中国散裂中子源4K低温恒温器研制及测试

中国散裂中子源(CSNS)中子谱仪的运行离不开低温设备提供的低温样品环境，考虑到中子散射的特殊性，样品处不能放置温度计，所以需要对样品温度进行校核。校核结果显示部分低温恒温器样品座测点温度与实际样品温度存在差值。针对该问题，对样品区域进行热工分析及建模求解后，给出了样品区匀温恒温器设计方案。据此CSNS样品环境组设计组装了一套匀温恒温器，该恒温器的温度测试结果显示，4～300 K之间样品温度与测点温度差值在±3 K之内，另外也对300～800 K之间减少样品温差的方案进行了计算和测试。样品区匀温恒温器的研制满足了CSNS对样品测温准确的要求，也对类似设备的匀温方案提供了一定参考，有助于大科学装置设备的国产化。     

等离子体源离子注入过程中半圆形碗状样品的两维温度分布

等离子体源离子注入过程(PSII)中样品温度是一个非常重要的参量。由于注入到样品上的能量很大，导致样品温度很高，所以在实验中获知样品的温度分布有着很重要的意义。本文利用热传导方程建立了半圆形碗状样品内部温度升高模型，研究样品内温度演化过程。以注入离子束流作为能量输入项，热辐射为能量损失项，并考虑了热辐射过程中样品的形状因子的影响。考察了离子注入过程中样品上所施加负偏压的脉冲宽度和频率对样品温度分布的影响。研究结果显示，脉冲频率达到一定值后，样品温度不再随频率增加而升高。     

系列退火条件下Bi2201相超导电性的进化

通过对Pb掺杂Bi2201相超导样品进行系列条件下的真空退火处理，固定退火时间，调节退火温度，使得样品氧含量随退火温度升高而降低，从而使样品载流子浓度随退火温度升高而依次降低，进而影响样品超导电性．我们系统研究了退火条件、正常态电阻率和超导电性之间的关联，确定了样品最高超导转变温度的退火条件，讨论了Bi2201相超导样品在系列退火条件下其超导电性的进化，并获得了该体系最高超导转变温度Tc^cnset=43K．     

一种手持便携式核磁共振样品管高压清洗器的设计与实现

在液体核磁共振（NMR）实验使用的耗材中，NMR样品管用量非常大，通常需经清洗后回收利用.NMR样品管的清洗效率及清洗后的洁净程度直接影响到NMR实验的进程，清洗过程中产生的废液也将对环境产生影响.本文首先介绍了一款自主设计的手持便携式NMR样品管高压清洗器，并对该装置的结构和功能做了详细的说明.然后，对曾装存过不同溶剂和溶液的NMR样品管，分别利用该装置和商用NMR样品管清洗装置进行清洗，并比较了清洗效率和效果.最后，对利用此高压清洗器清洗NMR样品管时，NMR样品管的损伤程度进行了评估.结果证实，对于没有样品严重附着管壁的NMR样品管，本文设计的装置清洗效果良好、效率高；并且清洗过程中不使用有毒的有机溶剂，非常环保；而且对NMR样品管损伤较小.     

Fe0.5Cu0.5BaSrYCu2Oy化合物的结构和超导电性研究

实验采用常压和高压分别制备出含铁的FexCu1-xBaSrYCu2Oy（x= 0～1）系列化合物，本文主要研究x=0.5时样品的结构和超导电性.测量结果显示，高压合成的样品均具有超导电性，对于x=0.5的样品超导转变温度Tc(onset)～57K， Tc(0)～40K，而常压合成的样品当Fe含量x>0.3时均不超导.为此，我们利用透射电子显微镜（TEM）研究了该体系的微观结构特性，并通过电子能量损失谱(EELS)揭示出高压合成导致样品中载流子浓度明显高于常压样品，证明样品制备过程中高压有利于超导电性的形成.同时对高压样品中的缺陷和局域晶体结构畸变进行了深入分析.     

低温差分化热的自动化测量系统

本介绍一种新的 差分比热测量方法即差分绝热连续加热量热法。此方法的特点是在绝热的条件下连续升温，升温速率由计算机通过样品架和参考样品架上的主加热器来控制（可事先设定），样品和参考样品间的温差信号经放大后由７０２控温器控制样品架和参考样品架上的副加热器，使其温差在测量过程中总是保持为零。差分比热值是通过同时测量样品升温速率和副加热功率来获得的，绝热条件是计算机控制内外两层辐射屏跟踪样品温度来获得。     

Hg对Bi系高温超导体织构生长的影响

用熔融织构工艺尝试制备的Ｂｉ系超导织构化样品并探索ＨｇＯ的加入对Ｂｉ系样品织构成形成的影响；结果发现，虽然样品（Ｂｉ，Ｐｂ）ＳｒＣａＣｕ的名义配比为２２２２３或２２３４，Ｘ射线衍射分析表明，所得织构样品均不为２２２３或２２３４相，而是２２１２相，原始样品的Ｈdisplay status     

YBa2Cu3O6＋x体系中反常的电阻率与载流子浓度关系

样品ＹＢａ２Ｃｕ２Ｏ６＋ｘ的载流子浓度通过４５０℃氮气流中退火来改变，电阻率与载流子浓度的关系由原位电阻测量确定，发现样品的电阻率随退火时间增是增大，这是 氮气氛中退火时间增加导致样品的氧含量减少，然而，当退火达三小时样品的电阻率出现反常，样品的电阻率迅速下降一个量级。     

高温高压下氧逸度的就位测量与控制

 通过在样品与氧库间置入一固体氧离子导体以及在样品与氧库间外加一直流电压，氧在该电压驱动下可独立于温度、压力自样品中就位抽出或灌入样品；通过在样品腔内置入一氧传感器，样品中氧逸度及其变化可得到就位监测。高温高压下样品中氧逸度由此可独立于温度、压力进行就位控制。以镍-氧体系作为样品的实验表明，该方法非常成功。无疑，该方法对日后的高压实验研究具有重要的意义。     

光声光谱在纤维样品分析中的应用

本文通过不同状态纤维样品的红外光声光谱的比较以及同一样品的红外光声光谱与红外光谱的比较表明：红外光声光谱用于纤维样品的分析，与红外光谱相比具有简单快速，分辨率好，信噪比高等优点，是研究纤维样品很好的分析手段。     

蔬菜中铁含量的测定及方法比较

用分光光度法直接测定蔬菜中铁的含量,方法简便、快速、准确.分别采用浓盐酸和浓硫酸两种消解方法对样品进行处理,并对其测定结果进行比较,实验结果表明,浓硫酸消解法消解能力更强,测定更为准确.5种蔬菜中木耳铁含量最高,对指导人们合理食用蔬菜进行补铁及进一步开发蔬菜产品提供了可靠的理论依据.     

Thermal conductivity of the Nb3Ge layer prepared by the continuous deposition method

The paper describes the measurement of thermal conductivity of the stainless steel tape on which the superconductive Nb₃Ge layer was vapour-deposited on both sides by the continuous method. The stainless steel 50 m substrate covered by the 2 m Nb layer was deposited with the layer of Nb₃Ge of the thickness of 10 m. Thermal conductivity in the temperature range within 5 up to 80 K was measured in lengthwise direction using the thermopotentiometric method in the bath cryostat. In the same experimental arrangement the measurement of thermal conductivity of the substrate and of the tape with the deposited layer of Nb₃Ge was performed. Specific thermal conductivity of the Nb₃Ge layer was calculated on the basis of measured values.     

In-situ monitoring and control of hydrogenated amorphous silicon–germanium band-gap profiling during plasma deposition process

In-situ germanium content monitoring and its characteristics in SiH₄/GeH₄/H₂ plasmas was studied during hydrogenated amorphous silicon–germanium (a-SiGe:H) film depositions. Since an appropriate band-gap profiling in a-SiGe:H deposition is very important to achieve high efficiency solar cell, the accurate monitoring and control of Ge contents are required. In this work, we found the spectral intensity ratio of silicon atom (288.2 nm) and germanium atom (303.9 nm) emission has strong relation with Ge content in plasmas. In typical, band-gap energy of films was decreased with the increasing of gas flow ratio GeH₄/SiH₄. However, at different total flow rate of GeH₄, the band-gap was different for same gas flow ratio cases because the Ge content in plasmas was changed due to the changes of electron temperature by hydrogen dilution. On the other hand, the emission intensity ratio Ge/Si detected the band-gap variation. Using this method, therefore, we measured and control Ge/Si to make a U-shape band-gap profile which was proved by an ellipsometer and Auger electron spectroscopy depth profile analysis.     

UHV/CVD硅锗膜的Raman光谱分析

本文提出一种用Raman光谱测量SiGe合金膜中的锗组分及应变的方法,方法是非破坏的。并用这一方法测量了几种不同锗组分和膜厚度的SiGe合金样品,它们都是用UHV／CVD设备生长的,其中两个样品还与X－射线双晶衍射的结果作了比较,两种方法的结果十分一致,这说明本文提出的方法是准确可靠的,这些样品用于制作SiGe/Si异质结PMOSFET,对0．5um 沟长器件,跨导达112ms.mm^-1。     

分光光度法测定芦荟中锗的含量

本文测定了鞍山地区的芦荟中有机锗和无机锗含量 ,以CTMAB为增溶剂 ,在酸性条件下使锗 苯芴酮络合物稳定地保持在水相中 ,直接测定吸光度。该体系的络合物在 5 30nm处有最大吸收峰 ;线性范围为 0 1～ 0 7μg·mL-1;线性回归方程A =0 0 817+0 86 77c53 0 (μg·mL-1) ;相关系数r =0 9797;检测限为 0 6 5 μg·mL-1。对芦荟样品测定总锗含量为 6 97 0～ 12 19 5ng·g-1之间 ,有机锗含量约占总锗的95 4 5 %～ 98 99% ,为充分利用芦荟提供了依据     

Strain relaxation in SiGe layer during wet oxidation process

The strain relaxation in SiGe layer on silicon substrate during wet oxidation at 1000 °C was investigated. It was proposed that the competition between Ge accumulation and diffusion led to different strain-relaxation behaviors. At the very beginning, Ge atoms at the oxidizing interface were quickly accumulated due to the high oxidation rate resulting in the additional nucleation of misfit dislocations (therefore a lot of threading dislocations) to relieve stress after the thickness of the Ge condensed layer was larger than the critical value. And then, when the Ge accumulation rate was less than the diffusion rate, Ge content started to decrease from a maximum value and the strain in the SiGe layer was mainly relieved through surface roughing and the degree of strain relaxation reached a maximum. When the samples were further oxidized, Ge accumulation could be neglected because of the self-limiting oxidation and the Ge diffusion dominated the consequent processes. As a result, Ge content at the interface was reduced, with the contribution of the strain relaxation in SiO₂ viscously, leading to the decrease of degree of strain relaxation in the SiGe layers slowly.     

Yb/Sr双原子复合填充的I-型YbxSr8－xGa16Ge30笼合物的合成及热电性能

用熔融法结合放电等离子烧结（SPS）合成了Yb/Sr双原子复合填充的n型Yb_xSr_8-xGa₁₆Ge₃₀（x=0,05,10,15）笼合物,研究了双原子复合填充及Yb填充量x对Yb_xSr_8-xGa₁₆Ge₃₀笼合物热电传输特性的影响规律.结果表 关键词： Ⅰ-型笼合物 双原子填充 热电性能     

Si1-xGex合金半导体中CiCs和CiOi缺陷随Ge含量的变化

采用从头计算(ab initio)的方法对Si和Si_1-xGe_x合金半导体材料中C_iC_s缺陷的性质进行探讨,同时也对比调查了C_iO_i缺陷在Si和Si_1-xGe_x合金中的性质. 在不同Ge含量的Si_1-xGe_{x关键词： 1-x}Ge_x合金')" href="#">Si_1-xGe_x合金 从头计算法 iC_s缺陷')" href="#">C_iC_s缺陷 iO_i缺陷')" href="#">C_iO_i缺陷     

STRUCTURE AND PHOTOELECTRIC PROPERTIES OF HYDROGENATED AMORPHOUS SILICON-GERMAN-IUM ALLOYS PRODUCED BY HIGH HYDROGEN DILUTION METHOD

A series of hydrogenated amorphous silicon-germanium alloys have been fabricated by high hydrogen dilution method. The Ge content in the film increasea from 0.4 to 0.8 and the corresponding optical bandgap is in the range of 1.48-1.22eV. The photoconductivity is 3.6×10^-6 S/cm and photosensitivity is as high as 7.3×10³ at an optical bandgap of 1.48eV. The deterioration of photoelectric properties with increasing Ge content could be attributed to the decrease of the bonded hydrogen content and the inhomogeneous structure in the alloy network.     

Effect of oxygen deficiency on the radiation sensitivity of sol-gel Ge-doped amorphous SiO2

We report experimental investigation by electron paramagnetic resonance (EPR) measurements of room temperature γ-ray irradiation effects in sol-gel Ge doped amorphous SiO₂. We used materials with Ge content from 10 up to 10⁴ part per million (ppm) mol obtained with different preparations. These latter gave rise to samples characterized by different extents of oxygen deficiency, estimated from the absorption band at ~5.15 eV of the Ge oxygen deficient centers (GeODC(II)). The irradiation at doses up to ~400 kGy induces the E'-Ge, Ge(1) and Ge(2) paramagnetic centers around g ~ 2 with concentrations depending on Ge and on GeODC(II) content. We found correlation between Ge(2) and GeODC(II) contents, supporting the suggestion that the latter defect is the precursor of Ge(2). Even if the concentration of E'-Ge and Ge(1) defects cannot be strictly related to GeODC(II) one, the concentration growth of these paramagnetic defects with irradiation evidences that the radiation sensitivity is enhanced by the oxygen deficiency for Ge doping above 1000 ppm mol and it is reduced below 100 ppm mol. Moreover, the investigation of samples with different GeODC(II) concentration but fixed Ge content has shown that the oxygen deficiency enhances the overall radiation sensitivity for [GeODC(II)]/[Ge] in the range 10^-3 10^-2.