实现微米级灭菌范围控制的微细等离子体射流装置

为了实现微细等离子体的精准灭菌,设计了新型微细等离子体射流装置,并对该装置产生的含氧活性粒子(Reac-tive Oxygen Species,ROS)和含氮活性粒子(Reactive Nitrogen Species,RNS)分布范围及其灭菌范围进行研究.淀粉碘化钾混合溶液里的碘离子可以被微细等离子体射流产生的ROS...     

Learning control for batch thermal sterilization of canned foods

A control technique based on Reinforcement Learning is proposed for the thermal sterilization of canned foods. The proposed controller has the objective of ensuring a given degree of sterilization during Heating (by providing a minimum temperature inside the cans during a given time) and then a smooth Cooling, avoiding sudden pressure variations. For this, three automatic control valves are manipulated by the controller: a valve that regulates the admission of steam during Heating, and a valve that regulate the admission of air, together with a bleeder valve, during Cooling. As dynamical models of this kind of processes are too complex and involve many uncertainties, controllers based on learning are proposed. Thus, based on the control objectives and the constraints on input and output variables, the proposed controllers learn the most adequate control actions by looking up a certain matrix that contains the state-action mapping, starting from a preselected state-action space. This state-action matrix is constantly updated based on the performance obtained with the applied control actions. Experimental results at laboratory scale show the advantages of the proposed technique for this kind of processes.     

自动土壤水分数据质量控制中的阈值确定

为了提高自动土壤水分资料的应用价值,采用数理统计学方法,分析不同深度人工观测土壤水分资料的历年分布和极值状况,研究确定各层土壤水分资料的阈值并应用于自动土壤水分监控,为实现全省土壤水分质量自动化监控和数据异常分析提供重要参数。     

乙烯压缩机防喘振控制

介绍了离心式压缩机工作过程中喘振产生的机理,喘振的危害。分析了造成喘振的主要因素,并对常用的防喘振控制方法进行了比较和分析。详细介绍了某装置压缩机防喘振控制的具体实现。     

气相色谱法测定环氧乙烷反应器气体中痕量1,2-二氯乙烷

在乙二醇和环氧乙烷工艺生产过程中,所用银催化剂的活性是靠加入痕量1,2-二氯乙烷来调节的.为了保证银触媒的活性和环氧乙烷的转化率,1,2-二氯乙烷的加入量是非常关键的.本文介绍了以硅油Ⅱ号固定液涂渍Chromosorb WHP 担体的色谱柱,采用气相色谱法准确测定了环氧乙烷反应器中痕量1,2-二氯乙烷含量.     

Tribocatalytic oxidation of ethylene in the rubbing of palladium against aluminum oxide

Friction experiments of palladium rubbed against aluminum oxide in ethylene/oxygen mixed atmosphere have been carried out. The complete oxidation of ethylene to carbon dioxide and water at room temperature was demonstrated. The evolution of carbon dioxide was initiated just after the start of friction; momentarily the pressure reached its equilibrium whereas water was produced gradually. On the other hand, by heating the palladium wire in the same partial pressure of both gases, carbon monoxide and hydrogen were generated at 600 K and above. By increasing oxygen partial pressure, carbon dioxide and water were produced. These results indicate that the ethylene oxidation activity on palladium catalyst is enhanced by the friction of catalyst. Two kinds of reactions, fast and slow, are attributed to near-contact and out-of-contact activities of friction surfaces. The near-contact reaction is governed by tribo-electron emission, whereas the out-of-contact activity is due to the generated nascent surface.     

基于PLC的真空挤砖机进料湿度控制系统的设计

针对人工凭经验控制真空挤砖机进料湿度的不足,采用西门子PLC开发了一套真空挤砖机进料湿度自动控制系统。通过功率变送器对双轴搅拌机电机和真空挤砖机搅拌部分电机的有功功率进行检测来间接判别进料湿度,并结合PLC构成一个具有主、副调节器的串级控制系统,实现了对挤砖机进料湿度的自动控制。应用结果表明,该系统安装简单,对进料湿度控制的精度高,可降低企业的人力成本和提高企业产品的质量,具有一定的实用价值。     

顶空毛细管气相色谱法测定曲克芦丁中环氧乙烷残留量

建立了顶空毛细管气相色谱法测定曲克芦丁中环氧乙烷残留量的方法。环氧乙烷浓度在0．1～3．0μg／mL范围内,线性与精密度良好,平均回收率为100．6％,最低检出限为0．04μg／mL,线性方程为Y=10247．99c=539．76,相关系数为0．999。方法简便,结果准确。     

预测函数控制在水分定量控制中的应用

针对抄纸过程中水分定量系统具有非线性和纯滞后的特征,提出了将预测函数控制方法应用到水分定量系统中,对水分定量的控制,改善了控制系统稳定性及性能指标。仿真实验表明该方法有较强的跟踪性和鲁棒性。实际运行结果表明该方法具有较好的鲁棒性和较好的控制精度。     

Modeling and control of ball mill system considering coal moisture

This study analyzes the dynamic characteristics of duplex inlet and outlet ball mill direct firing pulverizing system. A mass and energy balance-based model is built by thermodynamic analysis. As a critical parameter in pulverized coal humidity control, coal moisture is considered in the mechanism model, and an extended Kalman filter is designed to estimate the coal moisture. A multivariable control system is designed using extended state space predictive controller. The dynamic characteristic of the mill can be effectively forecasted using the established model. The system can rapidly track unit load changes while reducing the disturbance caused by coal moisture and other outlets.     

Preconditioning of projected SIRT algorithm for electromagnetic tomography

For Electromagnetic Tomography (EMT) Techniques, image reconstruction is one of the crucial steps, which directly affects the quality of reconstruction and real-time performance of the EMT system. Following analyzing a pre-iterative method for SIRT (simultaneous iterative reconstruction technique) algorithm, a preconditioning for the projected SIRT is proposed to accelerate the image reconstruction speed and alleviate the ill-posed nature of the EMT inverse problem. Experimental tests confirm that the quality of the reconstructed images using the preconditioning algorithm is enhanced with only a small number of iterations required.     

定量水分预测函数多变量控制的研究

造纸工业抄纸过程中,定量和水分的控制品质直接影响纸张的质量.针对其中存在的大时滞、大惯性以及强耦合的特点,提出了基于一阶加纯滞后对象的多变量预测函数控制算法.通过优化多变量性能指标求得控制律,并参考Smith预估思想对滞后时间进行补偿.定量水分系统的仿真结果说明了该算法能较好地达到控制性能的要求,并具有良好的鲁棒性.     

一种微振动光纤传感系统信号预处理电路

长距离分布式微振动光纤传感系统的系统噪声的重要产生原因是光源噪声。为了消除这类噪声,设计了预处理电路将一路光电信号转化为两路差分信号。电路将输入的光电流通过对管结构形成差分电流再分别转换成电压信号输出。仿真结果显示该电路可成功的输出两路差分信号,且带宽、增益和信号处理能力都比较强。     

An evaluation of the accuracy and reliability of ethylene oxide diffusion badge monitors

Ethylene oxide (EO) gas is widely used in hospitals to sterilize certain moisture- and heat-sensitive materials. Based on scientific studies indicating its potential as a human carcinogen and mutagen, and the possible genotoxic, reproductive, neurologic, and sensitization hazards associated with EO exposure, the Occupational Safety and Health Administration has recently lowered the permissible exposure limit (PEL) from 50 ppm to 1 ppm as an 8-hour time-weighted average (TWA). This standard also established an "action level" of 0.5 ppm for an 8-hour TWA, below which employers are exempted from such requirements as periodic employee exposure monitoring or medical surveillance. These much lower concentrations of EO in air now place greater demands upon the analytical techniques used to monitor exposure of hospital personnel to EO. In this study, the capabilities of five EO diffusion monitors were examined in the TWA concentration range of 0.25-3.7 ppm. Both accuracy and precision were tested by exposing these devices simultaneously to measured concentrations of EO in a stainless steel exposure chamber. Temperature and humidity conditions were controlled, as was the flow rate of the gases across the sampling areas of the diffusion monitors. All of the monitors tested were sensitive enough to measure EO at the new PEL level, but in this laboratory investigation only one type of monitoring badge was able to meet the National Institute for Occupational Safety and Health criteria of +/- 25% overall system accuracy at the 95% confidence level in the exposure range of 0.5-2.0 X the OSHA PEL.     

烧结混合料水分模糊PID控制系统设计

烧结混合料水分控制系统具有时变性、非线性和时滞性等特点,难以建立其精确的数学模型.由于传统PID控制技术在固定参数下难以保证系统性能的缺陷,基于烧结炉的结构特点和控制性能要求,本文提出了采用模糊推理方式自整定PID控制参数,设计了参数自整定模糊PID控制器,并将该模糊PID控制器用于烧结混合料水分控制系统.实际运行效果证明,该控制器比原有的PID控制器在性能上有较明显的提高,稳定了烧结混合料水分,改善了烧结生产状况,促进了产能提升.     

顶空气相色谱法测定医疗器械成品库空气中的环氧乙烷

建立了医疗器械成品库空气中环氧乙烷浓度的顶空气相色谱测定方法。空气样品用纯水吸收,用HP-5毛细管柱（30m×250um,0．25um）分离,氢火焰离子化检测器（FID）检测。在本法的测定条件下,环氧乙烷在0～15．768ug／mL浓度范围内线性良好,相关系数r=0．9992,相对标准偏差RSD〈2．1％,最低检出限1ug／mL。本方法可满足医疗器械成品库空气中环氧乙烷浓度检测的要求。     

Microwave desorption: a combined sterilizer/aerator for the accelerated elimination of ethylene oxide residues from sterilized supplies

Ethylene oxide gas is widely used in medical and related facilities for low-temperature sterilization of surgical devices. Evidence of its toxicity and, in particular, its mutagenicity and carcinogenicity provide sufficient reasons for caution in its use and for minimizing exposure. Little advancement has been made in the removal of ethylene oxide residuals from plastics into which the gas is heavily absorbed during sterilization, despite the fact that the gas has been used for 20 years or more. This article describes a novel process (PCT Application/GB85/00509) in which microwave irradiation of ethylene oxide-sterilized materials is utilized to enhance the rate at which the gas is desorbed. The experimental apparatus is described, and an explanation of the effect of microwaves on the energy of activation for diffusion is given. Data are presented in support of the authors' claim of a 400% improvement in the efficiency of the new process over conventional aeration procedures. The advantages and economy of an integrated sterilizer/microwave-enhanced desorber are discussed in the context of the implications that arise from the current regulatory debate.     

Local work function control of indium tin oxide by micro-contact printing for electroluminescent devices

We demonstrate here that light emission of an electroluminescent (EL) device was enhanced on chemically modified ITO areas over a patterned ITO anode with a self-assembled monolayer (SAM) of 4-chlorophenylphosphoryl dichloride (ClC₆H₄OPOCl₂: CPPDC) prepared by micro-contact printing (μ-CP). The EL device was fabricated by vapor-depositing a hole transport layer, a light emitting and electron transport layer, and a C₆H₅COOLi/Al bilayer cathode on the patterned ITO anode. The enhanced light emission under lower drive voltages on the modified areas can be interpreted by the increase in the work function of the ITO covered with the SAM measured with a Kelvin probe force microscope (KPFM) and thus the decrease in the hole injection barrier height. In addition, we could demonstrate the much smaller pattern images than the previously reported ones [F. Nüesch, Y. Li, L.J. Rothberg, Appl. Phys. Lett. 75 (1999) 1799] by the use of ink-pads.     

湿式微波杀菌试验装置谐振腔设计

为解决水产品杀菌过程中的加热均匀性问题,提出一种湿式微波杀菌的技术方案,将微波杀菌与常规热力杀菌相结合,热水和微波同时对食物杀菌,食品在短时间内可获得比单纯使用微波或水浴杀菌方式更高的温度均匀性。根据方案,研制湿式微波杀菌装置,并对装置关键部件——微波谐振腔进行有限元方法分析,以确保装置性能指标。