单链多聚核苷酸的喇曼光谱及其主要谱带指认

研究了4种单链多聚核苷酸(PolyA,PolyU,PolyG,PolyC)的喇曼光谱,分析了不同盐溶液浓度对核酸主链构象的影响,并给出了各种单链核酸主要谱带的初步指认.研究表明,喇曼光谱对于研究核酸的氢键配位、主链构象和碱基堆积来说是一种强劲的工具.     

安乃近片近红外定量分析模型的建立

目的：采用近红外漫反射光谱法对安乃近片的含量进行定量分析。方法：从某药业公司抽得安乃近片16批,在市场上购得该厂生产的安乃近片10批,经实验室检验含量是否合格。将这26批样品经内部交叉验证建立预测模型,从样品中自动选取55%为验证集,进行外部验证。结果：通过近红外测得的值跟实验室测得的值接近。结论：安乃近片用近红外漫反射光谱法预测含量,无损检测,比常规测量速度快且简便,用于药品检测及日常监管中具有可行性。     

Electrochemical investigation of DNA hybridization to ferrocene-labelled peptide nucleic acid on gold electrodes

An electrochemical DNA sensor based on ferrocene-labelled peptide nucleic acid （PNA-Fc） was prepared. The hybridization between PNA-Fc and DNA immobilized on a gold electrode was examined by cyclic voltammetry （CV） and differential pulse voltammetry （DPV）. PNA-Fc shows a good electrochemically activity and has a redox potential of 170 mV verus Ag/AgCl electrode after hybridization, representing the characteristic of ferrocene/ferrocenium （Fc/Fc＋） transformation. The results illustrate that PNA-Fe can be used as an effective electrochemical DNA probe sensor.     

食品分析课程中红外光谱法教学初探

近年来,红外光谱分析法在我国食品分析中的应用日趋广泛,为使学校教学内容更好的与社会实际应用接轨,探讨了＂一激发、二补提、三联比＂的教学方法,帮助学生连贯知识系统,弥补教学过程中各课程间知识衔接的不足,扩大知识面,加强理论与应用的联系,较好的达到了教学目标。     

固体螺杆清洗剂的综合分析

固体螺杆清洗剂是专门用于注塑成型、挤压成型及吹塑成型机螺杆和料筒清洗的产品,是机器转色、换料和维护的绝佳帮手．目前国内几乎没有高效、环保的固体螺杆清洗剂产品,所使用的产品主要依赖进口．本研究采用红外光谱、X射线粉末衍射等现代分析手段,对国外某公司的高效固体螺杆清洗剂进行了综合分析．结果表明：该固体螺杆清洗剂的载体树脂为苯乙烯类树脂、主要助剂为烷基磺酸盐类物质、烷基芳基酯类物质．此结果为国内固体高效螺杆清洗剂的研发提供重要参考,大大缩短产品研发周期．     

用Simth Chart软件实现微波阻抗匹配

论述了微波阻抗匹配的重要性及史密斯圆图的构成原理与特性,阐述了利用史密斯圆图设计微波阻抗匹配的直观性与简便性.通过微波阻抗匹配的典型实例,应用Smith Chart软件,快速而精确获得了典型实例的微波阻抗匹配网络.     

ATR-FTIR imaging of albumen photographic prints

The preservation of early 20th century, late 19th century albumen prints is of great concern to collection managers and conservators of photographic materials. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopic imaging is presented for the first time as analytical methodology for the study of albumen photographs. This paper shows the feasibility of obtaining FTIR images of samples from albumen photographs with a high spatial resolution using a Ge ATR objective coupled with an infrared microscope. The improved spatial resolution compared to FTIR images obtained by the reflection method is due to the high refractive index of the ATR crystal, which gives a high numerical aperture and hence, a higher spatial resolution. The technique reveals detailed information on the organic functional group distribution in the individual layers of embedded cross sections and is used complementary to visual microscopy and scanning electron microscopy/energy dispersed X-ray spectroscopy. The main results of the study are discussed with regard to their historical and artistic significance, and they are compared with data from historical and conservation literature.     

The effects of 4 weeks normobaric hypoxia training on microvascular responses in the forearm flexor

Intermittent exposure to hypoxia can lead to improved endurance performance. Currently, it is unclear whether peripheral adaptions play a role in improving oxygen delivery and utilization following both training and detraining. This study aimed to characterize skeletal muscle blood flow (mBF), oxygen consumption (mV?O₂), and perfusion adaptations to i) 4-weeks handgrip training in hypoxic and normoxic conditions, and ii) following 4-weeks detraining. Using a randomised crossover design, 9 males completed 30-min handgrip training four times a week in hypoxic (14% FiO₂ ~ 3250m altitude) and normoxic conditions. mBF, mV?O₂ and perfusion were assessed pre, post 4-weeks training, and following 4-weeks detraining. Hierarchical linear modelling found that mV?O₂ increased at a significantly faster rate (58%) with hypoxic training (0.09 mlO₂·min^?1 · 100g^?1 per week); perfusion increased at a significantly (69%) faster rate with hypoxic training (3.72 μM per week). mBF did not significantly change for the normoxic condition, but there was a significant increase of 0.38 ml· min^?1 · 100ml^?1 per week (95% CI: 0.35, 0.40) for the hypoxic condition. During 4-weeks detraining, mV?O₂ and perfusion significantly declined at similar rates for both conditions, whereas mBF decreased significantly faster following hypoxic training. Four weeks hypoxic training increases the delivery and utilisation of oxygen in the periphery.     

The effects of skin and core tissue cooling on oxygenation of the vastus lateralis muscle during walking and running

Skin and core tissue cooling modulates skeletal muscle oxygenation at rest. Whether tissue cooling also influences the skeletal muscle deoxygenation response during exercise is unclear. We evaluated the effects of skin and core tissue cooling on skeletal muscle blood volume and deoxygenation during sustained walking and running. Eleven male participants walked or ran six times on a treadmill for 60 min in ambient temperatures of 22°C (Neutral), 0°C for skin cooling (Cold 1), and at 0°C following a core and skin cooling protocol (Cold 2). Difference between oxy/deoxygenated haemoglobin ([diffHb]: deoxygenation index) and total haemoglobin content ([tHb]: total blood volume) in the vastus lateralis (VL) muscle was measured continuously. During walking, lower [tHb] was observed at 1 min in Cold 1 and Cold 2 vs. Neutral (P?0.05). Lower [diffHb] was seen at 1 and 10 min in Cold 2 vs. Neutral by 13.5 ± 1.2 µM and 15.3 ± 1.4 µM and Cold 1 by 10.4 ± 3.1 µM and 11.1 ± 4.1 µM, respectively (P?0.05). During running, [tHb] was lower in Cold 2 vs. Neutral at 10 min only (P = 0.004). [diffHb] was lower at 1 min in Cold 2 by 11.3 ± 3.1 µM compared to Neutral and by 13.5 ± 2.8 µM compared to Cold 1 (P?0.001). Core tissue cooling, prior to exercise, induced greater deoxygenation of the VL muscle during the early stages of exercise, irrespective of changes in blood volume. Skin cooling alone, however, did not influence deoxygenation of the VL during exercise.     

地线的干扰与抑制

地线的连接在高速电路板的设计中是必须要涉及到的环节,而由于地线阻抗的存在,必然会对电路的性能产生一定的负面影响。主要介绍在电路板制作中产生地线干扰的原因,并提出抑制地线干扰的方法。