功率型白光LED的热特性研究

大功率LED照明单元在光通量提高的同时伴随着散热，且普通功率型白光LED多采用蓝光芯片激发荧光粉的方法，随着温度的提升，荧光粉对应的波长会发生漂移。本文从功率型白光LED的发热原理出发，试验了其在脉冲源作用下，用于照明的可能性。试验表明，在此激励源的作用下，LED输出与散热很好，并从理论上进行了解释。     

Achieving precision and reproducibility for writing patterns of n-alkanethiol self-assembled monolayers with automated nanografting

Nanografting is a high-precision approach for scanning probe lithography, which provides unique advantages and capabilities for rapidly writing arrays of nanopatterns of thiol self-assembled monolayers (SAMs). Nanografting is accomplished by force- induced displacement of molecules of a matrix SAM, followed immediately by the self-assembly of n-alkanethiol ink molecules from solution. The feedback loop used to control the atomic force microscope tip position and displacement enables exquisite control of forces applied to the surface, ranging from pico to nanonewtons. To achieve high-resolution writing at the nanoscale, the writing speed, direction, and applied force need to be optimized. There are strategies for programing the tip translation, which will improve the uniformity, alignment, and geometries of nanopatterns written using open-loop feedback control. This article addresses the mechanics of automated nanografting and demonstrates results for various writing strategies when nanografting patterns of n-alkanethiol SAMs.     

低剂量率γ射线杀伤肿瘤细胞机制的实验研究

用60Co源以1Gy/min剂量率照射Hela细胞,剂量分别为1、2、5、10、15Gy.用AnnexinV和PI双染法观察凋亡细胞形态;DNA梯形条带证实凋亡存在;克隆形成分析细胞增殖能力.结果显示:(1)Hela细胞凋亡率随照射剂量和时间的增加呈上升趋势,照射后168h组各剂量点凋亡率高于其他各时间组.2Gy以下时凋亡率改变不大,达5Gy时凋亡率显著增加,且达峰值(72.57±2.04)%(P＜0.001).(2)早期凋亡细胞,PS外翻,胞膜呈绿色荧光圈.凋亡晚期出现Annexin V-FITC及PI染色均阳性的外绿内红的细胞图像.坏死细胞则为红色.(3)凋亡细胞碎片呈"梯状"条带.(4)1Gy/min的剂量率照射,剂量为2-15Gy,克隆形成率由(58.95±0.36)%降至(1.67±0.35)%(P＜0.001).表明低剂量率γ射线照射可诱导Hela细胞凋亡,其凋亡率与照射剂量相关,在5Gy时凋亡率最高.     

The effect of replacing dietary fish oil with canola oil on fatty acid composition and expression of desaturase and elongase genes in Jade Tiger hybrid abalone

This study investigates the effect of graded substitution of dietary fish oil (FO) with canola oil (CO) on fatty acid composition and expression of Δ-6 desaturase and elongase 2 genes in the muscle of Jade Tiger hybrid abalone. The control diet contained 1.5% FO supplement (0% CO). Four other diets contained FO/CO in ratios of 3:1 (CO 25%), 1:1 (CO 50%), 1:3 (CO 75%) and 100% CO. The result demonstrated that abalone fed the diets supplemented with 25% and 50% CO showed similarly high levels of total omega-3 polyunsaturated fatty acid (n-3 PUFA), eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) (P < 0.05) as the 0% CO group. The highest levels of total PUFA and total monounsaturated fatty acids were found in the 100% CO group (P < 0.05). The results also showed that Δ-6 desaturase and elongase 2 gene expression was increased in a graded manner by increasing dietary CO (P < 0.05). It was concluded that replacement of FO by CO at the levels of 25-50% can improve the contents of health-benefiting EPA and DHA in abalone.     

基于采动和承压水作用下断层突水关键路径的力学分析

 断层突水是煤矿典型的动力灾害,是煤岩体在采动和承压水共同作用下失稳破坏过程。论文针对导水断层缩短了煤层和含水层距离特点,建立了断层突水的关键路径力学模型。将极限平衡理论和尖点突变理论引入断层突水分析,建立了承压水及采动影响下断层突水关键部位失稳破坏模型,获得了断层突水的力学判据,以及防突煤柱预留临界宽度。同时分析了断层参数、煤柱参数对突水条件的影响规律     

浅谈土壤源热泵系统的发展及其应用

概述了土壤源热泵系统的特点，阐述了土壤源热泵技术在国内外的发展、研究现状，最后介绍了土壤源热泵技术在发展中面临的问题及在制冷空调中的广阔应用前景。     

On-bead combinatorial approach to the design of chiral stationary phases for HPLC

A library of 36 L-amino acid anilides, which are potential selectors for chiral HPLC, was synthesized in solution and attached to functionalized macroporous polymer beads. The best selector from the library was identified by a deconvolution process using the HPLC separation of several racemic N-(3,5-dinitrobenzoyl)-alpha-amino acid alkylamides as a probe. In each deconvolution step, a series of chiral stationary phases (CSPs) containing a subset of the amino acid anilide selector library was screened for enantioselectivity. After the best CSP was chosen, the library was further deconvoluted until the single best selector was found. The highest selectivity was obtained with a L-proline-1-indananilide that exhibited alpha values up to 23 under normal-phase HPLC conditions. In addition, six CSPs were prepared using individual selectors from the library, and screening results indicate that the deconvolution process indeed led to the most selective receptor.     

Solution structure of the sodium channel inactivation gate

The sodium channel initiates action potentials by opening in response to membrane depolarization. Fast channel inactivation, which is required for proper physiological function, is mediated by a cytoplasmic loop proposed to occlude the ion pore via a hinged lid mechanism with the triad IFM serving as a hydrophobic "latch". The NMR solution structure of the isolated inactivation gate reveals a stably folded core comprised of an alpha-helix capped by an N-terminal turn, supporting a model in which the tightly folded core containing the latch motif pivots on a more flexible hinge region to occlude the pore during inactivation. The structure, in combination with substituted cysteine mutagenesis experiments, indicates that the IFM triad and adjacent Thr are essential components of the latch and suggests differing roles for the residues of the IFMT motif in fast inactivation.     

Synthesis and biological evaluation of certain new thiazolopyrimidines

A series of 5-methyl-3-phenyl thiazolo[5,4-e][1,2,4]triazolo[1,5-c] pyrimidin-2-thiones and 5-methyl-3-phenyl thiazolo[5,4-e]pyrimidino[3,4-b][1,2,4]triazin-2-thiones were prepared as potential antimicrobial and antitumor agents. Some of the tested compounds showed promising activity. The detailed synthesis, spectroscopic and biological data are reported.