碳氧比能谱测井中能谱及探测器响应的数值模拟

利用蒙特卡罗中子粒子(MCNP)联合输运程序,对在井几何条件下地层中碳、氧、硅、钙等元素发生非弹性散射产生的伽马射线的测量谱及不同探测器的响应进行了模拟。结果表明,同种尺寸的BGO探测器比NaI(Tl)探测器的探测效率大;在谱处理过程中BGO探测器选择光电峰和第一逃逸峰的和作为特征能窗,而NaI(Tl)探测器以光电峰和第一、第二逃逸峰的和作为特征能窗。探测效率以及伽马光子计数与源距关系的模拟结果显示,长源距探测器晶体几何体积应为短源距探测器晶体体积的8倍左右时,二者才具有相当的测量精度。此模拟结果与实验谱具有较好的一致性,这为碳氧比能谱测井的谱处理奠定了基础。     

赤霉素A环重排反应催化剂研究

 简介了赤霉素A环的重排反应,即1,2位及1,10位之间双键的移动及相应内酯环的重排.在利用重排反应构建赤霉素A环的1,2位双键时,首次发现商品化试剂苯基二氯化硼与二苯基溴化硼及二甲基溴化硼一样可用于催化此反应.     

Influences of Electrolytes on Soap-Free P（ST-MMA-AA） Emulsion Polymerization

1 Introduction Functional polymer microspheres are kinds of polymer particles with special structures, morphologies or functional groups~([1]), and have been gained much attention because of their specific properties and their application since 1980s. Although some researches have investigated that the latex particle size and its distribution, as well as the stability of polymerization and the resultant latex were strongly influenced by introducing electrolyte into the emulsion polymerization …     

Effect of density of hydrogen-bonding donor on hydrogen-bonded multilayer buildup

The effect of density of hydrogen-bonding donor （HBD） on the formation of layer-by-layer assemblies of poly（4-vinylpyridine） and poly（4-vinylphenol） was investigated. For this purpose, a series of ethyl-substituted poly（4-vinylphenol） （EsPVPhf） with variable ethyl substitute percentage was synthesized by grafting the phenol moiety along the poly（4-vinylphenol） backbone with 1-bromoethane. UV-vis spectroscopy revealed a uniform deposition process of the hydrogen-bonded multilayer consisting of poly（4- vinylpyridine） （PVPy） and EsPVPhf with variable density of HBD. Notably, it was found that increasing the HBD density of EsPVPhf resulted in a marked decrease of both amount of polymers adsorbed and film thickness, which should be related to the EsPVPhf conformation change from coiled state to extended conformation in ethanol solution. Compared with the effect of charge density in polyelectrolyte multUayer, however, there does not exist a critical density of HBD in our case of hydrogen-bonded multilayer assembly. In addition, surface structures of PVPy/EsPVPhf multilayer films also can be tailored controllably by adjusting HBD density of EsPVPhf. As a result, a new method for tuning the structure of hydrogen-bonding-directed multilayer films was developed.     

Application of microfluidic chip to realize controllable pH gradient

A kind of PH gradient microfluidic chips through soft-lithography microfabrication for isoelectric focusing (IEF) and high performance liquid chromatography (HPLC) is introduced here. These pH gradient chips have the advantages such as easy fabrication, controllable pH range and precision, isoelectric focusing and separation at the same time, low voltage for isoelectric focusing, and time stable pH gradient. This method has potential application to sample preparation, separation and analysis of microfluidic chips.     

High resolution stalagmite δ18O records over the past 1000 years from Dongge Cave in Guizhou

Based on MC-ICP-MS U-series dating andstable O-isotope analysis results, a 4-5 years resolution monsoon record over the past 1000 years has been established for two stalagmites from Dongge Cave, Guizhou. The high resolution oxygen isotope record serves as a proxy for variations in rainfall of Asian southwest monsoon over the Yunnan-Guizhou Plateau. A close relation of the δ18O record with the A^14C record from tree rings largely reflects impact of centennial-scale solar activity on the monsoon climate changes. The conspicuous decrease in the δ18O value at AD 1720 indicates an abrupt increase in monsoon rainfall, suggesting that an atmospheric-oceanic couple over the tropical Indian Ocean plays an important role in rapid increase of the Northern Hemisphere temperature over the last century.     

Synthesis, characterization and properties of diamidodisilanes and azocyclosilane

Organosilicon compounds have been widely researched and have the maximum species besides hydrocarbons. In the progress of the research work, many scientists pay attention to the organic silicon compounds that have vari-ety reactive functional groups[1,2]. The difunctional disi-lanes are very active; they could react with not only the compounds containing reactive hydrogen atoms, but also the reactive polymers. Therefore, the disilanes with di-functional groups could be used as disilane substit…     

Br+C2H4→CH2CHBr+H的从头计算研究

用MP2方法，6-311＋G（d，p）基组，研究了反应Br＋GH4→CH2CHBr＋H的可能反应路径和过渡态以及中间体CH2BrCH2的分解过程．给出了最可能的反应路径及相应的反应物、过渡态和产物零点能修正后的能量．     

磁处理碳酸钙过饱和溶液析晶过程中的"磁记忆效应"

利用双道析晶动力学实时监测系统(DPMS)和时间延迟摄像显微镜(TLVM)系统,验证了磁场抑制碳酸钙过饱和溶液析晶过程中“磁记忆效应”的存在。根据析晶动力学曲线和TLVM图片,比较了磁处理溶液静置不同时间(10,27,45,70、80h)后“磁记忆效应”的差异,首次提出了“磁记忆效应”存在峰值。TLVM光学实验照片清晰显示:溶液磁处理之后静置时间约30h时,沉析物中文石所占比例最多,方解石和球霰石所占比例最少,从而形成软垢,达到最佳阻垢效果;且还发现磁记忆时间至少可以达80h。     

N＋NO2反应动力学研究

采用UMP2(full)/6-31G*方法从理论上对N和NO2的反应进行了研究,计算了各反应通道上所有驻点的构型参数和振动频率,根据相对的G2MP2能量绘制的势能剖面图详细给出了N和NO2的反应机理.在此基础上,应用经Wigner校正的Eyring过渡态理论计算了在280~1 500 K温度范围内,1大气压下该反应3个反应通道的活化热力学量、反应速率常数、频率因子.计算结果表明:N NO2→IM→TS1→N2 O2是主要反应通道,N2和O2为主要产物.