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Research progress on the water vapor channel within the Yarlung Zsangbo Grand Canyon, China 被引量:1
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作者 Xuelong Chen yajing liu +9 位作者 Yaoming Ma Xiangde Xu Xin Xu Luhan Li Dianbin Cao Qiang Zhang Gaili Wang Maoshan Li Siqiong Luo Xin Wang 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第5期10-15,共6页
The Second Tibetan Plateau Scientific Expedition and Research Program tasked a research team with the“Investigation of the water vapor channel of the Yarlung Zsangbo Grand Canyon(INVC)”in the southeastern Tibetan Pl... The Second Tibetan Plateau Scientific Expedition and Research Program tasked a research team with the“Investigation of the water vapor channel of the Yarlung Zsangbo Grand Canyon(INVC)”in the southeastern Tibetan Plateau(TP).This paper summarizes the scientific achievements obtained from the data collected by the INVC observation network and highlights the progress in investigating the development of heavy rainfall events associated with water vapor changes.The rain gauge network of the INVC can represent the impacts of the Yarlung Zsangbo Grand Canyon(YGC)topography on precipitation at the hourly scale.The microphysical characteristics of the precipitation in the YGC are different than those in the lowland area.The GPM-IMERG(Integrated MultisatellitE Retrievals for Global Precipitation Measurement)satellite precipitation data for the YGC region should be calibrated before they are used.The meridional water vapor flux through the YGC is more important than the zonal flux for the precipitation over the southeastern TP.The decreased precipitation around the YGC region is partly due to the decreased meridional water vapor flux passing through the YGC.High-resolution numerical models can benefit precipitation forecasting in this region by using a combination of specific schemes that capture the valley wind and water vapor flux along the valley floor. 展开更多
关键词 Water vapor channel Land-air interaction Mountian meteorology Extreme rainfall Observation network
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TP-PROFILE: Monitoring the Thermodynamic Structure of the Troposphere over the Third Pole
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作者 Xuelong CHEN yajing liu +6 位作者 Yaoming MA Weiqiang MA Xiangde XU Xinghong CHENG Luhan LI Xin XU Binbin WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第6期1264-1277,共14页
Ground-based microwave radiometers(MWRs)operating in the K-and V-bands(20–60 GHz)can help us obtain temperature and humidity profiles in the troposphere.Aside from some soundings from local meteorological observatori... Ground-based microwave radiometers(MWRs)operating in the K-and V-bands(20–60 GHz)can help us obtain temperature and humidity profiles in the troposphere.Aside from some soundings from local meteorological observatories,the tropospheric atmosphere over the Tibetan Plateau(TP)has never been continuously observed.As part of the Chinese Second Tibetan Plateau Scientific Expedition and Research Program(STEP),the Tibetan Plateau Atmospheric Profile(TPPROFILE)project aims to construct a comprehensive MWR troposphere observation network to study the synoptic processes and environmental changes on the TP.This initiative has collected three years of data from the MWR network.This paper introduces the data information,the data quality,and data downloading.Some applications of the data obtained from these MWRs were also demonstrated.Our comparisons of MWR against the nearest radiosonde observation demonstrate that the TP-PROFILE MWR system is adequate for monitoring the thermal and moisture variability of the troposphere over the TP.The continuous temperature and moisture profiles derived from the MWR data provide a unique perspective on the evolution of the thermodynamic structure associated with the heating of the TP.The TP-PROFILE project reveals that the low-temporal resolution instruments are prone to large uncertainties in their vapor estimation in the mountain valleys on the TP. 展开更多
关键词 microwave radiometer thermodynamic structure vertical profile Tibetan Plateau
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Comparative Transcriptomic Analysis of Two Tomato Cultivars with Different Shelf-Life Traits
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作者 Abdul Karim Amin Yan He +8 位作者 Xianglong Wang Pengwei Li Muhammad Ahmad Hassan Mohammad Yousof Soltani Yiling Zhang Mohammad Alem Amin Ahmad Shah Ahmadzai yajing liu Songhu Wang 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第8期2075-2093,共19页
Tomato(Solanum lycopersicum)is a perishable fruit because of its fast water loss and susceptibility to pathogens in the post-harvest stage,which leads to huge economic losses every year.In this study,firstly from 19 t... Tomato(Solanum lycopersicum)is a perishable fruit because of its fast water loss and susceptibility to pathogens in the post-harvest stage,which leads to huge economic losses every year.In this study,firstly from 19 tomato cultivars,we screened out two cultivars,Riogrand and SalarF1,having long and short shelf-life spans,respectively.Secondly,shelf-life analysis was carried out for both cultivars at room temperature.Results exhibited that Riogrand showed higher firmness and less weight loss than SalarF1.The ethylene production was higher in SalarF1,compared with Riogrand during post-harvest storages.We performed transcriptomic analysis of both cultivars in different storage stages.We discovered 2913,2188,and 11,119 differentially expressed genes(DEGs)for three post-harvest stages(0,20,and 40 Days Post-Harvest(DPH)),respectively.These genes are enriched in ethylene biosynthesis and response,as well as cell wall-related genes.Ethylene response factor(ERF)ERF2 and ERF4 were highly expressed in SalarF1 with a short shelf life in 40 DPH,and the ethylene biosynthetic genes ACO1,ACO4,ACS6,and ACS2 were significantly upregulated in SalarF1.Regarding cell wall loosening and cell wall-related genes XTH3,XTH7,XTH23,1,3;1,4-β-D-Gluc-like,pGlcT1,Cellulase,PGH1,PL5,PL-like 1,PL-like 2 exhibited the highest levels of significance,being notably upregulated in the last stage of SalarF1.The quantitative real-time polymerase chain reaction(qRT-PCR)analysis validated these gene expressions,which is in line with the transcriptome analysis.The findings suggested that the extension of tomato fruit shelf life is mostly dependent on ethylene biosynthesis,signaling pathway genes,cell wall loosening,and cell wall-associated genes. 展开更多
关键词 Shelf life transcriptome analysis TOMATO differentially expressed genes(DEGs) ETHYLENE
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Understanding the alkyl effect of geminal dinitropropyl ester energetic plasticizers on hydroxyl terminated polybutadiene(HTPB):Simultaneous tuning on low temperature behavior and processability 被引量:2
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作者 Baodong Zhao Yinglei Wang +3 位作者 Fulei Gao yajing liu Weixiao liu Feng Ding 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第2期364-371,共8页
Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane ... Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane chain parts, and systematically investigate their structure-property relationships.Results show that DNPEPs have impact sensitivities all higher than 25.2 J, thermal decomposition temperatures all higher than 254 ℃, and glass transition temperatures(T_(g)) lower than-90 ℃.Furthermore, the effects of DNPEPs as plasticizer are studied on hydroxyl terminated polybutadiene(HTPB) in detail, including the viscosity, glass transition temperatures and others. It is noteworthy that 2,2-dinitropropyl nonanoate(DNPNc) among these DNPEPs exhibits the most expected simultaneous tuning effects on both viscosity and T_(g) of HTPB systems, providing favorable potentials to replace the conventional plastizers as dioctyl sebacate(DOS) in the HTPB based propellants and explosives. 展开更多
关键词 Molecular simulation Experimental validation Preparation Energetic plasticizer Glass transition temperature Viscosity
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Preface to the special collection of Induced Earthquakes 被引量:3
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作者 HongFeng Yang XiaoWei Chen +1 位作者 Rebecca Harrington yajing liu 《Earth and Planetary Physics》 CSCD 2021年第6期483-484,共2页
It has been long recognized that a variety of anthropogenic activities may cause earthquakes(Ellsworth et al.,2013;Yang HF et al.,2017).In the recent decades,induced earthquakes have been found in many settings and be... It has been long recognized that a variety of anthropogenic activities may cause earthquakes(Ellsworth et al.,2013;Yang HF et al.,2017).In the recent decades,induced earthquakes have been found in many settings and become a growing concern,in particular for regions that are undergoing with resource development. 展开更多
关键词 SETTING EARTHQUAKE EARTHQUAKES
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西加拿大沉积盆地中的水力压裂和地震活动 被引量:1
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作者 Gail M.Atkinso David W.Eaton +11 位作者 Hadi Ghofrani Dan Walker Burns Cheadle Ryan Schultz Robert Shcherbakov Kristy Tiampo Jeff Gu Rebecca M.Harrington yajing liu Mirko van der Baan Honn Kao 张汨 《国际地震动态》 2018年第10期2-19,共18页
绝大多数非常规油气资源的开发有赖于向地下注入大量的液体,这可能使附近断层活动从而诱发地震。在过去5年里,加速的油田注水已经导致北美部分地区的地震频率急剧增加。在美国中部,大多数诱发地震起因于与油气开采相伴生的废水的排放。... 绝大多数非常规油气资源的开发有赖于向地下注入大量的液体,这可能使附近断层活动从而诱发地震。在过去5年里,加速的油田注水已经导致北美部分地区的地震频率急剧增加。在美国中部,大多数诱发地震起因于与油气开采相伴生的废水的排放。形成对比的是,在加拿大西部,大多数最近的诱发地震在时间和空间上与水力压裂高度相关,在水力压裂过程中,为诱发局部岩石破裂,在钻井结束的过程中,高压液体被注入。并且,与水力压裂相关的观测到的最大地震震级似乎超越了预测的、经常引用的注入液体体积与最大期望震级之间的关系。这些发现对评估诱发地震危害具有深远的意义。 展开更多
关键词 西加拿大沉积盆地 水力压裂 地震活动 最大地震震级 非常规油气资源 诱发地震 高压液体 断层活动
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大跨径拱桥劲性骨架施工定额编制方法研究 被引量:1
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作者 田膨溢 李小静 +2 位作者 刘亚静 李继朋 王振芝 《青海交通科技》 2019年第6期95-100,共6页
鉴于当前大跨径拱桥劲性骨架施工应用广泛,以及对劲性骨架施工定额编制的紧迫性,本文以缆索吊“斜拉扣挂+分环分段”法施工为基础,构建了基于AHP-模糊数学的施工定额编制模型。首先研究列举影响施工定额评价指标,然后选择与研究定额相关... 鉴于当前大跨径拱桥劲性骨架施工应用广泛,以及对劲性骨架施工定额编制的紧迫性,本文以缆索吊“斜拉扣挂+分环分段”法施工为基础,构建了基于AHP-模糊数学的施工定额编制模型。首先研究列举影响施工定额评价指标,然后选择与研究定额相关的5个已完建项目作为测定对象,并由AHP法确定评价指标权重,然后专家对测定对象评价指标打分,同时引入隶属度函数“梯形分布”确定隶属度,最后计算大跨径拱桥劲性骨架施工额定综合代表值。实例验证结果表明该模型具有可操作性和合理性。 展开更多
关键词 施工定额 劲性骨架 隶属度 AHP-模糊数学 大跨径拱桥
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Information service platform for science and technology innovation and entrepreneurship: New information service practice in the NSLC 被引量:1
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作者 Ping JIA yajing liu +4 位作者 Xiwen liu Yu DENG Yue YOU Su WANG Xiaohua PENG 《Chinese Journal of Library and Information Science》 2015年第3期22-37,共16页
Purpose: This study explores new content, forms, and fields of science and technology(S&T;) innovation and entrepreneurship information services of the National Science Library of the Chinese Academy of Sciences(N... Purpose: This study explores new content, forms, and fields of science and technology(S&T;) innovation and entrepreneurship information services of the National Science Library of the Chinese Academy of Sciences(NSLC).Design/methodology/approach: We cooperated with incubator enterprises and set up an "S&T; Innovation and Entrepreneurship Information Service Platform." We designed five series of activities, including industrial information release, project financing and roadshows, entrepreneurial sharing, entrepreneurial coaching sessions, and entrepreneurial salons. Based on the implementation of these activities, we designed new NSLC library services for S&T; innovation and entrepreneurship.Findings: Since the construction of the platform, these five series of activities have attracted more than 80 business projects, 90 investors, and 30 researchers. Furthermore, more than 20 media representatives and nearly 300 entrepreneurs have participated in the activities that the NSLC has organized in the past two years. Through these activities, we have defined an S&T; innovation and entrepreneurship knowledge service model for the NSLC.Research limitations: The service practice of the NSLC is still in the demonstration phase. Due to staffing limitations of our service teams, the expansion of our service activities has been greatly restricted.Practical implications: The innovation and entrepreneurship information services of the NSLC provide a lot of material for transformation of library services for domestic and foreign special libraries.Originality/value: It is useful to transform library and business services by embedding them into ways in which we serve innovation and entrepreneurial activities. This opens up a new field of library knowledge services in China. 展开更多
关键词 Makerspace Hackerspace Entrepreneurial service SCI
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A new approach to assessing the science and technology competitiveness of China's provincial academies of sciences
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作者 Huifang XU Shushu CHEN +2 位作者 yajing liu Ling LENG Wenjiao GUO 《Chinese Journal of Library and Information Science》 2015年第4期18-31,共14页
Purpose: This study aims to establish a new framework for evaluating science and technology (S&T) competitiveness that is appropriate to meet the needs of provincial academies of sciences (PASs) in China.Design/... Purpose: This study aims to establish a new framework for evaluating science and technology (S&T) competitiveness that is appropriate to meet the needs of provincial academies of sciences (PASs) in China.Design/methodology/approaches: An evaluation index, including such assessing indicators as research strength, research impact, research development and trends, and regional contributions, is developed for China's PASs. Taking the Jiangxi Academy of Sciences (JXAS) as an example, we first explain how to apply this framework to analyze the strengths and weaknesses of PASs in China. Then, we compare the results of all 17 PASs in order to get a comprehensive understanding of their competitiveness.Findings: Our results show the development path, current status, innovation advantages, and weaknesses of JXAS very clearly. Based on our comparative analysis, we ranked the 17 PASs from the perspective of different dimensions, by which their competitiveness strengths and weaknesses can be highlighted for improvement.Research limitations: In this analysis, we did not take S&T policies, S&T systems, or historical factors into consideration. Thus, we may have ignored the influence of the soft individual differences of different PASs in China..Practical implications: The evaluation index developed in this paper provides a useful insight into an analytical method that can be used by PASs or other provincial research institutions (PRIs) to assess their competitiveness.Originality/value: Compared with existing evaluation frameworks, our method has two main characteristics: First, we added three new dimensions, including the PASs' applicable research outputs, regional contributions, and comparative advantages; second, we conducted a comparative analysis of local research institutes in their different advantaged industrial areas, which makes our analytical method more comprehensive for local research institutions. 展开更多
关键词 Science and technology (S&T) competitiveness Provincial academy ofsciences (PASs) Research strength Research impact Competitiveness evaluation
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To design and construct an embedded knowledge integration service platform:Taking ISCAS subject group platform as an example
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作者 yajing liu Jinhui ZHOU +1 位作者 Yanxi WANG Dan HAO 《Chinese Journal of Library and Information Science》 2014年第1期1-15,共15页
Purpose:As scientific resources are widely distributed,researchers often have difficulties in acquiring information from different individual sources.This paper intends to present a new approach to construct a subject... Purpose:As scientific resources are widely distributed,researchers often have difficulties in acquiring information from different individual sources.This paper intends to present a new approach to construct a subject-knowledge-based integration platform which was carried out by the Institute of Software,Chinese Academy of Sciences(ISCAS).Our aim is to use technique tools to strengthen the library service by combining a variety of information service resources with knowledge tools.Design/methodology/approach:Based on the analysis of users’ needs,we established a collaborative team across ISCAS Library,National Science Library of CAS(NSL CAS),and ISCAS’ research groups or research labs.With the service tools developed by ISCAS Library,we embedded other multipurpose utility tools of knowledge integration into the platform as to make full use of software tools in knowledge integration,knowledge fusion,and intelligent push of library services to end users.Findings:With a hard effort of the construction team,the ISCAS subject group platform(hereinafter as ISCAS Platform) has integrated such information resources as institutional repository(IR) of ISCAS,open resources from websites and subject resources of computer sciences.Up to date,ISCAS platform can provide integrated information services including data collection for computer science and intelligent generation of citation reports,by means of embedding self-developed discovering tools for domain experts and subject content,and generation tools for scientific citation reports.Research limitations:Knowledge organization need be further improved in the ISCAS subject group platform.In addition,functions for academic exchanges need be maximized as to meet the individual demands of researchers for library services at the Platform.Practical implications:Since we Platform has been put into use through the Library website of the ISCAS in June 2012,many academic libraries from both domestic universities and CAS institutes have showed their strong interest for our self-developed tools,among which more than 10 cooperation partnerships have been formed.Originality/value:Through self-developed service tools and the integration of multiple-type resources,our Platform has solved such key problems as timely access and update of the trusted resources from a third party,and the rapid fusion and extension of library resources while establishing subject knowledge environment.So the ISCAS library can provide a flexible customization of library services according to the need of different users. 展开更多
关键词 Subject group platform Knowledge integration Embedded service Supporting tools Automatic push
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Critical state uniqueness of dense granular materials using discrete element method in conjunction with flexible membrane boundary
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作者 Chenglong Jiang yajing liu +2 位作者 Lingling Zeng Chengshun Xu Peng Cao 《Particuology》 SCIE EI CAS CSCD 2024年第12期124-144,共21页
An explanation of the meso-mechanism of sand granular materials for the uniqueness of critical state is presented by means of the discrete element method(DEM)under flexible boundary loading conditions.A series triaxia... An explanation of the meso-mechanism of sand granular materials for the uniqueness of critical state is presented by means of the discrete element method(DEM)under flexible boundary loading conditions.A series triaxial drainage shear test(DEM simulations),in conjunction with the flexible boundary technique,of were performed for sand samples subjected to various physical states and with different particle size distributions.After carefully investigating the critical status of the results of the numerical calculation,the macroscopic failure modes and shear band evolution of sand,as well as the velocity vector field due to different initial states,were explored and classified.Furthermore,the evaluation rules and discrepancies between overall void ratios of the specimen and local void ratios within the shear band under the critical state were recorded and analyzed.The results proved that a sample with a small void tends to form a shear band,and the rotation of the particles in the non-shear zone is negligible.Conversely,sandy soil with large initial void ratios exhibited limited development of significant shear bands,and the change in void ratios within the shear region and the non-shear area are not significant.Interestingly,the particle-size distribution exerts minimal influence on the evolution rule which the void ratio converges within the shear band and diverges outside the shear region for both multi-stage and single-stage specimens.The void ratio within the shear band and deviator stress ratio tend to exhibit consistently for the same specimen with different initial physical states,thereby distinguishing the critical state.There is a significantly higher change in void ratio within the shear band compared to outside of it,yet it remains stable within a relatively similar range.Additionally,the invariant of the fabric tensor used to describe the critical state characteristics also demonstrates a high degree of consistency within the shear band.These findings strongly indicate that the critical state exists within the shear failure surfaceand is highly likely to beunique. 展开更多
关键词 Critical state Flexible membrane boundary Evolution of the void ratio Shear band Fabric tensor
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多声学技术参数联合血清学指标对非酒精性脂肪性肝病肝脂肪变性阶段的诊断价值
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作者 赵亚楠 方明 +5 位作者 徐绍岩 魏树梅 张慧 黄奕宁 刘亚静 黄品同 《中华医学超声杂志(电子版)》 CSCD 北大核心 2023年第11期1164-1173,共10页
目的探讨多声学技术参数对非酒精性脂肪性肝病(NAFLD)脂肪变性阶段的诊断效能,并进一步探讨声学技术参数联合血清学参数是否能提高其诊断效能。方法从2020年6月至2021年12月前瞻性连续入组在浙江大学医学院附属第二医院就诊的临床可疑NA... 目的探讨多声学技术参数对非酒精性脂肪性肝病(NAFLD)脂肪变性阶段的诊断效能,并进一步探讨声学技术参数联合血清学参数是否能提高其诊断效能。方法从2020年6月至2021年12月前瞻性连续入组在浙江大学医学院附属第二医院就诊的临床可疑NAFLD并行肝穿刺活检的病例。所有病例穿刺前均经过衰减成像(ATI)、归一化局部方差(NLV)、肝肾强度对比(Ratio)值等肝多声学技术参数检查,同时收集患者临床背景数据和血清学数据。以病理结果为金标准,采用Spearman秩相关分析评估多声学技术参数和临床参数与肝脂肪变性之间的相关性,绘制受试者操作特征曲线评价多声学技术参数对肝脂肪变性的诊断效能,并探索最佳声学技术参数与血清学参数联合是否能提高NAFLD肝脂肪变性的诊断效能。结果本研究共纳入病例75例,其中肝脂肪变性分级S0、S1、S2、S3级分别为15、41、13、6例。肝脂肪变性分级与声学技术参数衰减系数(AC)值、Ratio值呈显著正相关(相关系数r=0.519、0.285,P<0.001、=0.016),与声学技术参数NLV、NLV的标准差(NLV-SD)呈显著负相关(r=-0.391、-0.356,P=0.001、0.002)。当AC值<0.62 dB/(cm·MHz)或谷草转氨酶(AST)<18 IU/L时,ATI和AST并联诊断肝脂肪变性≥S1级的曲线下面积(AUC)为0.864(95%CI:0.765~0.933),其敏感度和特异度分别为91.5%、80.0%;当AC>0.75 dB/(cm·MHz)且AST>25 IU/L时,ATI和AST串联诊断肝脂肪变性≥S2级的AUC为0.761(95%CI:0.645~0.854),其敏感度和特异度分别为55.6%、92.5%。结论在NAFLD患者中,声学技术参数AC、NLV、NLV-SD、Ratio值均在诊断肝脂肪变性分级中具有一定的价值。将AC值和血清学指标AST并联诊断可以进一步提高肝脂肪变性≥S1级的诊断效能,而AC值和AST串联诊断可以进一步提高肝脂肪变性≥S2级的诊断效能。 展开更多
关键词 非酒精性脂肪性肝病 衰减成像 归一化局部方差 肝肾强度比 肝脂肪变性 诊断效能
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火药用叠氮含能增塑剂 被引量:10
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作者 赵宝东 高福磊 +3 位作者 汪营磊 刘亚静 陈斌 潘永飞 《化学进展》 SCIE CAS CSCD 北大核心 2019年第2期475-490,共16页
叠氮增塑剂具有较好热稳定性、较低玻璃化转变温度、钝感及与黏合剂物理化学相容性好等特点,在低易损性、低特征信号推进剂和发射药中有着广阔的应用前景。本文从叠氮增塑剂的合成、表征、性能及应用等方面对近年来取得的研究进展进行... 叠氮增塑剂具有较好热稳定性、较低玻璃化转变温度、钝感及与黏合剂物理化学相容性好等特点,在低易损性、低特征信号推进剂和发射药中有着广阔的应用前景。本文从叠氮增塑剂的合成、表征、性能及应用等方面对近年来取得的研究进展进行了综述,梳理了叠氮增塑剂研究中存在的问题,指出了今后叠氮增塑剂在结构设计、合成、制备工艺、表征及应用等方面的几个潜在发展方向,以期为含能材料合成、配方应用及性能表征等相关的研究者提供参考。 展开更多
关键词 含能材料 叠氮增塑剂 热稳定性 玻璃化转变温度 相容性
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植物群落稀有种维持机制与土壤反馈的研究进展 被引量:7
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作者 戴冬 邢华 +3 位作者 杨佳绒 刘雅静 蔡焕满 刘宇 《生物多样性》 CAS CSCD 北大核心 2021年第12期1687-1699,共13页
自Janzen-Connell(J-C)假说提出后半个世纪以来,生态学家在热带及亚热带森林对该假说开展的大量实证研究表明,由专性天敌导致的J-C效应所引起的负密度制约是维持森林多样性和决定群落组成的重要驱动力,该假说成功地解释了热带及亚热带... 自Janzen-Connell(J-C)假说提出后半个世纪以来,生态学家在热带及亚热带森林对该假说开展的大量实证研究表明,由专性天敌导致的J-C效应所引起的负密度制约是维持森林多样性和决定群落组成的重要驱动力,该假说成功地解释了热带及亚热带森林的丰富多样性。土壤病原真菌所引起的植物–土壤负反馈是J-C效应最主要的表现形式。然而,对于植物–土壤负反馈是否能够维持森林群落中的大量稀有种仍然存在许多争议。基于当代物种共存理论的"稀有种优势"假说认为,只有在满足"可入侵准则"(即物种在稀有时具有种群增加的趋势)的前提下,稀有种才能在群落中与其他物种长期共存。然而,当前基于土壤反馈的实验结果与该理论预测相悖,因此在稀有种的维持机制方面仍存在较大的分歧。本文通过介绍植物–土壤反馈理论,整合了可能对稀有种维持有较大影响的因素,包括共生菌根真菌、土壤养分以及植物细根性状等在影响土壤负反馈方面的相关研究,并对这些因素如何影响群落中物种多度和稀有种在群落中的维持进行了探讨。最后,我们也从其他角度探讨了一些对稀有种维持的研究。我们认为在未来对稀有种的研究中,探讨使其长期存续的"优势"和制约其种群扩大的"限制"同等重要,将当代物种共存理论与新技术、新方法相结合对于探究稀有种的维持机制具有重要的意义,可为稀有种保护提供理论依据。 展开更多
关键词 同种负密度制约 森林群落 入侵准则 Janzen-Connell假说 植物–土壤反馈 稀有种 物种多度
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Progressive loss of striatal dopamine terminals in MPTP-induced acute parkinsonism in cynomolgus monkeys using vesicular monoamine transporter type 2 PET imaging([^(18)F]AV-133) 被引量:6
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作者 yajing liu Feng Yue +5 位作者 Rongping Tang Guoxian Tao Xiaomei Pan Lin Zhu Hank F.Kung Piu Chan 《Neuroscience Bulletin》 SCIE CAS CSCD 2014年第3期409-416,共8页
The 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine (MPTP)-induced parkinsonism model, particularly in non-human primates, remains the gold-standard for studying the pathogenesis and assessing novel therapies for Parki... The 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine (MPTP)-induced parkinsonism model, particularly in non-human primates, remains the gold-standard for studying the pathogenesis and assessing novel therapies for Parkinson's disease. However, whether the loss of dopaminergic neurons in this model is progressive remains controversial, mostly due to the lack of objective in vivo assessment of changes in the integrity of these neurons. In the present study, parkinsonism was induced in cynomolgus monkeys by intravenous administration of MPTP (0.2 mg/kg) for 15 days; stable parkinsonism developed over 90 days, when the symptoms were stable. Noninvasive positron emission tomographic neuroimaging of vesicular monoamine transporter 2 with 9-[18F] fluoropropyl-(+)-dihydrotetrabenazine ([18F]AV-133) was used before, and 15 and 90 days after the beginning of acute MPTP treatment. The imaging showed evident progressive loss of striatal uptake of [18SF]AV-133. The dopaminergic denervation severity had a significant linear correlation with the clinical rating scores and the bradykinesia subscores. These findings demonstrated that [18F]AV-133 PET imaging is a useful tool to noninvasively evaluate the evolution of monoaminergic terminal loss in a monkey model of MPTP-induced parkinsonism. 展开更多
关键词 Parkinson's disease non-human primate [18F]AV-133 VMAT2 positron emission tomography
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Healthy campus by open space design: Approaches and guidelines 被引量:4
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作者 Stephen Siu Yu Lau Zhonshua Gou yajing liu 《Frontiers of Architectural Research》 CSCD 2014年第4期452-467,共16页
This paper examines the architectural and Landscape design strategies and intentions for green, open spaces facilities targeting stress aLLeviation for learning environments such as those of university campuses in a c... This paper examines the architectural and Landscape design strategies and intentions for green, open spaces facilities targeting stress aLLeviation for learning environments such as those of university campuses in a compact urban setting. Literature reviews provide three prevailing perspectives for physical design pedagogical operatives: healing gardens where greenery and plants produce restorative effects; flexible spaces that accommodate functional needs of different activities; and green buildings that incorporate open space as a catalyst for integrated eco-system. Corresponding design approaches (Landscape design, spatial design and green design) are scrutinized by case study. A comparison of two university campuses with different urban contexts is conducted to identify challenges and opportunities for applying these design approaches. For a compact campus, high-dense surroundings may limit the size of an open space and may handicap circulation and accessibility; on the other side, a small open space may provide its users more intimate contact with natural restorative elements and also a more controllable microclimate for physical comfort. A healthy campus should encompass diverse open spaces to satisfy different purposes. Finally, a framework that integrates the three approaches is combined to produce a sustainable design rubric. 展开更多
关键词 Healthy campus Open space Healing gardens ARCHITECTURE Green building
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Generation of isogenic single and multiplex gene knockout mice by base editing-induced STOP 被引量:3
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作者 Guang Yang Tianyu Zhu +9 位作者 Zongyang Lu Guanglei Li Hao Zhang Songjie Feng yajing liu Jianan Li Yu Zhang Jia Chen Xuejiang Guo Xingxu Huang 《Science Bulletin》 SCIE EI CSCD 2018年第17期1101-1107,共7页
Although CRISPR/Cas9 has been widely used to generate knockout mice, two major limitations remain:the founders usually carry a mixture of genotypes, and mosaicism harboring multiple genotypes.Therefore, it takes a lon... Although CRISPR/Cas9 has been widely used to generate knockout mice, two major limitations remain:the founders usually carry a mixture of genotypes, and mosaicism harboring multiple genotypes.Therefore, it takes a long time to get homozygous mutants. Recently developed base editing(BE) system,which introduces C-to-T conversion without double strand DNA cleavage, has been used to introduce artificial stop codons(i-STOP) to prematurely terminate translation, providing a cleaner strategy for genome engineering. Using this strategy, we generated CD160 KO and VISTA/CD160 double KO mice by microinjection of a single sg RNA targeting CD160 and a mixture of sg RNAs targeting VISTA and CD160,respectively. The BE system induced STOP efficiently in mouse embryos and consequently in founder mice without detectable off-target. Most interestingly, the majority of the mutants harbor same genetic modifications, indicating we generated isogenic single and multiplex gene mutant mice by BE-induced STOP. We also obtained homozygous mutant mouse in F1 mice, demonstrating the accelerated strategy in generating animal models. 展开更多
关键词 Base editing i-STOP isogenic KNOCKOUT VISTA CDI60
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Photocaged prodrug under NIR light-triggering with dual-channel fluorescence: in vivo real-time tracking for precise drug delivery 被引量:3
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作者 Zhiqian Guo Yaguang Ma +4 位作者 yajing liu Chenxu Yan Ping Shi He Tian Wei-Hong Zhu 《Science China Chemistry》 SCIE EI CAS CSCD 2018年第10期1293-1300,共8页
Light-triggered drug delivery system is an effective strategy for precise diagnosis and therapy in cancer treatment. However, it suffers from difficultly balancing the dosimetry of drug with light dose and a lack of i... Light-triggered drug delivery system is an effective strategy for precise diagnosis and therapy in cancer treatment. However, it suffers from difficultly balancing the dosimetry of drug with light dose and a lack of in vivo models for validating their clinical benefits. Here we report an unprecedented near-infrared(NIR) light photocaged cyanine-based prodrug Cy-CPT-Biotin with dual-channel fluorescence mode, enabling NIR light to precisely regulate where, when and how the intact and active prodrugs are delivered. The synergy of photochemical reaction and modulation in π-conjugated polyene backbone of cyanine can fully perform distinct dual-channel fluorescence changes in a NIR light-mediated manner. The prodrug has striking characteristics of excellent tumor-targeting ability, real-time monitoring of the in vivo behaviors by dual-channel mode and NIR-light triggering,especially for achieving fine regulation and on-demand drug release in the precise dosimetry of drug with light dose in living animals. This optical orthogonality strategy that conjuncts with NIR light-triggered and dual-channel fluorescence in vivo imaging provides a powerful tool for in vivo real-time tracking and finely tuning the prodrug release for precise drug delivery. 展开更多
关键词 near-infrared cyaninc dye dual-channel fluorescence DRUG-RELEASE photocage tumor targeting
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Defect-related luminescent bur-like hydroxyapatite microspheres induced apoptosis of MC3T3-E1 cells by lysosomal and mitochondrial pathways 被引量:2
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作者 Yi Jin Shizhu Chen +5 位作者 Nan Li yajing liu Gong Cheng Cuimiao Zhang Shuxiang Wang Jinchao Zhang 《Science China(Life Sciences)》 SCIE CAS CSCD 2018年第4期464-475,共12页
When orthopedic joints coated by hydroxyapatite(HA) were implanted in the human body, they release wear debris into the surrounding tissues. The generation and accumulation of wear particles will induce aseptic loosen... When orthopedic joints coated by hydroxyapatite(HA) were implanted in the human body, they release wear debris into the surrounding tissues. The generation and accumulation of wear particles will induce aseptic loosening. However, the potential bioeffect and mechanism of HA-coated orthopedic implants on bone cells are poorly understood. In this study, defect-related luminescent bur-like hydroxyapatite(BHA) microspheres with the average diameter of 7–9 μm which are comparable to that of the wear-debris particles from aseptically loosened HA implants or HA debris have been synthesized by hydrothermal synthesis and the MC3 T3-E1 cells were set as a cells model to study the potential bioeffect and mechanism of BHA microspheres. The studies demonstrated that BHA microspheres could be taken into MC3 T3-E1 cells via endocytosis involved in micropinocytosisand clathrin-mediated endocytosis process, and exert cytotoxicity effect. BHA microspheres could induce the cell apoptosis by intracellular production of reactive oxygen species(ROS), which led to not only an increase in the permeability of lysosome and release of cathepsins B, but also mitochondrial dysfunction and DNA damage. Our results provide novel evidence to elucidate their toxicity mechanisms and might be helpful for more reasonable applications of HA-based orthopaedic implants in the future. 展开更多
关键词 defect-related luminescence hydroxyapatite microspheres OSTEOBLASTS apoptosis
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Indiscriminate ssDNA cleavage activity of CRISPR-Cas12a induces no detectable off-target effects in mouse embryos 被引量:2
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作者 Yu Wei Yingsi Zhou +8 位作者 yajing liu Wenqin Ying Ruiming Lv Qimeng Zhao Haibo Zhou Erwei Zuo Yidi Sun Hui Yang Changyang Zhou 《Protein & Cell》 SCIE CSCD 2021年第9期741-745,共5页
Dear Editor,Newly discovered characteristics like"collateral effect"or trans-cleavage in CRISPR-Cas13 and CRISPR-Cas12 systems have enabled their usage in nucleic acid detection(Gootenberg et al.2017,2018;Ch... Dear Editor,Newly discovered characteristics like"collateral effect"or trans-cleavage in CRISPR-Cas13 and CRISPR-Cas12 systems have enabled their usage in nucleic acid detection(Gootenberg et al.2017,2018;Chen et al.2018).The collateral RNA cleavage of Cas13a has been reported to be harmful for cell development(Wang et al.2019;Buchman et al.2020).As a representative gene editor of CRISPR-Cas12 system,CRISPR-Cas12a(Cpf1)holds great potential for therapeutic applications in the future(Zetsche et al.2015;Koo et al.2018;Campa et al.2019). 展开更多
关键词 al. CLEAVAGE holds
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