用于硅多条阵列探测器的48路前置电荷灵敏放大器的研制

介绍了一套用于硅多条阵列探测器中的高密度多通道电荷灵敏放大器的研制和阵列探测器电子学的发展现状和工作原理,提出了设计原则和设计思路,特别介绍了一个新开发的用于硅多条探测器中的48路电荷灵敏前置放大器的设计和实际测量结果。它具有低成本、高密度的特点,好于1%的能量分辨和良好的长期稳定性。

长白山各植被带主要树种凋落物分解速率及模型模拟的试验研究

2001～2003年在长白山自然保护区内3个垂直植被带的典型群落红松阔叶林、云冷杉林和岳桦林内,利用网袋埋藏法对群落内的6个主要优势乔木树种凋落物进行埋藏分解试验,研究凋落物分解速率及其变化动态;同时利用分解模型,模拟预测凋落物的分解进展,为深入研究这6个树种的营养策略、群落养分循环等奠定基础,也为森林生态系统管理提供理论依据。研究结果表明,所研究的6个树种凋落物都表现出随时间进程失重率增大的现象,但失重率并不与时间呈线性相关。在分解的638d(1.75a)后,6种叶凋落物的分解速率明显升高。到分解实验结止时(699d),叶凋落物干重剩余率从小至大依次为白桦(24.56%)、紫椴(24.81%)、红松(38.48%)、鱼鳞云杉(41.15%)、岳桦(41.53%)和臭冷杉(42.62%)。枝凋落物分解速率明显低于叶,枝干重剩余率从小至大依次为紫椴(44.98%)、臭冷杉(64.62%)、红松(72.07%)、鱼鳞云杉(73.51%)、白桦(77.37%)和岳桦(80.35%)。在同一海拔高度,阔叶树种叶凋落物分解速率大于针叶树种。并且随着海拔的升高,叶凋落物分解速率逐渐减慢。模型分析预测结果表明,长白山北坡各垂直植被带的优势树种叶凋落物分解95%需4.5～8.0a;年分解系数为紫椴(0.686)>白桦(0.624)>红松(0.441)>鱼鳞云杉(0.406)>臭冷杉(0.397)>岳桦(0.385);枝凋落物分解95%需7.8～29.3a,不同树种间的差异明显。枝年分解系数为紫椴(0.391)>臭冷杉(0.204)>红松(0.176)>鱼鳞云杉(0.157)>白桦(0.148)>岳桦(0.102)。

Study of the mechanism of nanocrystalline Pb(Zr0.52Ti0.48)O-3 prepared by accelerated sol-gel process

Nanocrystalline Pb(Zr0.52Ti0.48)O-3 was prepared from lead acetate, zirconium oxynitrate and titanium tetra-n-butoxide by a sol-gel method. It is found that both the crystallization temperature of precursor PZT and PZT product size were increased with increase of V(C3H8O2)/V(H2O) ratio in solution used. At V(C3H8O2)/V(H2O) = 4.47 the gel was formed moderately quick, and the nanocrystalline PZT with uniform granularity and low crystallizing temperature could be obtained. The diameter of the final nanocrystalline was ranged 60similar to70 nm as measured by atomic force microscopy (AFM). The crystallizing temperature of the precursor PZT was 443degreesC and the crystallization reaction was completed at 500degreesC by DTA and TG. The sol-gel reaction process was monitored by FT-IR and XRD.

制备巯基官能化MCM-48介孔分子筛的方法

一种制备巯基官能化ＭＣＭ－４８介孔分子筛的方法是将巯丙基三甲氧基硅烷溶解于甲苯中，再加入经过焙烧的ＭＣＭ－４８分子筛，回流１２～２４小时；产物经离心分离后，用甲苯洗涤直至无未反应的巯丙基三甲氧基硅烷存在，于１００℃－１２０℃下烘干，得到巯基官能化的ＭＣＭ－４８分子筛；具有巯基官能化的产品具有三维孔道结构，不易堵塞，对汞离子的吸附效果好的优点。

MCM-48介孔分子筛的制备方法

本发明公开了一种ＭＣＭ－４８介孔分子筛的制备方法，按原料组成质量百分比将３．１～１６．８％的十六烷基三甲基溴化铵和０．７５～１．６３％的氢氧化钠溶解在６６．４～８７．１％的去离子水中，在强烈搅拌下缓慢加入正硅酸乙酯，继续搅拌反应３０分钟后，转移至密闭反应器中在８０～１５０℃晶化１～３天后，加入ＨＣｌ调节ｐＨ值到６～９，再在８０～１５０℃继续晶化２天；将晶化产物经过滤、洗涤、晾干后，在５５０℃下焙烧６小时，得到ＭＣＭ－４８分子筛。分子筛的产率高达９７％，ＢＥＴ比表面积达到１１３７ｍ↑［２］／ｇ，孔径为２．６纳米左右，该制备方法简单、易操作。

Preparation and characterization of luminescent cubic MCM-48 impregnated with an Eu3+ beta-diketonate complex

We report on the preparation of luminescent silica mesoporous molecular sieves (MCM-48) activated by the europium complex Eu(DBM)(3) . 2H(2)O (where DBM = dibenzoylmethane), using a simple wet impregnation method. Different concentrations of Eu(DBM)(3) . 2H(2)O were introduced into the MCM-48 cubic structure, and the resulting samples were washed with ethanol for different times. UV-Vis absorption measurements and thermogravimetric analysis were used to estimate the amount of Eu complex that has been incorporated within the pores of the MCM-48 host. The various samples were characterized by X-ray powder diffraction (XRD), infrared spectroscopy, diffuse reflectance (DR) and fluorescence measurements. The results reveal that Eu complexes have been successfully introduced into the pores of MCM-48 without disrupting the structure. All the impregnated MCM-48 materials show the typical red luminescence of Eu3+ when excited with a UV lamp. Shifts of the absorption maxima were observed in the DR and fluorescence excitation spectra and will be discussed in relation with guest-host interactions between the organic complex and the silica matrix. The decay profiles of the europium luminescence in the different samples were also measured and discussed.