检索结果-南通市图书馆

Preparation and microstructure of CuO-CoO-MnO/SiO2.nanocomposite aerogels and xerogels as catalyst carriers

Progress in Natural Science:Materials International 2011年第4期21卷 330-335页

作者： Yue-qing ZHAO~1,Ying-hua LIANG~2.xi-zhe ZHAO~3,Qian-yi JIA~4,Hong-sheng LI~4 1.college of Light Industry,Hebei United university,Tangshan 063000,{2. 2.college of Chemical engineering,Hebei United university,Tangshan 063009,{2. 3.college of Printing and Packaging engineering,Beijing Institute of Graphic Communication,Beijing 102.00,{2. 4.college of Materials Science and engineering,Hebei United university,Tangshan 063009,{2. [a] college of Light Industry Hebei United University Tangshan 063000 China [b] college of Chemical engineering Hebei United University Tangshan 063009 China [c] college of Printing and Packaging engineering Beijing Institute of Graphic Communication Beijing 102600 China [d] college of Materials Science and engineering Hebei United University Tangshan 063009 China

CuO-CoO-MnO/SiO2.anocomposite aerogels and xerogels were prepared using tetraethyl orthosilicate（TEOS） as Si source,and aqueous solution of Cu,Co and Mn acetates as the precursor via sol-gel process,CO2.upercritical drying（SCD） technique or ambient pressure drying *** microstructure of the CuO-CoO-MnO/SiO2.anocomposite aerogels and xerogels were characterized by field emission scanning electron microscopy（FE-SEM）,transmission electron microscopy（TEM） and X-ray diffraction（XRD）.The specific surface area,pore size and pore size distribution of the nanocomposite aerogels and xerogels were determined by the Brunauer-Emmett-Teller（BET） *** results showed that CuO-CoO-MnO/SiO2.anocomposite aerogels are porous,with a pore size distribution of 2.50 nm,an average pore size of 19.4 nm,a specific surface area of 384.9 m2.g and a particle size distribution of 10-150 nm,whereas the pore size distribution of CuO-CoO-MnO/SiO2.omposite xerogels is 1.7-12..6 nm,the average pore size is only 9.9 nm,the specific surface area is only 99.1 m2.g,and the particle size distribution is 100-500 *** structure of CuO-CoO-MnO/SiO2.anocomposite aerogels is favorable to increase the loading of catalysts.

关键词： composite aerogel composite xerogel catalyst carrier preparation microstructure

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

B-cell lymphoma-2.phosphorylation at Ser70 site-related autophagy mediates puerarin-inhibited the apoptosis of MC3T3-E1 cells during osteoblastogenesis

引用

Journal of Traditional Chinese Medicine 2024年第1期44卷 27-34页

作者： LI xi LIN xiangquan CHEN Dongdong LIU Hui the Third Clinical Medical college Fujian Medical University Department of Orthopedics Fuzhou Second HospitalFuzhou 350007China

OBJECTIVE:To explore the relationship between autophagy and apoptosis regulated by puerarin during ***:In this study,the effects of puerarin on the autophagic activity and apoptosis level of osteoblast precursors(MC3T3-E1 cells)was ***,the roles of puerarin on B-cell lymphoma-2.Bcl-2.phosphorylation at different sites in osteoblast precursors were *** effect of puerarin on the interaction between Bcl-2.and autophagy regulatory molecule or pro-apoptotic molecule was also investigated using Co-immunoprecipitation *** addition,the effect of puerarin on mitochondrial membrane potential of osteoblast precursors was also identified by mitochondrial membrane potential fluorescence probe ***:Our results showed that puerarin can promote the autophagic activity and apoptosis level of *** addition,puerarin promoted Bcl-2.hosphorylation at Ser70 site,and the dissociation of Bcl-2.Beclin1 ***,puerarin could enhance the binding of Bcl-2.Bcl-2.Associated X(Bax)complex in MC3T3-E1 ***,puerarin increased the mitochondrial membrane potential of MC3T3-E1 ***:Therefore,puerarin promotes Beclin1into autophagy flux through Bcl-2.phosphorylation at Ser70,thereby enhancing autophagy of osteoblast precursors,which mediates its anti-apoptotic role during ***,the dissociation of Bcl-2.Beclin1 complex is conducive to the binding of Bcl-2.Bax complex,which resists the apoptosis of osteoblast precursors via the increased mitochondrial membrane potential.

关键词： puerarin osteoblasts autophagy apoptosis lymphoma B-cell

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On Depolymerization

引用

CCS Chemistry 2024年第2期6卷 297-312页

作者： Bo Qin xi Zhang college of Chemistry and Chemical engineering Hunan UniversityChangsha 410082 Department of Chemistry Tsinghua UniversityBeijing 100084

Polymers have become an essential part of modern life and the global economy on account of their costeffectiveness and versatile ***,most postconsumer polymer wastes are unrecycled,leading to environmental pollution and resource ***,as an efficient chemical recycling approach,holds great promise in establishing a circular polymer *** this review,we attempt to highlight recent and significant advancements in depolymerization *** key research topics are discussed:(1)depolymerization of commodity polymers to produce reusable monomers and high-value chemicals;(2.depolymerization of intrinsically depolymerizable *** is anticipated that this review will reflect the present status and future trends of this rapidly evolving realm of depolymerization.

关键词： depolymerization chemical recycling sustainable polymers circular polymer economy catalysis dynamic covalent chemistry

来源：

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

Integrating host biological and ecological variables to predict probability of haemosporidian infection in raptors

引用

Avian Research 2024年第2期15卷 255-264页

作者： Kai Gao Xuemei Yang xi Huang Wenhong Deng Ministry of Education Key Laboratory for Biodiversity Science and Ecological engineering College of Life SciencesBeijing Normal UniversityBeijing100875China

Variations in host traits that influence their exposure and susceptibility may impact probability of vector-transmitted ***,identifying the predictors of infection probability is necessary to understand the risk of disease outbreaks during expanding environmental ***,we conducted a large survey based on microscopic examination and molecular analysis of haemosporidian parasite infection in raptors rescued at the Beijing Raptor Rescue *** these data with biological and ecological variables of the raptors,we determined predictors that affect the probability of haemosporidian infection using generalized linear mixed models and multimodel *** results showed that infection probability exhibited considerable variation across host species in raptors,and body mass,sex,and evolutionary history played relatively weaker roles in driving infection ***,activity pattern,age,geographic range size,migration distance,and nest type were important predictors of the probability of haemosporidian infection,and the role of each predictor differed in the three main haemosporidian genera(Plasmodium,Haemoproteus,and Leucocytozoon).This macro-ecological analysis will add to our understanding of host traits that influence the probability of avian haemosporidian infection and will help inform risk of emerging diseases.

关键词： Activity pattern Emerging infectious diseases Infection probability Interspecific variation Migratory exposure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

PROPERTIES AND MORPHOLOGY OF UNSATURATED POLYESTER/ACRYLATE-TERMINATED POLYURETHANE/ORGANO-MONTMORILLONITE NANOCOMPOSITES

引用

Chinese Journal of Polymer Science 2005年第5期23卷 471-478页

作者： chang-jiang You Jin-guo Xu Song xi xiao-xia Duan Jie Shen and De-min Jia college of Materials Science and {2.,South china university of Technology,Guangzhou 510640,china S china Univ Technol Coll Mat Sci & Engn Guangzhou 510640 Peoples R China

Unsaturated polyester resin （UPR）/acrylate-terminated polyurethane （ATPU）/organo-modified montmorillonite （OMMT） nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prepared by the sequential mixing, i.e. mixture of the ATPU and styrene （S） and OMMT were prepared in the first step; UPR was then added to the pre-intercalates of ATPU/S/OMMT. Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT. Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites, but the tensile strength, flexural strength and heat resistance of the materials are obviously decreased. When the weight ratio between UPR, ATPU and OMMT were 82.15：3, the impact strength and heat distortion-temperature of nanocomposite were greatly improved, meanwhile there was little change for other properties of the nanocomposites. The synergistic enhancement effects of ATPU and OMMT on the composites were observed. The structures and morphology of the composites were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.

关键词： Unsaturated polyester Acrylic terminal polyurethane Organo-modified montmorillonite Nanocomposite.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Deep Mantle Source for the Late Neoarchean Metamorphosed Basalts in Eastern Hebei,North china Craton:Insights from Whole-Rock Geochemistry and Sm-Nd Isotopes,and Zircon U-Pb-Hf Isotopes

引用

Journal of Earth Science 2024年第1期35卷 29-40页

作者： Zhuang Li Chunjing Wei Chuan Yang xi Zhang college of Geosciences China University of PetroleumBeijing 102249China MOE Key Laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking UniversityBeijing 100871China china Transport Telecommunications and Information Center Beijing 100011China

The basalts within the greenstone belt worldwide serve as an ideal target to decipher the nature of Archean mantle sources and further to extend the understanding of the early stages of Earth's *** provide important insights into the issues,we carried out a detailed investigation of whole-rock geochemistry and Sm-Nd isotopes,and zircon U-Pb-Hf isotopes for the Late Neoarchean metamorphosed basalts in eastern Hebei,North china Craton.U-Pb isotopic dating using the LA-ICPMS on zircons reveals that the basalts in eastern Hebei erupted at ca.2.48-2.51 Ga and subsequently experienced multiple regional metamorphic events at 2.77 and 1798 Ma,*** metamorphosed basalts are featured by low SiO_(2.,MgO,K_(2.O+Na_(2.O,and high Fe O contents,endowed with the subalkaline and high-Fe tholeiitic *** radiogenic initial Nd and Hf isotope values and correlations among V,Ni and Cr contents strongly imply that the basalts experienced significant clinopyroxene and olivine fractionation and minor crustal contamination during magma *** are also characterized by the relatively low total REE contents and exhibit significant depletions to moderate enrichments in the LREE contents,indicating the derivation from a deep mantle source in an Archean proto-mantle plume setting.

关键词： zircon U-Pb-Hf isotopes geochemistry Late Neoarchean basaltic magmatism North china Craton Archean proto-mantle plume

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Review on abort trajectory for manned lunar landing mission

引用

Science china(Technological Sciences) 2010年第10期53卷 2691-2698页

作者： xi xiaoNing1, HUANG WenDe2.& WANG Wei2.3 1 college of Mechatronics engineering and Automation, National {2. of Defense Technology, changsha 410073, china 2.college of Aerospace and Material engineering, National {2. of Defense Technology, changsha 410073, china 3 School of Surveying and Spatial Information System, {2. of New South Wales, Sydney, NSW 2.52. Australia 1. college of Mechatronics engineering and Automation National University of Defense Technology Changsha 410073 China2. College of Aerospace and Material Engineering National University of Defense Technology Changsha 410073 China3. School of Surveying and Spatial Information System University of New South Wales Sydney NSW 2052 Australia

Abort trajectory is a passage that ensures the astronauts to return safely to the earth when an emergency occurs. Firstly,the essential elements of mission abort are analyzed entirely based on summarizing the existing studies. Then,abort trajectory requirement and rational selection for different flight phases of typical manned lunar mission are discussed specifically. Considering a trade-off between the two primary constrains of an abort,the return time of flight and energy requirement,a general optimizing method for mission abort is proposed. Finally,some suggestions are given for china’s future manned lunar landing mission.

关键词： manned lunar landing mission abort trajectory design free return trajectory

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Petrogenesis of Songshugou dunite body in the Qinling orogenic belt, Central china: Constraints from geochemistry and melt inclusions

引用

Science china Earth Sciences 2005年第8期48卷 1146-1157页

作者： SU Li1,2. SONG Shuguang3 & ZHOU Dingwu1 1. Key Laboratory of Continental Dynamics of the Ministry of Education, Department of Geology, Northwestern university, xi’an 710069, china 2. The {2. Lab Center, china university of Geosciences (Beijing), Beijing 100083, china 3. Key Laboratory of Orogenic Belts of the Ministry of Education, Department of Geology, Peking university, Beijing 100871, china 1. Key Laboratory of Continental Dynamics of the Ministry of Education Department of Geology Northwestern University 710069 Xi’an China 2. The geological Lab Center China University of Geosciences 100083 (Beijing)Beijing China 3. Key Laboratory of Orogenic Belts of the Ministry of Education Department of Geology Peking University 100871 Beijing China

The Songshugou dunite body, which occupies an area of about 2. km2. is the largest ultramafic massif in the eastern Qinling orogenic belt, Central china. The major compo-nent of this body is dunitic rocks including mylonitic dunite and coarse-grained dunite; they oc-cupy about 95 vol% of the total body. Petrography, mineral composition, major and trace ele-ments and primitive melt inclusions have been investigated in this paper; all revealed that this dunite body is the product of melt-rock interaction by porous percolation flow. In comparison with dunite sills or veins in harzburgite from the basal part of Oman ophiolite, this dunite body is characterized by lower contents of Al2.3, CaO and HREE but higher content of highly incom-patible elements and Zr and Hf. The LREE enriched patterns and primitive mantle normalized spidergrams of trace elements are also different from the Oman dunite. Combining with melt in-clusions observed in olivines, we conclude that this dunite body is the product of large- scale porous percolation flow of high-MgO melts within depleted mantle peridotites. The high-MgO magma, in essence, was most probably produced at the hot head of an upwelling mantle plume. The occurrence of the Songshugou dunite body is closely associated with the activity of mantle super-plume in Neo-Proterozoic era in the Yangtze Craton.

关键词： Songshugou dunite body, geochemistry, melt inclusion, mantle plume, Qinling orogenic belt.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Colloid-facilitated release of polybrominated diphenyl ethers at an e-waste recycling site: evidence from undisturbed soil core leaching experiments

引用

Frontiers of Environmental Science & engineering 2024年第2期18卷 91-101页

作者： Zebin Huo Mengjun xi Lianrui Xu Chuanjia Jiang Wei Chen college of Environmental Science and engineering Ministry of Education Key Laboratory of Pollution Processes and Environmental CriteriaTianjin Key Laboratory of Environmental Remediation and Pollution ControlNankai UniversityTianjin 300350China

Polybrominated diphenyl ethers (PBDEs), a class of persistent organic pollutants, have been frequently detected in soil at e-waste recycling sites. However, the key factors controlling the transport of PBDEs from surface soil to the vadose zone and groundwater are unclear. Here, colloid-enhanced leaching of PBDEs from undisturbed soil cores collected at an e-waste recycling site in Tianjin, china, is reported. Spatially heterogeneous release of colloids and PBDEs was observed in all the tested soil cores under chemical and hydrodynamic perturbations, indicating the presence of preferential flow paths. Colloid concentration in the effluent significantly increased as ionic strength decreased (from 10 to 0.01 mmol/L), probably due to the stronger electrostatic repulsion between colloidal particles and the soil matrix at lower ionic strength. In contrast, colloid mobilization was not significantly affected by the changes in pH of the influent (from 4.0 to 10.0) and flow rate (from a Darcy velocity of 1.5 to 6.0 cm/h). The concentrations of 2.2.,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-2.9), the predominant PBDE congener at the site, detected in the leachate (ranging from 1.09 to 3.43 ng/L) were much lower than previously reported results from packed column leaching tests, and were positively correlated with colloid concentrations. This indicates that remobilization of colloids at e-waste recycling sites can promote the leaching and downward migration of PBDEs from surface soil. The findings highlight the potential risk of surface soil PBDE contamination to groundwater quality and call for further understanding of colloid-facilitated transport for predicting the fate of PBDEs at e-waste recycling sites.

关键词： Polybrominated diphenyl ether Colloid-facilitated transport E-waste recycling site Undisturbed soil core Groundwater quality

来源：

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

Chain Extender-induced Hydrogen Bonding Organization Determines the Morphology and Properties of Thermoplastic Polycarbonate Polyurethane

引用

Chinese Journal of Polymer Science 2024年第1期42卷 87-96,I0009页

作者： Yi-Lang Qin Ping Zhu Chen-xi Ouyang xia Dong Fuwai Hospital Chinese Academyof Medical Sciences&Peking Union Medical College/National Center for Cardiovascular DiseasesBejing 100037China CASKey Laboratoryof engineering Plastics CAS Research/Education Centerfor Excellence in Molecular SciencesInstitute ofChemistryChinese Academy of SciencesBeijing 100190China university of Chinese Academy of Sciences Beijing 100049China

Thermoplastic polycarbonate polyurethanes(PCUs) are multiblock copolymers that have been applied for medical devices for long time. Aliphatic diols are common chain extenders(CE) involved in the composition of the hard segments of PCU. However, limited knowledge was discovered about how the chemical structure of CE affects the hydrogen bonding organization within PCUs and their mechanical *** investigate this problem, a group of PCUs were synthesized respectively by extending the polymer chain with 1,4-butanediol(BDO),aminoethanol(MEA), ethanediol(EO) as three kinds of chain extenders. Tiny differences in the CE chemical structure results in remarkable variations in phase separation, condensed morphologies, thermal and mechanical properties, which are characterized by Fourier transform infrared spectrometer, atomic force microscopy, small-angle X-ray scattering, differential scanning calorimetry, and tensile tests. The microstructural evolution during unilateral deformation and the different mechanism induced by the different CEs was probed and unveil by in situ wide-and small-angle X-ray diffraction. Symmetry of CE can improve the organization of the hydrogen bonding. The coherence strength of the urethane/urea group also plays a key role by comparing the two PCUs with ethanediol and aminoethanol.

关键词： Thermoplastic polycarbonate polyurethane Chain extender Hydrogen bonding Mechanical properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：