中小城镇住宅消防设施现状及建设管理探索

通过对西部某小城市的住宅消防设施建设和管理现状的调查 ,反映了占西部绝大部分城市面积的中小城镇的住宅消防设施十分令人担忧的现状 ,分析了造成这一现状的原因 ,提出了解决这一问题的建设管理思路     

Chitosan particles agglomerated scaffolds for cartilage and osteochondral tissue engineering approaches with adipose tissue derived stem cells

In the XML file of the original article, H. Redl’s affiliation is incorrect. It is listed correctly in both the paper and PDF versions of the article, and can be found below: The online version of the original article can be found at     

Direct Instantaneous Torque Control in Direct Drive Permanent Magnet Synchronous Motors—a New Approach

In this paper, a novel direct instantaneous torque control scheme for a direct drive (DD) permanent magnet synchronous motor (PMSM) is presented. A hybrid control structure combining the internal model principle and the variable structure control (VSC) approach is proposed. First, a variable structure torque controller is adopted to regulate the torque angle increment according to the torque feedback error. Second, the appropriate control voltage vector is determined using the reference stator flux vector and the estimated dynamic back electromotive force (EMF) vector, as an internal model, in a deadbeat control manner. Subsequently, better disturbance rejection can be obtained with the proposed cascaded control structure. To robustly obtain the instantaneous torque and flux information, a robust adaptive motor model is proposed. The Lyapunov stability theory is used to analyze the stability of the augmented robust adaptive motor model and to give a guideline for tuning model parameters. Experimental results are presented to demonstrate the validity and effectiveness of the proposed instantaneous torque control scheme.     

A novel approach for the design of pulse shaping filters

In this work, we propose a new class of pulses for PAM type digital signals. The pulses are designed based on minimization of a figure of merit that is the product of the Cramer-Rao bound of the timing jitter variance and the mean eye closure rate. The new pulses are seen to yield significantly better performances as compared to the classical ones.     

锝化学研究 Ⅸ.脑显像剂Tc~(Ⅴ)ON_2S_2类配合物结构稳定性和价态的研究

采用改进的ＣＮＤＯ／２法模拟了ＢＡＴ类脑显像剂Ｔｃ（Ⅴ）Ｏ配合物价态的转换过程，发现Ｎ２Ｓ２类配体与Ｔｃ（Ⅴ）Ｏ核配位时，可能存在配位平衡离子Ｘ。在溶液中由于Ｘ离子的优先解络，瞬间存在＋１价对称性９９Ｔｃｍ配合物，并且，它又自动向相对稳定的０价不对称性９９Ｔｃｍ配合物转换，在动态转换过程中，将导致仅有一个配位Ｎ原子保留一个质子，这与实验结果一致。采用键级削弱百分数概念，表征配位过程的二个配位Ｎ原子上保留程度，解释了Ｔｃ（Ⅴ）Ｏ核、Ｔｃ（Ⅴ）≡Ｎ核Ｎ２Ｓ２类配合物两个Ｎ－Ｈ键上质子保留程度不同的原因，为今后设计不同价态锝配合物结构提供理论依据。     

Molecular analysis of p21 and p27 genes in human pituitary adenomas

OBJECTIVES: To determine the prevalence of thyroid dysfunction in institutionalised elderly people in Cape Town and to assess the usefulness of an abnormal thyroid-stimulating hormone (TSH) concentration as a screening test in this group. DESIGN: Cross-sectional survey. SETTING: Four old-age homes in Cape Town. SUBJECTS: Old-age home residents aged 60 years and over. OUTCOME MEASURES: Serum concentrations of TSH, free thyroxine and free tri-iodothyronine. RESULTS: Serum TSH estimations were performed on 658 participants, and were abnormal in 103 (15.6%)-41 (6.2%) being elevated (> 5.0 microU/ml) and 62 (9.4%) being low (> 0.4 microU/ml). There were 3 newly diagnosed cases of hyperthyroidism and 7 of hypothyroidism. Subclinical disease was diagnosed in 40 subjects. The overall prevalence of thyroid dysfunction in this population was 11.2%. In 22 (3.4%) this had previously been recognised, while in 50 (7.8%) the dysfunction was newly diagnosed by the current survey. The positive predictive value of a TSH concentration > 20 microU/ml in predicting hypothyroidism is 67%, while it will predict 100% of cases of subclinical hypothyroidism. A TSH concentration < 0.1 microU/ml will predict 23% of cases of hyperthyroidism, but 81% of cases of subclinical disease. CONCLUSIONS: The prevalence of thyroid dysfunction in institutionalised elderly people in Cape Town is similar to that reported for elderly people in other centres. Thyroid dysfunction had not previously been recognised in approximately two-thirds of the subjects in this study. The serum TSH concentration is a reliable screening test for thyroid dysfunction in the elderly, but is less useful if used to identify biochemical thyroid disease. An elevated TSH concentration is a better predictor of thyroid dysfunction in the elderly than a depressed TSH concentration.     

A high-stability fiber amplifier source for the fiber opticgyroscope

We demonstrate an erbium-doped fiber amplifier (EDFA) source for the fiber gyroscope with an overall mean wavelength stability of four parts per million. This source, which amplifies the gyroscope signal before detection, is shown to be more stable than a similar single-pass source in a standard configuration. The effects of varying the fiber temperature, pump power, pump wavelength, gyroscope feedback power and signal polarization state on the output mean wavelength are individually explored. Experimental results are in excellent agreement with simulations     

Computer-aided design and analysis of direct-driven wheel motordrive

This paper presents the computer-aided design (CAD) and performance analysis of a novel direct-driven wheel brushless DC motor drive for electric vehicles (EVs). The proposed motor is a permanent magnet square-wave motor, whose rotor with rare earth magnets forms the exterior of the motor, which can be fitted with a wheel tire to realize the direct drive for each wheel of an EV. The interior stator with its windings is rigidly mounted onto the suspension and frame structure of the vehicle. In order to achieve the direct drive without any mechanical transmission for EVs, the wheel motor has been designed as a low-speed high-torque motor. The design and optimization of the motor geometry was achieved with the aid of finite-element electromagnetic field analysis. Simulation studies on the transient performance of the motor drive were also carried out. This involved the creation of the motor transient model and formulation of a motor control strategy to ensure the wheel motor drive runs efficiently in the entire permitted speed and load range. The application of CAD techniques in the design of this very unconventional drive is described in this paper