A Setup for Studying Microstructural,Thermo- and Electro-Optical Properties of Light-Scattering Film Materials

A setup based on an optical polarizing microscope and a technique for simultaneously studying the morphology of light-scattering film materials and measuring their thermo- and electro-optical characteristics are described. The setup is equipped with a specially developed thermocuvette, a laser, a CCD video camera, a photodetector, units for processing electronic signals, and a computer. The performance capabilities of the apparatus are demonstrated using examples of optically anisotropic composite films of polymer carrying out liquid crystals with controlled light scattering.     

用于制备材料样品库的喷射控制系统的设计和应用

设计了一套基于新型单片机PIC为主控制芯片、一系列电磁阀和X-Y-Z平台为受控对象、液晶屏为监控显示单元的自动喷射控制系统。采用喷头后混合技术,即先将A、B、C三种组分按预先设定的比例注入混合池,经充分混合后再喷打到基片上。通过逐点改变组分的比例,就可以在短时间内在同一块基片上制备出一个含有大量材料样品的样品库。应用结果表明：该系统对提高材料样品库制备精度和效率起到了很重要的作用,同时,也对国内组合化学的进一步发展有借鉴作用。     

Fabrication of combinatorial polymer scaffold libraries

We have designed a novel combinatorial research platform to help accelerate tissue engineering research. Combinatorial methods combine many samples into a single specimen to enable accelerated experimentation and discovery. The platform for fabricating combinatorial polymer scaffold libraries can be used to rapidly identify scaffold formulations that maximize tissue formation. Many approaches for screening cell-biomaterial interactions utilize a two-dimensional format such as a film or surface to present test substrates to cells. However, cells in vivo exist in a three-dimensional milieu of extracellular matrix and cells in vitro behave more naturally when cultured in a three-dimensional environment than when cultured on a two-dimensional surface. Thus, we have designed a method for fabricating combinatorial biomaterial libraries where the materials are presented to cells in the form of three-dimensional, porous, salt-leached, polymer scaffolds. Many scaffold variations and compositions can be screened in a single experiment so that optimal scaffold formulations for tissue formation can be rapidly identified. In summary, we have developed a platform technology for fabricating combinatorial polymer scaffold libraries that can be used to screen cell response to materials in a three-dimensional, scaffold format.     

Mass spectrometry in combinatorial chemistry

In the fast expanding field of combinatorial chemistry, profiling libraries has always been a matter of concern--as illustrated by the buoyant literature over the past seven years. Spectroscopic methods, including especially mass spectrometry and to a lesser extent IR and NMR, have been applied at different levels of combinatorial library synthesis: in the rehearsal phase to optimize the chemistry prior to library generation, to confirm library composition, and to characterize after screening each structure that exhibits positive response. Most of the efforts have been concentrated on library composition assessment. The difficulties of such analyses have evolved from the infancy of the combinatorial concept, where large mixtures were prepared, to the recent parallel syntheses of collections of discrete compounds. Whereas the complexity of the analyses has diminished, an increased degree of automation was simultaneously required to achieve efficient library component identification and quantification. In this respect, mass spectrometry has been found to be the method of choice, providing rapid, sensitive, and informative analyses, especially when coupled to chromatographic separation. Fully automated workstations able to cope with several hundreds of compounds per day have been designed. After a brief introduction to describe the combinatorial approach, library characterization will be discussed in detail, considering first the solution-based methodologies and secondly the support-bound material analyses.     

Theoretical study on evaporation of sessile water droplets on a glass panel with infrared radiation

An evaporation model of a water droplet on a glass substrate is developed to estimate the process time needed to manufacture a liquid crystal display panel (LCD). By using an infrared (IR) lamp as a radiation source to evaporate the droplet, the changes in droplet size and evaporation time are calculated. The peak wavelength of the lamp and initial droplet size are used to estimate the process time. A change in the distribution of droplets is calculated to practically apply the model used in the drying process. By analyzing the contributions of radiation and conduction, we found that the evaporation process is driven by different heat transfer mechanisms according to the peak wavelength of the lamp.     

Some aspects of the silicon behaviour under femtosecond pulsed laser field evaporation

Three dimension atom probe analysis of semiconductor materials requires the ability to bring high electric field at the specimen apex to remove atoms. It is shown that, if voltage pulses are used to evaporate doped silicon, the resistivity of the material has to be lower than about 10(2) Omega cm. To overcome this problem, voltage pulses have been replaced by femtosecond laser pulses. The laser pulses give rise to field evaporation by two processes. Both thermal and optical field evaporation have been observed. Thermal evaporation takes place at high laser intensities and with short wavelengths while the evaporation is assisted by the rectification of the optical field for lower intensities and in the infrared domain. Using the optical field evaporation, reproducible and good analyses in term of spatial and mass resolutions could be conducted.     

Combined micro-Raman/UV-visible/fluorescence spectrometer for high-throughput analysis of microsamples

Combined micro-Raman/UV-visible (vis)/fluorescence spectroscopy system, which can evaluate an integrated array of more than 10,000 microsamples with a minimuma size of 5 microm within a few hours, has been developed for the first time. The array of microsamples is positioned on a computer-controlled XY translation microstage with a spatial resolution of 1 mum so that the spectra can be mapped with micron precision. Micro-Raman spectrometers have a high spectral resolution of about 2 cm(-1) over the wave number range of 150-3900 cm(-1), while UV-vis and fluorescence spectrometers have high spectral resolutions of 0.4 and 0.1 nm over the wavelength range of 190-900 nm, respectively. In particular, the signal-to-noise ratio of the micro-Raman spectroscopy has been improved by using a holographic Raman grating and a liquid-nitrogen-cooled charge-coupled device detector. The performance of the combined spectroscopy system has been demonstrated by the high-throughput screening of a combinatorial ferroelectric (i.e., BaTi(x)Zr(1-x)O(3)) library. This system makes possible the structure analysis of various materials including ferroelectrics, catalysts, phosphors, polymers, alloys, and so on for the development of novel materials and the ultrasensitive detection of trace amounts of pharmaceuticals and diagnostic agents.     

用于镀制超薄银膜的一种有效的监控方法

银经常被应用于制备诱导增透滤光片,在这种宽带滤光片中,银膜的厚度一般在几个纳米,这样使得精确监控银的厚度很困难。提出一种简单易行的改进方法,通过在蒸发源上方加一个调速挡板,结合晶振膜厚仪,可以获得±0.4nm以内控制精度的超薄银膜。     

Tunable eletro-optical modulators based on a split-ring resonator

We present a novel design of an electro-optical modulator setup, consisting of a mechanically tunable cavity which allows the modulation frequency to be varied over a broad range. The design is based on the frequently used geometry of a split-ring resonator which allows for high-efficiency sideband generation. Normally such a configuration has the limitation of a narrow excitation band width ( approximately 20 MHz). Our adjustable setup offers broad-range tunability over several hundred megahertz while still keeping the modulation efficiency. Such a widely tunable modulator may find applications in a variety of experiments in atomic physics.     

High-throughput characterization of stresses in thin film materials libraries using Si cantilever array wafers and digital holographic microscopy

We report the development of an advanced high-throughput stress characterization method for thin film materials libraries sputter-deposited on micro-machined cantilever arrays consisting of around 1500 cantilevers on 4-inch silicon-on-insulator wafers. A low-cost custom-designed digital holographic microscope (DHM) is employed to simultaneously monitor the thin film thickness, the surface topography and the curvature of each of the cantilevers before and after deposition. The variation in stress state across the thin film materials library is then calculated by Stoney's equation based on the obtained radii of curvature of the cantilevers and film thicknesses. DHM with nanometer-scale out-of-plane resolution allows stress measurements in a wide range, at least from several MPa to several GPa. By using an automatic x-y translation stage, the local stresses within a 4-inch materials library are mapped with high accuracy within 10 min. The speed of measurement is greatly improved compared with the prior laser scanning approach that needs more than an hour of measuring time. A high-throughput stress measurement of an as-deposited Fe-Pd-W materials library was evaluated for demonstration. The fast characterization method is expected to accelerate the development of (functional) thin films, e.g., (magnetic) shape memory materials, whose functionality is greatly stress dependent.     

Qplus AFM driven nanostencil

We describe the development of a novel setup, in which large stencils with suspended silicon nitride membranes are combined with atomic force microscopy (AFM) regulation by using tuning forks. This system offers the possibility to perform separate AFM and nanostencil operations, as well as combined modes when using stencil chips with integrated tips. The flexibility and performances are demonstrated through a series of examples, including wide AFM scans in closed loop mode, probe positioning repeatability of a few tens of nanometer, simultaneous evaporation of large (several hundred of micron square) and nanoscopic metals and fullerene patterns in static, multistep, and dynamic modes. This approach paves the way for further developments, as it fully combines the advantages of conventional stenciling with the ones of an AFM driven shadow mask.     

Searching for noble Ni–Nb–Zr thin film amorphous alloys for optical glass device molding die materials

This paper presents a search for Ni–Nb–Zr thin film amorphous alloys for use as optical glass device molding die materials. To efficiently search for candidate materials, we used a combinatorial method to evaluate thermal stability. First, compositionally spread Ni–Nb–Zr libraries were fabricated by combinatorial arc plasma deposition (CAPD). To evaluate thermal stability, the Ni–Nb–Zr amorphous CAPD samples in the libraries were annealed in vacuum at 723 K, representing the molding temperature for glass devices, for various time periods. The phases of the annealed CAPD samples were identified using X-ray diffractometry (XRD). From XRD identification, candidate amorphous compositions with high thermal stabilities were screened. Sputter-deposited samples with the same candidate amorphous compositions were subsequently fabricated. Other desired properties for optical glass device molding die materials, including mechanical strength, linear expansion coefficient, oxidation resistance, machinability and anti-sticking properties to molten glass, were evaluated. The investigation revealed Ni₃₆Nb₃₉Zr₂₅ to be a suitable composition for a new glass lens molding die material. This material exhibited a high fracture stress, σ_f, of 1.3 GPa, good heat resistance, good oxidation resistance, similar linear expansion coefficient as glass, good machinability, and excellent anti-sticking properties to molten glass.     

Model, prediction, and experimental verification of composition and thickness in continuous spread thin film combinatorial libraries grown by pulsed laser deposition

Pulsed laser deposition was used to grow continuous spread thin film libraries of continuously varying composition as a function of position on a substrate. The thickness of each component that contributes to a library can be empirically modeled to a bimodal cosine power distribution. We deposited ternary continuous spread thin film libraries from Al(2)O(3), HfO(2), and Y(2)O(3) targets, at two different background pressures of O(2): 1.3 and 13.3 Pa. Prior to library deposition, we deposited single component calibration films at both pressures in order to measure and fit the thickness distribution. Following the deposition and fitting of the single component films, we predict both the compositional coverage and the thickness of the libraries. Then, we map the thickness of the continuous spread libraries using spectroscopic reflectometry and measure the composition of the libraries as a function of position using mapping wavelength-dispersive spectrometry (WDS). We then compare the compositional coverage of the libraries and observe that compositional coverage is enhanced in the case of 13.3 Pa library. Our models demonstrate linear correlation coefficients of 0.98 for 1.3 Pa and 0.98 for 13.3 Pa with the WDS.     

紫外光谱作为车用润滑油失效判断的研究

提出基于紫外光谱法的油液监测方法,通过试验研究润滑油的主要理化指标酸值与其紫外吸光度之间的变化规律,建立紫外吸光度的威布尔模型。结果表明,紫外光谱法作为润滑油的劣化评价指标是可行的,并给出了不同可靠度下的紫外吸光度变化量作为指标的油液失效阈值。     

面成型光固化方法研究

阐述了一种面成型的光固化成型加工方法,系统采用普通紫外光作为成型光源,它的频谱可以与光敏树脂的吸收频谱匹配,从而固化树脂材料.紫外光经过椭球反射镜的反射后,汇聚到聚光透镜的焦点位置,并且通过透镜产生平行的紫外光束.成型零件的截面特征是由位于光敏树脂上方的掩模产生的,通过对比实验F46薄膜、聚四氟乙烯薄膜、THV610薄膜、聚酯薄膜、石英玻璃、有机玻璃等掩模材料对于紫外光的透射率,证实几种塑料薄膜的紫外光透射率差别不大.在临界光学系统下进行的工艺实验结果表明,该成型方式能大幅提高零件的成型速度,是一种有效的成型方法.     

Broadening the applications of the atom probe technique by ultraviolet femtosecond laser

Laser assisted field evaporation using ultraviolet (UV) wavelength gives rise to better mass resolution and signal-to-noise ratio in atom probe mass spectra of metals, semiconductors and insulators compared to infrared and green lasers. Combined with the site specific specimen preparation techniques using the lift-out and annular Ga ion milling in a focused ion beam machine, a wide variety of materials including insulating oxides can be quantitatively analyzed by the three-dimensional atom probe using UV laser assisted field evaporation. After discussing laser irradiation conditions for optimized atom probe analyses, recent atom probe tomography results on oxides, semiconductor devices and grain boundaries of sintered magnets are presented.     

A Peltier cells differential calorimeter with kinetic correction for the measurement of cp(H,T) and Δs(H,T) of magnetocaloric materials

In this paper we describe and test a setup for the characterization of the magnetocaloric effect around room temperature. The setup is a differential calorimeter able to measure both the specific heat c(p)(H,T) under constant magnetic field H and the isothermal entropy change induced by changing H, Δs(H,T), in the room temperature range. The setup uses miniaturized Peltier cells to measure the heat flux, with resolution of about 1 μW, and power Peltier cells to regulate the temperature in the range from 243 K (-30 °C) to 343 K (+70 °C). The kinetic effects due to the heat capacity of the measuring cells are taken into account by a simple model of the heat flux diffusion in the calorimetric cell. As measurement examples, we show the characterization of the magnetocaloric effect in magnetic materials with a second order transition [without latent heat and without hysteresis, as in the La(1)(Fe(1-x-y)Co(y)Si(x))(13) alloy with x=0.077 and y=0.079] and with a first order transitions (with latent heat and hysteresis as in Ni(50)Mn(36)Co(1)Sn(13)). As a result we compare the entropy change Δs(H,T) derived from (i) the integration of the specific heat c(p)(H,T) and (ii) the direct isothermal measurements, obtaining an excellent agreement.     

The ProteoMiner and the FortyNiners: searching for gold nuggets in the proteomic arena

The present review covers modern aspects of combinatorial peptide ligand libraries (CPLL), as used to analyze the "low-abundance proteome" in association with mass spectrometry. First, the capturing properties of baits of different lengths (from single amino acid to hexa-peptides) are described to show that a plateau is rapidly reached above a tetra-peptide in length, thus confirming the validity of having adopted hexapeptides for the considered application. The mechanism of interaction with proteins from very complex proteomes and the ability to decrease the dynamic concentration range is demonstrated with the help of mass spectrometry analysis. Examples are given on how treatment with CPLLs dramatically improves the detectability of peptides in mass spectrometry analysis, permitting detection of a very large number of proteins as compared with control, untreated samples. The use of complementary libraries is discussed with the aim to discover additional low-abundance species that escaped the first library. A discussion on the possibility to discover extremely rare gene products, and the quantitative aspect of the technology when associated with mass spectrometry is also provided. Some insights on the applications for hidden, low-abundance biomarkers are also presented.     

温度变化对紫外分光光度法测量COD的影响

紫外分光光度(UV)法测定COD技术中,温度是影响的重要因素之一,通过实验测定出标准溶液的紫外吸光度随温度变化的数据,利用多元线性回归的方法对数据进行拟合,得出两者之间的关系,以消除温度的影响.     

Versatile platform for creating gradient combinatorial libraries via modulated light exposure

This article details the design, construction, and operation of flexible system that modulates light exposure for the purpose of fabricating continuous and discrete gradient combinatorial libraries. Designed for versatility, the device combines "off the shelf" components, modular accessories, and flexible computer control, so that it can be used for a variety of combinatorial research applications. Salient aspects and capabilities of the instrument are illustrated through two practical examples. The first case demonstrates how user defined exposure functions can be used to create continuous surface energy gradient libraries with a linear profile. The second example illustrates the creation of continuous and discrete libraries for mapping exposure-property functions in a photocurable polymer system.