X-RAY SPECTROSCOPIC CHARACTERISTICS OF DIAMOND AND ITS ASSOCIATED MINERALS AND APPLICATION OF COLOR FILTER IN X-RAY SELECTION

On the basis of study on X-ray spectroscopic characteristics of diamond and its associated minerals, this paper, according to the difference between the two spectroscopic peak value bands and lightening intensities, explores the probability of introducing colour filter to attenuate the spectroscopic peak bands of associated minerals and enhance the resolution of diamond X-ray selection, and comparatively analyses,through experiment,the different selection effects produced by using different kinds of colour filters, finally deciding Chinese-built QB4 colour filter as the optimum selection colour filter in diamond X-ray selection.

Photoelectric characteristics of silicon P–N junction with nanopillar texture:Analysis of X-ray photoelectron spectroscopy

Silicon nanopillars are fabricated by inductively coupled plasma （ICP） dry etching with the cesium chloride （CsCl） islands as masks originally from self-assembly. Wafers with nanopillar texture or planar surface are subjected to phosphorus （P） diffusion by liquid dopant source （POCl3） at 870 ℃ to form P-N junctions with a depth of 300 nm. The X-ray photoelectron spectroscopy （XPS） is used to measure the Si 2p core levels of P-N junction wafer with nanopillar texture and planar surface. With a visible light excitation, the P-N junction produces a new electric potential for photoelectric characteristic, which causes the Si 2p core level to have a energy shift compared with the spectrum without the visible light. The energy shift of the Si 2p core level is -0.27 eV for the planar P-N junction and -0.18 eV for the nanopillar one. The difference in Si 2p energy shift is due to more space lattice defects and chemical bond breaks for nanopillar compared with the planar one.

Selection rules for electric multipole transition of diatomic molecule in scattering experiments

The knowledge of the energy level structures of atoms and molecules is mainly obtained by spectroscopic experiments. Both photoabsorption and photoemission spectra are subject to the electric dipole selection rules （also known as optical selection rules）. However, the selection rules for atoms and molecules in the scattering experiments are not identical to those in the optical experiments. In this paper, based on the theory of the molecular point group, the selection rules are derived and summarized for the electric monopole, electric dipole, electric quadrupole, and electric octupole transitions of diatomic molecules under the first Born approximation in scattering experiments. Then based on the derived selection rules, the electron scattering spectra and x-ray scattering spectra of H2, N2, and CO at different momentum transfers are explained, and the discrepancies between the previous experimental results measured by different groups are elucidated.

Properties of Optical and X-ray Selected AGN-Probing the Unified Model of AGN

We have compiled a sample of two subsets of AGN selected from their optical and X ray data. The first subset was selected for very broad and/or peculiar optical emission line profiles, the second for a high X ray flux. Here we will discuss properties of these galaxies and show that both subsets are very similar in the multi wavelength view. Furthermore, we will discuss differences between the two subsets and their implications for a Unified Model of AGN.

Fe-Mn/Al_2O_3 catalysts for low temperature selective catalytic reduction of NO with NH_3

A series of Fe‐Mn/Al2O3 catalysts were prepared and studied for low temperature selective catalytic reduction （SCR） of NO with NH3 in a fixed‐bed reactor. The effects of Fe and Mn on NO conversion and the deactivation of the catalysts were studied. N2 adsorption‐desorption, X‐ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, H2 temperature‐programmed reduction, NH3 temperature‐programmed desorption, X‐ray photoelectron spectroscopy （XPS）, thermal gravimetric analysis and Fourier transform infrared spectroscopy were used to character‐ize the catalysts. The 8Fe‐8Mn/Al2O3 catalyst gave 99%of NO conversion at 150？？ and more than 92.6%NO conversion was obtained in a wide low temperature range of 90–210？？. XPS analysis demonstrated that the Fe3＋was the main iron valence state on the catalyst surface and the addition of Mn increased the accumulation of Fe on the surface. The higher specific surface area, enhanced dispersion of amorphous Fe and Mn, improved reduction properties and surface acidity, lower binding energy, higher Mn4＋/Mn3＋ratio and more adsorbed oxygen species resulted in higher NO conversion for the 8Fe‐8Mn/Al2O3 catalyst. In addition, the SCR activity of the 8Fe‐8Mn/Al2O3 cata‐lyst was only slightly decreased in the presence of H2O and SO2, which indicated that the catalyst had better tolerance to H2O and SO2. The reaction temperature was crucial for the SO2 resistance of catalyst and the decrease of catalytic activity caused by SO2 was mainly due to the sulfate salts formed on the catalyst.

Catalytic Performance of Carbon Materials Supported Pd Nanoparticles in Selective Hydrogenation of Acetylene

Pd/C catalysts were prepared by deposited Pd nanoparticles （NPs） on different carbon supports including activated carbon （AC）, graphite oxide （GO）, and reduced graphite oxide （rGO） using sol-immobilization method. Through transmission electron microscopy, powder X-ray di raction, and X-ray photoelectron spectroscopy, the role of the carbon supports for the catalytic performances of Pd/C catalysts was examined in selective hydrogenation of acetylene. The results indicate that Pd/AC exhibited higher activity and selectivity than Pd/GO and Pd/rGO in the gas phase selective hydrogenation of acetylene. Thermal and chemical treatment of AC supports also have some effect on the catalytic performance of Pd/AC catalysts. The differences in the activity and selectivity of various Pd/C catalysts were partly attributed to the metal-support interaction.

Measurement of Mass Attenuation Coefficients of Indium With Characteristic X-rays From Targets Excited by Energetic Proton

The mass attenuation coefficients of indium are systematically measured byusing the characteristic X-rays from elemental or compound targets excited by energeticproton in the X-ray energy range 2.6 to 29.1 keV.The accuracy of experimental data isimproved to be±1%.The photoeletric cross sections are obtained by subtracting thescattering cross section from the measured total cross sections.Comparisons of our ex-perimental results with the available data of earlier investigations as well as with thetheoretical calculations are presented and discussed.

预选抛废技术发展现状

随着我国矿产资源的不断开发与利用,天然高品位矿石资源逐步减少,低品位矿石成为目前我国矿产资源的主要来源,因此,预选抛废成为一个必要的选矿环节。重点阐述了人工拣选抛废、光电选抛废、磁选抛废、重选抛废以及浮选抛废五种抛废技术,并介绍了不同技术在预选抛废时使用的设备和工作原理,指出了各种预选抛废技术的优缺点,为预选抛废技术能进一步工业应用提供了一定借鉴意义。

TOPCon太阳能电池选择性发射极工艺研究

为提升隧穿氧化钝化接触(TOPCon)太阳能电池的光电转换效率,采用硼扩散和激光掺杂的方式形成选择性发射极结构,研究了硼扩散方阻、激光功率输出比、氧化时间等对电池发射极钝化性能的影响。实验结果表明,当扩散方阻为140Ω/□,氧化温度为1 020℃,氧化时间为30 min时,发射极轻掺杂区域(p+)的方块电阻为320Ω/□,隐开路电压值达到729 mV,暗饱和电流密度为12 fA/cm^(2)。发射极重掺杂区域(p++)的方块电阻为113Ω/□,隐开路电压值为710 mV,暗饱和电流密度为26 fA/cm^(2)。基于该工艺方案制备的TOPCon电池最高光电转换效率达到24.75%,电池开路电压高达720 mV,短路电流提升30 mA,相比现有TOPCon电池光电转换效率提升了0.26个百分点。

光源发散角对航天级小型光电编码器信号的影响

针对现有的光源发散角对信号影响不明确等问题,本文从光电编码器光电信号产生原理出发,理论分析了光源发散角对光通量的影响,仿真分析了不同发散角情况下的光场分布和光通量变化情况及其组成成分。构建了莫尔条纹光电信号并分析受发散角影响下的细分误差变化情况。实验结果表明:当将发散角为17°的光源更换为15°时,细分误差峰峰值可由0.74″降至0.56″,下降幅度达到24%。因此,光源发散角对于光电编码器输出信号的影响不可忽略,在选取光源时应该予以考虑。本文可用于预测其细分误差的大小和趋势,为航天级小型光电编码器初始光源的选取提供依据和参考。

磷矿光电分选可选性研究方法探讨

光电分选在中低品位磷矿抛废提质中应用前景广阔。采用实验室小型光电分选设备将磷矿原矿分选成多个阶梯品位的“分阶分选”方法,得到原料矿石的“分阶分选”结果,绘制“光电分选可选性曲线”,将这一特性曲线资料用于反映该原料的分选特性。该曲线可用于确定不同产品要求下的理论分选指标,并提出用评价指标η量化评价矿石使用光电分选方法进行分选的难易程度。

Variation of microfibril angle and its correlation to wood properties in poplars

The microfibril angle of seven poplar clones was determined by using X-ray diffraction technique. Microfibril angle, wood basic density, fiber length, fiber width and cellulose content were assessed for every growth ring at breast height for all sample trees. Significant variation in microfibril angle was observed among growth rings. Mean microfibril angle (MFA) at breast height varied from 7.8?to 28?between growth rings with cambial age and showed a consistent pith-to-bark trend of decline an-gles. Analysis of variance also indicated that there were significant differences in wood basic density, fiber length, fiber width and cellulose content between the growth rings, which had an increasing tendency from pith to bark. Correlations between MFA and examined wood properties were predominantly large and significant negative (?0.01), and the coefficients were -0.660 for cellulose content, -0.586 for fiber length, -0.516 for fiber width and -0.450 for wood basic density, respectively. Regression analysis with linear and curve estimation indicated that a quadratic function showed the largest R2 and the least standard error for describing the relationships between microfibril angle and measured wood properties, and the correlation coefficients were over -0.45 (n=125). The results from this study suggested that microfibril angle would be a good characteristic for improvement in the future breeding program of poplars.

光电旋转编码器的研究与应用

介绍光电旋转编码器的关键技术及选型中所应考虑的条件。对于光电旋转编码器的推广应用有一定的促进作用。

光电选矸识别系统的研制与测试

本文根据煤与矸石的漫反射特征 ,研制了光电选矸图像识别系统 ,并进行了现场模拟。同时提出了图像识别和确定物体的具体算法。其结果表明 ,该系统对煤矸石的识别率高于 95 %

硅光电二极管光谱响应度的分析

从光电二极管的工作原理出发,对硅光电二极管的光谱响应度进行了论述。分析表明,入射光子的能量、材料的禁带宽度和吸收系数是光谱响应曲线具有波长选择性的主要原因。

光电转换和热光电转换的实现和应用

为了降低光电转换产品的成本,提高光电转换的效率和能量的利用率,在介绍了光电转换和热光电转换的基本原理以及发展方向后,从动力学角度推导了热光电转换过程中选择发射器的性能与发射器材料的微观作用参数的依赖关系,为寻找用于有效热光电转换过程的高性能选择发射器材料指明了方向;最后介绍了当前光电转换和热光电转换的应用情况。

常用光电器件的特性与选用技巧

在光电技术产业化的过程中,光电器件的重要性日益现显。光电器件的种类很多,功能各异。如何掌握各种光电器件的特性及正确选用光电器件是光电技术实际应用中的关键。在对一个光电系统的性能指标进行评价时,系统所选用的光电器件的性能参数指标已经成为最重要的影响因素之一。介绍了常用光电器件的特性,讨论了光电器件应用选择时的注意事项与技巧,并对选用光电器件的基本原则进行了总结。

基于影响度的光电测量设备测试性验证试验样本抽取方法

为解决目前光电测量设备测试性验证试验中,因样本抽取方法不合理导致试验结论可信度低的问题,通过考虑危害度和故障扩散强度这两个与测试性相关的重要因素,提出了影响度的概念。从功能特征出发,构建功能模块-故障信息模型,利用该模型提出了基于影响度的样本抽取方法并给出试验抽取流程。此方法依据影响度相对比率,随机抽取出被测单元的故障样本,可较好地提高样本集代表性,确保试验结论置信度。并以某型光电测量设备中的时统终端单元为例,利用基于影响度的方法进行样本抽取,比较分析抽取结果证明该方法有效可行。

雪崩光电探测器最佳噪声分配方法研究

从设计光电探测系统的实际需要出发,提出了雪崩式光电探测器最佳噪声分配的分析方法;给出了雪崩光电探测器和组件式探测器的最佳噪声分配方法以及分配比例关系式;尤其是把雪崩探测器最佳工作点的选择问题转化为前置放大器增益选择问题,对于简化、优化设计光电接收系统具有实际意义.

船载测量设备光电偏差动态评估方法

在现有光电偏差标定方法的基础上,针对海上动态环境下多种方法测量及标定船载测量设备光电偏差结果一致性较差且难以选择的问题,提出了一种船载测量设备光电偏差计算及动态评估方法。该方法利用空间目标精轨信息能够反演计算高精度测元的特性,结合船载测量设备的测量数据建立测量方程计算光电偏差,以该计算结果为理论值对多种方法得到的光电偏差进行多属性优选,实测数据表明能有效解决动态测量情况下直接标定结果差异较大难以取舍的难题。