高效液相色谱法同时测定催化反应液中氨基葡萄糖盐酸盐和氨基葡萄糖酸

向制备氨基葡萄糖酸的催化反应液中加入亚硝酸盐试剂,在25℃下衍生反应5 min,所得含有氨基葡萄糖盐酸盐和氨基葡萄糖酸衍生物的溶液用作高效液相色谱分析。选用AminexHPX-87H离子排斥色谱柱为固定相,以5 mmol·L^-1硫酸溶液为流动相进行淋洗,用示差折光检测器进行检测,提出了同时测定氨基葡萄糖盐酸盐和氨基葡萄糖酸的高效液相色谱法。2种化合物的色谱峰面积与其浓度均在50 mmol·L^-1以内呈线性关系,检出限（3S/N）依次为0.014,0.034 mmol·L^-1。方法用于5批催化反应液中氨基葡萄糖盐酸盐和氨基葡萄糖酸的测定,加标回收率依次在99.3%～100%,99.2%～102%之间;测定值的相对标准偏差均小于2.5%。     

纳米镁铝水滑石的合成、微结构及吸附性能研究

本文以硝酸镁、硝酸铝为原料,以碳酸钠和氢氧化钠为沉淀剂和pH值调节剂,采用液相沉淀法制备了纳米镁铝水滑石层状化合物(Mg-Al-LDHs),利用X射线衍射(XRD)、扫描电镜(SEM)及X射线能谱分析仪(EDS)系统比较研究了pH值、反应温度、镁铝比等条件对合成LDHs晶体微结构及晶体生长的影响,同时利用生长基元的配位体理论对其生长机理进行了初步探讨,在此基础上,以甲基橙(MO)模拟染料废水为吸附对象,考察了最佳条件下制备的LDHs培烧产物的吸附性能和吸附机理.研究结果表明:pH值、温度的增加有利于生成结构单一、结晶性、规整性较好的镁铝水滑石晶体,产物晶粒尺寸及径厚比呈增大趋向.当反应温度等于或大于80℃时,温度的升高对镁铝水滑石晶体的形态影响较小.镁铝比的改变对产物的物相影响较小,但影响产物的结晶及生长,当镁铝比为3∶1时,所得产物晶粒的规整度、均一性最好,尺寸约为70-100 nm,厚度为20 nm左右,镁铝比为1∶1时,晶粒粒径明显减小,约为30 nm左右.最佳条件下合成的纳米镁铝水滑石焙烧产物具有较好的吸附性能,随着时间的增加,吸附脱色率逐渐增加,当吸附时间达到70 min,LDO对染料的吸附逐渐达到饱和平衡,脱色率达到90;以上,吸附动力学研究表明LDHs对甲基橙的吸附过程更符合准一级动力学方程,其R2值更接近1,吸附等温线符合Iangmuir模型.     

晚清时期译日化学教科书述评*——以1907年版《中等最新化学教科书》为例

晚清时期由日本吉田彦六郎著、何燏时翻译的《中等最新化学教科书》是癸卯学制颁布后第一本较有影响的译日中等学校化学教科书。从出版背景发现其是效法日本教育的产物,内容体系意在传递给学生较完备的化学知识,化学名词术语翻译趋向标准化,晚清时期译日化学教科书使我国中学化学教材的编制上升了一个新台阶。     

Non-monotonic dependence of current upon i-width in silicon p–i–n diodes

Silicon p–i–n diodes with different i-region widths are fabricated and tested. It is found that the current shows the non-monotonic behavior as a function of i-region width at a bias voltage of 1.0 V. In this paper, an analytical model is presented to explain the non-monotonic behavior, which mainly takes into account the diffusion current and recombination current contributing to the total current. The calculation results indicate that the concentration ratio of p-region to n-region plays a crucial role in the non-monotonic behavior, and the carrier lifetime also has a great influence on this abnormal phenomenon.     

Numerical simulation of the magnetoresistance effect controlled by electric field in p–n junction

The magnetoresistance effect of a p–n junction under an electric field which is introduced by the gate voltage at room temperature is investigated by simulation. As auxiliary models, the Lombardi CVT model and carrier generationrecombination model are introduced into a drift-diffusion transport model and carrier continuity equations. All the equations are discretized by the finite-difference method and the box integration method and then solved by Newton iteration.Taking advantage of those models and methods, an abrupt junction with uniform doping is studied systematically, and the magnetoresistance as a function of doping concentration, SiO_2 thickness and geometrical size is also investigated. The simulation results show that the magnetoresistance(MR) can be controlled substantially by the gate and is dependent on the polarity of the magnetic field.     

Numerical simulation study of organic nonvolatile memory with polysilicon floating gate

A polysilicon-based organic nonvolatile floating-gate memory device with a bottom-gate top-contact configuration is investigated,in which polysilicon is sandwiched between oxide layers as a floating gate.Simulations for the electrical characteristics of the polysilicon floating gate-based memory device are performed.The shifted transfer characteristics and corresponding charge trapping mechanisms during programing and erasing(P/E) operations at various P/E voltages are discussed.The simulated results show that present memory exhibits a large memory window of 57.5 V,and a high read current on/off ratio of ≈ 10~3.Compared with the reported experimental results,these simulated results indicate that the polysilicon floating gate based memory device demonstrates remarkable memory effects,which shows great promise in device designing and practical application.     

水热体系中表面活性剂对合成羟基磷灰石晶体的影响

以CaCO3和CaHPO4·2H2O为前驱物,利用XRD、SEM及FT-IR系统研究了水热体系中不同表面活性剂对合成羟基磷灰石(HAP)晶体微结构及晶体生长的影响,同时利用配位体理论对其生长机理进行了探讨.结果表明:不同类型表面活性剂对合成HAP晶体的分散性、微结构及结晶度有一定的影响,添加菲离子型表面活性剂制备的HAP晶体规整性、完整性、分散性、均一性、结晶度较好,长径比较大,呈一维纳米结构.非离子型表面活性剂种类的不同对HAP晶体的微结构及分散性也有一定的影响.阳离子型表面活性剂的加入对HAP晶体a、b轴方向的OH-Ca6,生长基元起到一定的促进作用,合成的HAP晶体长径比较小,长约1.1～1.5 μm,径向直径约为100～140 nm,阴离子型的促进作用明显大于阳离子型表面活性剂.EDS及FT-IR分析证实,水热环境下表面活性剂仅起到形貌调控和分散作用,对HAP产物的纯度没有任何影响.