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1.
通过将中央空调系统与手术室净化层流空调系统、静脉药物配置中心并网运行的实例,引出如下思考:在医院建设过程中,将空调系统的应用要求分类归纳,并进行整体规划、设计和施工,对节能、满足不断产生的服务需求和设备运行安全等方面大有裨益。  相似文献   

2.
本文通过线性系统极点配置,李雅普诺夫方法研究了已烯雌酚在人体各器官转移模型的变结构控制问题,得到了使系统尽快达到稳定平衡点的变结构控制器.该问题为生物模型综合控制问题的研究奠定了基础.  相似文献   

3.
运用拓扑度方法给出高维非自治系统全爱化型小参数问题周期解存在性的一些简明的判别方法,即在非线性项满足强制性条件时,无需计算便能判别周期解的存在。  相似文献   

4.
本文应用极点排序和位置向量排序的方法对广东13个森林群落进行排序分析,并分别用极点排序图和位置向量排序的二维图和三维图表示排序的结果。同时对排序图的生态学意义及排序方法的优缺点进行讨论。结果表明,三维位置向量排序图能较好地把性质相近的群落类型聚在一起,可作为植被分类的辅助方法;积点排序图从一定程度上反映了植被的连续变化;极点排序与位置向量排序虽然取得一定结果,但由于同属线性排序,损失的信息量较多,寻求非线性排序方法是研究的方向。  相似文献   

5.
线性广义系统的无源控制   总被引:5,自引:0,他引:5  
研究线性广义系统在有界能量外部输入作用下的无源控制问题,给出广义系统容许且具有严格无源性的充分条件,并且在一定条件下设计一个状态反馈控制器使得闭环系统容许,同时具有严格无源性.  相似文献   

6.
针对一类不确定非线性系统,提出将生物个体对外界环境的适应对策引入到间接模糊自适应控制方法.本方法的特点是将生物个体的主动自适应性与模糊控制相结合,将反应生物特性能力的结构单位生态位作为模糊规则后件,利用生物的自适应来设计控制器和自适应律,使系统在外界环境的扰动下具有主动适应性.根据Lyapunov稳定性理论,证明闭环系统的全局稳定性.最后对肌型血管系统进行了仿真,结果证明了该方法的有效性和可行性.  相似文献   

7.
本文对一类食饵种群具有常数收获率的Kolmogolov系统进行了非线性分析,研究了 系统平衡点的性态,在较宽的条件下证明了系统不存在闭轨线;并获得了系统存在两个极限环的条件。  相似文献   

8.
人口动力学中非线性发展方程解的爆破现象   总被引:1,自引:0,他引:1  
讨论描述人口发展规律的一类非线性发展方程具有第三类非线性边界条件的混合问题.在已知函数满足某些假设条件下,证明了其解在有限时间内爆破.  相似文献   

9.
目的:市售SYD-4228生理学学生实验系统没有配置心电图导联电缆及导联选择装置,不能进行观察心电图的实验,为此研制本心电导联转换仪。方法:设计并制作兼容网络与导联输入电缆,组装成新型的转换仪。结果:本转换仪配合SYD系统在高血钾实验中使用,满足了SYD系统进行心电图实验的需要。结论:本转换仪既适用于SYD系统,也适用于各型心电图机,可以同步对比观察不同导联的心电图。  相似文献   

10.
为制备可满足临床需要的可注射磷酸钙骨水泥,以自制纳米羟基磷灰石/壳聚糖复合材料作为骨水泥的固相粉体,将柠檬酸、醋酸等按一定比例配置成溶液作为液相,设计正交试验以简化实验,从凝固时间和抗压强度两方面来确定该骨水泥体系的最佳配比。再通过转靶X射线衍射仪、傅立叶变换红外光谱仪、扫描电子显微镜手段分析了各个组分对凝固时间和抗压强度的影响。此外,还通过细胞培养实验评价了最优条件下骨水泥的生物相容性。  相似文献   

11.
V R Mattox  R D Litwiller 《Steroids》1979,34(2):227-239
A group of moderately polar C21 steroids (3-5 oxygen functions) has been chromatographed in 9 solvent systems. Using the concept that standard deviation of the mean RF is an index of chromatographic resolution, and that coefficients of correlation between sets of RF data can be used to quantify the similarities of chromatographic systems, we have evaluated the resolving properties of the systems when used individually, and also when used in combinations of two, three and four. The discriminating powers of some of the most effective individual systems, and some of the sequences of systems which are most efficient, are shown graphically as chromatography trees. The relationship between the total effective standard deviation of a group of systems which are used in sequence and the probability that a pair of compounds will be separated by more than 0.10 RF is discussed.  相似文献   

12.
Proteins play a central role in a systems view of biologic processes. This review provides an overview of proteomics from a systems perspective. We survey the key tools and methodologies used, present examples of how these are currently being used in the systems biology context, and discuss future directions.  相似文献   

13.
Biocatalytic reactions can be carried out in aqueous-organic two-phase systems. Several models to describe the thermodynamically-determined equilibrium position in such systems have appeared in the literature. Some of these models are only valid for dilute systems, whereas others can also be used for nondilute systems. In this paper, these models are described and compared. It is explained in what way the equilibrium constants of each model can be used to predict the product concentration in different organic solvents.  相似文献   

14.
Biocatalytic reactions can be carried out in aqueous-organic two-phase systems. Several models to describe the thermodynamically-determined equilibrium position in such systems have appeared in the literature. Some of these models are only valid for dilute systems, whereas others can also be used for nondilute systems. In this paper, these models are described and compared. It is explained in what way the equilibrium constants of each model can be used to predict the product concentration in different organic solvents.  相似文献   

15.
ObjectivesTo compare the use of three electronic medical records systems by doctors in Norwegian hospitals for general clinical tasks.DesignCross sectional questionnaire survey. Semistructured telephone interviews with key staff in information technology in each hospital for details of local implementation of the systems.Setting32 hospital units in 19 Norwegian hospitals with electronic medical records systems.Participants227 (72%) of 314 hospital doctors responded, equally distributed between the three electronic medical records systems.ResultsMost tasks listed in the questionnaire (15/23) were generally covered with implemented functions in the electronic medical records systems. However, the systems were used for only 2-7 of the tasks, mainly associated with reading patient data. Respondents showed significant differences in frequency of use of the different systems for four tasks for which the systems offered equivalent functionality. The respondents scored highly in computer literacy (72.2/100), and computer use showed no correlation with respondents'' age, sex, or work position. User satisfaction scores were generally positive (67.2/100), with some difference between the systems.ConclusionsDoctors used electronic medical records systems for far fewer tasks than the systems supported.

What is already known on this topic

Electronic information systems in health care have not undergone systematic evaluation, and few comparisons between electronic medical records systems have been madeGiven the information intensive nature of clinical work, electronic medical records systems should be of help to doctors for most clinical tasks

What this study adds

Doctors in Norwegian hospitals reported a low level of use of all electronic medical records systemsThe systems were mainly used for reading patient data, and doctors used the systems for less than half of the tasks for which the systems were functionalAnalyses of actual use of electronic medical records provide more information than user satisfaction or functionality of such records systems  相似文献   

16.
This review examines the electrochemical techniques used to study extracellular electron transfer in the electrochemically active biofilms that are used in microbial fuel cells and other bioelectrochemical systems. Electrochemically active biofilms are defined as biofilms that exchange electrons with conductive surfaces: electrodes. Following the electrochemical conventions, and recognizing that electrodes can be considered reactants in these bioelectrochemical processes, biofilms that deliver electrons to the biofilm electrode are called anodic, ie electrode-reducing, biofilms, while biofilms that accept electrons from the biofilm electrode are called cathodic, ie electrode-oxidizing, biofilms. How to grow these electrochemically active biofilms in bioelectrochemical systems is discussed and also the critical choices made in the experimental setup that affect the experimental results. The reactor configurations used in bioelectrochemical systems research are also described and the authors demonstrate how to use selected voltammetric techniques to study extracellular electron transfer in bioelectrochemical systems. Finally, some critical concerns with the proposed electron transfer mechanisms in bioelectrochemical systems are addressed together with the prospects of bioelectrochemical systems as energy-converting and energy-harvesting devices.  相似文献   

17.
This review examines the electrochemical techniques used to study extracellular electron transfer in the electrochemically active biofilms that are used in microbial fuel cells and other bioelectrochemical systems. Electrochemically active biofilms are defined as biofilms that exchange electrons with conductive surfaces: electrodes. Following the electrochemical conventions, and recognizing that electrodes can be considered reactants in these bioelectrochemical processes, biofilms that deliver electrons to the biofilm electrode are called anodic, ie electrode-reducing, biofilms, while biofilms that accept electrons from the biofilm electrode are called cathodic, ie electrode-oxidizing, biofilms. How to grow these electrochemically active biofilms in bioelectrochemical systems is discussed and also the critical choices made in the experimental setup that affect the experimental results. The reactor configurations used in bioelectrochemical systems research are also described and the authors demonstrate how to use selected voltammetric techniques to study extracellular electron transfer in bioelectrochemical systems. Finally, some critical concerns with the proposed electron transfer mechanisms in bioelectrochemical systems are addressed together with the prospects of bioelectrochemical systems as energy-converting and energy-harvesting devices.  相似文献   

18.
Thin-layer and paper chromatographic systems were used to detect and determine the concentration of cephaloglycin and its biologically active metabolites in serum and urine. Data are presented on the procedures, solvent systems, and specific techniques used in this evaluation.  相似文献   

19.
Resilience theory offers a framework for understanding the dynamics of complex systems. However, operationalizing resilience theory to develop and test empirical hypotheses can be difficult. We present a method in which simple systems models are used as a framework to identify resilience surrogates for case studies. The process of constructing a systems model for a particular case offers a path for identifying important variables related to system resilience, including the slowly-changing variables and thresholds that often are keys to understanding the resilience of a system. We develop a four-step process for identifying resilience surrogates through development of systems models. Because systems model development is often a difficult step, we summarize four basic existing systems models and give examples of how each may be used to identify resilience surrogates. The construction and analysis of simple systems models provides a useful basis for guiding and directing the selection of surrogate variables that will offer appropriate empirical measures of resilience.  相似文献   

20.
Since it is generally accepted that a tight metabolic control might prevent the chronic complications of diabetes mellitus, several systems have been developed in which insulin is administered in a manner that mimicks the characteristics of insulin secretion. 1) In the so-called closed-loop systems, insulin delivery is regulated by the concomitant plasma glucose level. These systems, which involve continuous measurement of plasma glucose concentration are not to date implantable and have been used so far only for short-term studies. 2) By contrast, in the "open-loop systems", no glucose sensor is needed and insulin delivery is pre-programmed to achieve a constant basal infusion with peaks of insulin delivery during the meal periods. These systems have been used in man for several months. The present achievement and limitations of both kinds of systems are discussed in this review.  相似文献   

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