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Bibliographic Information
The evidence of Sm-Nd isochron age for the early Paleozoic ophiolite in Mangya area, Altun Mountains [China]. Liu, Liang; Che, Zicheng; Wang, Yan; Luo, Jinhai; Wang, Jianqi; Gao, Zhangjian. Dep. Geology, Northwest Univ., Xian, Peop. Rep. China. Chinese Science Bulletin (1998), 43(9), 754-756. CODEN: CSBUEF ISSN: 1001-6538. Journal written in English. CAN 129:151322 AN 1998:352570 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
The REE patterns of the basic volcanic rocks in Mangya area, Altun, southwest margin of Tarim plate, are slightly enriched in LREE with (La/Yb)N = 1.69-3.20, (La/Sm)N = 1.37-1.87. Other trace element ratios of these rocks are Th/Ta » 1 (for a few samples greater than 1.5), Nb/Y = 0.34-0.62, Ti/Y = 310-443 (av. 381), Ti/V = 37-62, Zr/Nb = 9.4-12.4, Sr/Rb = 12-80 (av. 37), and Nb/Th = 7.7-16.8. These features are similar to the chem. of E-MORB or OIB. The eNd(t) value, being 3.95-4.12, shows that the source of the volcanic rocks is derived from depleted asthenosphere mantle mixed with materials from enriched mantle. These, together with the information of geol. setting and rock assemblages, indicate that the basic volcanic rocks are of ophiolitic origin. The Sm-Nd isotope ages for the eight basic volcanic rock samples conform to a straight line with good correlation, and the calcd. isochron age is (481.3 ± 53)Ma. In addn., the eight calcd. eNd(t) and model ages are close to each other, which suggests that they are homologous, so the isochron is not a mixed line. The isochron age ((481.3 ± 53) Ma) is lower than the model ages (TDM = 1004-1534 Ma) of the samples, suggesting that the isochron age represents the formation age of the basic volcanic rocks, whereas the ophiolite belt in Mangya area, Altun, formed in the early Paleozoic (Cambrian-Ordovician). In spite of the great uncertainty in the age, it is still reliable because it is consistent with the age constrained by the regional strata.
Bibliographic Information
Studies of the surface property and dynamics of PET under CF4/CH4 plasma treatment. III. Application of the surface energy method in surface dynamics research. Zhang, Liang; Wang, Jianqi; Zhang, Xinsheng. State Key Lab. Mesoscopic Physics, Dep. Physics, Peking Univ., Beijing, Peop. Rep. China. Yingyong Huaxue (1998), 15(2), 88-90. CODEN: YIHUED ISSN: 1000-0518. Journal written in Chinese. CAN 129:5199 AN 1998:316186 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
The static state contact angle technique has been used in study the properties of the CF4/CH4 plasma modified PET [poly(ethylene terephthalate)] surface. The surface free energy, polar component and dispersion component before and after plasma treatment and water impregnation were calcd. by Keable method. The hydrophobicity property of the modified PET surface was improved and the CF4/CH4 plasma exhibited a stronger effect than the CF4 plasma.
Bibliographic Information
An approach to the flame retardancy of EVA copolymer by plasma treatment. Shi, Laishun; Wang, Jianqi. Beijing Institute of Technology, School of Chemical Engineering and Materials Science, Beijing, Peop. Rep. China. Journal of Beijing Institute of Technology (English Edition) (1997), 6(4), 313-320. CODEN: JBITE5 ISSN: 1004-0579. Journal written in English. CAN 128:244876 AN 1998:235266 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique. Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent sapon. and metal ion exchange expediting the charring of polymers upon heating. Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers (MAA, AA and AAm) indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications.
Bibliographic Information
On the electron-beam (EB) irradiation and grafting of acrylic monomers onto EVA copolymers. Zhang, Sheng; Wang, Jianqi; Xie, Liqing; Wen, Chenlin. State Key Laboratory of Flame Retardant Materials, Beijing Institute of Technology, School of Chemical Engineering and Materials Science, Beijing, Peop. Rep. China. Chinese Science Bulletin (1997), 42(18), 1549-1554. CODEN: CSBUEF ISSN: 1001-6538. Journal written in English. CAN 128:75782 AN 1998:50374 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
Electron beams are used to graft either methacrylic acid, acrylic acid, or acrylamide onto EVAs of varied structure. The flame retardancies of the resulting polymers are examd.
Bibliographic Information
A cone calorimetric study of flame retardancy and smoke emission of PVC. I. The effect of cuprous and molybdic oxides. Li, Bin; Wang, Jianqi. National Laboratory Flame Retarded Materials, School Chemical Engineering Materials Science, Beijing Institute Technology, Beijing, Peop. Rep. China. Journal of Fire Sciences (1997), 15(5), 341-357. CODEN: JFSCDV ISSN: 0734-9041. Journal written in English. CAN 128:35440 AN 1997:804392 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
Cone calorimetry in air at irradiance of 25, 35, and 50 kW/m2 was used to study the flame retardancy of Cu2O and MoO3 on PVC. Mechanistic aspects on flame retardancy and smoke generation of PVC formulations are described in terms of heat release rate, time to ignition, and specific extinction area. PVC formulations contg. MoO3 showed slower onset of smoke emission and longer time to ignition in the burning cycle than those contg. Cu2O. The flame retardancy of PVC/Cu2O and PVC/MoO3 systems relative to PVC is attributed to lower heat release rate and higher char residue.
Bibliographic Information
An XPS investigation of thermal degradation and charring processes for polymers in the condensed phase III. Wang, Jianqi; Huang, Xianbo. National Laboratory of Flame Retarded Materials, Beijing Institute of Technology, School of Chemical Engineering and Materials Science, Beijing, Peop. Rep. China. Recent Advances in Flame Retardancy of Polymeric Materials (1997), Volume Date 1996, 7 282-292. CODEN: RAFMFH Journal written in English. CAN 127:234717 AN 1997:586054 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
The pseudo-transformation temp. from mesophase to graphitic structure of the char residues for polymers with carbon-contg. backbones was studied with emphasis on the effect of catalysts and flame retardants.
Bibliographic Information
Approaches to the flame retardancy of polymers. Part I.: Electron-beam pre-irradiation and grafting of acrylic monomers onto EVA copolymers. Wang, Jianqi; Zhang, Sheng; Xie, Liqing; Wen, Chenlin. Natl. Lab. Flame Retarded Maters., Beijing Inst. Technol., Beijing, Peop. Rep. China. Journal of Fire Sciences (1997), 15(1), 68-85. CODEN: JFSCDV ISSN: 0734-9041. Journal written in English. CAN 126:158243 AN 1997:142140 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
An attempt has been made to impart flame retardancy to polymers with grafting induced by the electron-beam (EB) pre-irradn. technique. Based on EVA copolymers with different VA contents (%), the authors have tried to use EB pre-irradn. followed by grafting with or without subsequent sapon. to expedite the charring of polymers upon heating. Grafting with methacrylic acid, acrylic acid, or acrylamide improved the fire retardancy of EVA, and EVA grafted with methacrylic acid and then sapond. had the best results.
Bibliographic Information
Synthesis and characterization of rare earth 2,3-dichloroisobutanoates. Liu, Muqing; Wang, Jianqi; Gao, Yici; Shen, Fengjia; Shi, Qzhen. Chem. Dep., Shangrao Teachers Coll., Shangrao, Peop. Rep. China. Huaxue Yanjiu Yu Yingyong (1996), 8(4), 489-492. CODEN: HYYIFM ISSN: 1004-1656. Journal written in Chinese. CAN 126:152017 AN 1997:91254 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
Rare earth 2,3-dichloroisobutanoate complexes RE(L)3×H2O (RE = La, Ce, Nd, Sm, Eu, Gd, Dy, Ho, Yb; L = ClCH2CMeClCO2-) were prepd. in abs. EtOH. The complexes were characterized by elemental anal., molar conductance, IR and UV absorption spectra, DTA, TG and XPS. The molar conductance data reveal that these complexes are non-ionic. The frequency difference, Dn = nas,CO2-ns,CO2, shows that the combination mode between the carboxylato ions and rare earth ions takes the form of the sym. chelating bidentate binding mode in the complexes.
Bibliographic Information
An XPS investigation of thermal degradation and charring processes for PVC and PVC/Cu2O systems in the condensed phase. II. Tu, Hongbin; Wang, Jianqi. College of Chemical Engineering and Materials Science, Beijing Institue of Technology, Beijing, Peop. Rep. China. Polymer Degradation and Stability (1996), 54(2-3), 195-203. CODEN: PDSTDW ISSN: 0141-3910. Journal written in English. CAN 126:90103 AN 1997:56242 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
Exptl. evidence convincingly shows that the combination of XPS and TGA/FTIR enables the provision of significantly more information on degrdn. and smoke emission of polymers. PVC and PVC/Cu2O were chosen as systems to be investigated. Qual. and quant. information concerning these two processes in the condensed phase indicates that early crosslinking plays the most important role, in particular, in the presence of catalyst Cu2O during degrdn. and charring processes. The interaction between PVC and Cu2O was exptl. confirmed with the help of the shake-up satellites and Auger parameter a*, showing that the redox cycle of the catalyst itself works quite well: Cu2O ® CuCl ® Cu ® Cu2O as the temp. rises from ambient to 500°C, which is in complete agreement with the reductive-coupling mechanism. The valence band structures also turn out to be quite informative in the elucidation of both processes.
Bibliographic Information
Investigation on the surface dynamics of PET treated by CF4 and CF4/CH4 plasmas. 1. By static contact angle and angle-dependent XPS techniques. Zhang, Liang; Chen, Xiaodong; Wang, Jianqi. Sch. Chemical Eng. Maters. Sci., Beijing Inst. Technol., Beijing, Peop. Rep. China. Beijing Ligong Daxue Xuebao (1996), 16(2), 155-159. CODEN: BLXUEV ISSN: 1001-0645. Journal written in Chinese. CAN 126:89992 AN 1996:666299 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
PET was treated by CF4 and CF4/CH4 plasmas, and the modified surface was characterized by angle-dependent XPS and contact angle techniques. The modified PET surface became more hydrophobic. CF4/CH4 plasma exhibited stronger effects than CF4 plasma alone. The hydrophobic behavior of the plasma treated PET surface rapidly deteriorated upon immersing in water due to the turnover of the fluorine-contg. groups from the surface to the bulk in the water environment. The CF4/CH4 plasma improved the surface stability.
Bibliographic Information
Kinetics and mechanism of CO substitution of [h5-CpFe(CO)3]PF6 with PPh3 in the presence of substituted pyridine N-oxide. Wang, Jianqi; Gao, Yici; Shi, Qizhen. Department of Chemistry, Lanzhou University, Lanzhou, Peop. Rep. China. Inorganica Chimica Acta (1995), 240(1-2), 153-7. CODEN: ICHAA3 ISSN: 0020-1693. Journal written in English. CAN 124:261275 AN 1996:104254 CAPLUS (Copyright 2004 ACS on SciFinder (R))
Abstract
The kinetics of substitution reactions of [h5-CpFe(CO)3]PF6 with PPh3 in the presence of R-PyOs were studied. For all the R-PyOs (R = 4-OMe, 4-Me, 3,4-(CH)4, 4-Ph, 3-Me, 2,3-(CH)4, 2,6-Me2, 2-Me), the reactions yield the same product [h5-CpFe(CO)2PPh3]PF6, according to a 2nd-order rate law that is 1st order in concns. of [h5-CpFe(CO)3]PF6 and of R-PyO but zero order in PPh3 concn. These results, along with the dependence of the reaction rate on the nature of R-PyO, are consistent with an associative mechanism. Activation parameters further support the bimol. nature of the reactions: DH¹ = 13.4 ± 0.4 kcal mol-1, DS¹ = -19.1 ± 1.3 cal k-1 mol-1 for 4-PhPyO; DH¹ = 12.3 ± 0.3 kcal mol-1, DS¹ = -24.7 ± 1.0 cal K-1 mol-1 for 2-MePyO. For the various substituted pyridine N-oxides studied the rates of reaction increase with the increasing electron-donating abilities of the substituents on the pyridine ring or N-oxide basicities, but decrease with increasing 17O chem. shifts of the N-oxides. Electronic and steric factors contributing to the reactivity of pyridine N-oxides were quant. assessed. 上一頁(yè) [1] [2] [3] [4] [5] [6] [7] [8] 下一頁(yè)
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