基于支持向量机的肤色滤波器

为了探测图像中的肤色像素，提出了一种新的方法-支持向量机（SVM：Support Vector Machine）方法.它是一种基于肤色的非特定人的面部定位方法，是非接触人机交互技术和机器视觉中的一个重要内容.实验结果表明，采用支持向量机方法较传统人工神经网络方法不仅有更高的探测准确性，而且具有更好的推广性能.由于SVM采用结构风险最小化（SRM：Structural Risk Minimization）准则，在最小化训练误差（经验风险）的同时，尽量缩小模型预测误差的上界，从而使模型有更好的泛化能力.     

用于光学神经网络硬件系统误差纠正的虚拟神经网络

提出了一种用于修正光学神经网络硬件系统误差的虚拟神经网络模型，光学实验结果表明该网络能够有效地消除硬件系统误差对实验结果的影响。     

Development and applications of an on-line thermal neutron prompt-gamma element analysis system

This paper introduces the principles, instrumentation, implementation, and industrial applications of an on-line thermal neutron prompt-gamma element analysis system (using a²⁵²Cf neutron source, Am–Be neutron source, or neutron generator). The energy resolution of the system at the H prompt-gamma full-energy photopeak (2.22325 MeV) is 3.6 keV. The concentration measurement error of Al₂O₃, FeO₃, CaO, and SiO₂ is ±0.3%, ±0.1%, ±0.4%, and ±0.4%, respectively. The system has been tested on-site at both the Shandong and the Zhengzhou Aluminium Works. Our preliminary on-site measurements confirm that the stability, reliability, measurement range, and accuracy of the system can meet the requirements of the aluminium production process. Facilitation of this measurement at aluminium plants is expected to reduce plant costs by over 3 million dollars annually through reduced energy consumption, more rapid qualification of pulps being mixed during the production process, and in reduced labor costs.Other participants of Shandong and Zhenghou Aluminium Works are: Wang Aili, Zengshen, Dei Jianguo and Lu Jinnan, Wang Deyu, Jin Hequan.     

Computation of auxiliary functions in STO molecular integrals up to arbitrary accuracy. I. evaluation of incomplete gamma function En(x) by forward recursion

A new inequality and an approximate relation of incomplete Gamma function E_n(x) are derived in this paper. Applying both to simplify the error analysis on the recursive algorithm of E_n(x), we analytically derived a criterion about relative error. The criterion decides whether the forward recursive relation can be used to compute {E_n(x), n = 0, 1, ?, N} with an acceptable loss of significant figures. Further analytical exploration leads to another criterion that decides whether the group of E_n(x) can be evaluated with an acceptable absolute error by the same methods. Both criteria are not only superior to those given in previous work by other authors, but also strongly supported by our numerical experiments. A strategy is illustrated to explain how to apply both criteria to evaluate molecular integral over Slater-type orbitals. © 1993 John Wiley & Sons, Inc.     

CeO2及Pt/CeO2催化剂上H2、O2的作用特性

采用TPD、TPR、FT-IR和TPEC等方法研究了CeO_2及Pt/CeO_2上H_2、O_2作用特性。结果表明, Pt促进CeO_2还原, 并形成高活动性氢物种。Pt的存在使吸H_2和放氢温度下阵达300 ℃。部分还原的CeO_2常温下吸附氧形成分子离子氧物种(O_2~-, O_2~(2-)), Pt的存在改变氧化铈催化剂在常温下氧吸附物种的形态, 以解离态存在。氧化铈上吸附的氧物种在升温时可部分脱附, 高于170 ℃时则转化为晶格氧。     

载体对Rh基催化剂上甲烷解离活性的影响

采用脉冲反应技术、原位CO吸附和吡啶吸附红外光谱,考察了Al2O3和SiO2负载的Rh基催化剂上Rh-CeO2相互作用和CH4解离活性.结果表明,载体酸性对Rh-CeO2相互作用有显著影响.Rh/Al2O3催化剂中添加CeO2增加了载体Al2O3的Lewis酸位,使Al2O3接受电子的能力增强,从而降低Rh的电子密度,有利于CH4解离活化.相反,Rh/SiO2催化剂中添加CeO2减少了载体SiO2的Lewis酸位和酸强度,使SiO2难于接受电子,导致Rh的电子密度增加,不利于CH4解离活化.     

Pt/TiO_2催化剂上的氢—氧作用 Ⅰ.氢、氧的吸咐—脱附行为以及相互促进作用

本文采用程序升温脱附(TPD)技术研究了光沉积方法制备的Pt/TiO_2催化剂经过氧化、还原后氧、氢的脱附行为.光沉积过程中,Pt/TiO_2表面上可以生成大量的吸咐氢,在TPD中脱附;同时Pt/TiO_2表面上化学吸附的水在TPD过程中也可以分解释氢.氧化处理的Pt/TiO_2在TPD过程中于550～750K温区出现氧脱附峰,随着氧化温度升高,脱附峰位向高温移动,经实验证明,这种可脱附活泼氧物种的生成是由样品前身中留存氢引起的.还原处理的Pt/TiO_2在TPD过程中分别在300～600和大于600K出现两个氢脱附峰,认为是由于表面羟基和钛—氢(Ti~(4+)—H~-)物种的分解释氢引起的Pt/TiO_2上活泼氧物种的存在,增加了样品在室温条件下的吸氢量;在中温(473～573K)这种活泼氧物种则和氢发生反应,减少了TPD过程中的脱氢量;Pt/TiO_2在大于673K温度还原,可以消除活泼氧物种的影响.     

Pt/TiO_2催化剂上的氢—氧作用——Ⅱ. 程序升温还原和程序升温氧化研究

本文采用TPR、TPO技术分别考察了氧处理Pt/TiO_2上氧物种的还原行为和氢还原样品的氧化过程.TPR结果表明,表面含有活泼氧物种的Pt/TiO_2样品对氢很活泼,室温条件下可以吸附大量氢,并且这些吸附氢又可以在TPR过程中脱附.表面活泼氧物种与氢的反应温度在500—673K之间,当大于673K时,Pt/TiO_2继续耗氢,可能是氢与还原产生的表面Ti~(3+)离子进一步反应生成钛—氢物种,并向TiO_2体相扩散与TiO_2体相晶格氧发生反应.对于773K还原的Pt/TiO_2作品,室温吸附氧在TPD过程中可以与表面吸附氢反应;473K氧化处理可以消除表面的吸附氢,但并不能完全去除体相储氢;573K氧化处理则基本上恢复了原样品的氧化状态.不同温度氢还原处理的Pt/TiO_2样品在动态氧化过程(TPO)中,在300-600K温区,气相氧与样品上表面吸附氢和表面氧空位反应;在大于600K温区,氧主要与表面钛—氢物种发生反应,并向体相扩散,与体相氢发生反应.文中描述了气相氢、氧分别与Pt/TiO_2催化剂存在的氧或氢物种作用的形式.     

Reducibility of Mo species in Pt/MoO3 and PtMo/Al2O3 catalysis

Recucibility of Mo species in Pt/MoO₃ and PtMo/Al₂O₃ has been investigated by temperature-programmed reduction (TPR), temperature-programmed desorption of hydrogen (H₂-TPD) and temperature programmed electronic conductivity (TPEC) techniques. In Pt/MoO₃ at H₂ atmosphere, it was found by TPEC and TPR that, a slight amount of Pt could activate the transfer of the species and H atoms between H₂ and MoO₃, and thus accelerate the reduction of MoO₃. In PtMo/Al₂O₃, TPR and H₂-TPD revealed that the reduction of surface Mo species could also be facilitated by Pt. Two kinds of hydrogen molybdenum species were proposed on the surface of the catalyst after prereduction.     

MXenes的制备及其在环境领域的应用

MXenes是一类新型的二维过渡金属碳/氮化物或碳氮化物,是由Mn₊₁AXn相物质(MAX相)通过剥离而得到的单层或薄层纳米片。独特的二维层状结构、较大的比表面积以及出色的导电性、机械稳定性和磁性等性能,使MXenes迅速成为研究热点,并已广泛应用于储能、催化、吸附等众多领域。本文总结介绍了二维材料MXenes的制备方法,并重点综述其近年来在环境领域的应用研究进展,如吸附重金属、吸附放射性金属、吸附有机物、二氧化碳的选择性吸附、光催化、电催化、膜分离、传感器、生物活性、电磁吸收与屏蔽等进行了总结与回顾,最后对现阶段存在的问题和未来发展进行了分析。