多氯代二苯并二口恶口英降解性的量子化学初探

采取半经验的量子化学计算方法研究了所有75种多氯代二苯并二口恶口英(PCDDs)的生成热和前线分子轨道能量,从还原脱氯和光激发难易的角度考察了PCDDs的降解性和结构之间的关系.研究发现氯取代数少、尤其是侧位(2-、3-、7-和8-)氯取代数较少的PCDDs更难降解.     

多氯代二苯并二E Ying降解性的量子化学初探

采取半经验的量子化学计算方法研究了所有75种多氯代二苯并二E Ying（PCDDs)的生成热和前线分子轨道能量。从还原脱氯和光激发难易的角度考察了PCDDs的降解性和结构之间的关系。研究发现氯取代数少、尤其是侧位（2－、3－、7－和8－）氯取代数较少的PCDDs更能降解。     

氯代二苯并二(口恶)英(PCDDs)的光谱性质的理论研究

用含时密度泛函理论(TDDFT)和差分密度泛函理论(△SCF-DFT)研究了氯代二苯并二恶英(PCDDs)的紫外可见电子吸收光谱。通过对分子轨道组成成份的详细分析以及电子跃迁过程的模拟,对吸收光谱中的每个峰进行了归属。同时研究了氯取代基对PCDDs吸收光谱的影响,发现随着氯取代基数目的增加,在低能区激发能几乎没有变化,而在较高能区激发能迅速降低,这与TCDD光谱图中第一个峰是氧和碳环之间的电子跃迁相一致。这说明与氯取代基相关的跃迁位于高能区,故用光降解方法试图减少氯取代基数目以降低PCDDs的毒性是不可能有效的。     

单苯环氯取代指数法预测二噁类化合物PCDDs的正辛醇/水分配系数

采用单苯环氯取代指数作为氯代二苯并二口恶口英类化合物 (PCDDs)的分子结构描述符 ,通过正向逐步线性回归方法建立了PCDDs的logKow与分子结构描述符之间的定量关系模型。与文献报道的MOD模型相比 ,该模型不仅具有显著的相关性 (n =43,Radj=0 898,SE =0 195 ,在α =0 0 5时 ,F =2 0 45 5 ,p =0 0 0 0 0 ) ,而且对于分子结构具有更好的区分能力。利用建立的模型 ,对没有logKow文献值的其他 33种PCDDs化合物给出了预测值     

拓扑量子方法预测二噁(口英)类化合物PCDDs的正辛醇/水分配系数

二噁(口英)类化合物PCDDs的毒性与其正辛醇/水分配系数(logK_(ow))有关。由于PCDDs类化合物性质相似,分离困难,其中许多化合物的logK_(ow)难以测定,只能理论预测。以往的研究采用基团/原子贡献、热力学、化学图论和神经网络等方法进行研究,可得到较好的结果。本文提出拓扑量子方法,即考虑分子图顶点的性质,直接用二噁(口英)类化合物PCDDs的分子碎片的电离能I_p为主元来构建邻接矩阵。结果表明新的拓扑量子邻接矩阵的特征根与二噁(口英)类化合物的正辛醇/水分配系数(logK_(ow))有良好的相关性:logK_(ow)=-4.86201+0.00617S_R-0.71375 HLOMO R=0.9238,s=0.285,F=116.45,n=43     

氯代二苯并二噁英(PCDDs)的光谱性质的理论研究

用含时密度泛函理论（TDDFT）和差分密度泛函理论（ASCF—DFT）研究了氯代二苯并二嗯英（PCDDs）的紫外可见电子吸收光谱。通过对分子轨道组成成份的详细分析以及电子跃迁过程的模拟，对吸收光谱中的每个峰进行了归属。同时研究了氯取代基对PCDDs吸收光谱的影响，发现随着氯取代基数目的增加，在低能区激发能几乎没有变化，而在较高能区激发能迅速降低，这与TCDD光谱图中第一个峰是氧和碳环之间的电子跃迁相一致。这说明与氯取代基相关的跃迁位于高能区，故用光降解方法试图减少氯取代基数目以降低PCDDs的毒性是不可能有效的。     

对多氯代二苯并二噁的定量结构-气相色谱保留行为关系研究

采用分子电性距离矢量(MEDV)描述子表征多氯代二苯并二(口惡)(口英)(PCDDs),结合基于预测的变量选择和建模方法(VSMP),从MEDV中挑选出1-2个描述子,对不同固定相下PCDDs的气相色谱保留值建立定量线性模型。结果表明MEDV分子描述子对分子结构具有很好的分辨能力。利用VSMP方法挑选的MEDV描述子很好表达了描述子与气相色谱保留值之间的相关关系,所建立的模型相关系数(R)均大于0.98,留一法交互检验的相关系数(q)均大于0.97;并均匀挑选2/3有实验数据的异构体作为训练集,余下的1/3作为检验集,进行了变量挑选、建模,结果表明,挑选的变量与用全部已知样本建模时一致,最后对没有实验值的异构体进行了预测。     

单苯环氯取代指数法预测二EYing类化合物PCDDs的正辛醇／水分配系数

采用单苯环氯取代指数作为氯代二苯并二EYing类化合物（PCDDs）的分子结构描述符,通过正向逐步线性回归方法建立了PCDDs的logKow与分子结构描述符之间的定量关系模型。与文献报道的MOD模型相比,该模型不仅具有显著的相关性（n=43,Radj=0.898,SE=0.195,在α＝0．05时,F＝20．455,p=0.0000),而且对于分子结构具有更好的分区能力。利用建立的模型,对没有logKow文献值的其他33种PCDDs化合物给出了预测值。     

多氯代二苯并呋喃(PCDFs)光解性质的量子化学研究

多氯代二苯并呋喃(PCDFs)是持久性有机污染物之一，其光化学降解是其主要的环境降解途径，本文是采用量子化学方法对PCDFs光解性质进行研究。本文采取AMl半经验量子化学计算方法计算了所有135种PCDFs的生成热和前线分子轨道能量，据此讨论了PCDFs分子光激发和还原脱氯难易程度与分子结构之间的关系。结果表明生成热可以成功解释PCDFs在水相中随着分子氯取代数目增加而光解速率降低的规律，而前线分子轨道能则可以解释正构烷烃溶剂中随氯原子取代数目增加而还原脱氯在降解机理中越占主导地位的规律，从而从量子化学的角度为实验结果提供了理论解释。     

对多氯代二苯并二噁(口英)的定量结构-气相色谱保留行为关系研究

采用分子电性距离矢量（MEDV）描述子表征多氯代二苯并二噁[口英]（PCDDs）,结合基于预测的变量选择和建模方法（VSMP）,从MEDV中挑选出1-2个描述子,对不同固定相下PCDDs的气相色谱保留值建立定量线性模型。结果表明MEDV分子描述子对分子结构具有很好的分辨能力,利用VSMP方法挑选的MEDV描述子很好表达了描述子与气相色谱保留值之间的相关关系,所建立的模型相关系数（R）均大于0．98,留一法交互检验的相关系数（q）均大于0．97;并均匀挑选2／3有实验数据的异构体作为训练集,余下的1／3作为检验集,进行了变量挑选、建模,结果表明,挑选的变量与用全部已知样本建模时一致,最后对没有实验值的异构体进行了预测。     

Network properties and acid degradability of epoxy-based SU-8 resists containing reactive gamma-butyrolactone

SU-8 is an octafunctional epoxy-based negative resist supplied with a reactive diluent, gamma-butyrolactone (GBL). This paper characterizes the network properties and acid degradability of cured SU-8 resists with varying GBL monomer content and ultraviolet (UV) irradiation time. The SU-8/GBL network structure was characterized by Fourier transform infrared (FTIR) spectroscopy, ¹³C nuclear magnetic resonance (NMR) spectroscopy and gas chromatography–mass spectrometry (GC/MS). GBL was found to copolymerize with epoxy to bridge two neighbouring epoxy groups and does not homopolymerize. The maximum GBL:SU-8 molar ratio whereby all GBL fully reacted with available epoxy functionalities in the network was found to be 8:1. Excess GBL beyond the maximum GBL:SU-8 ratio remains in the network as a plasticizer. GBL content and UV irradiation time affect glass transition temperature (T_g), epoxy conversion and molecular weight between cross-links (M_c) which were measured by dynamic mechanical analysis (DMA) and FTIR. The mechanism of cross-linked network acid degradation was found to be surface erosion. Lower epoxy conversion, higher M_c and higher GBL content resulted in a higher dissolution rate, which can be exploited in applications requiring SU-8 removal. A patterned SU-8 grating with relatively high-GBL content (10%) was successfully used as a template for Cu electroforming.     

Reduction of waste biosolids by RAS-ozonation: Model validation and sensitivity analysis for biosolids reduction and nitrification

Biosolids reduction model by return activated sludge ozonation was validated by simulating nitrification data compiled from our pilot-scale and the literature studies. Then, a global sensitivity analysis (GSA) was performed to identify influential and non-influential parameters for biosolids reduction efficiency, change in specific nitrification activity (SNA), and alteration to expected nitrification stability. In general, the model outputs were sensitive to operational and ozone reaction parameters, but not to biochemical parameters. For operational parameters, mainly temperature and initial solids retention time (SRT) influenced all model outputs. For biosolids reduction, increase in the degradability of the influent COD decreased the reduction efficiency. For SNA, the changes were highly dependent on the influent TKN/COD ratio. Our findings also imply that the stability of the nitrification process in ozonated systems should be enhanced at constant MLVSS for warm temperatures, but could be reduced at temperatures below 12 °C and aerated SRTs below 10 days.     

QoS-Aware Admission Control and Dynamic Resource Provisioning Framework in Ubiquitous Multimedia Computing Environments

A ubiquitous service deployment is emerging in the multimedia, networking, and wireless mobile computing area. Therefore, there has been an increasing demand for ubiquitous computing environments to support a certain degree of quality of service (QoS) to meet various service requirements from different computing and networking applications, and to better utilize the computing resources. However, supporting QoS in the ubiquitous computing environments has also raised great concerns regarding the applicability of any QoS solution. Management of such ubiquitous multimedia applications requires new mechanisms, i.e., Soft-QoS framework, to be developed for admission control, negotiation, allocation, and scheduling. In this paper, we present a novel negotiated admission control algorithm that exploits the degradability property of applications to improve the performance of the system. The algorithm is based on setting aside a portion of the resources as reserves and managing it intelligently, so that the total utility of the system can be maximized. The mixed greedy and predictive strategy leads to an efficient protocol that also improves the system performance. We use the constructs of application benefit functions and resource demand functions in the integrated admission control and negotiation protocol. We applied our Soft-QoS framework to the admission controlling and resource scheduling for ubiquitous multimedia devices such as Continuous Media (CM) or Video-On-Demand (VOD) servers, where multimedia applications can generally tolerate certain variations on QoS parameters by providing multiple classes with consistently proportional rather than absolute QoS. Extensive simulation experiments are presented in the paper to evaluate the performance of the novel mechanisms and compare it against some other methods used in the past.This work was in part funded by DARPA through the SPAWARSYSCEN under Contract Number N66001-97-C-8525 and SK Telecom, Korea, under Contract Number (KU-R0405721).     

分子印迹聚合物预组装体系计算机模拟

使用Gaussian 03软件研究了以苯丙氨酸为模板,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,三氟乙酸为助溶剂的分子印迹预组装体系。通过计算机模拟考察了功能单体浓度、交联剂浓度和助溶剂浓度对模板-功能单体复合物浓度的影响,从理论上计算了苯丙氨酸分子印迹聚合物的最佳合成条件。通过模拟,有助于解释实验现象以及合成高特异性和亲和性分子印迹聚合物。     

Asymptotic rejection of asymmetric periodic disturbances in output-feedback nonlinear systems

This paper deals with asymptotic rejection of periodic disturbances which may have asymmetric basic wave patterns. This class of disturbances covers asymmetric wave forms in the half-period such as alternating sawtooth wave form, some disturbances which are generated from nonlinear oscillation such as Van de Pol oscillators, as well as disturbances with symmetric half-period wave forms such as sinusoidal disturbances and triangular disturbances etc. The systems considered in this paper can be transformed to the nonlinear output feedback form. The amplitude and phase of the disturbances are unknown. The novel concept of integral phase shift is introduced together with the newly introduced half-period integration operator to investigate the invariant properties of asymmetric periodic disturbances. They are used for the estimation of unknown disturbances in the systems, together with observer design techniques to deal with nonlinearity. The proposed control design with the disturbance estimation asymptotically rejects the unknown disturbance, and ensures the overall stability of the system.     

基于接地弹簧及配点法的系统动态特性分析

核电设备和部件的动态特性包括其固有频率和相应模态。对于动态特性受支承条件影响的核电设备,将之简化为带接地弹簧的质量一弹簧系统．并分析接地弹簧刚度的变化对该系统动态特性的影响。在此基础上,从带罚数的有限元配点法出发,推导接地弹簧的有限元等价形式,证明接地弹簧刚度与罚数的等价性,并由此等价性,阐明支承条件在施加设备边界条件过程中所起的作用。     

基于多频扫描的硅微谐振压力传感器测试方法

为了对硅微谐振压力传感器进行快速、高精度的开环特性测试,提出了一种基于多频扫描的频率特性测试方法.通过数字电路将多个不同频率的扫频信号叠加作为驱动信号,以实现在整个测试频带范围内高效且高精度的频率特性测试.搭建了以现场可编程门阵列(FPGA)为核心的多频扫描测试系统,采用4个正弦扫频信号叠加进行测试,结果表明:多频扫描测试与稳态扫描测试精度基本一致,但测试效率提高了4倍.多频扫描测试方法在保证测试精度的前提下,显著提高了测试效率,能够更好地满足高Q值传感器及其在批量生产过程中的测试需求.     

A ball and beam tracking and balance control using magnetic suspension actuators

A new ball and beam system is constructed using a pair of magnetic suspension actuators in this paper. The proposed system can be used not only as a control theory verification and practice platform, but also as an educational demonstration and training tool for system integration of electrics, mechanics and cybernetics. The proposed control system activates two magnetic suspension actuators on either side of the beam. The magnetic force, as a function of position and coil current, was measured and modelled by a quadratic function. The system mathematical model is derived by the Lagrangian function. For control performance, a single chip microprocessor as control kernel with basic electronic components is designed and implemented. The ball and beam system hardware as well as microprocessor-based control circuit is implemented and tested. The static and dynamic performance of the ball and beam system is tested with several different scenarios. The system operation on oscillatory stabilization and sinusoidal tracking is verified with excellent operational characteristics.