检索结果-南通市图书馆

A novel poly[acrylonitrile-co-(3-ammoniumcarboxylate-butenoic acid-methylester)]copolymer for carbon fiber precursor

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2012年第11期23卷 1307-1310页

作者： An qi ju Shan Yi Guang Hong Yao Xu College of Materials Science and Engineering&State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Donghua UniversityShanghai 201620China College of Chemistry&Chemical Engineering Donghua UniversityShanghai 201620China

A novel bifunctional comonomer 3-ammoniumcarboxylate-butenoic acid-methyl ester （ACBM） was synthesized tor preparing poly[acrylonitrile-co-（3-ammoniumcarboxylate-butenoic acid-methyl ester）] [P（AN-co-ACBM）] copolymer as a carbon fiber precursor. Differential scanning calorimetry results show that the P（AN-co-ACBM） exhibits a significantly improved stabilization performance compared with polyacrylonitrile （PAN）, such as lower cyclization temperature and smaller rate of heat release, which is mainly attributed to the initiation of ACBM through an ionic cyclization mechanism. Simultaneously, the rheological analysis shows that P（AN-co-ACBM） possesses better spinnabilitv than PAN.

关键词： Polyacrylonitrile Carbon fiber Thermal analysis DSC Polymerization

Distributions of dimethylsulfide in the Bohai Sea and Yellow Sea of China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2003年第6期15卷 762-767页

作者： HU Min TANG Xiao-yan LI Jin-long MA qi-ju State Joint Key Laboratory of Environmental Simulation and Pollution Control Center for Environmental Sciences Peking UniversityBeijing 100871China.

Dimethylsulfide(DMS) measurements in the surface seawater of China eastern coastline were conducted during March 9—10, 1993 in Bohai Sea along the cruise from Dalian to Tianjin and during September 24—25, 1994 in Yellow Sea along the cruise from Shanghai to qingdao. On the cruise in Bohai Sea DMS concentrations varied from 0.11 to 2.63 nmol/L with an average of 1.31 nmol/L, while DMS flux was estimated to be 0.85 μmol/(m 2·d) with the range of 0.04—3.12 μmol/(m 2·d). On the cruise in Yellow Sea DMS concentrations varied from 0.95 to 7.48 nmol/L with an average of 2.89 nmol/L, and DMS flux was estimated to be 7.94 μmol/(m 2·d) with the range of 0.11—18.88 μmol/(m 2·d). Variations in DMS concentrations along the latitude in Yellow Sea were observed larger than those along the longitude in Bohai Sea. DMS concentrations and fluxes had a similar spatial trend both in Bohai Sea and Yellow Sea with the correlation coefficients of 0.75 and 0.64, respectively.

关键词： dimethylsulfide sea-to-air flux China Bohai Sea China Yellow Sea

Poly(acrylonitrile-co-3-aminocarbonyl-3-butenoic acid methyl ester):A better precursor material for carbon fiber than acrylonitrile terpolymer

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2014年第9期25卷 1275-1278页

作者： An-qi ju Meng-juan Li Miao Luo Ming-qiao Ge Key Laboratory of Eco-textiles Ministry of EducationJiangnan University College of Textile & Clothing Jiangnan University School of Pharmacy East China University of Science and Technology

In order to improve the stabilization and spinnability of polyacrylonitrile, a bifunctional comonomer containing both ester and amide groups was synthesized to prepare poly（acrylonitrile-co-3- aminocarbonyl-3-butenoic acid methyl ester） [P（AN-co-ABM）] copolymers used as the carbon fiber precursor instead of poly（acrylonitrile-acrylamide-methyl acrylate） [P（AN-AM-MA）] terpolymer. The differential scanning calorimetry and thermogravimetry results show that the stabilization of P（AN-co- ABM） have been remarkably improved by ABM compared with P（AN-AM-MA） terpolymer, such as lower initiation temperature, broadened exothermic peak and smaller activation energy. Moreover, the spinnability of P（AN-co-ABM） is also improved by ABM due to the lubrication of ester groups in ABM. This study clearly shows that P（AN-co-ABM） copolymer is a better material for use as a carbon fiber precursor than P（AN-AM-MA） terpolymer.

关键词： Polymerization Stabilization DSC Spinnability Carbon fiber

Application of calcium alumino-titanate to taphole clay

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2022年第7期29卷 1089-1100页

作者： Mao-qi ju Man-fei Cai Yong-he Liang Jian-hua Nie Meng-zhen Guo The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Calcium alumino-titanate(CAT)can be used as a raw material owing to its excellent refractoriness and thermal ***-containing taphole clay(THC)with different particle sizes was prepared and *** results indicated that THC with CAT aggregate has better thermo-mechanical performance than that with a fine CAT powder because of different sintering *** CAT aggregate and SiO_(2)reacted and formed liquid phase covering their surface,enhancing the bonding of the particle–matrix and promoting the internal transformation of the ***,the mullite was formed in aggregate with the interwoven network *** CAT powder has a higher specific surface area,and its surface energy decreases with the particle *** could cause a reaction between CAT and SiO_(2)at relatively low temperature,making it unable to form a core–shell structure similar to that of the aggregate,with the excessive liquid phase affecting the performance of the ***,the liquid phase was formed to close the pores and cover the SiC surface,and this was found to enhance the oxidation resistance.A corrosion test confirmed that the THC refractories with CAT aggregates showed better corrosion resistance than other *** electron microscopy and energy-dispersive spectrometry results indicated that Ti(C,N)transformed by TiO_(2)in CAT was deposited at the interface between the molten slag and the refractory,and it efficiently prevented the penetration and reaction owing to its high melting point and small wetting angle with the slag.

关键词： Taphole clay Calcium alumino-titanate Microstructure Corrosion resistance

PCR-DGGE Analysis of Nematode Diversity in Cu-Contaminated Soil

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

Pedosphere 2008年第5期18卷 621-627页

作者： WANG Shi-Bin LI qi LIANG Wen-ju JIANG Yong JIANG Si-Wei Key Laboratory of Terrestrial Ecological Process Institute of Applied Ecology Chinese Academy of Sciences Shenyang110016 （China）.

A wheat pot experiment was conducted under greenhouse conditions to assess the effect of copper contamination on soil nematode diversity by polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） method and morphological analysis. The soil was treated with CuSO4.5H2O at the following concentrations： 0, 50, 100, 200, 400, and 800 mg kg^-1 dry soil, and the soil samples were collected at wheat jointing and ripening stages. Nematode diversity index （H′） from morphological analysis showed no difference between the control and the treated samples in either of the sampling dates. At the wheat ripening stage, nematode diversity obtained by the PCR-DGGE method decreased noticeably in the Cu800 treatment in comparison with the control. With optimization of the method of nematode DNA extraction, PCR-DGGE could give more information on nematode genera, and the intensity of the bands could reflect the abundance of nematode genera in the assemblage. The PCR-DGGE method proved promising in distinguishing nematode diversity in heavy metal coritaminated soil.

关键词： copper contamination morphological analysis nematode diversity PCR-DGGE

Permian integrative stratigraphy,biotas,paleogeographical and paleoclimatic evolution of the qinghai-Tibetan Plateau and its surrounding areas

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第4期67卷 1107-1151页

作者： Shuzhong SHEN Yichun ZHANG Dongxun YUAN Haipeng XU qi ju Hua ZHANG Quanfeng ZHENG Mao LUO Zhangshuai HOU State Key Laboratory for Mineral Deposits Research School of Earth Sciences and Engineering and Frontiers Science Center for Critical Earth Material CyclingNanjing UniversityNanjing 210023China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Nanjing 210049China School of Resources and Geosciences China University of Mining and TechnologyXuzhou 221116China

The Permian Period was a critical time interval during which various blocks of the qinghai-Tibetan Plateau have experienced profound and complex paleogeographical *** supercontinent Pangea was formed to its maximum during this interval,hampering a global east-to-west trending equatorial warm ocean ***,a semi-closed Tethys Ocean warm pool formed an eastward-opening oceanic embayment of Pangea,and became an engine fostering the evolutions of organisms and environmental changes during the Paleozoic-Mesozoic *** and preserved fossil groups have proved extremely useful in understanding such changes and the evolutionary histories of the qinghai-Tibetan *** distributed Permian deposits and fossils from various blocks of the qinghai-Tibetan Plateau exhibited varied characteristics,reflecting these blocks’different paleolatitude settings and drifting *** Himalaya Tethys Zone south to the Yarlung Zangbo suture zone,located in the northern Gondwanan margin,yields fossil assemblages characterized by cold-water organisms throughout the Permian,and was affliated to those of the *** of the exotic limestone blocks within the Yarlung Zangbo suture zone are Guadalupian(Middle Permian)to Early Triassic in *** exotic limestone blocks bear fossil assemblages that have transitional affinities between the warm Tethys and cold Gondwanan regions,suggesting that they most probably represent seamount deposits in the Neo-Tethys *** the Asselian to Sakmarian(Cisuralian,also Early Permian),the Cimmerian microcontinents in the northern part of Gondwana preserved glacio-marine deposits of Asselian to Sakmarian,and contained typical Gondwana-type cold-water *** the middle Cisuralian(~290-280 Ma),the Cimmerian microcontinents rifted off from the Gondwanaland,and drifted northward allometrically due to the active magmatism of the Panjal Traps in the northern margin of the Indian *** slices of micro

关键词： Permian Tethys Ocean qinghai-Tibetan Plateau Biotas Paleogeography

Effect of recombination process in femtosecond laser-induced modification on Ge crystal

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第11期29卷 356-363页

作者： Jia-qi ju Zi-Yao qin ju-Kun Liu Hong-Wei Zhao Yao-qing Huang Rong-Rong Hu Hua Wu College of Science Shanghai Institute of TechnologyShanghai 201418China College of Science Xi’an Shiyou UniversityXi’an 710065China

The dynamics of produced excited carriers under the irradiation of Ge crystal is investigated theoretically by using femtosecond laser pulse.A two-temperature model combined with the Drude model is also used to study the nonequilibrium carrier density,carrier and lattice temperatures,and optical properties of the *** properties of the surface plasmon wave when excited are also *** influences of non-radiation and radiative recombination process on the photoexcitation of the semiconductor during pulse and the relaxation after the pulse are described in *** results show that the effects of Auger recombination on the nonequilibrium carrier density and optical properties of the crystal and the properties of the surface plasmon polariton are great,whereas the effect of radiative recombination is extremely small.

关键词： two-temperature model Ge crystal Auger recombination radiative recombination surface plasmon

Effect of ferrotitanium slag on microstructure and properties of Al_(2)O_(3)-SiC-C castables for iron runner

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第9期31卷 2122-2132页

作者： Tu Long Hua-zhi Gu Mei-jie Zhang Ao Huang Lv-ping Fu Ding Chen Wen-dong qiu Mao-qi ju The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430081HubeiChina Baowu Equipment Intelligent Technology Co. Ltd.Shanghai200000China MCC Group Wuhan Research Institute of Metallurgy Construction Co.Ltd.Wuhan430081HubeiChina

Ferrotitanium slag(FS)is a waste slag produced during the smelting of ferrotitanium alloys by thermite *** alumina content is high and can be used as alumina raw *** runner castables containing different amounts of FS were prepared and *** results show that the introduction of FS is beneficial to the sintering of the castables *** the FS concentration is 11.2 wt.%,the aggregate and matrix of the castables sample have a good combination,and the mechanical strength of the Al_(2)O_(3)–SiC–C castable reaches a maximum at room ***,excessive introduction of FS generates a large amount of anorthite phase,which reduces the mechanical strength of the Al_(2)O_(3)–SiC–C castable at room *** addition,the high-melting phase CaTiO_(3)is formed in FS,which has good mechanical ***,the cracks of FS are reduced,and the combination between phases is closer,thus significantly improving the hot modulus of rupture of the *** the FS concentration is not above 33.6 wt.%,the castables show good slag *** TiO_(2)in FS is transformed into TiC by carbothermal reaction,which is enriched at the boundary and prevents further reaction of the slag.

关键词： Ferrotitanium slag Al_(2)O_(3)-SiC-C castable Hot modulus of rupture Slag resistance

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

含稀土镁合金的摩擦磨损性能

中国有色金属学报 2006年第7期16卷 1219-1226页

作者：祁庆琚宝山钢铁股份有限公司技术中心上海201900

研究稀土对AZ91和AM60镁合金摩擦磨损性能的影响。结果表明:在所研究的范围内,稀土镁合金的摩擦磨损特性明显优于基体合金;含稀土镁合金与不含稀土镁合金的磨损速率都随载荷的增加而增加,AZ91镁合金的耐磨性要远远高于AM60稀土镁合金。... 详细信息

研究稀土对AZ91和AM60镁合金摩擦磨损性能的影响。结果表明:在所研究的范围内,稀土镁合金的摩擦磨损特性明显优于基体合金;含稀土镁合金与不含稀土镁合金的磨损速率都随载荷的增加而增加,AZ91镁合金的耐磨性要远远高于AM60稀土镁合金。磨损机制在实验条件下都相同,均发生由轻微磨损向严重磨损的转变;稀土的加入细化合金组织,改善镁合金的综合性能,增强磨损表面氧化膜的稳定性,提高稀土镁合金的承载能力,有效地延迟由轻微磨损向严重磨损的转变过程。

关键词： AZ91 AM60 稀土 Mg-Al合金摩擦磨损