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

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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 {3. of sciences, Chengdu 610041, china 2. Sichuan Fire Research Institute of Public Security Ministry, Chengdu 61183., china 3. graduate school of the chinese academy of sciences, beijing 10003., china correspondence should be addressed to zhang zejiang (email: zzjzzjzz@***) 1. Chengdu Institute of Organic Chemistry Chinese Academy of Sciences 610041 Chengdu China 2. Sichuan Fire Research Institute of Public Security Ministry 611830 Chengdu China 3. graduate school of the chinese academy of sciences 100039 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 SiO2film 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 2p, Mg 2p, Si 2s 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 SiO2on 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 244.67℃ and 43..13., whose corresponding heat absorption capacities are 412.28 J/g and 3.6.3. J/g, respectively. In contrast, the coated nano-LDHs have only one endothermic peak at 243.60℃ with a heat absorption capacity of 221.25 J/g.

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

Pitfalls in the analysis of ancient human mtDNA

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chinese Science Bulletin 2003年第8期48卷 826-830页

作者： YAO Yonggang1,3.& zhang Yaping1,2 1. Laboratory of Molecular Evolution and Genome Diversity, Kunming Institute of Zoology, chinese academy of {3., Kunming 650223. china 2. Laboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming 650091, china 3. graduate school of the chinese academy of sciences, beijing 10003., china correspondence should be addressed to zhang Yaping (e-mail: zhang- yp1@***) Laboratory of Molecular Evolution and Genome Diversity Kunning Institute of Zoology Chinese Academy of Sciences China graduate school of the chinese {3. of sciences China Laboratory for Conservation and Utilization of Bio-resource Yunnan University China

The retrieval of DNA from ancient human specimens is not always successful owing to DNA deteriora-tion and contamination although it is vital to provide new insights into the genetic structure of ancient people and to reconstruct the past history. Normally, only short DNA fragments can be retrieved from the ancient specimens. How to identify the authenticity of DNA obtained and to uncover the information it contained are difficult. We employed the ancient mtDNAs reported from Central Asia (including Xin-jiang, china) as an example to discern potentially extraneous DNA contamination based on the updated mtDNA phylog-eny derived from mtDNA control region, coding region, as well as complete sequence information. Our results demon-strated that many mtDNAs reported are more or less prob-lematic. Starting from a reliable mtDNA phylogeney and combining the available modern data into analysis, one can ascertain the authenticity of the ancient DNA, distinguish the potential errors in a data set, and efficiently decipher the meager information it harbored. The reappraisal of the mtDNAs with the age of more than 2000 years from Central Asia gave support to the suggestion of extensively (pre)historical gene admixture in this region.

关键词：古代人类遗传构造 DNA 脱氧核糖核酸

Quantitative reconstruction of the paleosalinity at Qinghai Lake in the past 900 years

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chinese Science Bulletin 2004年第7期49卷 730-734页

作者： zhang Enlou1,2,SHEN Ji1,WANG Sumin1,YIN Yu1,ZHU Yuxin1 & XIA Weilan1 1.Key Laboratory of Lake Sediment and Environment,Nanjing institute of Geography and Limnology,chinese academy of {3.,Nan-jing 210008,china 2.graduate school of chinese academy of {3.,beijing 10003.,china {13. should be addressed to zhang Enlou(e-mail:elzhang@ ***) Key Laboratory of Lake Sediment and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China graduate school of chinese {3. of sciences Beijing 100039 China

Based on the function relationship between the shell length of Limnocythere inopinata and the salinity of its living water in Tibetan Plateau lakes, the paleosalinty of Qinghai Lake in the past 900 years was reconstructed through the measurement of the adult body length of Limno-cythere inopinata. Meanwhile, the paleosalinity sequence of Qinghai Lake during the same period was rebuilt by the Sr/Ca ratio of the shell of Eucypris inflata combined with the Sr/Ca ratio of living ostracod valves from the species of ge-nus Eucypris inflata and the host water. The paleosalinity results obtained by two different methods were compared and assessed in this paper. To check the result, it was also contrasted with other historical climatic sequences of this area including tree ring and ice core. It was shown that the paleosalinity sequence rebuilt by adult ostracod body length had high reliability, and the paleosalinity reconstruction method by trace elements of ostracod shells was not suitable for Qinghai Lake. From the reconstructed paleosalinty se-quence of Qinghai Lake, it can be found that low salinity during 1160—1290 AD showed the humid climate condition on the Mediaeval Warm Period in this area, while the high salinity during 1410—1540 AD, 1610—1670 AD and 1770—1850 AD which was corresponding to the three cold pulses of the Little Ice Age with a dry climate condition. And the high salinity in the latest several decades was consistent with re-cent warm and dry trends of the climate in this area. The good consistency of the reconstructed palaeosalinity sequence and the precipitation sequence in this area rebuilt by tree ring proves the reconstruction of past lake salinity is reliable.

关键词：青海湖数量重建成体特异湖浪介古盐度树轮海底沉积物介形亚纲动物

Assembly of gold nanoparticles with H_(10)TTPR (3., 4, 5, 8, 9, 9a, 10, 11-octa-hydro-2H,3.-1,6,7,12-tetrathia-perylene) as the rigid cross-linker

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chinese Science Bulletin 2004年第8期49卷 789-792页

作者： SHAO Xiangfeng1,2, WANG Tongxin1, zhang Deqing1, XU Wei 1 & ZHU Daoben1 1. Organic Solids Laboratory, Center for Molecular sciences, Institute of Chemistry, chinese {3. of sciences, beijing 100080, china 2. graduate school, chinese {3. of sciences, beijing 100080, china correspondence should be addressed to Zhu Daoben or zhang Deqing (e-mail: dqzhang@***) Organic Solids Laboratory Center for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China graduate school Chinese Academy of Sciences Beijing 100080 China

Gold nanoparticles were assembled with the rigid cross-linker, H10TTPR. The assembly process was stud-ied with the UV-vis spectroscopy and TEM. By adjusting the amount of H10TTPR added to the gold nanoparticle solutio... 详细信息

关键词：纳米金粒子集成刚性交叉连接 TEM UV-力光谱学