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1.
Abstract The effect of quantum dispersion (i.e. a multitude of quantum states corresponding to each value of an observable) on laboratory feedback optimal control is studied. It is shown by numerical and analytical means that including the variance of the observable in the objective functional as well as the presence of modest noise in the controls can steer the system into a low-variance quantum state or, if possible, into an eigenstate of the observable. 相似文献
2.
针对焓差法空调机性能试验室环境控制中被控对象具有大滞后、慢时变、非线性及不确定干扰因素多等特点,将具有自学习、自适应功能的神经元PID控制器应用于温度控制系统中,通过数学建模并在MATLAB环境下的计算机仿真,证明了神经元PID控制的实用性和有效性。 相似文献
3.
A multiobjective design and control optimization problem for functionally graded (FG) plates is presented using a first-order plate theory including the normal strain effect. The aim of the optimization is to minimize the vibrational response and to maximize the buckling loads of FG plates with constraints on the control energy and plate thickness. An integrated approach for the simultaneous design and active control optimization is presented to determine the optimal level of a closed loop control function. Plate thickness and a homogeneity parameter of FG plates are used as design variables. Numerical results for the optimal control force and the total energy of FG plates are presented in various cases of boundary conditions. The influence of the normal strain effect on the accuracy of the obtained results is illustrated. The effectiveness of the present control and design procedures are examined. 相似文献
4.
Radiation safety was determined to maintain quality control in the cyclotron laboratory. Based on the results of 438 runs in the Faraday cup (20 microA for 10 min), 20 runs on 18O-water target (40 microA for 2 h) and 10 runs on 18O-gas targets (30 microA for 45 min), we have established that occupationally exposed workers remain 10 +/- 5 times below federal regulatory limits (FRLs) in the cyclotron vault, 30 +/- 8 times below FRL in the radiochemistry laboratory and 200 +/- 10 times below the FRL outside the cyclotron laboratory during beam operation. (The FRL for unrestricted area are <20 microSv in 1 h.) The non-occupationally exposed workers serving in offices in the vicinity of the cyclotron vault within 100 m distance remained 200 times below the FRL irrespective of beam being on or off, suggesting that routine beam operation of 40 microA for 2 h once a day during office hours is safe provided quality control and system performance measures as discussed in this report are strictly maintained. 相似文献
5.
联合国《全球化学品统一分类和标签制度》(GHS)和欧盟《化学品注册、评估许可和限制法规》(REACH)法规都要求在化学品进入市场前提供健康危害和环境危害数据。为了保证全球检测数据的一致性和可比性,要求检测数据来自通过良好实验 相似文献
6.
比较混合通风、置换通风、地板送风各自的原理及特性,分析这3种气流组织方式在实验室的适用性,及其对实验室污染物控制的影响。在此基础上,针对实验室通风和污染物控制的进一步深入研究提出建议。 相似文献
7.
朱华明 《制冷与空调(北京)》2006,6(2):102-104
讨论宽温度段(+5~-25℃)低温实验室精密温度控制系统的设计难点,并从工程应用的角度,提出利用变流量二次供冷的方式精密控制低温实验室温度的理论和手段。 相似文献
8.
信息化管理在检测实验室的应用及其质量控制 总被引:1,自引:0,他引:1
信息化管理在检测实验室的应用愈来愈广泛,为确保检测数据的准确、公正,质量控制要求应嵌入信息化管理系统中.本文信息化管理在检测实验室的应用及其质量控制进行简要论述. 相似文献
9.
以中国计量科学研究院生物安全量值溯源传递实验室工程项目为例,从通风空调的角度探讨生物安全防护实验室的环境控制,并在此基础上给出最不利状况,即送排风系统出现运行故障时,避免房间出现正压,确保安全运行的具体做法,以期对类似项目的设计、施工和运行起到一定参考和指导作用。 相似文献
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11.
Hughes MS Marsh JN Agyem KF McCarthy JE Maurizi BN Wickerhauser MV Wallace KD Lanza GM Wickline SA 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(11):2361-2369
Duchenne muscular dystrophy (DMD) is an X-linked genetic disease characterized by progressive weakness and wasting of skeletal and cardiac muscle; boys present with weakness by the age of 5 years and, if left untreated, are unable to walk without assistance by the age of 10 years. Therapy for DMD has been primarily palliative, with oral steroids emerging as a first-line approach even though this treatment has serious side-effects. Consequently, low-cost imaging technology suitable for improved diagnosis and treatment monitoring of DMD would be of great value, especially in remote and underserved areas. Previously, we reported use of the logarithm of the signal energy, log [E(f)], and a new method for ultrasound signal characterization using entropy, H(f), to monitor prednisolone treatment of skeletal muscle in a dystrophin-deficient mouse model. Three groups were studied: mdx mice treated with prednisolone, a control group of mdx mice treated with saline, and a control group of wild-type mice treated with saline. It was found that both log [E(f)] and H(f) were required to statistically differentiate the three groups. In the current study, we show that preprocessing of the raw ultrasound using optimal smoothing splines before computation of either log [E(f)] or a rapidly computable variant of Hf, denoted I(f,∞), permits delineation of all three groups by either metric alone. This opens the way to the ultimate goal of this study, which is identification and implementation of new diagnostically sensitive algorithms on the new generation of low-cost hand-held clinical ultrasonic imaging systems. 相似文献
12.
M.H. Van de Voorde 《Materials at High Temperatures》2013,30(4):195-200
Development of technology to meet the energy problems facing the industrialized countries depends strongly on the availability of improved constructional materials, in order to achieve more efficient conversion and utilization of energy. Due to the use of high temperatures and aggressive environments, ceramic and composite materials have to be considered, as well as steels and superalloys. In turn, the development of materials technology relies upon research into the relationships between structure and properties of materials.This paper argues that scientific training for materials scientists is now much more urgently needed than in the past, in order to ensure the adequate and timely development of the required materials. Materials science should therefore be reassessed and its technological aspects emphasized. Finally, proposals are made for intensified international cooperation between materials laboratories and institutions to accomplish this task. 相似文献
13.
Packagings for the transport of dangerous goods are tested by four tests:- free fall, leakproofness, hydraulic pressure and stacking. However, the test procedures can be interpreted in different ways, particularly the stacking test. Some test authorities apply a guided load to the top of the package and others, including the LNE in France, use non-guided loads. The objective of recent research carried out at LNE was to evaluate the risk (in terms of stack stability for dangerous goods packagings) if the stacking tests are performed with guided loads rather than non-guided loads. The stacking tests were carried out on a limited number of plastic drums (200 of four types) submitted for qualification testing using the above four tests, with either guided or non-guided loads. From the results we conclude that:
- i for the transport of dangerous goods of Danger Group I, the field of use is not altered when tested by either procedure.
- ii with goods of Danger Groups II and III, the use of either procedure does not alter the position as far as transport is concerned. However, there is a risk in warehousing: the non-guided procedure being preferred.
14.
Wallace KD Marsh JN Baldwin SL Connolly AM Keeling R Lanza GM Wickline SA Hughes MS 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(11):2291-2299
Duchenne muscular dystrophy is a severe wasting disease, involving replacement of necrotic muscle tissue by fibrous material and fatty infiltrates. One primary animal model of this human disease is the X chromosome-linked mdx strain of mice. The goals of the present work were to validate and quantify the capability of both energy and entropy metrics of radio-frequency ultrasonic backscatter to differentiate among normal, dystrophic, and steroid-treated skeletal muscle in the mdx model. Thirteen 12-month-old mice were blocked into three groups: 4 treated mdx-dystrophic that received daily subcutaneous steroid (prednisolone) treatment for 14 days, 4 positive-control mdx-dystrophic that received saline injections for 14 days, and 5 negative-control animals. Biceps muscle of each animal was imaged in vivo using a 40-MHz center frequency transducer in conjunction with a Vevo-660 ultrasound system. Radio-frequency data were acquired (1 GHz, 8 bits) corresponding to a sequence of transverse images, advancing the transducer from "shoulder" to "elbow" in 100-micron steps. Data were processed to generate both "integrated backscatter" (log energy), and "entropy" (information theoretic receiver, Hf) representations. Analyses of the integrated-backscatter values delineated both treated-and untreated-mdx biceps from normal controls (p<0.01). Complementary analyses of the entropy images differentiated the steroid-treated and positive-control mdx groups (p<0.01). To our knowledge, this study represents the first reported use of quantitative ultrasonic characterization of skeletal muscle in mdx mice. Successful differentiation among dystrophic, steroid-treated, and normal tissues suggests the potential for local noninvasive monitoring of disease severity and therapeutic effects. 相似文献
15.
The paper develops a sociological model to explain collisions between two drivers or more. The "Social Accident" model presented here integrates empirical findings from prior studies and extant sociological theories. Sociological theory posits that social groups have unique cultural characteristics, which include a distinctive world view and ways of operating that influence its members. These cultural characteristics may cause drivers in different groups to interpret a given situation differently; therefore, they will make conflicting decisions that may possibly lead to road accidents. The proposed model may contribute to an understanding of the social mechanism related to interactions and communication among drivers by presenting new directions for understanding accidents and collisions. The paper concludes with suggestions for future research that will employ the model to assess its predictive and practical utility. 相似文献
16.
This work reports on the optical and structural properties of nanostructured films formed by Ag nano-objects embedded in amorphous aluminium oxide (a-Al(2)O(3)) prepared by alternate pulsed laser deposition (PLD). The aim is to understand the importance of the energetic species involved in the PLD process for nanostructuring, i.e.?for organizing nanoparticles (NPs) in layers or for self-assembling them into nanocolumns (NCls), all oriented perpendicular to the substrate. In order to change the kinetic energy of the species arriving at the substrate, we use a background gas during the deposition of the embedding a-Al(2)O(3) host. It was produced either in vacuum or in a gas pressure (helium and argon) while the metal NPs were always produced in vacuum. The formation of NPs or NCls is easily identified through the features of the surface plasmon resonances (SPR) in the extinction spectra and confirmed by electron microscopy. The results show that both the layer organization and self-assembling of the metal are prevented when the host is produced in a gas pressure. This result is discussed in terms of the deceleration of species arriving at the substrate in gas that reduces the metal sputtering by host species (by ≈58%) as well as the density of the host material (by ≥19%). These reductions promote the formation of large voids along which the metal easily diffuses, thus preventing organization and self-organisation, as well as an enhancement of the amount of metal that is deposited. 相似文献
17.
A likelihood-ratio-based EWMA control chart for monitoring variability of multivariate normal processes 总被引:1,自引:0,他引:1
To effectively monitor small changes of variability of multivariate normal processes, a new control chart is proposed and studied. The proposed control chart is constructed based on taking the exponentially weighted moving averages of the logarithm of the likelihood ratio for testing the hypothesis that two variance-covariance matrices are equal. The applicability of the proposed control chart in detecting changes in process variability is demonstrated through an example. The simulation studies further show that the proposed control chart outperforms the existing procedures in most cases. 相似文献
18.
A R Newman 《Analytical chemistry》1990,62(20):1063A-1065A
19.
Scientometrics - The differentiation of scientific fields into sub-fields can be studiedon the level of the 'scientific content' of the sub-field, thatis on the level of the products, as... 相似文献