检索结果-南通市图书馆

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.

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

在线全文

学校读者我要写书评

暂无评论

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.

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

在线全文

学校读者我要写书评

暂无评论

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

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

在线全文

学校读者我要写书评

暂无评论

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.

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

在线全文

学校读者我要写书评

暂无评论

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.

Constructing globally consecutive 3D conductive network using P-doped biochar cotton fiber for superior performance of silicon-based anodes

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第6期173卷 181-191页

作者： Jun Cao Jianhong Gao Kun Wang Zhuoying Wu Xinxin Zhu Han Li Min Ling chengdu Liang Jun Chen Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China institute of Zhejiang University-Quzhou Zheda Road 99Quzhou 324000China

The inferior conductivity and drastic volume expansion of silicon still remain the bottleneck in achieving high energy density Lithium-ion Batteries(LIBs).The design of the three-dimensional structure of electrodes by compositing silicon and carbon materials has been employed to tackle the above challenges,however,the exorbitant costs and the uncertainty of the conductive structure persist,leaving ample room for ***,silicon nanoparticles were innovatively composited with eco-friendly biochar sourced from cotton to fabricate a 3D globally consecutive conductive *** network serves a dual purpose:enhancing overall electrode conductivity and serving as a scaffold to maintain electrode *** conductivity of the network was further augmented by introducing P-doping at the optimum doping temperature of 350℃.Unlike the local conductive sites formed by the mere mixing of silicon and conductive agents,the consecutive network can affirm the improvement of the conductivity at a macro ***,first-principle calculations further validated that the rapid diffusion of Li^(+)is attributed to the tailored electronic microstructure and charge rearrangement of the *** prepared consecutive conductive Si@P-doped carbonized cotton fiber anode outperforms the inconsecutive Si@Graphite anode in both cycling performance(capacity retention of 1777.15 mAh g^(-1) vs.682.56 mAh g^(-1) after 150 cycles at 0.3 C)and rate performance(12.4.2. mAh g^(-1) vs.370.2. mAh g^(-1) at 2.0 C).The findings of this study may open up new avenues for the development of globally interconnected conductive networks in Si-based anodes,thereby enabling the fabrication of high-performance LIBs.

关键词： 3D conductive network Biochar carbon-silicon anode Heteroatoms doping strategy DFT calculation Lithium-ion battery

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

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

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.

On the Friction and Wear Behaviors of Dental Machinable Porcelain

在线全文

学校读者我要写书评

暂无评论

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

Molecular tagging of a genic male-sterile gene in rice

在线全文

学校读者我要写书评

暂无评论

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.

EFFECT OF PAN-MILLING STRESS ON CRYSTAL STRUCTURES OF HIGH DENSITY POLYETHYLENE

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2000年第4期18卷 363-367页

作者： Hua Huang Polymer research institute, {2. University, chengdu 610065, china School of chemistry and Chemical Technology,Shanghai Jiao Tong University ,Shanghai 2.02.0,china 四川大学四川成都

A detailed study was performed on the crystal structures of pan-milled high-density polyethylene (HDPE) using differential scanning calorimetry (DSC) and X-ray diffraction. The crystallinity of HDPE first decreased slightly, followed by a gradual increase with increasing milling times. Monoclinic crystals appeared after 4 cycles of milling. With increasing times of milling, the proportion of monoclinic crystals increased significantly while the proportion of orthorhombic crystals decreased gradually. With increasing times of milling, the crystallite size of orthorhombic form decreased greatly, while the size of monoclinic crystallites kept almost constant during milling.

关键词： high-density polyethylene pan-milling crystal structure