利用红外光谱和渐进因子分析研究牛血清白蛋白的热动力学过程

利用红外光谱和渐进因子分析(Evolving factor analysis,EFA)对水溶液中牛血清白蛋白(Bovine serum albu-min,BSA)的热动力学过程进行了研究.三因子EFA的结果表明加热导致了牛血清白蛋白的结构变化经历了轻微变化和剧烈变化两个阶段,它们分别发生在温度区间56~76℃和68~82℃.研究显示了渐进因子分析在解析水溶液中蛋白质温度相关红外光谱中的重大作用.     

二维相关红外光谱研究溶液中蛋白质的结构

概述了二维相关红外光谱基本原理以及它在研究蛋白质结构变化方面的最新应用，所综述的内容主要包括以下几个方面：(1)二维相关掠角反射红外光谱研究蛋白质分子在样品池上的吸附过程；(2)重点概述二维相关红外光谱在研究温度、酸度等物理变量诱导蛋白质变性及结构变化方面的应用。     

聚乙烯亚甲基面内摇摆振动二维红外光谱研究

在293~393 K范围内,分别测定聚乙烯的一维红外光谱、二阶导数红外光谱、四阶导数红外光谱和去卷积红外光谱来确定聚乙烯分子结构。进一步采用二维红外光谱研究了聚乙烯亚甲基面内摇摆振动模式(ρCH2)。研究发现,聚乙烯分子中同时存在晶区和非晶区。随着测定温度的升高,聚乙烯分子中ρCH红外吸收强度变化快慢顺序为:720cm-1(ρ2(CH2)crystalline)>731cm-1(ρ(CH2)crystalline)>725 cm-1(ρ(CH2)amorphous)。此项研究显示出二维红外光谱在高分子材料热变性分析中的重大作用。     

微波加热植物油的红外光谱分析

利用傅里叶变换红外光谱法并结合二维相关光谱技术对微波加热及传统加热下的三种植物油进行分析。对加热过程中红外光谱的峰位、峰形、峰强进行比较,一维红外光谱图没有明显的区别,而二维相关谱图中,同步、异步图差异比较明显。根据自动峰强度可比较同一植物油在不同加热方式下其分子结构变化的异同。另外与一维红外光谱相比,二维相关光谱的分辨率较高,在揭示分子内或分子间的相互作用研究中发挥了作用,增强了对谱图的识别能力。初步实验表明微波加热与传统加热过程中,植物油的分子结构变化是不一样的。     

低速湍流中的气动光学效应实验研究

应用二维哈特曼(Hartmann)波前测量系统，对光束在二维低速热射流传输中的气动光学效应进行了测量。应用模式法，通过孔径斜率进行了波前重构，结果表明热射流使波前产生较强的随机畸变。同时通过对子孔径波前斜率的时间变化测量结果进行了相关函数计算，计算显示出互相关函数随空间相对位置表现出一定规律的变化，由此分析了热射流场中涡结构的运流速度、涡结构尺度等湍流中重要的特性。这些初步测量和分析结果表明通过哈特曼波前测量法既可研究光束在湍流场中引起的波前变化规律，同时还可以应用于湍流场流场参数的间接分析。     

光谱法研究甲啶铂与牛血清白蛋白的相互作用

甲啶铂(picoplatin)是一种新型的抗癌药物,但其在体内的作用机制尚不明确.利用荧光光谱技术研究模拟人生理条件(Tris-HCl缓冲溶液体系,pH7.4)下甲啶铂与牛血清白蛋白(BSA)的相互作用,甲啶铂对BSA的内源荧光(336 nm)有猝灭作用.在室温296 K和模拟人体温度310 K条件下,甲啶铂对BSA的...     

碳酸钠红外光谱研究

采用衰减全反射红外光谱(ATR-FTIR)技术,研究了碳酸钠的结构。实验发现:碳酸钠同时存在着CO3不对称伸缩振动模式(νas CO3),CO3对称伸缩振动模式(νs CO3),CO3面外弯曲振动模式(rCO3)和CO3面内弯曲振动模式(?CO3)等4种红外吸收模式。采用二维相关红外光谱技术(2D-IR)进一步来研究温度变化对于碳酸钠结构的影响。     

硬脂酸亚甲基变角振动二维红外光谱研究

在293~393 K温度范围内,分别采用一维红外光谱、二阶导数红外光谱和二维红外光谱测定硬脂酸亚甲基变角振动模式(?CH2)。实验发现:在1440~1480 cm-1范围内,硬脂酸?CH2存在"第一特征频率谱带"和未见文献报道的"第二特征频率谱带",并进一步研究了温度对于硬脂酸δCH2红外吸收强度及变化顺序的影响。本项研究显示出二维红外光谱在材料热变性分析中的重大作用。     

光电子技术

0600347 近红外光谱分析磷酸缓冲溶液中的血糖含量[刊,中]／王文明／／山东理工大学学报(自然科学版)．-2005,19 (2)．-95-97(G) 测定了溶解于磷酸缓冲溶液中血糖在8000- 5000cm-1波数范围的近红外光谱,用偏最小二乘法建立了测定血糖含量的模型。根据数据特点,提出了按浓度大小选择预测集样本的方法,用来进行最佳模型隐变量个数的选择。结果显示,利用近红外光谱并结合化学计量学方法能够成功地进行血糖的定量分析, 方法的测定误差为0．197g／L。参7     

浓度扰动下DBP/葵花油分子基团的二维相关红外光谱研究

测量了邻苯二甲酸二丁酯(Dibutyl Phthalate, DBP)/葵花油混合物的傅里叶变换红外吸收光谱。结合二维相关光谱技术,将所测光谱分为500~1500 cm-1、1500~2000 cm-1和2500~3200 cm-1三个波段进行了分析。分析结果表明,在500~1500 cm-1波段,混合物中苯环、与苯环直接相连的官能团对DBP浓度变化不太敏感;在1500~2000 cm-1波段,葵花油中饱和羧酸酯的C=O键的伸缩振动对DBP浓度变化更敏感;而在2500~3200 cm-1波段,利用二维相关光谱技术将2854 cm-1和2925 cm-1等处的重叠峰分开为2854 cm-1、2873 cm-1、2916 cm-1、2925 cm-1和2940cm-1等多个峰。随着DBP浓度的升高,甲基中C-H键的伸缩运动比亚甲基中的明显。结果表明,傅里叶变换红外光谱结合二维相关光谱技术可为直接快速检测塑化剂以及研究塑化剂的迁移规律提供新的思路和方法。     

AlGaN/GaN HEMT结构热时间常数谱提取方法的研究

利用电学法对AlGaN/GaN 高电子迁移率晶体管(HEMTs)有源区瞬态温升进行测量.利用非参数拟合算法—局部加权回归散点平滑法(LOWESS)对原始测量数据进行平滑去噪处理,进而得到热时间常数谱,分析AlGaN/GaN HEMTs热传导路径物理结构。与传统平滑去噪方法—多阶指数拟合相比,通过LOWESS算法得到的热时间常数谱更丰富,得到RC网络更多,进而热传导路径结构分析更精细。结果表明,LOWESS非参数拟合算法能够更好的去除测量数据噪声,保留原始离散数据细微的变化趋势。通过该方法所提取的热时间常数谱能描述AlGaN/GaN HEMTs有源区温度细微变化,帮助研究人员精确分析热传导路径层次构成。     

真空还原制备的VO_2热致相变薄膜光学性质研究

本文对不同衬底制备的VO2 薄膜进行了表面形貌测试 ,对其红外透射光谱和Raman光谱进行了研究 ,并进行 370nm -90 0nm波段的光透射测试以及 90 0nm波长的热滞回线特性测试 ,表明所制备VO2 薄膜具有优良的热致相变光学特性 ,薄膜为纳米结构 ,并且结晶状态不同的薄膜其Raman谱位置有明显改变 ,室温时的红外光谱表现出较好的红外振动特性。讨论了薄膜结晶状态对Raman位移的影响以及VO2 薄膜的红外光谱     

Fine grain thermal modeling and experimental validation of 3D-ICs

3D die stacking is a promising technique to allow miniaturization and performance enhancement of electronic systems. Key technologies for realizing 3D interconnect schemes are the realization of vertical connections, either through the Si die or through the multilayer interconnections. The complexity of these structures combined with reduced thermal spreading in the thinned dies complicate the thermal analysis of a stacked die structure. In this paper a methodology is presented to perform a detailed thermal analysis of stacked die packages including the complete back end of line structure (BEOL), interconnection between the dies and the complete electrical design layout of all the stacked dies. The calculations are performed by 3D numerical techniques and the approach allows importing the full electrical design of all the dies in the stack. The methodology is demonstrated on a 2 stacked die structure in a BGA package. For this case the influence of through-Si vias (TSVs) on the temperature distribution is studied. The modeling results are experimentally validated with a dedicated test vehicle. A thermal test chip with integrated heaters and diodes as thermals sensors is used to successfully validate the detailed temperature profile of the hot spots in the top die of the die stack.     

Floorplanning for low power IC design considering temperature variations

Non-uniformity in thermal profiles of integrated circuits (ICs) is an issue that threatens their performance and reliability. This paper investigates the correlation between the total power consumption and the temperature variations across a chip. As a result, floorplanning guidelines are proposed that uses the correlation to efficiently optimize the chip's total power and takes into account the thermal uniformity. It is demonstrated that optimizing a floorplan to minimize either the leakage or the peak temperature can lead to a significant increase in the total power consumption. In this paper, the experimental results show that lowering the temperature variations across a chip not only addresses performance degradation and reliability concerns, but also significantly contributes to chip power reduction. In addition, it is found that although uniformity in the thermal profile can be very effective in lowering the total power consumption, the most uniform temperature distribution does not necessarily correspond to the highest power savings. Consequently, for some applications, a 2% deviation from the minimum total power is traded for up to a 25% increase in thermal uniformity. The presented method is implemented for an Alpha 21264 processor running Spec 2000 benchmarks.     

Thermal measurements and analyses of low-cost high-power LED packages and their modules

The thermal behaviors of high-power light emitting diode (LED) chip-on-plate (COP) package and module are investigated by experimental measurements (with LED junction temperature (T_j) tester, thermocouples, and thermal imager), a thermal resistance circuit (TRC) method, a commercial finite element code (ANSYS), and a computational fluid dynamics code (CFdesign). Based on the experimental results, the thermal resistance of the COP package was found to be comparable to those for the commercial packages. Furthermore, it was also found that the T_j and thermal resistances of the COP package and module, calculated from 2D ANSYS, 3D TRC and 3D CFdesign, are consistent well with those from the experiments. Besides, the uncertain equation-based convection coefficients used in ANSYS and TRC for the thermal analysis of the COP module were closely examined and discussed in detail by comparing with those from CFdesign analysis. Moreover, the validated ANSYS and CFdesign models were used for parametric studies of the COP module and further provided useful design parameters. Finally, the COP module under natural and forced convection conditions was studied, and the results showed that the junction-to-air thermal resistances are sensitive to the flow conditions, but not for thermal resistances from the junction to aluminum substrate and to heat sink.     

2.5D封装结构回流焊过程热应力分析

对一种典型2.5D封装结构在回流焊工艺过程的热应力进行仿真。通过对比分析传统热力学仿真方法与基于生死单元技术的热力学仿真方法,研究了计算方法对热应力计算结果的影响。在相同参考温度下,由不同计算方法得到的硅通孔(TSV)转接板应力结果相差不大,从焊球应力结果可推测出,基于生死单元技术的热力学仿真方法考虑了残余应力的累积模拟更适合于回流焊过程的热应力仿真。研究了2.5D封装回流焊过程中参考温度的选择对计算结果的影响,选用最高参考温度作为各个组件的参考温度,通常得到TSV转接板的应力值偏大,模拟的结果会更加偏于激进。通过对2.5D封装结构回流焊过程进行热应力分析,对比分析了计算模拟方法和参考温度的选择对最终计算结果的影响。该方法同样可用于指导其他同类2.5D封装结构应力的计算和分析。     

Thermal effect on the electroluminescence of InGaN/GaN multiquantum-well light-emitting devices

A steady-state thermal model is presented to investigate the temperature and injection-current dependence of the electroluminescence (EL) in InGaN/GaN multiquantum-well light-emitting devices. The important mechanisms for the carrier dynamics, including thermal emission, recapturing, radiative and nonradiative recombination, are taken into account in this model. From the measured EL spectra, it is found that the S-shaped temperature dependence of the peak energy disappears at a high injection-current level. The temperature-dependent emission energies of the EL spectra are calculated with this model. The band-filling effect and the heating effect are considered in our investigation of this phenomenon, and the simulation results are in fair agreement with the experimental data. It is observed that both the band-filling and heating effects influence the temperature dependence of the EL emission spectra of InGaN/GaN multiquantum-wells. Quantitative discussion reveals that the heating effect becomes more apparent when the device is working at high injection-currents.     

Raman spectra of the laser-irradiated GaSe single crystals

The specific features of the crystal structure of the lamellar GaSe crystals of various polytypes are analyzed. The possibility of identifying the phase transitions, which occur as a result of variations in temperature, pressure, and composition, is considered from the standpoint of resonance Raman scattering. The effects of high-temperature thermal annealing and pulsed laser irradiation on Raman spectra is investigated. It is found that pulsed laser radiation gives rise to regions with different polytype composition and regions with residual stress.     

1D and Q2D thermal resistance analysis of micro channel structure and flat plate heat pipe

Heat pipes and two-phase heat transfer devices are widely used in electronics cooling, and the thermal resistance is a key issue to ensure the system performance and reliability. In this study, the traditional one dimensional (1D) and quasi-two dimensional (Q2D) methods were utilized to analyze the thermal resistance of the previous boiling experiments of evaporator tests with silicon (Si) and copper (Cu) micro channel structures as well as the existing flat-plate heat pipe tests with aluminum micro channels as wick structures. The temperature distributions and variations under different test conditions were collected, and the 1D and Q2D methods were applied to calculate the overall thermal resistance for evaporator tests and heat pipe tests and compared with the experimental data. The results showed that the Q2D method can predict the overall thermal resistance for the evaporator region and the whole heat pipe with a higher accuracy because the spreading resistance was significant and should be considered under small heater area (hot spot) conditions. Detailed distributions of thermal resistance and the calculated errors of each test sample under different heat loads were presented and compared. For present tests, the Q2D method can reach a lower average error (about 10%) and is recommended for calculations. Furthermore, the spreading resistance of Q2D method is further applied to calculate the selected test cases to investigate the wall thickness effects. The spreading resistance of the selected evaporator tests and heat pipe tests may decrease and increase, respectively, as wall thickness increases due to different evaporative heat transfer conditions. The present results demonstrate the applicability of the Q2D methods for both evaporator and heat pipe tests, and the present analyses can be a reference for future thermal management and electronic cooling designs.     

基于MOSFET漏电流温度特性的室温红外探测器

基于MOSFET的漏电流温度特性，提出了一种可与CMOS工艺兼容的新型室温红外探测器。它采用在SOI衬底上实现的MOSFET作为探测红外灵敏元，在MOSFET的钝化层上制作可提高红外吸收率的光学谐振腔，并利用硅微机械加工技术将SOI的隐埋氧化层悬空，形成热绝缘微桥结构。MOSFET在担当探测红外辐射灵敏元的同时，又作为放大处理电路的一部分，简化了电路。分析表明，探测器的探测率可高达10^9-10^10cmHz^1/2W^-1.