Performance analysis of WCDMA wireless access standard

Based on the transmitting power of a mobile station and the maximum cell capacity, the analysis of a wide-band code-division multiple access (WCDMA) standard and the comparison of the corresponding parameters with CDMA2000 or evolution-data only (EV-DO) are given in this paper. The result proves that the mobile station of WCDMA cannot provide the required transmitting power on the specified frequency band and data rate, and the symmetrical capacity in an up-downlink cannot meet the requirement of a mobile Internet. It is questionable for the International Telecommunication Union (ITU) to select the frequency band of 2 GHz for vehicular mobile telecommunication and unreasonable to distribute it over the downlink and uplink channels symmetrically. Only CDMA2000 1X EV-DO or enhanced data rate for GSM evolution (EDGE), which adopts the Time Division Multiple Access (TDMA) mode, can provide the high-speed data rate for a wireless access. Translated from Journal of Nanjing University of Posts and Telecommunications (Natural Science), 2006, 26(3): 42–48 [译自: 南京邮电大学学报(自然科学版)]     

智能大流量电动执行机构设计

为了解决电动机械控制中大功率执行机构的的精确定位问题,提出一种新型电动执行机构的设计方案.该方案介绍了执行机构各功能元件的选型与设计、阀位及速度控制原理以及各种关键问题的解决方法.将阀门、伺服电机、控制器合为一体,采用8031单片机、变频技术实现了阀门的动作速度和位置控制,解决了阀门的精确定位、阀门柔性开关、极限位置判断、电机保护及模拟信号隔离等技术问题.     

Continuous data aggregation and capacity in probabilistic wireless sensor networks

Due to the existence of many probabilistic lossy links in Wireless Sensor Networks (WSNs) (Liu et al., 2010)  [25], it is not practical to study the network capacity issue under the Deterministic Network Model (DNM). A more realistic one is actually the Probabilistic Network Model (PNM). Therefore, we study the Snapshot Data Aggregation (SDA) problem, the Continuous Data Aggregation (CDA) problem, and their achievable capacities for probabilistic WSNs under both the independent and identically distributed (i.i.d.) node distribution model and the Poisson point distribution model in this paper. First, we partition a network into cells and use two vectors to further partition these cells into equivalent color classes. Subsequently, based on the partitioned cells and equivalent color classes, we propose a Cell-based Aggregation Scheduling (CAS) algorithm for the SDA problem in probabilistic WSNs. Theoretical analysis of CAS and the upper bound capacity of the SDA problem show that the achievable capacities of CAS are all order optimal in the worst case, the average case, and the best case. For the CDA problem in probabilistic WSNs, we propose a Level-based Aggregation Scheduling (LAS) algorithm. LAS gathers the aggregation values of continuous snapshots by forming a data aggregation/transmission pipeline on the segments and scheduling all the cell-levels in a cell-level class concurrently. By theoretical analysis of LAS and the upper bound capacity of the CDA problem, we prove that LAS also successfully achieves order optimal capacities in all the cases. The extensive simulation results further validate the effectiveness of CAS and LAS.     

A demonstration of level-anchored ratio scaling for prediction of grip strength

Level-anchored ratio scaling, such as the Borg CR10 scale^® and the Borg CR100 scale^®, uses verbal anchors in congruence with numbers to give ratio data together with natural levels of intensity. This presupposes that the anchors possess natural positions in the subjective dynamic range and also “numerical” inter-relations. In an experiment, subjects had to produce a force of handgrip corresponding to their conception of “Strong”, followed by a “Maximal” performance. By using the previously found relationship between “Strong” and “Maximal” of 1:2 together with knowledge of the exponent in the power S-R-function (R = c × Sⁿ) for grip strength, n = 1.8, predictions of individual maximal performances were obtained. The predicted values correlated 0.76 with, and deviated only 3% (ns) from, actual maximal performances of grip strength. This result –as previously also found for aerobic capacity–gives a strong support for the use of verbal anchors, so common in category scaling, also in “ratio scaling” and that the Borg CR-scales fulfill the requirements for ratio scales. For estimation of muscular strength, such as grip strength, this present study points to the value of using submaximal determinations as a compliment to maximal performances (e.g., to obtain measures of functional capacity). The results also support the increasingly common use of the CR-methodology in other ergonomic settings concerning suitable design of tools and equipment.     

[bmim]FeCl_4离子液体催化氧化硫化氢的研究

研究了[bmim]FeCl4离子液体催化氧化硫化氢的性能。结果表明,[bmim]FeCl4离子液体催化氧化硫化氢时具有良好的再生性能,不过其氧化硫化氢时的实际硫容不仅小于理论硫容而且随温度的升高逐渐降低,这可能与[bmim]FeCl4离子液体的强酸性以及其作为介质和催化剂的双重功能密切相关,减弱[bmim]FeCl4离子液体的酸性可能是增加硫容的关键。     

Effect of γ-radiation on green onion DNA integrity: Role of ascorbic acid and polyphenols against nucleic acid damage

The effect of γ-radiation on green onion DNA integrity, phenol content, oxygen radical absorbance capacity, employing pyrogallol red and fluorescein as probes, as well as ascorbic acid content has been evaluated. Measurements using thiazole orange-DNA fluorescence and agarose gel electrophoresis show that γ-radiation does not lead to an apparent DNA change in green onion. However, it was readily cleaved upon irradiation from the previously isolated nucleic acid. Furthermore, green onion exposure to γ-radiation produces slight increases in the polyphenol concentrations (163–188 μM Trolox eq.) and a decrease in the oxygen radical absorbance using fluorescein (from 245 to 200 Trolox eq.) Interestingly, a high ascorbic acid content (364 μM), which decreases by 40% after γ-ray exposure was measured by using pyrogallol-red-based oxygen radical absorbance capacity induction times from green onion aqueous extracts. Thus, our results suggest that ascorbic acid present in green onion plays a fundamental role in the plant antioxidant response toward γ-radiation exposure, while polyphenols remain largely unchanged, as revealed from oxygen radical absorbance capacity, employing pyrogallol red.     

超细石墨插层化合物的制备及性能测试

以浓硫酸和重铬酸钾为强氧化剂,对2—5μm微粉石墨进行了浓硫酸和冰醋酸插层。通过控制反应物之间的比例,可制各出膨胀容积为7．6～13．6mL/g的超细石墨插层化合物。应用FTIR光谱仪和大气采样器研究了产物的红外消光能力和空中飘浮能力。结果表明,该产物与原石墨、市售可膨胀石墨相比有较大的空中飘浮能力及红外遮蔽能力。     

WCDMA与其它蜂窝系统共存时电磁兼容性能研究

通过系统级仿真对WCDMA与相邻频段其它蜂窝系统的电磁兼容问题进行了研究.基于系统级蒙特卡罗仿真技术,提出了一个完整的系统共存仿真容量方案,研究由于射频干扰造成的WCDMA系统的容量损失情况.在计算系统间干扰时,提出了一种称为等效技术的方法,大大提高了仿真速度.给出了可能存在的四种蜂窝系统的干扰造成的容量损失结果.     

矿区资源承载力预测研究——以马钢南山矿区为例

要实现矿区的持续发展,需定量地知道矿区资源承载力未来将发生怎样的变化,以保证其资源消耗在承载力允许范围内。矿区是一个开放复杂巨系统,且常缺乏资源情况的历史数据。系统动力学不需要历史数据就能揭示开放复杂巨系统的运行规律;情景分析法通过定量地设定未来多种可能的发展情景,能解决使用系统动力学模型进行预测时,控制变量难以定量的问题。以马钢南山矿区为例,证实系统动力学与情景分析法的结合定量预测矿区资源承载力的可行性,并阐述如何利用该方法进行资源承载力的预测。     

袋式除尘器与电除尘器在选型方面的比较

从工艺要求,基建投资和维修难易方面对袋除尘器和电除尘器进行比较,为设计选型提供依据和参考。