5% on average,and the total proportion of untransformed organic matters plus retained hydrocarbons is greater than 70%.The relative hydrocarbon expulsion efficiency of the Chang 7_(3) shale is 60%on average,that is,about 40% of hydrocarbons retain in the shale.The Chang 7_(3) shale corresponds to Chang 7_(1+2) and Chang 8 sandstones as the roof and floor,respectively,and is further overlaid by Chang 6 shale,where extensive low porosity and low permeability–tight oil reservoirs have formed in the parts with relatively good porosity and permeability.Moreover,the Chang 7_(3) shale is tested to be in a negative pressure system(the pressure coefficient of 0.80–0.85).Therefore,the roof/floor sealing conditions of the Chang 7_(3) shale are poor.The retained hydrocarbons appear mostly in absorbed status,with low mobility.It is concluded that the medium–high mature shale oil is not the major enrichment type of shale oil in the Chang 7_(3) shale,but there may be enrichment opportunity for shale oil with good mobility in the areas where the sealing conditions are good without faults and fractures and oil reservoirs are formed off Chang 7_(1+2),Chang 6 and Chang 8.Furthermore,low–medium mature shale oil is believed to have great potential and is the major enrichment type of shale oil in the Chang 7_(3) shale.It is recommended to prepare relevant in-situ conversion technologies by pilot test and figure out the resource availability and distribution. 展开更多
关键词 organic matter transformation ratio hydrocarbon expulsion efficiency sealing condition continental shale oil major enrichment type Chang 7_(3)shale Triassic Ordos Basin
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Neuroprotective effects of ischemic adaptation on cognitive dysfunction in mice with cerebral ischemia-reperfusion injury
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作者 Yongxin Ma Meng Zhang +3 位作者 Meng Geng Wenjing Zhou Xiuhua Bai Yaoming Xu 《Journal of Translational Neuroscience》 2023年第3期20-27,共8页
Objective: To observe the effects of remote ischemia on cognitive function and neuronal pathological damage in rats with cognitive impairment induced by bilateral common carotid artery occlusion(BCAO).Methods:Male SD ... Objective: To observe the effects of remote ischemia on cognitive function and neuronal pathological damage in rats with cognitive impairment induced by bilateral common carotid artery occlusion(BCAO).Methods:Male SD rats were selected to establish the cognitive impairment model induced by cerebral ischemia reperfusion caused by BCAO.The tests included three groups of rats:a sham group,a model group with vascular cognitive impairment (VCI) , and a remote ischemic conditioning (RIC) group (VCI + RIC group). From 24 h after operation, both hind limbs of rats in VCI + RIC group were treated with RIC. After 28 d, Morris water maze test and HE staining was used to observe the pathological changes of white matter and hippocampus in each group.Results: After 3 d mice in VCI group began to improve gradually. The recovery of rats in the VCI + RIC group was relatively slow,but they started to recover rapidly 2 d after the operation.Morris water maze test showed that the escape latency of rats in VCI group and VCI+RIC group was longer than that in the sham group, and the score of VCI+RIC group was better than that of the VCI group, but there was a significant difference between the two groups(P<0.05).The space exploration experiment was performed at 7 d and 28 d after the operation;the VCI+RIC group outperformed the VCI group in both trials;the difference between the two groups was statistically significant (P<0.05).In the target quadrant exploration time, the difference between the VCI group (33.5±11.3 s) and the VCI+RIC group (41.2±9.7 s) was statistically significant (P<0.05).Results from the hematoxylin and eosin(HE)staining showed that compared with VCI group, cortical cells in VCI + RIC group had loose stroma, thinner nerve fibers, fewer broken cells, and slightly shrunken cells. Compared with VCI group, neurons in VCI + RIC group had a little vacuolar degenera-tion and slightly shrunken cell volume.Conclusion:Cerebral ischemia-reperfusion injury can cause learning and memory impairment in rats, leading to VCI. RIC can significantly improve VCI and play a neuroprotective role. 展开更多
关键词 remote ischemic conditioning cere-bral ischemia-reperfusion cognitive impairment hippo-campal changes NEUROPROTECTION
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基于耕地资源质量分类监测的土壤条件变化对粮食产量的影响——以河南省兰考县为例
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作者 樊鹏 王自威 +3 位作者 邵红旗 杨青伟 王磊 杨喜会 《中国农学通报》 2024年第10期83-88,共6页
为突出土壤条件变化对粮食产量的影响,采用趋势分析法和对比分析法,以兰考县耕地资源质量分类监测工作为例,分析土壤监测样点不同年份的土壤条件变化对当地粮食产量造成的影响。研究表明,土壤有机质含量的增加和土壤pH在合理范围内的增... 为突出土壤条件变化对粮食产量的影响,采用趋势分析法和对比分析法,以兰考县耕地资源质量分类监测工作为例,分析土壤监测样点不同年份的土壤条件变化对当地粮食产量造成的影响。研究表明,土壤有机质含量的增加和土壤pH在合理范围内的增加都能够提升粮食产量。建议以测土配方施肥为基础,增加有机肥的使用量,提升土壤有机质含量,并针对当地土壤的实际情况和主要作物类型,提出有针对性的改良土壤pH的措施,以提升粮食产量。 展开更多
关键词 耕地资源质量分类 监测 土壤条件 变化 粮食产量 影响
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翅片增强空气式相变储能装置蓄热性能模拟研究
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作者 冯国会 马天娇 赫娜 《沈阳建筑大学学报(自然科学版)》 CAS 北大核心 2024年第3期478-485,共8页
目的为解决空气式相变储能装置中存在的蓄热时间过长等问题,探究该装置蓄热性能的优化措施。方法利用FLUENT仿真软件对添加不同体积分数、厚度和高度翅片空气式相变储能装置的温度场进行数值模拟,并对模拟结果进行比较分析。结果翅片体... 目的为解决空气式相变储能装置中存在的蓄热时间过长等问题,探究该装置蓄热性能的优化措施。方法利用FLUENT仿真软件对添加不同体积分数、厚度和高度翅片空气式相变储能装置的温度场进行数值模拟,并对模拟结果进行比较分析。结果翅片体积分数为15%,厚度为8 mm,高度为14 mm时,空气式相变储能装置蓄热时间缩短最显著,可缩短46.97%。结论翅片的添加对相变储能单元的熔化具有促进作用,通过优化翅片体积分数、厚度和高度参数,可以提高空气式相变储能装置的蓄热性能。 展开更多
关键词 相变材料 蓄热工况 传热性能提升 翅片 参数优化
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污染物胁迫及环境条件改变对拟南芥根系生长影响的研究进展
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作者 张成丽 李小龙 +4 位作者 张浩杰 鲍金铭 马嘉玉 闫帅腾 荆杰 《化学研究》 CAS 2024年第2期181-188,共8页
拟南芥生长周期短,基因组简单,对其根系的相关研究可为研究污染物和外界条件胁迫对其他植物的毒害作用及影响机制提供依据,污染物胁迫和环境条件的改变,都将会影响拟南芥根系的正常生长。因此,拟南芥根系在胁迫环境中所作出的应激反应... 拟南芥生长周期短,基因组简单,对其根系的相关研究可为研究污染物和外界条件胁迫对其他植物的毒害作用及影响机制提供依据,污染物胁迫和环境条件的改变,都将会影响拟南芥根系的正常生长。因此,拟南芥根系在胁迫环境中所作出的应激反应和响应机制是至关重要的,相关研究已经取得一系列进展。本文分别从无机污染物、有机污染物、环境条件改变三个方面,综述了拟南芥根系发生的不同应激反应及其机制,发现拟南芥根系在面对不同胁迫环境时的响应不尽相同:1)较低浓度的金属离子会促进拟南芥根系的生长发育,反之,则会抑制根系的生长发育。2)有机污染物对拟南芥根系的影响普遍是抑制的,致使其主根长度降低,侧根数量减少。3)外界条件胁迫发生时则相对复杂,不同外界条件干扰拟南芥会发生不同的应激反应。 展开更多
关键词 拟南芥 根系生长 无机污染物 有机污染物 环境条件改变
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基于机器学习的不同环境条件下松散回潮水分变化的预测
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作者 李自娟 李宜馨 +5 位作者 赵海洋 陈娇娇 吕萱 孙朔 方世航 李晓 《包装工程》 CAS 北大核心 2024年第17期119-128,共10页
目的明确温湿度对松散回潮工序水分变化量的影响。方法使用K-means聚类分析法划分张家口市环境温湿度区间,利用梯度提升决策树筛选松散回潮水分变化量相关的工艺参数作为特征变量,构建不同温湿度区间下松散回潮工序水分变化量的机器学... 目的明确温湿度对松散回潮工序水分变化量的影响。方法使用K-means聚类分析法划分张家口市环境温湿度区间,利用梯度提升决策树筛选松散回潮水分变化量相关的工艺参数作为特征变量,构建不同温湿度区间下松散回潮工序水分变化量的机器学习预测模型,同时探究车间温湿度对水分变化量的影响,并对最终模型进行优化。结果根据外界环境全年的温湿度,可划分为低温中湿、中温低湿、高温高湿、中温中湿4个区间,且中温低湿与高温高湿区松散回潮工序水分变化量的差异最为显著;分别对中温低湿和高温高湿区构建松散回潮工序水分变化量的LSR、SVR、DT、RF预测模型,综合对比可知,SVR、RF预测模型的精度最高;将车间温湿度作为特征变量后,松散回潮工序水分变化量SVR、RF模型的预测精度均有所上升,其R^(2)'(R^(2)与1的差值)分别降低了25%、46%,说明车间温湿度对松散回潮工序水分变化量的影响较大;对中温低湿和高温高湿区SVR、RF松散回潮工序水分变化量预测模型进行优化后,最终模型的R^(2)'分别达到0.08、0.04。结论松散回潮水分变化量受到外界和车间温湿度的影响,根据不同温湿度区间构建的中温低湿RF模型和高温高湿SVR模型对水分变化量的拟合效果较好,预测准确,能够可靠地应用于松散回潮工序水分变化量的预测,且可拓展用于纸质卷烟包装材料的水分预测和控制,对提升烟丝的卷接包装质量具有重要的理论意义和实际应用价值。 展开更多
关键词 温湿度 松散回潮 水分变化量 机器学习
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城市国土空间监测初探
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作者 曾成强 张剑峰 +3 位作者 张届 雒建艳 段彩梅 王录芳 《城市勘测》 2024年第2期1-8,共8页
城市国土空间监测是我国首次基于土地利用大规模对城市自然资源和人文地理要素实施全面监测的一项重要举措,是一项涉及行业众多,时间和空间尺度各不相同,内容繁杂的科技工程。本文通过试点探索项目关键技术和作业流程,总结组织管理和实... 城市国土空间监测是我国首次基于土地利用大规模对城市自然资源和人文地理要素实施全面监测的一项重要举措,是一项涉及行业众多,时间和空间尺度各不相同,内容繁杂的科技工程。本文通过试点探索项目关键技术和作业流程,总结组织管理和实施中的问题,为《技术方案(征求意见稿)》(自然资调查函[2022]30号和36号)提出补充完善意见,提升生产效率和质量,归纳可复制,可推广的经验,形成一套行之有效的管理模式,推动城市国土空间监测项目关键技术创新。 展开更多
关键词 城市国土空间监测 地理国情 国土变更调查 自动处理
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基于深度学习的地表覆盖变化检测方法研究
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作者 李天 彭敏 《城市勘测》 2024年第2期81-83,共3页
研究地表覆盖的自动变化检测对于常态化地理国情监测具有重要意义。结合全卷积神经网络(FCN)和孪生(Siam)神经网络,设计了一种全卷积孪生网络模型(FCSCN),并通过构建城市地表覆盖变化样本库、模型训练和测试、精度评价,得到了适用于沈... 研究地表覆盖的自动变化检测对于常态化地理国情监测具有重要意义。结合全卷积神经网络(FCN)和孪生(Siam)神经网络,设计了一种全卷积孪生网络模型(FCSCN),并通过构建城市地表覆盖变化样本库、模型训练和测试、精度评价,得到了适用于沈阳城市地表覆盖变化检测的深度学习模型。以2022年度地理国情监测项目局部区域为试点,开展了实践探索,结果发现该方法可以提高作业效率,对于高频次、全覆盖的地理国情监测具有一定的实践参考意义。 展开更多
关键词 深度学习 地理国情监测 地表覆盖 变化检测 卷积神经网络
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