Cloning, construction of prokaryotic expression vector and expression ofEscherichia coli cytosine deaminase gene

Cytosine deaminase gene ofEscherichia coli strain H-30 was cloned, and its initiation codon of ‘GTG’ was mutated to ‘ATG’ by PCR. Prokaryotic recombinant expression vector pBV220-CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine deaminase. 5-FC(5-FC, 5-fluorocytosine) could induce the lethal toxicity to cells containing active CD gene. DNA sequence analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide by comparing DNA sequence of the clone H-30-CD-11 with high enzyme activity with CD gene reported in Gene Bank.     

Diamond synthesis from a system of chromium-carbide and Ni70Mn25Co5 alloy

In order to ascertain the mechanism of interaction between carbide and metallic catalyst and formation of diamond under high pressure and high temperature, and find a new method to synthesize diamond with special properties, it is necessary to investigate the reaction behavior of different carbides and metallic solvent_catalysts under high pressure and high temperature. A system of Cr-3C-2 powder and Ni 70Mn 25Co 5 alloy in weight ratio of 1∶6 was treated under 6 0 GPa and 1 500℃ for 20, 30 or 60 min respectively. X_ray diffraction of the samples indicated the Cr 3C 2 decomposed partially after high pressure and temperature treatment, and Cr 7C 3, Cr and diamond formed respectively. There was not any trace of graphite in the samples. The result suggested that the separated carbon atoms could form diamond directly without conversion process of graphite into diamond. The observation of SEI, WDX and EDX also showed that diamond crystals were synthesized in the system, which have perfect surfaces and shapes, with the average grain size of about 40 μm. The properties of the crystals are being investigated.     

HDTV视频编码器的场景切换

当图象序列的帧与帧之间发生场景切换时,会影响视频编码器的编码质量．为提高高清晰度电视（ＨＤＴＶ）的视频编码器的编码质量,针对其采用的国际标准ＭＰＥＧ－２中ＧＯＰ的结构,提出按场景切换对齐的一种新的ＧＯＰ格式．软件模拟结果显示,ＭＳＥ值明显缩小,ＳＮＲ提高了３ｄＢ,效果较好．     

北疆高产棉花(2250kg皮棉/hm~2)生理特性的研究

通过对北疆高产（２０００ｋｇ皮棉／ｈｍ２）棉田的研究表明,“强源、大库、畅流”是北疆棉花达到高产的重要生理基础,“密、早、矮、膜、大铃”综合栽培技术是获得高产的措施途径。高产还可以提高新疆水资源的利用效率。     

Construction of High Level Expression Cell Lines of Erythropoietin *

Ｅｒｙｔｈｒｏｐｏｉｅｔｉｎ（ＥＰＯ）ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｒｅｇｕｌａｔｏｒｙｆａｃｔｏｒｓｄｕｒｉｎｇｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｍａｍｍａｌｉａｎｅｒｙｔｈｒｏｃｙｔｅ,ａｃｔｉｎｇｍａｉｎｌｙｏｎｔｈｅｅｒｙｔｈｒ...     

区域自然灾害系统基本单元研究(Ⅲ)──湖南省农业自然灾害灾情综合区划

在区域自然灾害系统基本单元概念体系的指导下,以灾害系统基本单元为最小空间单位,选取对湖南省农业生产影响较大的水灾、旱灾、低温冷害、风雹灾及病虫害5种自然灾害,以民政部1978～1993年农业灾情统计数据为标准,并以综合农业灾情强度（16年年平均状况）为指标,在地理信息系统支持下,“自下而上”逐级综合,提出了湖南省农业自然灾害灾情综合区划方案,将全省划分为东西分异的3个一级区及18个二级亚区．通过检验,分区方案合理,较前人在此方面的研究工作有较大的进展     

高频高压E类逆变电源

研制了可用于塑料薄膜表面电晕处理的高频高压Ｅ类逆变电器,逆变器的开关管为ＩＧＢＴ,最大输出电压峰值３０ｋＶ,频率３０ｋＨｚ最大电晕放电功率１ｋＷ,该电源已用工业生产,运行稳定,可靠。     

FD-TRT耐热逆转录酶的特性分析

从嗜热细菌ＦＤ３００９中克隆并分离纯化得到的耐热逆转录酶（ＦＤ－ＴＲＴ）,逆转录反应在６５℃高温下进行,可克服常温逆转录酶的许多缺点,以酵母核糖体ｒＲＮＡ为模板,以与２５５和１８Ｓ ｒＲＮＡ匹配的寡聚脱氧核苷酸为引物,探明了ＦＤ－ＴＲＴ的最适反应条件： ２５ｍｍｏｌ／Ｌ Ｔｒｉｓ－ＨＣｌ（ｐＨ ８．５,２５℃）,２５ ｍｍｏｌ／Ｌ（ＮＨ４）２ＳＯ４,２ ｍｍｏｌ／Ｌ ＭｎＣｌ２,１００ μｇ／ｍｌ明胶．５ ｕｎｉｔ ＲＮａｓｉｎ,２５０ ｍｍｏｌ／Ｌ ４种 ｄＮＴＰ, １μＣｉ３ Ｈ－ｄＣＴＰ, １２ｕｇ ＲＮＡ,２５ ｐｍｏｌ引物,并在此条件下测得 ＦＤ－ＴＲＴ和 Ｔａｑ ＤＮＡ 聚合酶逆转录活力与聚合酶活力的相对比值分别为０．０５６,０．００４５．     

稀土元素(镝、钬、铒、铥、镱、镥、钇和钪)高分辨率ICP光谱谱线表与光谱图的编制

讨论并建立了高分辨率光谱仪参数,在带宽为3pm的光谱条件下摄取了稀土元素的高分辨率等离子发射光谱（ICP）,鉴定了在240～450um波长范围内的谱线,和估测了这些谱线的强度．在实验中也观测到了谱线复杂的物理轮廓,包括超精细结构和未完全分辨的定线轮廓．     

Ru原子高Rydberg态能级的唯象势计算

将文[4]提出的用于碱金属原子的唯象势推广到一般原子的高Rydberg态,并对Ru原子4d7（4F）ns（n＝28－45）和4d7（4F）nd（＝26－48）系列的Ryd－berg能级进行PWKB计算．在理论值与实验数据之间进行比较的基础上,讨论了所得结果的物理意义．