Low-power switching of phase-change materials with carbon nanotube electrodes

Phase-change materials (PCMs) are promising candidates for nonvolatile data storage and reconfigurable electronics, but high programming currents have presented a challenge to realize low-power operation. We controlled PCM bits with single-wall and small-diameter multi-wall carbon nanotubes. This configuration achieves programming currents of 0.5 microampere (set) and 5 microamperes (reset), two orders of magnitude lower than present state-of-the-art devices. Pulsed measurements enable memory switching with very low energy consumption. Analysis of over 100 devices finds that the programming voltage and energy are highly scalable and could be below 1 volt and single femtojoules per bit, respectively.     

Thermal, catalytic, regiospecific functionalization of alkanes

The formation of a single product from terminal functionalization of linear alkanes from a transition metal-catalyzed reaction is reported. The rhodium complex Cp*Rh(eta(4)-C(6)Me(6)) (Cp*, C(5)Me(5); Me, methyl) catalyzes the high-yield formation of linear alkylboranes from commercially available borane reagents under thermal conditions. These reactions now allow catalytic, regiospecific functionalization of alkanes under thermal conditions. The organoborane products are among the most versatile synthetic intermediates in chemistry and serve as convenient precursors to alcohols, amines, and other common classes of functionalized molecules.     

诊断试剂用己糖激酶的制备工艺研究

为获得微生物工程菌株来源的己糖激酶(Hexokinase,HK)并提高HK的发酵水平,对已构建产HK的大肠工程菌株BW25113-pYBE/schk进行发酵工艺优化,为HK法血糖检测试剂盒的配制提供技术支撑。本研究采用正交试验对菌株发酵工艺进行优化,并对超声破壁获取粗酶及粗酶的纯化工艺进行研究。结果表明:工程菌株BW25113-pYBE/schk的最佳发酵培养条件为:装液量80mL/500mL,发酵液初始pH 6.5,发酵温度37℃,接种量2%,诱导剂添加时间为接种后1h,转速180r/min。超声破壁最佳工艺为:功率200 W,工作1.5s间歇1s,破壁5min。在最佳发酵和破壁工艺条件下,HK的发酵活力稳定在157U/mL,经过Ni-Agarose His标签蛋白试剂纯化获得60kD的HK。本研究建立了高产己糖激酶大肠杆菌工程菌株的发酵工艺,有利于降低己糖激酶法血糖试剂盒的成本,为糖尿病患者的准确诊断及普及提供便利条件。     

硫琼脂提取工艺的响应面法优化

采用EDTA-Na2法提取硫琼脂,采用硫酸钡比浊法及苯酚-硫酸法分别测定硫琼脂的硫酸根含量和总糖含量。在单因素试验的基础上,利用响应曲面法优化提取工艺,建立了EDTA-Na2加入量(A)、洗脱时间(B)和洗脱温度(C)与硫琼脂的主要理化指标(硫酸根+总糖)含量(Y)之间的数学模型,确定了硫琼脂提取的最佳工艺条件为:EDTA-Na2加入量为5.90g.L-1、洗脱时间2.2h、洗脱温度为53℃。按此最佳工艺提取的硫琼脂的主要理化指标(硫酸根+总糖)含量为(84.00±0.45)%。     

固体氧化钴pH电极的研制

本文制备了一种可用于溶液pH值测定的固体氧化钴印刷电极。该电极可在2～12pH范围内呈现出良好的Nernst响应。文中就氧化钴的合成方法及印刷电极的制备工艺参数对电极响应行为的影响进行讨论。     

Chlorinated indium tin oxide electrodes with high work function for organic device compatibility

In organic light-emitting diodes (OLEDs), a stack of multiple organic layers facilitates charge flow from the low work function [~4.7 electron volts (eV)] of the transparent electrode (tin-doped indium oxide, ITO) to the deep energy levels (~6 eV) of the active light-emitting organic materials. We demonstrate a chlorinated ITO transparent electrode with a work function of >6.1 eV that provides a direct match to the energy levels of the active light-emitting materials in state-of-the art OLEDs. A highly simplified green OLED with a maximum external quantum efficiency (EQE) of 54% and power efficiency of 230 lumens per watt using outcoupling enhancement was demonstrated, as were EQE of 50% and power efficiency of 110 lumens per watt at 10,000 candelas per square meter.     

不同药剂处理对百合籽球膨大的影响

研究不同药剂处理对百合籽球膨大的影响,结果表明:K、Ca、KT、芸薹素内酯、膨大素对百合膨大均有一定效果,NAA对百合籽球的生长有毒害作用;以K浓度500mg/kg处理效果最好,种球鲜重提高42.12%,极显著高于对照。     

水相凝胶色谱法测定草炭土溶解态有机质的分子质量及分子质量分布

以水为流动相,宽分布葡聚糖为标准,用水相凝胶色谱法测定土壤溶解态有机质的分子质量及分子质量分布.样品的进样量、流动相流速对测定结果无明显影响,测定结果的相对标准偏差小于10%.     

响应面法优化污泥生物干燥工艺条件的研究

运用响应面法对木薯酒糟沼气发酵后污泥的生物干燥工艺条件进行优化。首先,用Plackett-Burman方法对8个相关影响因素的效应进行评价,并筛选出对污泥含水率降低有显著影响的通风量、温度、接种量3个因素;然后,用最陡爬坡试验逼近污泥含水率最低区域;最后,由中心组合试验及响应面分析确定了影响污泥含水率的最佳干燥条件,即通风量6.5 L/h、温度36℃、接种量1.5%,干燥96 h后污泥含水率降低到24.53%。     

Fabrication and use of nanometer-sized electrodes in electrochemistry

Electrodes with electrochemical dimensions as small as 10 angstroms have been fabricated and used for electrochemical studies. These nanometer-scale electrodes have enabled the measurement of electron-transfer rate constants, k(het), that are two orders of magnitude faster than k(het) values accessible with any other electrochemical method.     

香料线滤棒爆口探索及其解决方案研究

为解决香料线滤棒(橙味香料)的爆口问题,进行滤棒成型试验。结果表明:橙味香料中的桔子油和甜橙精油会溶解滤棒搭口粘合剂热熔胶,从而引起滤棒爆口。针对此问题,采用了搭口冷热双胶线技术和伺服同步可调胶量的泵压式供胶系统,并结合对不同厂家提供的冷胶进行筛选,最终有效地解决了橙味香料引起的滤棒爆口。同时,为滤棒爆口和高透成形纸渗胶2个技术难题提供了解决思路。     

猪狂犬病分子生物学的快速诊断

比较狂犬病病毒N基因的同源性,成功设计了一对引物N 1/N 2,该对引物扩增长度为460bp,其中包含有一个特异性的酶切位点,可以把目的片段切成130bp和330bp两个片段。利用该方法对一例猪狂犬病进行了诊断,证实该技术不仅敏感、特异,而且快速,很适合于实验室应用。     

Direct imaging of transient molecular structures with ultrafast diffraction

Ultrafast electron diffraction (UED) has been developed to study transient structures in complex chemical reactions initiated with femtosecond laser pulses. This direct imaging of reactions was achieved using our third-generation apparatus equipped with an electron pulse (1.07 +/- 0.27 picoseconds) source, a charge-coupled device camera, and a mass spectrometer. Two prototypical gas-phase reactions were studied: the nonconcerted elimination reaction of a haloethane, wherein the structure of the intermediate was determined, and the ring opening of a cyclic hydrocarbon containing no heavy atoms. These results demonstrate the vastly improved sensitivity, resolution, and versatility of UED for studying ultrafast structural dynamics in complex molecular systems.     

应用分子方法进行捕食者中肠分析的研究进展

捕食行为是生态学相互作用研究中最困难的问题之一。生态学者已经采用了多种方法来研究节肢动物的捕食行为。其中对田间收集的捕食者进行中肠分析成为获得关于捕食行为数据最清楚、有效的方法。文章综述了对捕食者进行中肠分析的主要方法,特别介绍了单克隆抗体技术和DNA技术的应用进展。     

响应面法优化南极磷虾油提取工艺(英文)

研究南极磷虾油有机溶剂提取工艺,探讨不同冻藏温度、提取剂比例、提取时间、干燥温度和料液比对南极磷虾油提取率的影响在单因素试验基础上,通过响应面法分析确定最佳的提取工艺条件:冻藏温度为-38.5℃、料液比为1 g∶6.7 ml干燥温度是66.8℃,此时南极磷虾油提取率为13.71%。     

保水剂在节水抗旱农业中的应用

本文论述保水剂在农业节水抗旱中应用的重要意义、效果、方法和需要注意的问题.     

Low-temperature synthesis of zintl compounds with a single-source molecular precursor

Thermolysis of the heterobimetallic phosphinidene complex [Sb(PCy)3]2- Li6.6HNMe2 (Cy = C6H11) at 303 to 313 kelvin gives Zintl compounds containing (Sb7)3- anions. The complex thus constitutes a stable molecular single-source precursor to Zintl compounds and provides a potential low-temperature route to photoactive alkali metal antimonates. The new chemical reaction involved, which is driven thermodynamically by the formation of P-P bonds, has implications in the low-temperature synthesis of other technologically important materials (such as gallium arsenide).