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Polycistronic strategy for cyanobacterial expression vector construction: Co-transcription of a human gene and a selective marker gene

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Progress in Natural science:Materials International 2005年第9期15卷 798-803页

作者： ZHANG Yukun1, SHI Dingji2, ZHAO Feifei1, YU Meimin1 and RU Binggen1(1. college of life science, Peking university, Beijing 100871, china 2. college of Marine sciences & Engineering, Tianjin university of science & technology, Tianjin 300450, china) college of life science Peking University Beijing 100871 China college of Marine sciences and Engineering Tianjin University of Science and Technology Tianjin 300450 China

A polycistronic expression vector, pKGA-NTF1, was constructed for the cyanobacterium. Within this vector, the spectinomycin/streptomycin resistance gene (aadA) facilitated the selection of transformants when co-transcribed with favorite genes. A natural glnA gene was selected as the platform to introduce the plasmid into a neutral site of the Synechococcus sp. PCC 7002 chromosome. Function of the vector was demonstrated by the insertion of a modified human Trefoil factor 3 gene (NTF1) to upstream of the aadA gene and by the analyses of the transformed strains. Antibiotics resistance assays showed that the dicistronic expression cassette conferred high spectinomycin resistance to both the E. coli cells and the Synechococcus cells. PCR analysis and Western-blot analysis were carried out to confirm the integration and expression of the NTF1 gene, respectively. Through simple molecular manipulations, the artificial polycistronic structure described here can be conveniently used to express other favorable genes or operons in cyanobacteria, and to study the cyanobacterial gene expression as well.

关键词： cyanobacterial transformation human Trefoil factor 3 polycistronic expression Synechococcus sp. PCC 7002 vector construction.

Pelagodictyon Clarke,a newly recorded nanodiatom genus for china

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Journal of Systematics and Evolution 2009年第2期47卷 179-182页

作者： 1,2Yang LI 2Ya-Hui GAO 1(Key Laboratory of Ecology and Environmental science in Guangdong Higher Education,college of life science,South china Normal university,Guang-zhou 510631,china) 2(School of life sciences,Xiamen university,Xiamen 361005,china) Key Laboratory of Ecology and Environmental science in Guangdong Higher Education College of Life Science South China Normal University Guangzhou 510631 China School of life sciences Xiamen University Xiamen 361005 China

Marine nanoplanktonic diatoms have been frequently either underestimated or overlooked in phyto-plankton investigations due to their small size(2-20 μm),which allows most of them to pass through a regular phytoplankton net of 70-μm pore *** nanoplanktonic diatom classification,water samples(each 2000 mL) were collected from several representative sea areas of Chinese coast from May 2002 to May *** Clarke was identified as a newly recorded nanodiatom genus for china under transmission electron microscope(TEM).This genus is characterized by the delicate structure of the valve *** striae are seen to be formed by ribs with cross-ribs(frets) and the intervening spaces are occupied by polygonal cribra situated much close to the exterior face of the *** one species was found,i.e.,*** *** description of the taxonomic characteristics with TEM photographs of this species and its ecological habitat and distribution are given in this *** characteristics comparisons among several resembling genera were discussed.

关键词： china fret nanodiatom new record Pelagodictyon Stephanodiscaceae

The theoretical study on diagonal wave interaction with perforated-wall breakwater with rock fill

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Acta Oceanologica Sinica 2009年第6期28卷 103-110页

作者： LIU Hongjie LIU Yong LI Yucheng Zhejiang Provincial Planning Design ＆ Research Institute of Communications Hangzhou 310006 China college of Engineering Ocean University of China Qingdao 266100 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China

The interaction of diagonal waves with perforated-wall breakwater partially filled with rock fill is studied using the linear potential theory. By means of the matched eigenfunction expansion method, an analytical method is presented to calculate the reflection coefficient and the wave force coefficient of the breakwater. The calculated results of the reflection coefficient for limiting cases are the same to the existing results. The main effect factors of the reflection coefficient and the wave force coefficient are analyzed by numerical examples. With the increasing of thickness of rock fill, the wave force coefficient on the perforated wall generally decreases, while the reflection coefficient increases. With the increasing of the incident angle of the wave, the reflection coefficient of the breakwater first decreases, reaches its minimum, and then increases monotonously.

关键词： diagonal wave perforated wall rock fill reflection coefficient wave force

The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science china(Technological sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3, WANG Guilan1 & ZHENG Qiguang2 1. School of Material science and technology, Huazhong university of science and technology, Wuhan 430074, china 2. Institute of Laser technology and Engineering, Huazhong university of science and technology, Wuhan 430074, china 3. Mechanical Engineering college, Hubei university of technology, Wuhan 430068, china School of Material science and technology Huazhong University of Science and Technology Wuhan China Mechanical Engineering college Hubei University of Technology Wuhan China Institute of Laser technology and Engineering Huazhong University of Science and Technology Wuhan China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

Scenario simulation and forecast of land use/cover in northern china

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Chinese science Bulletin 2008年第9期53卷 1401-1412页

作者： LI YueChen 1,2,3 & HE ChunYang 3 1 college of Geographical science, Chongqing Normal university, Chongqing 400047, china 2 college of Resources and Environmental science, Chongqing university, Chongqing 400044, china 3 college of Resources science & technology, Beijing Normal university, Beijing 100875, china college of Geographical science Chongqing Normal University Chongqing China college of Resources and Environmental science Chongqing University Chongqing China college of Resources science & technology Beijing Normal University Beijing China

Modeling land use/cover scenario changes and its potential impacts on structure and functions of ecosystem in typical regions are helpful to understanding the interactive mechanism between land use/cover system and ecosystem. Based on the analysis of the existing land use/cover simulation and forecast models, a land use/cover scenario dynamics model by the integration of System Dynamics (SD) model, Back Propagation Neural Network (BPNN) and Cellular Automata (CA) model is developed with land use/cover scenario changes in northern china in the next 30 years and simulated in this paper. The model is to simulate the land use/cover scenario demands by using a SD model at first, and then allocating the land use scenario patterns at the local scale with the considerations of land use/cover suitability, inheritance ability and neighborhood effect by using BPNN-CA model to satisfy the balance between land use/cover scenario demands and supplies. It integrates the advantages of SD, BPNN and CA. Macro-driving factors and the micro-spatial pattern are also fully taken into account. The BPNN simplifies the identification of the factors’ weights used in CA model and improves the reliability of the simulation results. The simulation accuracy of the model developed in this paper was found to be about 74%. It suggests that the model has the ability to reflect the complexity of land use/cover system at different scales to some extent and it is a useful tool for assessing the potential impacts of land use system on ecosystem. The simulated results also indicate that the urban land, water area and forest will increase significantly, and farmland and unable land will decrease gradually. Obvious land use/cover changes will take place in the farming-pastoral zone and the southeast area of northern china.

关键词：土地利用中国北方细胞自动机系统动力学

Physiological and ultralstructural changes of Chlorella sp. induced by UV-B radiation

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Progress in Natural science:Materials International 2005年第8期15卷 678-683页

作者： YU Juan1, TANG Xuexi1*, ZHANG Peiyu 1,2, TIAN Jiyuan1 and DONG Shuanglin1(1. Division of life science and technology, Ocean university of china, Qingdao 266003, china 2. college of life sciences, Qufu Normal university, Qufu 2731653, china) Division of life science and technology Ocean University of China Qingdao 266003 China college of life sciences Qufu Normal University Qufu 2731653 China

In order to investigate the mechanisms of enhanced UV-B radiation on algae, the effects of UV-B radiation on the physiological and ultrastructural changes of Chlorella sp. were examined. The results showed that UV-B radiation could inhibit the growth and photosynthesis of microalgae. UV-B radiation at lower doses increased the photosynthetic pigment (chlorophyll a (Chla) and carotenoid (Car)) contents, while at higher doses of UV-B radiation Chla and Car contents were decreased. The ultrastructure of Chlorella sp. without exposure to UV-B showed that the thylakoid lamellae were clear and regular, the stroma of its chloroplast was apparent and clear. The globules with photosynthetic pigments and the cristae of mitochondria were clearly seen. After exposure to UV-B radiation at dose of 2.88 kJ/m2, the thylakoid lamellae of Chlorella sp. were lost and dissolved, the globules which contained photosynthetic pigments in chloroplast were bleached; some mitochondria cristae were dissolved; slight plasmolysis was found in some Chlorella sp. cells. After exposure to 5.76 kJ/m2 UV-B radiation, the thylakoid was in disarray and disintegration, plasmolysis was found in most cells, and the cell wall was broken and began to fall out. Many blank areas were observed in cells, mitochondria were seriously deformed and most of the mitochondria cristae were dissolved. Also, globules containing photosynthetic pigments in chloroplast were bleached and some empty globules were found in chloroplast. Therefore, UV-B radiation could damage cell structure of Chlorella sp., and this damage increased with the dose of UV-B radiation they exposed to.

关键词： UV-B radiation physiological changes ultrastructure Chlorella sp.

Microstructure and formation mechanism of twins of laths of austenite with high nitrogen

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science china(Technological sciences) 2007年第6期50卷 755-764页

作者： WU CuiLan1,2 & LUO ChengPing2 1 Center for High Resolution Electron Microscopy, college of Materials science and Engineering, Hunan university, Changsha 410082, china 2 college of Mechanical Engineering, South china university of technology, Guangzhou 510641, china Center for High Resolution Electron Microscopy College of Materials Science and Engineering Hunan University Changsha China college of Mechanical Engineering South China University of Technology Guangzhou China

The microstructure of composite diffusion layer of the nitrided and chromized 0.2% carbon steel is investigated using TEM and EDS. It is found that laths of austenite with high nitrogen (γ N) precipitate from α-ferrite matrix in the deeper zone of the diffusion layer. These γ N laths are all twins, with their {111} twinning planes parallel to the lath axis, thus forming a characteristic "back-to-back" morphology. There are two types of γN lath. The first is a genuinely {111} twin, and γ N and α keep the accurate K-S relationship, and each γ N and α form a sharp and smooth γ N/α inter- face of {335}γN//{341}α, namely habit plane {335}fcc. The second is a pseudo-twin, with micro-twins {111} or faults formed within the two twin components. Localized lattice deformation (relaxation) seems to have occurred at the interfaces of the second type of γ N due to the formation of micro-twins or faults within the twin components. These micro-twins or faults make the orientation relationship (OR) between each of the γN and the α-matrix deviate from the accurate K-S OR, and the OR between two γ N twin components deviate from the genuine {111} twin relation- ship. In addition, the γ N/α interface of the second type of γ N is not as sharp or smooth as that of the first one.

关键词： austenite containing nitrogen, twins, steel 20, nitriding, composite chromizing

Effects of NaNbO_3-Co_2O_3 Co-additive on the Properties of PZN-PZT Ceramics

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Journal of Wuhan university of technology(Materials science) 2007年第4期22卷 722-724页

作者：邓毅华 college of Material science and Engineering South China University of Technology Department of Electronic science and technology Huazhong University of Science and TechnologyWuhan 430074China

NaNbO3-Co2O3 co-added PZN-PZT （PZCNNT） ceramics were prepared using conventional solid state reaction. The piezoelectric and dielectric properties were measured. The experimental results show that the addition of 0.3mo1% Co2O3 leads to low dielectric loss （tgδ） in PZCNNT ceramics and the proper addition of NaNbO3 not only improves piezoelectric properties but also decreases intensively dielectric loss and mechanical loss. The optimal ceramic having d33=310 pC/N, kp=0.59, εr=985, tgδ=0.0034, Qm=1380 was obtained.

关键词： PZN-PZT piezoelectric constant dielectric constant dielectric loss

Thermal stability conditions of a weakly interacting Fermi gas in a weak magnetic field

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Progress in Natural science:Materials International 2009年第1期19卷 121-124页

作者： Fudian Mena,Hui Liub,Houyu Zhua a college of Physics science and technology,china university of Petroleum(East china),Dongying 257061,china b college of science,Anhui science and technology university,Fengyang 233100,china college of Physics science and technology China University of Petroleum (East China) Dongying 257061 China college of science Anhui Science and Technology University Fengyang 233100 China

On the basis of the results derived from pseudopotential method and ensemble theory,thermal stability of a weakly interacting Fermi gas in a weak magnetic field is studied by using analytical method of *** exact analytical expressions of stability conditions at different temperatures are given,and the effects of interactions as well as magnetic field on the stability of the system are *** is shown that there is an upperlimit magnetic field for the stability of the system at low temperatures,and there is an attractive dividing value at high *** attractive interaction is lower than the critical value,the stability of the system has no request for magnetic field,but if attractive interaction is higher than the dividing value,a lower-limit magnetic field exists for the stability of the system.

关键词： Fermi gas Interaction Heat capacity Stability