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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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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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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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Sound-changes in Connected Speech and the Improvement of Listening Comprehension For NonEnglish Majors
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作者 Yin Guojie Zhong Yan Hu Zhu (Xichang Agricultural College,Xichang,Sichuan,615013) 《西昌农业高等专科学校学报》 1999年第3期39-44,共6页
It is well known that most Chinese nonEnglish majors can't understand the English materials they have heard,but they do understand them if the materials are in written form.Though there may be a lot of reasons (Su... It is well known that most Chinese nonEnglish majors can't understand the English materials they have heard,but they do understand them if the materials are in written form.Though there may be a lot of reasons (Such as phonological and psychological ones),this paper covers the influence of sound changes in connected speech upon the learners' listening comprehension.Non-English majors can improve their listening comprehension,to some degrees,by getting familiar with and being practiced in sound-changes in a flow of speech,with the help of a good attitude towards sound-changes in English speeches. 展开更多
关键词 非英语专业学生 听力理解力 英语学习 改进 连读 发音变化
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Response of a Grassland Ecosystem to Climate Change in a Theoretical Model 被引量:3
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作者 孙国栋 穆穆 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2011年第6期1266-1278,共13页
The response of a grassland ecosystem to climate change is discussed within the context of a theoretical model.An optimization approach,a conditional nonlinear optimal perturbation related to parameter(CNOP-P) appro... The response of a grassland ecosystem to climate change is discussed within the context of a theoretical model.An optimization approach,a conditional nonlinear optimal perturbation related to parameter(CNOP-P) approach,was employed in this study.The CNOP-P,a perturbation of moisture index in the theoretical model,represents a nonlinear climate perturbation.Two kinds of linear climate perturbations were also used to study the response of the grassland ecosystem to different types of climate changes.The results show that the extent of grassland ecosystem variation caused by the CNOP-P-type climate change is greater than that caused by the two linear types of climate change.In addition,the grassland ecosystem affected by the CNOP-P-type climate change evolved into a desert ecosystem,and the two linear types of climate changes failed within a specific amplitude range when the moisture index recovered to its reference state.Therefore,the grassland ecosystem response to climate change was nonlinear.This study yielded similar results for a desert ecosystem seeded with both living and wilted biomass litter.The quantitative analysis performed in this study also accounted for the role of soil moisture in the root zone and the shading effect of wilted biomass on the grassland ecosystem through nonlinear interactions between soil and vegetation.The results of this study imply that the CNOP-P approach is a potentially effective tool for assessing the impact of nonlinear climate change on grassland ecosystems. 展开更多
关键词 conditional nonlinear optimal perturbation parameter perturbation CNOP-P grassland ecosystem climate change
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The Effect of Wood Condition on Sound Wave Propagation 被引量:1
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作者 Ahmed El-Hadad Graham Ian Brodie Berhan Shiday Ahmed 《Open Journal of Acoustics》 2018年第3期37-51,共15页
This experiment aims to study the effects and modifications that occurred on acoustic signal harmonics when travelling through wood. The experiment measured the output amplitudes and frequencies of the travelling sign... This experiment aims to study the effects and modifications that occurred on acoustic signal harmonics when travelling through wood. The experiment measured the output amplitudes and frequencies of the travelling signals and compared them with the original input signal. The factors under investigation in this experiment included: wood type, wood moisture content (MC), input signal frequencies, signal travelling distance and wood condition (wood with/without cracks). The experiment findings demonstrated that higher input signal frequencies results in higher attenuation of acoustic emissions (AE) travelling through the wood. The results also indicate that: wood type, MC, the signal’s travelling distance, and the orientation of the travelling signal, compared to the wood’s grain direction, affected the signal propagation. 展开更多
关键词 Acoustic EMISSION sound WOOD Interaction MOISTURE Content sound Wave PROPAGATION WOOD conditION
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Sound Quality Prediction of Vehicle Interior Noise under Multiple Working Conditions Using Back-Propagation Neural Network Model 被引量:1
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作者 Zutong Duan Yansong Wang Yanfeng Xing 《Journal of Transportation Technologies》 2015年第2期134-139,共6页
This paper presents a back-propagation neural network model for sound quality prediction (BPNN-SQP) of multiple working conditions’ vehicle interior noise. According to the standards and regulations, four kinds of ve... This paper presents a back-propagation neural network model for sound quality prediction (BPNN-SQP) of multiple working conditions’ vehicle interior noise. According to the standards and regulations, four kinds of vehicle interior noises under operating conditions, including idle, constant speed, accelerating and braking, are acquired. The objective psychoacoustic parameters and subjective annoyance results are respectively used as the input and output of the BPNN-SQP model. With correlation analysis and significance test, some psychoacoustic parameters, such as loudness, A-weighted sound pressure level, roughness, articulation index and sharpness, are selected for modeling. The annoyance values of unknown noise samples estimated by the BPNN-SQP model are highly correlated with the subjective annoyances. Conclusion can be drawn that the proposed BPNN-SQP model has good generalization ability and can be applied in sound quality prediction of vehicle interior noise under multiple working conditions. 展开更多
关键词 Multiple Working conditions NEURAL Network BACK-PROPAGATION sound Quality PREDICTION ANNOYANCE
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Cool storage time of phase change wallboard room in summer 被引量:1
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作者 冯国会 陈其针 +2 位作者 黄凯良 牛润萍 王琳 《Journal of Central South University》 SCIE EI CAS 2009年第S1期75-79,共5页
More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the ... More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the parameters of the indoor thermal property in phase change wallboard room and ordinary room,the effects of using phase change wallboards on indoor temperature in summer and air conditioning are obtained. The combination of construct enclosure and phase change materials can stabilize indoor temperature,improve indoor thermal comfort,reduce the frequency of the operation of air conditioning facility,cut the initial investment and operation expense,and meanwhile play an practical role in "the power balancing between the peak period and the valley period" policy. Through the experiment and the test of the effects exerted by phase change wallboard room and ordinary room on the indoor thermal environment,it is obtained that the phase change wallboard can reduce the fluctuation range of indoor temperature and the heat flow from the outside into indoor environment in summer. According to the study,it is found that the effect of cool-storing for 5 h is obvious. Through the analysis of the phase change wallboard without air conditioning in daytime,it is obtained that the frequency of the operation of air conditioning in phase change wallboard room is smaller than that in the ordinary room,which can prolong the lifetime of the facility and reduce operation expense. 展开更多
关键词 PHASE change energy STORAGE PHASE change WALLBOARD room THERMAL STORAGE THERMAL exchange cool-storage air-conditioning
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The protective effects against noise trauma by sound conditioning in rats
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作者 ZHAI Suo-qiang,GUO Wei-wei,YU Ning Institute of Otorhinolaryngology,General Hospital of PLA,Beijing 100853 《Journal of Otology》 2009年第1期59-60,共2页
Objective To investigate the protective effects of sound conditioning against subsequent high -level noise trauma in rats.Method Rats were exposed to a 4 kHz octave band noise at 95 dB SPL for 10 hours,then to a traum... Objective To investigate the protective effects of sound conditioning against subsequent high -level noise trauma in rats.Method Rats were exposed to a 4 kHz octave band noise at 95 dB SPL for 10 hours,then to a traumatic exposure dose(105 dB SPL for 13 hours) delivered 12h later.Control animals were exposured to the traumatic dose only.ABR thresholds were obtained before and after noise exposure.Result Animals that had been sound conditioned demonstrated less ABR threshold shift compared to those that had not.Conclusion Moderate level sound exposure appears to have a toughening effect on the rat cochlea(or'conditioning') leading to decreased hearing loss from subsequent traumatic exposure. 展开更多
关键词 sound conditioning noise trauma RAT
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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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Climate Change, Variability and Rainfall Probability for Crop Planning in Few Districts of Central India
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作者 Suchit Kumar Rai Sunil Kumar +2 位作者 Arvind Kumar Rai Satyapriya   Dana Ram Palsaniya 《Atmospheric and Climate Sciences》 2014年第3期394-403,共10页
Trend and climate change were studied in annual rainfall data for the period of 62 years (1949-2010) of Sagar and 65 years (1945-2010) of Damoh districts of Bundelkhand region of central India. The analysis of weekly ... Trend and climate change were studied in annual rainfall data for the period of 62 years (1949-2010) of Sagar and 65 years (1945-2010) of Damoh districts of Bundelkhand region of central India. The analysis of weekly rainfall probability was also carried out at both the locations for field operations and crop planning in rainfed agricultural system for improving the farmer’s livelihood. Mean annual rainfall was 1233.8 mm with 32.6% variability for Sagar and 1225.1 mm with 30.3% variability for Damoh region. Sagar and Damoh region exhibited significant decreasing trend in the total amount of annual rainfall in the last 15 years (1996 to 2010). Also, both locations showed significant long-term decreasing trend in annual rainfall. Climate of both the regions have changed as in the recent 15 years annual rainfall had decreased by 156.4 and 310.7 mm at Sagar and Damoh from their long period average (LPA), respectively. The Initial and conditional rainfall probability analysis at Damoh reinforced that Initial probabilities {P (W)} of getting 10 mm rainfall per week was 76% during 25th (18-24 June) SMW. Thus, the seed bed preparation could be initiated during this week. Initial as well as conditional probability of wet week followed by wet week {P(W/W} of getting 20 mm rainfall was more than 80% during 27th SMW (2-7 July) in Sagar district. Therefore, this week is most suitable for sowing operation in this district. 展开更多
关键词 Climate change RAINFALL Trend Initial and conditional RAINFALL PROBABILITY and CROP PLANNING
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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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Factors for the Major Changes in the English Language
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作者 Lu Ling, Dept of Foreign Languages, Fuyang Teachers College, Fuyang 236032 《阜阳师范学院学报(社会科学版)》 2001年第1期42-44,共3页
本文阐述了引起英语变迁的历史因素-罗马人,条顿人,诺尔曼人的四次入侵;以及音变因素-e音的丢失和元音大转移。此外,印刷业的发展加速了拼写的标准化,十六、十七世纪英国文艺复兴极大地丰富了英语词汇。
关键词 英语拼写 语言变迁 历史 音变 e音 元音 文艺复兴 英语 词汇 印刷业 侵略 罗马人 条顿人 诺尔曼人
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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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聚氨酯型固-固相变储能材料对沥青调温效果的影响研究
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作者 张雪丽 孙伟清 郑君华 《储能科学与技术》 CAS CSCD 北大核心 2024年第3期841-843,共3页
聚氨酯型固-固相变储能材料可以有效提高沥青的相变储能能力,从而在调节路面温度的同时,减小温度波动。基于上述背景,针对聚氨酯型固-固相变储能材料对沥青调温效果的影响展开研究。确定相变材料的分类标准,并分别研究其储能原理及具体... 聚氨酯型固-固相变储能材料可以有效提高沥青的相变储能能力,从而在调节路面温度的同时,减小温度波动。基于上述背景,针对聚氨酯型固-固相变储能材料对沥青调温效果的影响展开研究。确定相变材料的分类标准,并分别研究其储能原理及具体应用情况,完成对聚氨酯型固-固相变储能材料特性的分析。在此基础上,定义周期性储热边界条件,根据沥青调温过程中内聚能密度的变化形式,推导相变储能材料的能量变化规律,从而确定聚氨酯型固-固相变储能材料对沥青调温效果的影响能力。 展开更多
关键词 聚氨酯 固-固相变储能材料 沥青调温效果 储热边界条件 内聚能密度 能量变化
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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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闽东方言变韵的机制与方向
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作者 袁碧霞 王非凡 《语言科学》 北大核心 2024年第3期301-317,共17页
从闽东方言的闽清县坂东镇新近出现的变韵现象出发,通过声学分析发现,变韵在不同声调条件下有不同的时长结构。闽东南北两片代表性方言(福州、连江、宁德、周宁)松紧复合韵母的声学分析显示,声调对元音时长的影响在先,继而元音时长的改... 从闽东方言的闽清县坂东镇新近出现的变韵现象出发,通过声学分析发现,变韵在不同声调条件下有不同的时长结构。闽东南北两片代表性方言(福州、连江、宁德、周宁)松紧复合韵母的声学分析显示,声调对元音时长的影响在先,继而元音时长的改变诱发其响度增减。因此,也可以说,声调影响元音时长,元音时长与相对响度相关,三者共同构成闽东方言变韵的机制。最后,结合闽东方言韵母的共时特点和历史演变,可以将变韵的基本规律归纳为首成分扩张与尾成分扩张两大类型,各韵母依声调环境而沿不同的方向演变。 展开更多
关键词 闽东方言 变韵 机制
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