TiO_2纳米粉的热处理过程研究

用溶胶凝胶法制备出纳米凝胶粉，于不同温度下热处理形成纳米晶，研究热处理温度对粒子大小、形貌、品相转变及吸附能力的关系．XRD、FT-IR、Raman光谱研究表明200～600℃热处理1h的TiO2纳米晶为锐钛矿相，在700℃热处理的纳米晶为锐钛矿相与金红石相共存，800℃热处理的纳米晶完全为金红石相;TEM、TG、XPS的结果证明热处理温度越高，纳米粒子的粒径越大，吸附能力也越弱.

Soluble and colorless polyimides from alicyclic diamines

A series of novel polyimides was synthesized from alicyclic diamines and various aromatic dianhydrides by one-step polymerization in m-cresol without a catalyst. The polymerization was conducted for 4 hours with refluxing, which was enough to obtain the polymers with high molecular weight. The inherent viscosities of the resulting polyimides were in the range of 0.30 similar to 1.29 dL/g. The prepared polyimides showed excellent thermal stabilities and good solubility. All the polymers were readily soluble in common organic solvents such as chloroform, tetrachloroethane (TCE), dimethylacetamide (DMAc), etc and the glass transition temperatures were observed at 199 to 311 degrees C. UV-visible spectra were obtained to measure the transparency of polymer films. All the polymers showed high transmission above 90% in the wavelength of 400 similar to 700 nm.

平台石墨炉原子吸收法测定饲料中痕量硒

研究了基体改进剂及其用量，硒的最佳灰化温度和原子化温度，以及共存元素的干扰。结果表明，用钯和钙作混合基体改进剂，不仅可以明显消除共存元素的干扰，而且还能大大提高硒的灰化温度和灵敏度。用平台石墨炉原子吸收法直接测定饲料中痕量硒，特征量为３９ｎｇ，检出限为０．１１μｇ／ｇ，相对标准偏差为４．９～７．７％，回收率为９２～１００％。

Bright blue electroluminescent devices utilizing poly (N-vinylcarbazole) doped with fluorescent dye

Bright blue electroluminescent devices have been fabricated using poly (N-vinylcarbazole) (PVK) doped with perylene as the emissive layer, poly(p-phenylenevinylene) (PPV) as the hole-transporting layer, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), tris(8-hydroxyquinoline)aluminum (Alq(3)) as the electron-transporting layer, and Al as the cathode. A luminance of 700 cd/m(2) and a luminescent efficiency of 0.8% are achieved at a drive voltage of 36 V. In the experiment, it is found that the introduction of electron-transporting layer PBD has a great effect on the emissive color of the electroluminescent devices prepared by PVK doped with perylene. Yellow-green emission is observed from the device structure of glass substrate/indium-tin-oxide/PVK:perylene/Al. The possible emissive mechanisms are given. The effect of the transporting layer on the electroluminescence is also discussed. (C) 1997 Elsevier Science S.A.

聚砜、聚二甲基硅氧烷、聚对羟基苯乙烯三元多嵌段共聚物的形态结构

利用动态力学分析（ＤＭＡ）．透射电子显微镜（ＴＥＭ）和小角Ｘ光光散射（ＳＡＸＳ）对聚砜（ＰＳＦ）、聚二甲基硅氧烷（ＰＤＭＳ）和聚对羟基苯乙烯（ＰＨＳ）三元多嵌段共聚物ＰＳＦ—ＰＤＭＳ—ＰＨＳｎ的形态结构进行了研究．结果表明，ＰＳＦ—ＰＤＭＳ—ＰＨＳｎ的形态结构出现了许多新的现象，除具有微相分离的基本特征外，还出现双连续相双分散相的特征．在适当的嵌段长度和组成下，通过ＴＥＭ观察到一种新的特殊形态蜂窝状形态结构，并在嵌段共聚物两相界面处直接观察到非常清晰的界面相．同时，对该形态的形成过程作了初步讨论.

STUDY ON THE NON-STIOCHIOMETRIC SNO2-X NANOCRYSTALLINE MATERIAL BY XRD, XPS AND ESR

Nonstiochiometric SnO2-x nanocrystalline material were successfully prepared through Sol-Gel process using anhydrous stannic chloride and iso-propyl alcohol. TEM observation shows that the mean diameter of the powder sintered at 700 degrees C for 2 hours is about 20 nm. By the investigation of XRD and ESR, we can conclude that the sample sintered at 300 degrees C for 2 hours was amorphous and it grew into nanocrystalline with the oxygen vacancies and defects when sintered at 700 degrees C for 2 hours. Using these conclusion, the ESR signals and the difference between the two SnO2-x samples are explained.

非化学计量比SnO_(2-x)纳米微晶材料的XRD,XPS和ESR研究

采用溶胶凝胶法,以无水四氯化锡及异丙醇为原料,制得非化学计量比的SnO_(2-x)纳米微晶材料.透射电镜图片显示700℃焙烧2h得到的粉体的粒度为20nm,由X射线衍射及X射线光电子能谱的分析可知,300℃焙烧2h得到颗粒边界部分原子无规排布的纳米粉体,而700℃焙烧2h得到的是晶格趋于完整的纳米微晶,它们都存在氧空位及晶格缺陷,利用这些结论可以解释SnO_(2-x)纳米微晶材料中出现的顺磁信号.

ELECTROCHEMICAL FORMATION OF NI-Y INTERMETALLIC COMPOUND LAYER IN MOLTEN CHLORIDE

The reduction of Y(III) ions in molten chloride is known to be a one-step three electron reaction [1, 2, 3], but a voltammogram of YCl3 in molten LiCl-KCl-NaCl at a nickel electrode shows at least two reduction peaks of Y(III) ions, indicating the possibility of formation of Ni-Y intermetallic compounds. Using a galvanostatic electrolysis method, samples were prepared at several current densities at 450, 500, 600 and 700-degrees-C, respectively, and were identified with X-ray diffraction (XRD) and electron probe microanalysis (EPMA) methods. The results show that Ni2Y, Ni2Y3 and NiY can be produced by electrolysis and Ni2Y is found to be the predominant Ni-Y intermetallic compound under the experimental conditions. Nickel appears to diffuse in Ni2Y faster than yttrium, and the diffusion process is the rate determining step during Ni2Y formation.

裂解色谱法研究环化顺-1,4-丁二烯-异戊二烯无规共聚物

如同顺-1,4-聚丁二烯(PBd)和聚异戊二烯(PIP),在一定的催化条件下,顺-1,4-丁二烯-异戊二烯无规共聚物(PBI,简称丁戊无规共聚物)可生成环化顺-1,4-丁戊无规共聚物(CP-BI)。作者曾报道用裂解色谱法表征环化顺-1,4-聚丁二烯(CPBd),本文对不同组成的CPBI和PBI进行了裂解色谱比较研究。 表1所列试样由实验室合成。用CDS pyro-probe 190型裂解器,SP-2305E型气相色谱仪,FID。裂解温度700℃,裂解时间5秒,色谱柱4mm×3m不锈钢柱,填充20%SE-30固定相(101白色担体),柱温106℃,载气氮气40mL/min。试样量约30μg,放于石英管内,后者再插入

固熔体60%NaAlSi_2O_6-40%CaMgSi_2O_6在高温高压下的相图的研究

在1.0～5.0GPa、700～1750℃条件范围内,对固熔体0.6NaAlSi_2O_6-0.4CaMgSi_2O_6进行了研究,探讨了该固熔体在高温高压下的存在行为,研究了由非晶态玻璃向翡翠转化过程中γT作用的相图,得到的透辉石翡翠的晶胞参数为α=0.9439nm,b=0.8573nm,c=0.5233nm,β=107.28°和V=0.41702nm~3。本实验中合成的宝石级翡翠为色泽温润,具有玻璃光泽,半透明的极富观赏性的透辉石翡翠。

Cloning and characterization of beta-carotene ketolase gene promoter in Haematococcus pluvialis

The unicellular green alga Haematococcus pluvialis accumulates a highly valuable ketocarotenoid, astaxanthin, under various environmental stresses. beta-carotene ketolase (BKT) plays a key role in astaxanthin biosynthesis in H. pluvialis. In this paper, an approximate 700 bp 5'-flanking region of the bkt gene containing a putative promoter was cloned through walking upstream. The results of the sequence analysis showed that this bkt 5'-flanking region might have cis-acting elements such as sterol regulatory element (SRE-1)-like motifs, the C-repeat/dehydration responsive element (DRE) and al-3 proximal element (APE)-like motifs, except for typical TATA and CCAAT boxes. The results of the P-galactosidase assay and the transient expression of lacZ driven by a series of sequential deletions revealed that a minimal promoter-like region might exist from -630 to -408 bp, and the highest promoter activity was observed to span the positions from -630 to -308 bp. The results of the site-directed mutagenesis of a C-repeat/DRE and two APE-like motifs in a promoter-like region (-630 to -308 bp) suggested that two APE-like motifs might be essential for transcriptional control of the bkt gene.

Growth promotion of vegetative gametophytes of Undaria pinnatifida by blue light

Through an acclimation period of 10 days, compared to white light, the maximal net photosynthetic rates were significantly higher for gametophytes of Undaria pinnatifida cultivated under blue light (400-500 nm), and were lower under red light (600-700 nm). Chlorophyll c and the carotenoid content of gametophytes were similar under blue light and red light but were much lower under white light. The growth rate of female gametophytes under blue light was higher than that under other lights, and the growth rate of male gametophytes showed little variation with respect to blue and white light. Male and female gametophytes were mixed together to form sporophytes under white, blue and red light. After approximately 5 days, 50% gametophytes became fertile under blue and white light, but remained vegetative under red light after 10 days.

Construction of shuttle, expression vector of human tumor necrosis factor alpha (hTNF-alpha) gene and its expression in a cyanobacterium, Anabaena sp. PCC 7120

The construction of the shuttle, expression vector of human tumor necrosis factor alpha (hTNF-alpha) gene and its expression in a cyanobacterium Anabaena sp. PCC 7120 was reported. The 700-bp hTNF cDNA fragments have been recovered from plasmid pRL-rhTNF, then inserted downstream of the promoter PpsbA in the plasmid pRL439. The resultant intermediary plasmid pRL-TC has further been combined with the shuttle vector pDC-8 to get the shuttle, expression vector pDC-TNF. The expression of the rhTNF gene in Escherichia coil has been analyzed by SDS-PAGE and thin-layer scanning, and the results show that the expressed TNF protein with these two vectors is 16.9 percent (pRL-TC) and 15.0 percent (pDC-TNF) of the total proteins in the cells, respectively, while the expression level of TNF gene in plasmid pRL-rhTNF is only 11.8 percent. Combined with the participation of the conjugal and helper plasmids, pDC-TNF has been introduced into Anabaena sg PCC 7120 by triparental conjugative transfer, and the stable transgenic strains have been obtained. The existence of the introduced plasmid pDC-TNF in recombinant cyanobacterial cells has been demonstrated by the results of the agarose electrophoresis with the extracted plasmid samples and Southern blotting with alpha-(32)p labeled hTNF cDNA probes, while the expression of the hTNF gene in Anabaena sp. PCC 7120 has been confirmed by the results of Western blotting with extracted protein samples and human TNF-alpha monoclonal antibodies. The cytotoxicity assays using the mouse cancer cell line L929 proved the cytotoxicity of the TNF in the crude extracts from the transgenic cyanobacterium Anabaena sp. PCC 7120.

An estimate of divergence time of parazoa and eumetazoa and that of cephalochordata and vertebrata by aldolase and triose phosphate isomerase clocks

Previously we suggested that four proteins including aldolase and triose phosphate isomerase (TPI) evolved with approximately constant rates over long periods covering the whole animal phyla. The constant rates of aldolase and TPI evolution were reexamined based on three different models for estimating evolutionary distances, It was shown that the evolutionary rates remain essentially unchanged in comparisons not only between different classes of vertebrates but also between vertebrates and arthropods and even between animals and plants, irrespective of the models used, Thus these enzymes might be useful molecular clocks for inferring divergence times of animal phyla, To know the divergence time of Parazoa and Eumetazoa and that of Cephalochordata and Vertebrata, the aldolase cDNAs from Ephydatia fluviatilis, a freshwater sponge, and the TPI cDNAs from Ephydatia fluviatilis and Branchiostoma belcheri an amphioxus, have been cloned and sequenced, Comparisons of the deduced amino acid sequences of aldolase and TPI from the freshwater sponge with known sequences revealed that the Parazoa-Eumetazoa split occurred about 940 million years ago (Ma) as determined by the average of two proteins and three models, Similarly, the aldolase and TPI clocks suggest that vertebrates and amphioxus last shared a common ancestor around 700 Ma and they possibly diverged shortly after the divergence of deuterostomes and protostomes.

Molecular cloning, genomic organization and functional analysis of an anti-lipopolysaccharide factor from Chinese mitten crab Eriocheir sinensis

Anti-lipopolysaccharide factor (ALF) represents one kind of basic proteins, which binds and neutralizes LPS and exhibits strong antibacterial activity against Gram-negative R-type bacteria. The ALF gene of Chinese mitten crab Eriocheir sinensis (Milne Edwards, 1853) (denoted as EsALF) was identified from haemocytes by expressed sequence tag (EST) and PCR approaches. The full-length cDNA of EsALF consisted of 700 nucleotides with a canonical polyadenylation signal-sequence AATAAA, a polyA tail, and an open-reading frame of 363 bp encoding 120 amino acids. The high similarity of EsALF-deduced amino acid sequence shared with the ALFs from other species indicated that EsALF should be a member of ALF family. The mRNA expression of EsALF in the tissues of heart, gonad, gill, haemocytes, eyestalk and muscle was examined by Northern blot analysis and mRNA transcripts of EsALF were mainly detected in haemocytes, heart and gonad. The temporal expression of EsALF in haemocytes after Vibrio anguillarum challenge was recorded by quantitative real-time RT-PCR. The relative expression level of EsALF was up-regulated rapidly at 2 h post-injection and reached 3-fold to that in blank group. After a drastic decrease to the original level from 4 to 8h, the expression level increased again and reached 4-fold to that in the blank group at 12 h post-injection. The genomic DNA sequence of EsALF gene consists of 1174bp containing three exons and two introns. The coding sequence of the EsALF mature peptide was cloned and expressed in Escherichia coli BL21(DE3)-pLysS to further elucidate its biological functions. The purified recombinant product showed bactericidal activity against both Gram-positive (G(+)) and Gram-negative (G(-)) bacteria, which demonstrated that the rEsALF was a broad-spectrum antibacterial peptide. All these results indicated that EsALF was an acute-phase protein involved in the immune responses of Chinese mitten crab, and provided a potential therapeutic agent for disease control in aquaculture. (c) 2007 Elsevier Ltd. All rights reserved.