Electrical conduction and thermal properties of Bi-doped Pr0·7Sr0·3MnO3 manganite

Electrical and thermal properties of Bi-doped Pr _0·7 Sr _0·3 MnO ₃ (PSMO) compounds are reported here. It is observed that Bi-doped PSMO compounds follow variable range conduction mechanism. Specific heat, thermal conductivity and thermo-power measurements show that larger Bi-ion, in place of smaller Pr ion, enhances their transition temperatures (T _MI, T _C, T _CP). Thermo-power measurements further strengthen our conclusion for the presence of magnetic polaron, generated due to hybridization of Bi ³⁺ –6s ² and O ^2? –2p orbital and polaronic conduction mechanism.     

X-ray Powder Diffraction Pattern of Bi_4(SiO_4)_3

In cooperation with figure-of-merits the Rietveld analysis can appraise both angular and intensity data of powder diffraction. In this work, X-ray diffraction pattern of Bi4(SiO4)3 was redetermined with intensity figure-of-merits, which qualify agreement between observed and calculated relative intensities. F30 is 158.90 (0.0059, 32), intensity figure of merit Rint is 8.7, I20(17), 8.0. The values of figure-of-merits show that the data of JCPDS cards are distorted. Both the experimental and calculated peak positions and heights are listed in detail.     

Recovery of Glutamic Acid from Fermentation Broth by Membrane Processing

Recovery of glutamic acid from the fermentation broth by membrane processing was investigated. The broth was ultrafiltered (UF), and the retentate was diafiltered (DF) to wash out the remaining product. The dilute DF permeate was concentrated by reverse osmosis (RO). Recovery of glutamic acid by UF (R_uf) was a function of the volume concentration ratio (VCR); R_uf= 1.052 – 1.048/VCR. High VCR, however, decreased UF flux (J) (J = 14.2 – 5.4 In VCR). The rate of recovery by DF was a function of the turnover ratio. A linear relationship between flux and pressure was found during RO. Separation of glutamic acid from bacterial cells by membrane processing could improve the efficiencies of subsequent evaporation and crystallization processes.     

Comparison of Microbiological and Radiometric Assays for Determining Total Folacin in Spinach

Several commercially available forms of spinach were analyzed for total folacin content by the microbiological assay using Lactobacillus casei and a radiometric assay. Types of products included frozen uncooked, fresh raw, microwave and conventionally cooked fresh and creamed strained spinach. Folacin content ranged from 0.62 mcg/g for strained spinach to 2.50 mcg/g for uncooked frozen spinach, when assayed microbiologically. With the radiometric assay, folacin values were significantly higher (P<0.05) than with the L. casei assay. The microbiological assay appears more suitable for determination of total folates in complex food matrices than the radioassay.     

一种新型脉冲微束斑X射线源的研究

通过控制栅极电压技术,有效地控制LaB6阴极电子枪发射系统电子束发射的通与断,成功实现了新型台式微束斑X射线源的脉冲辐射。该X射线源主要由三部分组成：LaB6单晶阴极电子枪发射系统,静电聚焦系统以及金属靶材系统。通过对该微束斑X射线源输出的X射线束斑、亮度等特性的初步实验测试,表明这种脉冲式微束斑X射线源具有束斑小、亮度高的特点,其中X射线束焦斑仅为10μm左右。     

The Pattern Growth of Carbon Nanotubes by Self-assembled Monolayers Techniques

The well controllable selective growth of carbon nanotubes (CNTs)on the desired area is an important issue for their future applications. In this study, a novel method for selective growth of CNTs was proposed by using the technology of self-assembly monolayers (SAMs) and the Fe-assisted CNTs growth. The Si wafers with the a ： Si/Si3N4 layer patterns were first prepared by low pressure chemical vapor deposition (LPCVD)and lithography techniques to act as the substrates for selective deposition of SAMs. The selectivity of SAMs from APTMS solution (N-(2-aminoethyl)-3-aminopropyltrimethoxsilane) is based on its greater reactivity of head group on a-Si than Si3N4 films. The areas of pattern with SAMs will first chelate the Fe3 ions by their diamine-terminated group. The Fe^3 ions were then consolidated to become Fe-hydroxides in sodium boron hydride solution to form the Fe-hydroxides pattern. Finally, the Fe-hydroxides pattern was pretreated in H plasma to become a well-distributed Fe nano-particles on the surface, and followed by CNTs deposition using Fe as catalyst in a microwave plasma-chemical vapor deposition (MP-CVD) system to become the CNTs pattern. The products in each processing step, including microstructures and lattice images of CNTs, were characterized by contact angle measurements, scanning electron microscopy (SEM), XPS, Auger spectroscopy, transmission electron microscopy (TEM) and high resolution TEM (HRTEM) deposition. The results show that the main process parameters include the surface activation process and its atmosphere, consolidation time and temperature, H plasma pretreatment. The function of each processing step will be discussed.     

Live cell tracking based on cellular state recognition from microscopic images

The analysis of cell motion is an essential process in fundamental medical studies because most active cellular functions involve motion. In this paper, a computer-assisted motion analysis system is proposed for cell tracking. In the proposed tracking process, unlike in conventional tracking methods, cellular states referring to the cellular life cycle are defined and appropriate strategies are adopted for cells at different states. The use of cellular state recognition allows detection of possible cell division and hence can improve the robustness of cell tracking. Experimental results show that cells can be successfully segmented and tracked over a long period of time, and the proposed system is found to be as accurate as manual tracking. Various quantitative analyses and visualizations are used to represent cell motion, which demonstrates the usefulness of the proposed system in the study of cell dynamics.     

基于C54X的TETRA系统的信道编码的实现

信道编码是通过在信息元中增加一定的冗余度达到在接收端进行纠错从而实现差错控制的目的,所以也称差错控制编码。文中主要叙述在TI公司的C54X系列芯片上实现TETRA(陆地集群无线电)系统的信道编解码,并详细阐述了TETRA系统中的信道编码中CRC(循环冗余校验)、卷积编码及其维特比译码、交织、扰频以及RM(30,16)的原理,并给出了相关的例程。     

利用高阶累积量实现OFDM信号的调制识别

针对OFDM系统中信号的调制方式，提出一种基于高阶累积量的算法。该算法可以有效地抑制高斯噪声，实现OFDM信号调制方式的识别。文章给出了理论分析和计算机仿真。结果说明算法的性能稳定，复杂度低，具有较高的识别率。     

Biological Evaluation of Protein Quality of Radiation-Pasteurized Haddock, Flounder and Crab

SUMMARY— The effects of radiation sub-sterilization or heat-treatment on the protein quality of haddock, crab and flounder were evaluated by determining the protein efficiency ratio (PER). The PER value of haddock radiated at either level was statistically equal to that of non-radiated haddock. The PER value of crab radiated at either level was statistically equal to non-radiated crab in one replication and significantly higher than non-radiated crab in another replication. The PER value of flounder radiated at the low level was significantly less than that of non-radiated flounder, whereas the PER value of flounder radiated at the high level was statistically equal to that of non-radiated flounder. Low PER values were obtained for heat-treated marine products and these values were significantly lower than those for all other marine product treatments investigated. The protein quality of haddock, crab and flounder was not significantly changed as a result of radiation pasteurization.