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Variation of soil organic carbon and bulk density during afforestation regulates soil hydraulic properties

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Journal of Mountain Science 2022年第8期19卷 2322-2332页

作者： GU Feng chen xue-jiao SU Zheng-an ZHANG Xin-bao ZHOU Ming-hua Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Sichuan Academy of Environmental Policy and Planning Chengdu 610093China School of Food and Bioengineering Xihua UniversityChengdu 610039China

Grain to Green program on arable land has been conducted for decades in semi-arid regions of North ***,it remains uncertain how afforestation practices affect soil hydraulic properties(SHP).Two afforestation types,***(SL)and woodland(WL),and the adjacent cropland(CL)were investigated to determine afforestation effects on SHP in this *** and undisturbed soil cores were collected in three experimental *** field capacity(FC),wilting point(WP),and available water capacity(AWC)increased in SL compared to the *** saturated water content,however,decreased significantly in both SL and *** and redundancy analysis identified that bulk density(BD)and soil organic carbon(SOC)were the main factors regulating SHP across different land *** saturated water contents in afforestation sites were likely driven by the higher BD,compared to the adjacent ***,WP,and AWC were positively correlated to SOC *** afforestation may not increase the saturated water content of a landscape,our results indicate that it can improve soil water retention and could be an effective practice for soil and water conservation.

关键词： Afforestation Bulk density Field capacity Soil hydraulic properties Soil organic carbon Soil water retention curve

Steam explosion of crop straws improves the characteristics of biochar as a soil amendment

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Journal of Integrative Agriculture 2019年第7期18卷 1486-1495页

作者： chen xue-jiao LIN Qi-mei Muhammad Rizwan ZHAO Xiao-rong LI Gui-tong College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193P.R.China Key Laboratory of Arable Land Conservation (North China) Ministry of Agriculture/Key Laboratory of Plant-Soil InteractionsMinistry of EducationBeijing 100193P.R.China

Five crop straws (wheat, rice, maize, oil-rape, and cotton) were first steam-exploded for 2 min at 210℃, 2.5 MPa and then pyrolyzed at 500℃ for 2 h. Steam explosion (SE) induced 47–95% and 5–16% reduction of hemicellulose and cellulose, respectively, in the crop straws. The biochars derived from SE-treated feedstocks had a lower specific surface area (SSA) and pore volume, compared to those from pristine feedstocks, with one exception that SE enhanced SSA of oil-rape straw biochar by approximately 16 times. After SE, biochars had significant higher anion exchange capacity (AEC) (6.88–11.44 cmol kg–1) and point of zero net charges (PZNC) (pH 3.61–5.32) values. It can thus be speculated that these biochars may have higher potential for anions adsorption. In addition, oil-rape straw might be suitable to SE pretreatment for preparing biochar as a soil amendment and sorbent as well. Further work is required for testing its application in soil.

关键词： crop straws steam explosion biochar characterization

In vitro Selection of DNA Aptamers and Fluorescence-Based Recognition for Rapid Detection Listeria monocytogenes

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Journal of Integrative Agriculture 2014年第5期13卷 1121-1129页

作者： LIU Guo-qing LIAN Ying-qi GAO Chao YU Xiao-feng ZHU Ming ZONG Kai chen xue-jiao YAN Yi School of Biotechnology and Food Engineering Hefei University of Technology Anhui Entry-Exit Inspection and Quarantine Bureau

Aptamers are specific nucleic acid sequences that can bind to a wide range of nucleic acid and non-nucleic acid targets with high affinity and specificity. Nucleic acid aptamers are selected in vitro from single stranded DNA or RNA ligands containing random sequences of up to a few hundred nucleotides. Systematic evolution of ligands by exponential enrichment （SELEX） was used to select and PCR amplify DNA sequences （aptamers） capable of binding to and detecting Listeria monocytogenes, one of the major food-borne pathogens. A simplified affinity separation approach was employed, in which L. monocytogenes in exponential （log） phase of growth was used as the separation target. A fluorescently-labeled aptamer assay scheme was devised for detecting L. monoeytogenes. This report described a novel approach to the detection of L. monocytogenes using DNA aptamers. Aptamers were developed by nine rounds of SELEX. A high affinity aptamer was successfully selected from the initial random DNA pool, and its secondary structure was also investigated. One of aptamers named e01 with the highest affinity was further tested in aptamer-peroxidase and aptamer-fluorescence staining protocols. This study has proved the principle that the whole-cell SELEX could be a promising technique to design aptamer-based molecular probes for dectection of pathogenic microorganisms without tedious isolation and purification of complex markers or targets.

关键词： aptamers systematic evolution of ligands by exponential enrichment (SELEX) Listeria monocytogenes,rapid detection

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一种基于分层的无线传感器网络路由协议

科学技术与工程 2012年第9期20卷 2074-2077页

作者：陈雪娇华南理工大学广州学院广州510800

合理使用节点的有限能量是无线传感器网络的关键技术之一,在LEACH协议及其一般改进协议基础上,提出了一种新的改进算法。该算法通过等间隔分层和层中分簇方式来平衡节点间的能量消耗,选择簇首时综合考虑了节点的能量及到基站的距离,给... 详细信息

合理使用节点的有限能量是无线传感器网络的关键技术之一,在LEACH协议及其一般改进协议基础上,提出了一种新的改进算法。该算法通过等间隔分层和层中分簇方式来平衡节点间的能量消耗,选择簇首时综合考虑了节点的能量及到基站的距离,给出了具体的簇首选举算法,并在簇首的数据发送中引进了单跳和多跳相结合的路由协议。仿真结果表明,新的改进算法相对原有算法有明显改进,极大地延长了网络寿命。

关键词：无线传感器网络 LEACH协议节能分层

基于固体酸HClO4/SBA-15催化的奥硝唑合成

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精细化工 2018年第4期35卷 716-720页

作者：陈灿龚福春夏姣云陈雪娇邹武长沙理工大学化学与生物工程学院

将分子筛SBA-15上负载高氯酸,制备了一种固体酸催化剂（HCl O4/SBA-15）,利用IR对其结构进行了表征。并以HCl O4/SBA-15为催化剂,2-甲基-5-硝基咪唑和环氧氯丙烷为原料合成了奥硝唑,考察了催化用量、反应时间、反应温度、不同溶剂对产... 详细信息

将分子筛SBA-15上负载高氯酸,制备了一种固体酸催化剂（HCl O4/SBA-15）,利用IR对其结构进行了表征。并以HCl O4/SBA-15为催化剂,2-甲基-5-硝基咪唑和环氧氯丙烷为原料合成了奥硝唑,考察了催化用量、反应时间、反应温度、不同溶剂对产物收率的影响。得到优化的反应条件为：催化剂质量分数为60%（以2-甲基-5-硝基咪唑的质量为基准,下同）,异丙醇作溶剂,在0℃下反应8 h,奥硝唑收率达76.3%,纯度（HPLC）为99.8%。采用1HNMR、^13CNMR和MS确认产物结构。该法合成的奥硝唑质量符合药典质量标准。催化剂重复使用3次后,产品收率仍能达到65.8%。

关键词：固体酸催化剂奥硝唑 HClO4/SBA-15 精细化工中间体

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非寿险保险人最优投资与资本市场线

中央财经大学学报 2021年第3期 24-36页

作者：陈雪娇周明中央财经大学保险学院中央财经大学中国精算研究院中国人民大学统计学院中国人民大学应用统计科学研究中心中国人民大学风险管理与精算研究中心

马科维茨投资组合理论是金融投资领域的基本理论依据之一。保险人作为金融市场的重要组成部分,其业务的特殊性没能在该理论中得以体现。本文以最大化非寿险保险人的长期收益率为目标,利用短期非寿险模型研究其最优投资策略,分析保险业... 详细信息

马科维茨投资组合理论是金融投资领域的基本理论依据之一。保险人作为金融市场的重要组成部分,其业务的特殊性没能在该理论中得以体现。本文以最大化非寿险保险人的长期收益率为目标,利用短期非寿险模型研究其最优投资策略,分析保险业务对投资策略的影响,揭示投资人进入保险领域的动机。我们发现,在不考虑利率因素时,保险人最优投资策略依赖于其初始资本的大小。同时,我们借助收益率给出了保险人视角下的资本市场线,揭示了保险业务可以为投资人带来高于金融市场的超额收益。

关键词：对数效用长期收益率资本市场线破产非寿险保险人

2001—2017年三江源区典型草地群落碳源/汇模拟及动态变化分析

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干旱区地理 2020年第6期43卷 1583-1592页

作者：陈雪娇周伟杨晗重庆交通大学建筑与城市规划学院重庆400074

碳源/汇是解释地球大气碳循环过程的重要指标,探究三江源的碳源/汇特征对于理解该地区植被对全球气候变化的响应具有重要意义。三江源以脆弱的草地生态系统为主,且对全球气候变化非常敏感。该地区生态环境极其脆弱,大部分地区条件恶劣... 详细信息

碳源/汇是解释地球大气碳循环过程的重要指标,探究三江源的碳源/汇特征对于理解该地区植被对全球气候变化的响应具有重要意义。三江源以脆弱的草地生态系统为主,且对全球气候变化非常敏感。该地区生态环境极其脆弱,大部分地区条件恶劣导致实测数据稀缺,很难对该地区的碳源/汇时空格局进行完整剖析。因此通过以三江源5种典型草地群落(金露梅、紫花针茅、风毛菊、小蒿草、及青藏薹草群落)为研究对象,基于BIOME-BGC模型,利用地理数据、气象数据和植被生理参数等数据,得出2001—2017年三江源草地群落的净初级生产力(NPP)、净生态系统生产力(NEP)模拟值,并对草地群落NPP、NEP变化特征与气温、降水相关性以及碳利用效率变化等特征进行了综合分析。结果表明:三江源区NPP、NEP在空间格局上,表现为由东南向西北数值逐渐递减趋势;5种典型草地群落多年NPP均呈现逐年增高趋势,其平均值为196.06 g C·m^-2·a^-1。其中,金露梅群落NPP平均值最高为342.00 g C·m^-2·a^-1,青藏薹草群落NPP平均值最低为55.93 g C·m^-2·a^-1;5种草地群落NEP的多年平均值为49.02 g C·m^-2·a^-1,金露梅、紫花针茅及青藏薹草3种植被群落的NEP值呈缓慢的上升趋势,风毛菊和小蒿草群落呈缓慢下降趋势。研究发现三江源草地生态系统具有显著的碳汇作用,且不同群落NPP、NEP对气温和降水的响应程度有所差异,5种群落NPP与气温均呈显著正相关,但NPP、NEP与降水量的相关性较低;5种群落均具有较强固碳潜力,除金露梅外其余植被群落的碳利用率均在0.625以上。

关键词：碳源/汇 NPP NEP BIOME-BGC模型气候因子三江源

基于DEA模型的广东财政支农资金使用效率分析

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广东农业科学 2014年第18期41卷 200-206,222页

作者：邹帆陈雪姣华南农业大学经济管理学院广东广州510642

以广东省为研究对象,研究了广东省财政支农资金的使用效率。运用主成分分析法(PCA)对数据进行处理,取消其变量间的相关性,保证运用DEA模型测算使用效率结果的准确性。应用DEA方法,以VRS模型计算效率值,得到技术效率、纯技术效率和规模... 详细信息

以广东省为研究对象,研究了广东省财政支农资金的使用效率。运用主成分分析法(PCA)对数据进行处理,取消其变量间的相关性,保证运用DEA模型测算使用效率结果的准确性。应用DEA方法,以VRS模型计算效率值,得到技术效率、纯技术效率和规模效率。分析过程主要从两个角度进行:一是对2011年广东省除深圳外的20个城市财政支农资金的使用效率进行横向分析,结果表明广东省大部分城市财政支农效率较低,存在改进的空间。二是对1995年税制改革以来广东全省的财政支农资金使用效率进行纵向分析,结果表明自1995年以来,广东省财政支农资金使用效率总体呈下降趋势,2010年以后有所回升。

关键词：财政支农效率广东数据包络分析主成分分析法

Advances in the Development of Gradient Scaffolds Made of Nano-Micromaterials for Musculoskeletal Tissue Regeneration

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NANO-MICRO LETTERS 2025年第1期17卷 1-46页

作者： Fang, Lei Lin, Xiaoqi Xu, Ruian Liu, Lu Zhang, Yu Tian, Feng Li, jiao jiao xue, Jiajia Beijing Univ Chem Technol Beijing Lab Biomed Mat Beijing 100029 Peoples R China Beijing Univ Chem Technol State Key Lab Organ Inorgan Composites Beijing 100029 Peoples R China Univ Technol Sydney Fac Engn & IT Sch Biomed Engn Sydney NSW 2007 Australia

This review highlights the gradient variations in the structural composition of musculoskeletal tissues and comprehensively examines recent progress in the fabrication and application of biomimetic gradient scaffolds for musculoskeletal *** challenges and prospects of gradient scaffolds for clinical application are discussed. The intricate hierarchical structure of musculoskeletal tissues, including bone and interface tissues, necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered substitutes. This has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic outcomes. Building on the anatomical characteristics of bone and interfacial tissues, this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues, specifically focusing on methods used to construct compositional and structural gradients within the scaffolds. The latest applications of gradient scaffolds for the regeneration of bone, osteochondral, and tendon-to-bone interfaces are presented. Furthermore, the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed, as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.

关键词： Gradient scaffolds Musculoskeletal tissues Advanced manufacturing Biomaterials Tissue regeneration