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High－Performance　Liquid　Chromatographic　Determination　Of　N－Nitrosoamines　by　pre－Column　Fluorescence　Derivatization　with　9－Phenanthrene　Chloride

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Chinese Chemical Letters 1996年第12期7卷 1113-1116页

作者： JinMao YOU Bin ZRAO QingCun ZHU(Department of Chemistry, Qufu Normal University, Qufu. Shandong 273 165) Department of Chemistry Qufu Normal University Qufu Shandong 273165

A sensitive high-performance chromatographic method for the detection of N-nitrosoamines with pre-column fluorescence derivatization has been *** representative N-nitrosoamines, which were separated on a reversed-phase C18column with methanol - Water-triethylamine as eluent, were used as model compounds to optimize the derivathation and the chromatographic conditions. The relative standard deviations(n=7) at an analytical concentration of 4×10-6 mol/L are less than 5%. The detection limits (signal-to-noise ratio=3) for the N-nitrosoamines compounds are in the range of 0.02～0. 14 nmol per injection volume(10μl).

关键词： pre Nitrosoamines Column Derivatization Chloride

pre-peak on the structure factor of liquid hypoeutectic Al-Fe alloy

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Chinese Science Bulletin 1998年第14期43卷 1219-1224页

作者： Jingyu Qin Xiufang Bian Weimin Wang Jiaji Ma Changye Xu Shandong Univ Technol Coll Mat Sci & Engn Jinan 250061 Peoples R China Shandong Univ Technol Dept Math & Phys Jinan 250061 Peoples R China

Using a θ-θ X ray diffractometer the structure of liquid hypoeutectic Al Fe alloy at 675℃ and its change with different thermal histories are investigated . Liquid Al is used as a reference system. It is found that a pre peak appears on the small angle part of the structure factor of the nonsuperheated hypoeutectic Al Fe alloy, but disappears after superheating whereas the structure factors of liquid Al hardly change with the different thermal histories, and no pre peak can be observed on them. The appearance of a pre peak is a mark of the intermediate range order (IRO). The pre peak is taken as the correlation between Fe atoms on the IRO length scale. Assume that the crystalline structure is the first order approximation of the liquid structure. A model structure is constructed. The basic unit is a cube formed by 8 Al atoms on its corner and one Fe atom occupying its center. The translation of such a unit along its fourbody diagonals by the length of a diagonal can meet the requirement of the Fe_Fe distance and gives a DO 3 like structure. If the vacancy among the units is filled with fcc like Al cells, the composition of the entity is about Al 7Fe, close to that of the metastable phase Al 6Fe from rapid solidification. It is speculated that there are Al 6Fe like clusters in the liquid hypoeutectic Al Fe alloy.

关键词： liquid hypoeutectic Al Fe alloy structure factor pre peak X ray diffraction.

Population collapses in the pre-modern period:case study of the Fuping County, Northwest China

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Chinese Journal of Population,Resources and Environment 2017年第4期15卷 365-373页

作者： Jie Fei David D.Zhang Institute of Chinese Historical Geography Fudan University Department of Geography The University of Hong Kong

The pre-modern history of population change in the Fuping County(Shaanxi Province, China)during the Ming and Qing Dynasties(AD 1368-1911) was reconstructed using historical *** Fuping County experienced two major population collapses, i.e. the late Ming Dynasty(1550-1640 s) and the 1860-1880 s. The first one was caused by the great AD 1556 earthquake and the extreme droughts and warfare in the 1630-1640 s. The second one was caused by warfare and extreme droughts. As a whole, natural disasters, including extreme drought and great earthquake, were the key direct causes of population collapse, and climatic cooling would be a potential indirect cause. It is very interesting that population collapses occurred almost synchronously in the Fuping County and whole China, and the trends of population change were also very similar. Climate-population relationship in China would be valid at finer geographic level,and climatic cooling could be a potential indirect cause of population collapse.

关键词：人口变化 pre 倒塌中国案例西北自然灾难冷却能

Transcriptional activation function of hepatitis B virus pre S1 protein in yeast

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Hepatobiliary & Pancreatic Diseases International 2003年第2期2卷 563-567页

作者： ShengXiang Xiao XuanXian Peng YongLie Chu ShengBin Xiao YanHong Wu ZhenPing Cao Laboratory of Molecular Biology Institute of Dermatology Second Hospital Xi'an Jiaotong University Xi'an 710004 China. xiaosx@***

OBJECTIVE: To explore the feasibility of cloning of the hepatocyte receptor interacting with the pre Slprotein of HBV by two-hybrid ***: Yeast expression plasmids encoding fusion proteins of full length or portions of pre Sl ofHBV and DNA binding domain of yeast protein GAL4 were constructed and used to transform yeastreporter strain SFY526. Reporter gene product β-galactosidase activity was assayed as a measure oftranscriptional activation in yeast, Mammalian expression plasmid encoding fusion proteins of full lengthpre Sl and DNA binding domain of GAL4 was constructed and used to cotransfect hepatoma cell lineHuh-7 together with CAT reporter plasmid. Cell extracts were assayed for CAT activity by ***: The fusion proteins of full length pre Sl protein and GAL4 DNA binding domain presentedtranscriptional activation function in yeast. The transcription activating sequence was localized to the 21 to47 amino acids of pre Sl protein. Fusion proteins of full length pre Sl and GAL4 DNA binding domaindid not show transcriptional activation function in mammalian ***: The transcription activating sequence of HBV pre Sl protein in yeast overlaps thehepatocyte receptor binding site. The transcriptional activation function of HBV pre Sl protein in yeastmay prevent researchers from using yeast two-hybrid system to clone HBV receptor interacting with pre Slprotein. However, the pre Sl protein does not show transcriptional activation function in mammaliancells. Mammalian two-hybrid system may be a practical method to clone the HBV hepatocyte receptorinteracting with pre Sl protein.

关键词： HBV pre S1 protein transcriptional activation yeast

Polymer Reaction Engineering(pre)─An overview and progress

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高校化学工程学报 1994年第S1期8卷 22-29页

作者： $$$$PAN Zuren(Zhejiang University, Hargzhou 310027)

ＰｏｌｙｍｅｒＲｅａｃｔｉｏｎＥｎｇｉｎｅｅｒｉｎｇ（ＰＲＥ）─ＡｎｏｖｅｒｖｉｅｗａｎｄｐｒｏｇｒｅｓｓＰＡＮＺｕｒｅｎ（ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｒｇｚｈｏｕ３１００２７）１．Ｉｎｔｒｏｄｕｃｔｉ... 详细信息

ＰｏｌｙｍｅｒＲｅａｃｔｉｏｎＥｎｇｉｎｅｅｒｉｎｇ（ＰＲＥ）─ＡｎｏｖｅｒｖｉｅｗａｎｄｐｒｏｇｒｅｓｓＰＡＮＺｕｒｅｎ（ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｒｇｚｈｏｕ３１００２７）１．Ｉｎｔｒｏｄｕｃｔｉｏｎ１．１Ｉｎｄｕｓｔｒｉａｌｂａ...

关键词： overview pre

这款键盘有点甜不止颜值出众的雷柏ralemo pre 5

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新潮电子 2022年第4期 94-95页

作者：王健鹏不详

在这个追求个性化的时代,颜值同样成为外设个性化的重要考量点,而对于一向强调工业设计的雷柏ralemo pre系列而言,新春版、圣诞版、心花怒放版、彩妆版等适合不同风格、不同情境的特殊版本给市场留下了极为深刻的印象。而今天,雷柏ralem... 详细信息

在这个追求个性化的时代,颜值同样成为外设个性化的重要考量点,而对于一向强调工业设计的雷柏ralemo pre系列而言,新春版、圣诞版、心花怒放版、彩妆版等适合不同风格、不同情境的特殊版本给市场留下了极为深刻的印象。而今天,雷柏ralemopre 5的出现,再次用颜值出道外设圈。

关键词：外设键盘不同情境个性化雷柏颜值 pre

pre-WARNING OF THE UPLAND ECOSYSTEM IN THE THREE-GORGE RESERVOIR AREA

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Natural Disaster Reduction in China 2002年第4期 30-36页

作者： Liu Shaoquan, Chen Guojie and Chen Zhijian (Chengdu Institute of Mountainous Region Hazards & Environment, Chinese Academy of Sciences & Ministry of Water Resources, Chengdu 610041, Sichuan, China)

The characters of the upland ecosystem in the Three Gorge Reservoir (TGR) area are presented. An index system and the mathematical models for pre warning of the upland ecosystem are proposed. A pre warning analysis is made on the presumption that no major investment will be made to control and restore the upland ecosystem in the TGR area, and the conclusion is reached that the complex ecosystem and all its subsystems will be in a state of reverse evolution, and the majority of them will be in a warning status by 2010. Based on the analysis, an outline of strategies for optimum control of the situation is given, and the essential strategy is to keep a balance between socio economic development and eco environment rehabilitation.

关键词： the Three Gorge Reservoir area upland ecosystem pre warning

PIP融合蛋白在大肠杆菌中的表达纯化及其与pre特异性的结合

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中华微生物学和免疫学杂志 2001年第4期21卷 355-358页

作者：邓庆丽黄志明王巍邵静中山医科大学孙逸仙纪念医院医学研究中心广州510120 中山医科大学孙逸仙纪念医院肿瘤科广州510120

目的　表达纯化PIP融合蛋白 ,探讨研究PIP与pre特异性结合的方法。方法　构建GST PIP融合蛋白表达质粒pGENKS PIP ,表达质粒在大肠杆菌BL2 1中诱导表达GST PIP融合蛋白 ,并用亲和层析柱加以纯化。利用这一融合蛋白通过Northwesternblot... 详细信息

目的　表达纯化PIP融合蛋白 ,探讨研究PIP与pre特异性结合的方法。方法　构建GST PIP融合蛋白表达质粒pGENKS PIP ,表达质粒在大肠杆菌BL2 1中诱导表达GST PIP融合蛋白 ,并用亲和层析柱加以纯化。利用这一融合蛋白通过Northwesternblot、UV crosslinking方法研究PIP与pre的特异性结合。结果　GST PIP融合蛋白表达质粒pGENKS PIP在大肠杆菌BL2 1中成功地诱导表达了可溶性GST PIP融合蛋白 ,纯化后获得了单一的GST PIP融合蛋白。Northwesternblot和UV crosslinking证实PIP与pre特异性结合。比较两种方法 ,前者较后者特异性高 ,灵敏度低 ,而后者操作简便。结论　表达和获得纯化的PIP融合蛋白。

关键词： PIP融合蛋白大肠杆菌表达纯化 pre 紫外交联试验

LAB 12与neat acoustics的中级搭配LAB 12 pre1/SUARA电子管前后级×neatacoustics ORKESTRA落地式音箱

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视听前线 2023年第4期 40-41页

希腊LAB12有一套前后级,是pre1电子管前级和SUARA电子管后级,我们曾经用它们来推动两对英国neat acoustics的落地式音箱,分别是lotaXplorer和ORKESTRA落地式音箱,试听之后,感觉ORKESTRA与LAB12的这套前后级更合配。

关键词：落地式音箱 SUA 电子管 LAB TRA OR pre