检索结果-南通市图书馆

Study on the coating of nano-scale SiO_2.film on the surface of nanocrystalline Mg-Al layered double hydroxides

Science china Chemistry 2005年第2期48卷 107-114页

作者： ZHANG Zejiang1,2.3, MEI Xiujuan2. XU Chenghua1 & QIU Fali1 1. chengdu institute of Organic Chemistry, Chinese Academy of Sciences, chengdu 610041, china 2. sichuan fire research institute of public security ministry, chengdu 611830, china 3. Graduate School of the Chinese Academy of Sciences, Beijing 100039, china Correspondence should be addressed to Zhang Zejiang (email: zzjzzjzz@***) chengdu institute of Organic Chemistry Chinese Academy of Sciences Chengdu China sichuan fire {2. institute of public security ministry Chengdu China Graduate School of the Chinese Academy of Sciences Beijing China

The coating process of a nano-scale SiO2.film on the nanocrystalline Mg-Al layered double hydroxides via a sol-gel process was investigated. The uniform and dense SiO2.ilm with a thickness of about 5 nm on the nano-LDHs particles was characterized by the solubility test in the dilute HNO3 or HCl acid, TEM and FT-IR, XRD, TG and DSC. The chemical shifts of binding en- ergies of Al 2., Mg 2., Si 2. and O 1s on the coated particles indicate that the coating of the SiO2.nano-film on the surface of the nano-LDHs proceeds through the formation of Mg-O-Si and Al-O-Si bonds. The thermal analysis shows that both the SiO2.coated nano-LDHs and the nano-LDHs have a similar mass loss process, in which there are three obvious stages of mass loss in the temperature range of 40—700℃. Furthermore, the more the coatedamount of SiO2.n the surface of the nano-LDHs is, the less the mass loss of the samples is at 700℃.The nano- LDHs have two obvious endothermic peaks at 2.4.67℃ and 430.13℃, whose corresponding heat absorption capacities are 412.2. J/g and 336.30 J/g, respectively. In contrast, the coated nano-LDHs have only one endothermic peak at 2.3.60℃ with a heat absorption capacity of 2.1.2. J/g.

关键词： layered double hydroxides, nanocrystalline, silica, coating.

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

Study on fire-retardant nanocrystalline Mg-Al layered double hydroxides synthesized by microwavecrystallization method

引用

Science china Chemistry 2004年第6期47卷 488-498页

作者： ZHANG Zejiang1, XU Chenghua1, QIU Fali1, MEI Xiujuan2. LAN Bin2.& ZHANG Shuosheng2.1. chengdu institute of Organic Chemistry, Chinese Academy of Sciences, chengdu 610041, china 2. sichuan fire research institute of public Safety ministry, chengdu 611830, china chengdu institute of Organic Chemistry Chinese Academy of Sciences Chengdu China sichuan fire {2. institute of public Safety ministry Chengdu China

Nanocrystalline Mg-Al layered double hydroxides with the particle size being 10—40 nm were firstly prepared by the technology of the microwave-crystallization and the vari- able-speed addition of the alkali. The obtained samples were characterized by TEM and XRD. The roles of the microwave and addition rate of the alkali were also discussed in the present work. The thermal decomposition activation energy of the nano-LDHs was calculated according to their TG, DTG and DSC curves by the Ozawa method. The results showed that the thermal decom- position of the nano-LDHs had four steps. Thereby the decomposition model of the nano-LDHs was supposed according to the analysis of their thermal decomposition. After PS, ABS, HDPE and PVC were filled with the nano-LDHs, their LOI values could be increased up to 2., 2., 2. and 33, respectively. When the fire-retardant coating contained 1.9% of the nano-LDHs that was 0.2. times the dosage of the conventional TiO2. its fire endurance time reached 32.75min that was 7.05 min longer than that of the best coating containing TiO2.according to the model big-panel combustion test method.

关键词： layered double hydroxides, nanocrystal, microwave synthesis, thermal decomposition, fire-retardant performance.

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

EFFECT OF PAN-MILLING ON RHEOLOGICAL PROPERTIES OF HIGH DENSITY POLYETHYLENE

引用

Chinese Journal of Polymer Science 2000年第5期18卷 397-403页

作者： Hua Huang Polymer research institute, {2. University, chengdu 610065, china 四川大学四川成都

The effect of pan-milling on the rheological properties of high density polyethylene (HDPE) was studied. An innovative milling apparatus, viz. an inlaid pan-mill, was used. Melt indexer, capillary rheometer, Haake Rheocord 90 single-screw extruder and Brabender rheometer were used to evaluate the rheological properties of HDPE. HDPE with higher initial molecular weight and larger particle size was easier to degrade under pan-milling stress, as indicated by the melt index. Pressure oscillation in capillary flow occurred at significantly higher shear stress and shear rate for milled HDPE than for unmilled HDPE. The apparent shear viscosity of HDPE decreased with increasing times of milling. After milling, the flow activation energy decreased and thus the sensitivity of viscosity to temperature was reduced. Die pressure and torque during single screw extrusion were reduced significantly after milling. Plasticizing time as measured in a Brabander mixer decreased markedly with increasing milling times.

关键词： high density polyethylene rheological properties pan-milling

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

Discovery of seismites in Upper Sinian stratiform lead-zinc deposits in Dadu River valley, sichuan, china: Implication for ore genesis

引用

Science china Earth Sciences 2006年第11期49卷 1135-1146页

作者： LIN Fangcheng1,2.& PAN Guitang2.1. Geoscience College, chengdu University of Technology, chengdu 610059,{2. 2. chengdu institute of Geology and Mineral Resources, chengdu 610082.{2. Geoscience College Chengdu University of Technology Chengdu China chengdu institute of Geology and Mineral Resources Chengdu China

A number of lead-zinc sulphide deposits have been discovered in recent years in dolo- mitic rocks of the Upper Sinian Dengying Formation in the Dadu River valley region, sichuan Province, china. The lead-zinc mineralization is closely associated with a black siliceous exhalite that has been traced over 50 km of strike. This makes Dadu River valley the most extensive stratiform non-ferrous sulphide horizon having been discovered to date in china. In a previous study by the first author (LIN), these deposits were recognised as belonging to the broad spectrum of lead-zinc sedimentary exhala- tive (SEDEX) deposits. In this paper, seismites and seismogenetic structures occurring in close association with the Dadu River valley mineralized zone are described. The close spatial and temporal relationship between the seismites and mineralization provides strong evidence for the hypothesis that the lead-zinc SEDEX deposits formed in direct response to earthquake activities around the Sinian-Cambrian boundary. The earthquakes are postulated to be an effective dynamic mechanism for triggering the upward migration of deep circulating ore fluids along synsedimentary growth faults and their exhalation onto the sea-floor to form the extensive deposits of stratiform lead-zinc sulphide ore.

关键词： seismites, earthquake, lead-zinc deposit, hydrothermal exhalation, Upper Sinian Dengying Age.

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

DC ice-melting model for wet-growth icing conductor and its experimental investigation

引用

Science china(Technological Sciences) 2010年第12期53卷 3248-3257页

作者： FAN SongHai1,2. JIANG XingLiang1, SHU LiChun1, SUN CaiXin1 & WANG DaXing1,2.1 State Key Laboratory of Power Transmission Equipment & System security and New Technology, Chongqing University, Chongqing 400044, china 2.{2. Electric Power Test and research institute, chengdu 610072. china State Key Laboratory of Power Transmission Equipment & System security and New Technology Chongqing University Chongqing China sichuan Electric Power Test and research {2. Chengdu China

Icicles are often formed under the downside surface of conductor in the wet growth icing of overhead power line. When the ice deposit around overhead power line is molten by Joule heat produced by current, the pattern of heat transfer of ice deposit with icicles is dissimilar to that without icicle, so the ice-melting model for the columnar icing conductor cannot be applied to icicle-shaped icing conductor. According to the heat-transfer characteristic of the icicle-shaped icing conductor, this paper puts forward a DC ice-melting model for the icicle-shaped icing conductor. Because this full model includes three-dimensional heat-transfer and interface movement, which cannot be solved in closed form, a finite element scheme in space-domain and a finite difference scheme in time-domain are employed to discretize the governing equations. Firstly the whole ice-melting process on the icicle-shaped icing conductor is simulated by this model. Then the simulated results are validated by ice-melting experiments in the artificial chamber. The study from the model and the experiments shows that the size and length of icicle as well as the space between the adjacent icicles are factors to affect ice-melting. With the shorter icicle space, the bigger icicle size and the longer icicle-length, the surface of ice layer is enlarged and then more heat is taken away by the convection and radiation, so the ice melting time will get longer.

关键词： power line icing ice storm ice melting icicle

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

Theoretical study of aging effects on LaNi_(5) tritium storage

引用

Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 676-686页

作者： PING Feilin1,2. JIANG Gang1, ZHANG Lin2.& ZHU Zhenghe1 1. institute of Atomic and Molecular Physics, sichuan University, {2. 610065, china 2. research Center of Laser Fusion, Mianyang 62.900, china institute of Atomic and Molecular Physics Sichuan University Chengdu China research Center of Laser Fusion Miangyang China

The electronic structure and energy of La2.i10H12.and La2.i10H11He (He is at tetrahedral, octahedral or twelve-face polyhedral interstitials) double cells have been calculated using the density functional theory. Their equilibrium structure, energy bands, electronic density of states (DOS) and X-ray diffraction are presented and discussed. The results indicate the helium-3 produced due to the decay of tritium is most possibly sited at twelve-face polyhedral and octahedral interstices and changes the thermodynamic properties of LaNi5 tritide system. The changes due to aging such as the reduction in the isotherm plateau pressure, increase of the isotherm plateau slope, and appearance of deeply trapped hydrogen are caused not only by the lattice expansion, but also by modification of the electronic structure due to the presence of He.

关键词： LaNi5 alloy, density functional theory, electronic structure, aging.

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

Land Use of the Three Gorges Reservoir Area and the Effect on Its Landscape Pattern in the Recent 50 Years

引用

Wuhan University Journal of Natural Sciences 2006年第4期11卷 910-914页

作者： HUANG Zhiqin 1,2.3 , ZHOU Wancun 1 ,ZHOU Jieming 4 , ZHU Mingcang 3,5 1. institute of Mountain Hazards and Environment, Chinese Academy of Sciences , chengdu 610041, {2., china 2. Graduate University of Chinese Academy of Sciences, Beijing 100049, china 3. {2. institute of Land Resource Management, chengdu 610041, {2. , china 4. Department of Resources and Environment Science, {2. Normal University , chengdu 610061, {2., china 5. College of Information Engineering, chengdu University of Technology, chengdu 610059, {2., china institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu Sichuan China Graduate University of Chinese Academy of Sciences Beijing China sichuan institute of Land Resource Management Chengdu Sichuan China Department of Resources and Environment Science Sichuan Normal University Chengdu Sichuan China College of Information Engineering Chengdu University of Technology Chengdu Sichuan China

The paper makes detailed analysis on the changing processes of the main types of land use in Three Gorges Reservoir Area through the techniques of RS （Remote Sense） and GIS （Geography Information System）. Based on the theory of landscape ecology, many types of landscape pattern indexes are calculated and made correlation analysis. The results indicate that： in 1995 the ecological environment of Three Gorges Reservoir Area was the most vulnerable in the recent 50 years, but resumed in 2.02. the landscape pattern diversity index, fractal dimension index and fragmentation index has close correlation with the area of land use/cover change （LUCC）. The research also releases that the increase of the cultivated land, grassland and construction land deteriorates the landscape ecological pattern, while the increase of forest land area will help restore the landscape ecological pattern to its original state. The rapid change of grassland is an important index of the change of landscape pattern, because it has the most effect on change of landscape pattern index.

关键词： the Three Gorges Reservoir Area land use/cover change landscape pattern.

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 the Friction and Wear Behaviors of Dental Machinable Porcelain

引用

材料热处理学报 2004年第5B期25卷 1171-1174页

作者： YUHai-yang ZHOUZhong-rong CAIZhen-Bing Tribologyresearchinstitute SouthwestJiaotongUniversityChengduChina Tribologyresearchinstitute SouthwestJiaotongUniversityChengduChina／／CollegeofHuaxiStomatologySichuanUniversityChengduChina

In order to well design tribosystems of dental CAD-CAM restorations, an understanding of the tribological mechanisms of dental machinable porcelain are essential. The friction and wear behavior of new generation industrially prefabricated Cerec Vitablocs Mark II against uniform Si3N4 ball has been performed using a small amplitude reciprocating apparatus under simulating oral conditions. The loads of 10-40 N, reciprocating amplitudes of 100-500 urn, frequencies of 1-4 Hz and two lubrications (no / artificial saliva lubrication) were selected. Tests lasting up to 10 000 cycles were conducted. The results show that Cerec Vitablocs Mark II record a friction coefficient of 0.55-0.84. Artificial saliva plays a lubricant effect during wear process. Among three parameters of the test on friction coefficient and wear depth of dental machinable porcelains, the load effect is prominent. Abrasive wear is the main wear mechanism, but brittle cracks and delamination are more popular especially under unlubricated friction.

关键词：磨损性能摩擦系数陶瓷材料齿轮

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

Molecular tagging of a genic male-sterile gene in rice

引用

Chinese Science Bulletin 2001年第1期46卷 66-69页

作者： CHEN Xuewei, LI Shigui, WANG Wenming, LI Hanyun, ZHOU Kaida & ZHU Lihuang1. institute of Genetics, Chinese Academy of Science, Beijing 100101, china 2. Rice {2. institute, sichuan Agricultural University, chengdu 611130, china institute of Genetics Chinese Academy of Science Beijing China Rice research institute Sichuan Agricultural University Chengdu China

The sterility of Pingxiang male-sterile rice (Pins), possibly derided from a spontaneous mutation in Pingxiang fertile rice (Pmf), was previously reported to be controlled by a single dominant nuclear gene. It can be restored to fertility either by a dominant epistatic gene or by higher temperature treatment at the early stage of inflorescence development. In order to tag the genie male-sterile gene, Pms, Pmf and Ce 64, a cytoplasmic male-sterile restoring line without the epistatic gene for Pms, were used to construct mapping populations. Two segregation populations, "(Pms/Ce 64) F1s (sterile plant)//Pmf" F1 and "Pms//(Pmf/Ce 64) F1" F1, were simultaneously developed. Subsequently, the genie male- sterile gene was mapped between a simple sequence length polymorphism marker, RM2.8, and a restriction fragment length polymorphism marker, G2.55, with distances of 14.9 and 2.6 cM, respectively. The tagged dominant genie male-sterile gene is temporarily designated Ms-p.

关键词： rice genie male-sterility molecular mapping molecular marker gene localization.

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

Ecological Footprint and Ecological security Evaluation in the Upper Min River Basin

引用

Wuhan University Journal of Natural Sciences 2005年第4期10卷 641-646页

作者： TU Jian-jun 1, 2.1. School of Resources and Environment Science, Southwest china Normal University, Chongqing 400715, china 2. {2. of Mountain Hazards and Environment, Chinese Academy of Sciences, chengdu 610041, sichuan, china School of Resources and Environment Science Southwest China Normal University Chongqing China institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu Sichuan China

On the basis of the ecological footprint (EF) model, this paper studied theecological security in the Upper Min River Basin ecosystem. The result shows that with 2. 038 2.hm^2.er capita ecological capacity (0. 42. 2.hm^2.higher than per capita EF) ,and 165 82. hm^2.ecologysurplus , the ecosystem in Upper Min River is generally secure at present. But the arable land isoverweighed and omens an eco-security crisis. Meanwhile, problems such as low forest coverage rate,severe loss of water and soil,enlargement of arid-valley area, frequent occurrence of mountainhazards and degradation of pastures have been major threats to the eco-security of this region. Thecalculation result of ten-thousand-yuan ( RMB) GDP shows that the use of natural resources isextensive, and there will be a rapid increase tendency of EF in the future. In order to maintain thepresent eco-security, the ways of use natural resources must be improved in the Upper Min RiverBasin.

关键词： ecological security ecological footprint ecological capacity quantitativeevaluation the Upper Min River Basin

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：