检索结果-南通市图书馆

Biodiversity metrics on ecological networks: Demonstrated with animal gastrointestinal microbiomes

在线全文

学校读者我要写书评

暂无评论

Zoological Research(Diversity and Conservation) 2024年第1期1卷 51-65页

作者： zhanshan(Sam)ma Lianwei Li Computational Biology and Medical Ecology Lab Kunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650201China Center for Excellence in Animal Evolution and Genetics Chinese Academy of SciencesKunmingYunnan650201China

Biodiversity has become a terminology familiar to virtually every citizen in modern *** is said that ecology studies the economy of nature,and economy studies the ecology of humans;then measuring biodiversity should be similar with measuring national ***,there have been many parallels between ecology and economics,actually beyond *** example,arguably the second most widely used biodiversity metric,Simpson(1949)’s diversity index,is a function of familiar Gini-index in *** of the biggest challenges has been the high“diversity”of diversity indexes due to their excessive“speciation”-there are so many indexes,similar to each country’s sovereign currency-leaving confused diversity practitioners in *** 1973,Hill introduced the concept of“numbers equivalent”,which is based on Renyi entropy and originated in economics,but possibly due to his abstruse interpretation of the concept,his message was not widely received by ecologists until nearly four decades *** Hill suggested was similar to link the US dollar to gold at the rate of$35 per ounce under the Bretton Woods *** Hill numbers now are considered most appropriate biodiversity metrics system,unifying Shannon,Simpson and other diversity ***,we approach to another paradigmatic shift-measuring biodiversity on ecological networks-demonstrated with animal gastrointestinal microbiomes representing four major invertebrate classes and all six vertebrate *** network diversity can reveal the diversity of species interactions,which is a necessary step for understanding the spatial and temporal structures and dynamics of biodiversity across environmental gradients.

关键词： Biodiversity on network Hill numbers Animal gut microbiome Network link diversity Network species diversity Network abundance-weighted link diversity

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

灵芝三萜提取工艺的优化

吉林大学学报（理学版） 2024年第2期62卷 452-463页

作者：温舒然马占山詹冬玲吉林农业大学食品科学与工程学院长春130118

以灵芝孢子粉为原料,使用体积分数为70%的乙醇为提取剂,采用酶解与超声辅助提取相结合的方法,将不同液固比、超声时间、酶解时间和酶用量设定为4个因素,进行单因素试验并设计响应面试验,以确定最优提取方式及其影响因素.利用大孔树脂层... 详细信息

以灵芝孢子粉为原料,使用体积分数为70%的乙醇为提取剂,采用酶解与超声辅助提取相结合的方法,将不同液固比、超声时间、酶解时间和酶用量设定为4个因素,进行单因素试验并设计响应面试验,以确定最优提取方式及其影响因素.利用大孔树脂层析法对灵芝三萜进行分离纯化,通过优化分离纯化工艺,确定最佳洗脱树脂、洗脱液体积分数、上样液流速以及上样液质量比.采用高效液相色谱法分析灵芝总三萜的组分差异.通过预实验分析,与单一提取法相比,酶+超声辅助提取更高效.采用乙醇为提取剂提取灵芝中三萜类化合物可提高三萜的纯度.最优条件下可实现对三萜含量的快速、精确测定,为灵芝三萜的分离纯化提供理论依据.

关键词：灵芝三萜提取工艺工艺优化分离纯化

低价氯化钛浆料直接电化学还原制备钛铝合金新工艺研究

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

钢铁钒钛 2024年第1期45卷 4-11,48页

作者：朱福兴马占山邓斌穆天柱邱克辉钒钛资源综合利用国家重点实验室攀钢集团研究院有限公司四川攀枝花617000 成都理工大学材料与化学化工学院四川成都610059 上海大学材料科学与工程学院上海200444

针对低价氯化钛(LTC)浆料熔盐电解制备钛铝合金存在的电化学行为研究不系统、合金产品的高温抗氧化特性不明晰等问题,采用电化学工作站、示差热重分析仪等手段对LTC浆料在熔盐体系中电化学行为及合金产品的高温抗氧化特性进行研究。结... 详细信息

针对低价氯化钛(LTC)浆料熔盐电解制备钛铝合金存在的电化学行为研究不系统、合金产品的高温抗氧化特性不明晰等问题,采用电化学工作站、示差热重分析仪等手段对LTC浆料在熔盐体系中电化学行为及合金产品的高温抗氧化特性进行研究。结果表明,LTC浆料在熔盐体系中可直接电化学还原制备Ti-Al合金,且为逐级还原的历程:Ti^(3+)→Ti^(2+),Al^(3+)→Al,Ti^(3+)/Al^(3+)→Ti-Al合金和Ti^(2+)→Ti;随着熔盐体系中Ti^(3+)离子浓度的增加,钛铝合金的组成变化规律为:Al/Al_(3)Ti→Al_(3)Ti_(2)/Al_(5)Ti_(2)→AlTi/Al_(0.64)Ti_(0.36)→Al_(0.64)Ti_(0.36)/AlTi_(3)→AlTi_(3)→AlTi_(3)/Ti→Ti,产品形貌变化规律为:粗枝晶→细枝晶→细球状结构→粗球状团聚体→细球状团聚体→细球多孔状→多孔状结构。钛铝合金中随着铝含量和产品致密性的增加,合金的抗高温氧化性能逐渐增强,Al_(0.64)Ti_(0.36)/AlTi_(3)合金经高温熔炼后呈Al含量更高的α_(2)/γ和γ组织,使其高温抗氧化性能优于商用Ti_(48)Al_(2)Cr_(2)Nb。钛铝合金产品高温氧化历程为:Ti-Al合金→铝酸钛→金红石/氧化铝,并且形成的氧化物层可有效防止钛铝合金的进一步氧化。

关键词：钛铝合金低价氯化钛浆料电化学还原高温抗氧化性

麦芽糖酶-葡萄糖淀粉酶D246A异源表达及性质表征

在线全文

学校读者我要写书评

暂无评论

吉林大学学报（理学版） 2024年第3期62卷 742-749页

作者：高雨晴董钢印张洪瑞马占山方丽詹冬玲吉林农业大学食品科学与工程学院长春130118 吉林农业大学生物质活性成分研究与高附加值农产品实验室长春130118

以大型真菌灵芝中的麦芽糖酶-葡萄糖淀粉酶(MGAM)为研究对象,采用同源序列比对、同源模建、底物对接和定点突变等方法成功构建酶活力显著降低的突变体D246A.酶学性质表征结果表明:最适反应温度由野生型(wild type,WT)的65℃减少至60℃,... 详细信息

以大型真菌灵芝中的麦芽糖酶-葡萄糖淀粉酶(MGAM)为研究对象,采用同源序列比对、同源模建、底物对接和定点突变等方法成功构建酶活力显著降低的突变体D246A.酶学性质表征结果表明:最适反应温度由野生型(wild type,WT)的65℃减少至60℃,突变体耐热能力下降;最适pH值由WT的6.0升高至7.0,有利于工程菌生长;半衰期由WT的2.0 h下降至1.5 h,酶稳定性降低.酶动力学结果表明:突变体D246A酶动力学曲线符合Michaelis方程,与WT相比,K_(m)值变大,表明酶与底物亲和力下降;V_(max)约降低至原来的1/4.

关键词：定点突变异源表达性质表征麦芽糖酶-葡萄糖淀粉酶

Heterogeneousα-Diimine Nickel Catalysts with Improved Catalytic Performance in Ethylene Polymerization

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2023年第10期41卷 1155-1162页

作者： zhanshan ma Mengli Xu Ningning Zhu Chen Tan Changle Chen CAS Key Laboratory of Soft matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationKey Laboratory of Environment-Friendly Polymeric Materials of Anhui ProvinceAnhui UniversityHefeiAnhui 230601China

Heterogenization can improve the thermal tolerance of olefin polymerization catalysts and result in good product morphology con-trol,which are two important parameters for industrial polyethylene *** this work,α-diimine nickel catalysts bearing-OH or-ONa anchoring groups were designed and *** anchoring groups can enable facile heterogenization of the cata-lysts on *** heterogeneous catalysts demonstrated enhanced thermal stabilities,along with high catalytic activity at 120℃(up to 5.5×10^(6)g·PE·mol·Ni^(-1)·h^(-1)).Furthermore,the heterogenization process results in the improvements of many other parame-ters,including polymer morphology control,catalytic activity(up to 1.9×10^(7)g·PE·mol·Ni^(-1)·h^(-1))and polyethylene molecular weight(Mn up to 2.3×10^(6)g·mol^(-1)).More importantly,the structure and properties of the polymer products can be controlled by catalyst structures,polymerization conditions and heterogenization to achieve good mechanical properties and elasticity.

关键词： Ethylene polymerization Mechanical properties Nickel Supported catalysts Heterogeneous catalysis Polymerization Morphology

Simulation Study of Cloud Properties Affected by Heterogeneous Nucleation Using the GRAPES＿SCM during the TWP-ICE Campaign

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Meteorological Research 2019年第4期33卷 734-746页

作者： Zhe LI Qijun LIU zhanshan ma Jiong CHEN Qingu JIANG National Meteorological Center China Meteorological AdministrationBeijing 100081 Numerical Weather Prediction Center of China Meteorological Administration Beijing 100081 College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875

This study used the Global/Regional Assimilation and PrEdiction System Single-Column Model(GRAPES_SCM)to simulate monsoon precipitation with deep convective cloud and associated cirrus during the Tropical Warm Pool International Cloud Experiment(TWP-ICE),especially during the active and suppressed monsoon *** cases with different heterogeneous nucleation parameterizations were simulated by using the ensemble *** simulations clearly separated the active and suppressed monsoon periods,and they reproduced the major characteristics of monsoonal cloud such as the total cloud hydrometeor mixing ratio distribution,and precipitation and radiation *** results showed that the number concentration production rate of different heterogeneous nucleation parameterizations varied substantially under the given temperature and water vapor mixing ***,ice formation and precipitation during the monsoon period were affected only slightly by the different heterogeneous nucleation *** study also captured clear competition between different ice formation processes.

关键词： Liuma microphysics scheme monsoon precipitation cloud microphysics heterogeneous nucleation GRAPES_SCM

高钙镁钛精矿沸腾氯化制备TiCl_(4)的热力学及动力学

在线全文

学校读者我要写书评

暂无评论

有色金属（冶炼部分） 2024年第6期 42-52页

作者：朱福兴马占山陈爱祥李良黄志鹏彭卫星钒钛资源综合利用国家重点实验室攀钢集团研究院有限公司四川攀枝花617000 攀钢集团(攀枝花)钛金属材料有限公司四川攀枝花617000

针对高钙镁钛精矿难以满足沸腾氯化制备四氯化钛工艺问题,从热力学和动力学角度对高钙镁钛原料碳热还原—沸腾氯化制备TiCl_(4)工艺进行了深入研究。结果表明:钛精矿高温碳热还原历程为:FeTiO_(3)→TiO_(2)+Fe→Ti_(n)O_(2) n-1(n=4~9)... 详细信息

针对高钙镁钛精矿难以满足沸腾氯化制备四氯化钛工艺问题,从热力学和动力学角度对高钙镁钛原料碳热还原—沸腾氯化制备TiCl_(4)工艺进行了深入研究。结果表明:钛精矿高温碳热还原历程为:FeTiO_(3)→TiO_(2)+Fe→Ti_(n)O_(2) n-1(n=4~9)+Fe→Ti_(3)O_(5)+Fe→Ti_(2)O_(3)+Fe→TiC_(x)O_(1-x)+Fe,碳氧钛生成的温度必须高于1400℃,此时钛精矿中的Ca、Mg、Al、Si、Mn等杂质元素在1800℃以内都不会被还原为对应的碳化物;高钙镁钛铁矿精矿碳热还原制备碳氧钛过程中,失重率随温度升高呈现4阶段上升,其中阶段1和3分别为受扩散控制生成金属Fe和碳氧钛的快速失重段,而阶段2和4分别为金属Fe和碳氧钛形核长大的缓慢失重阶段,4个阶段的表观活化能分别为49.84、-2.24、12.82、-2.53 kJ mol。沸腾氯化过程还原产物中的Fe、MgO和CaO均会优先被氯气氯化,但当存在TiO_(2)时,SiO_(2)和Al_(2)O_(3)则不易被氯化,碳氧钛较适宜沸腾氯化的温度为300~650℃,沸腾氯化前5分钟为还原产物中碳氧钛的快速氯化阶段,主要受表面化学反应的控制,而后5~20分钟为Ti_(2)O_(3)的缓慢氯化阶段,主要受颗粒内部扩散控制的影响。

关键词：高钙镁钛精矿沸腾氯化四氯化钛碳氧钛

在线全文

学校读者我要写书评

暂无评论

钛渣熔盐氯化用熔盐体系物相及物性研究

钢铁钒钛 2024年第2期45卷 20-27页

作者：徐健淋何艺霖马占山庞忠亚田丰张学强邹星礼朱福兴攀钢集团研究院有限公司钒钛资源综合利用国家重点实验室四川攀枝花617000 上海大学材料科学与工程学院上海200444

熔盐氯化法是针对高钙镁钛渣物料而开发的一种四氯化钛制备技术,在长期的生产实践中,发现氯化炉组分控制不当时熔盐会发生严重泡沫化,甚至出现影响生产的喷盐等现象。对此,采用XRD、SEM&EDS、DSCTGA等方法对正常盐和泡沫盐的成分、物相... 详细信息

熔盐氯化法是针对高钙镁钛渣物料而开发的一种四氯化钛制备技术,在长期的生产实践中,发现氯化炉组分控制不当时熔盐会发生严重泡沫化,甚至出现影响生产的喷盐等现象。对此,采用XRD、SEM&EDS、DSCTGA等方法对正常盐和泡沫盐的成分、物相及物性进行深入研究。结果表明,泡沫盐中的氧含量以及水不溶固相物远高于正常盐,固相多以Na_(2)Al_(0.5)Fe_(9.5)O_(15)、Mg_(1.6)Ti_(1.1)O_(4)等复合氧化物形式存在。泡沫盐在300~1280℃的失重率为48.71%,较正常盐低13.73%,熔点呈增大趋势。泡沫盐中氧含量较正常盐高约10%,经高温挥发后残余物为富含铁、镁、铝、硅、钙、氧等元素的不规则颗粒团聚体,而正常盐的残余物则为铁、镁和氧元素均匀分布的致密体。阿基米德法无法满足含固相物的正常盐和泡沫盐密度测定,但可采用体积密度法进行测定,两者密度分别为2.02 g/cm^(3)和1.77 g/cm^(3)。

关键词：钛渣熔盐氯化物相正常盐泡沫盐

Toward a Decision Support System for Integrated Pest management of Pine Caterpillar

在线全文

学校读者我要写书评

暂无评论

北京林业大学学报 1992年第S2期14卷 107-113页

作者： ma zhanshan Zhang Zhizhong Xu HouqingForest Resources College, Beijing Forestry UniversityWen XiujunForest Institute of Hebei Province. Shijiazhuang

A decision support system for IPM of the pine caterpillar, Dendrolimus spectabilis Buter, DS-IPM-DSS, has recently been developed using a GW-0520 CH microcomputer. The software system consists of , a Model Base and its management System, a Database and its management System, a Control Program, a Problem Analysis Program, and a User’s Interface System. Also further development aimed at expanding the DS-IPM-DSS into a more generalized and flexible package, i. e., making it helpful in creating computer-based system for other forest insect pests, are discussed.

关键词： integrated pest management pine caterpillar Chinese pine decision support system