基于ST-Developer10几何信息提取方法的研究

目的 为以通用性标准提取三维模型的几何信息．以STEPAP203数据模型为输入信息，研究三维模型几何信息的提取方法．方法 在ST—Developer10的环境下，以VC＋＋6．0为开发工具，使用ROSE库函数，将EXPRESS语言描述的AP203文件信息转换为STEP设计对象和C＋＋类，按AP203数据模型的几何信息属性的层次结构，逐次提取几何信息．结果 使用ROSEC＋＋类库提取AP203文件头段信息．设计了数据段信息提取的流程。分为信息转换、几何信息提取和三维实体显示三部分，实现三维几何信息的提取，并显示出提取结果．结论 以AP203文件的几何模型信息为源信息，进行几何信息的提取，其提取结果也是基于STEP标准的，通用性好，可在不同的CAX系统之间传递与共享，可作为CAPP系统设计的直接输入信息，对实现CAD／CAPP集成提供了技术支持，是实现STEP—NC的基础．     

无线局域网研究

介绍了WLAN概念,以及WLAN与有线局域网相比具有的优点,同时给出了WLAN的组网方式和所遵循的协议规范以及在安全性方面如何实现,以实例体现了WLAN在公司办公室中的具体应用。     

核电站堆外核测量系统的原理及工程实践

介绍了堆外核测量系统的原理和组成,比较了AP1000与二代加改进型压水堆核电站堆外核测量系统的异同,分析了各自的优缺点,并提出了堆外核测量系统的一个发展方向。     

Channel measurement-based access point selection in IEEE 802.11 WLANs

With the wide deployment of IEEE 802.11 Wireless Local Area Networks, it has become common for mobile nodes (MNs) to have multiple access points (APs) to associate with. With the Received Signal Strength Indicator (RSSI)-based AP selection algorithm, which is implemented in most commercial IEEE 802.11 clients, the AP with the best signal strength is selected regardless of the candidate AP’s available throughput, resulting in unbalanced distribution of clients among the APs in the network. Several studies have shown performance improvement in not just the new MN (nMN), but also the network as a whole when the selection process considers the current load status of candidate APs. However, the proposed algorithms in these studies assume that there are no hidden terminal problems that severely affect the performance of the network. Hidden terminal problems frequently occur in wireless networks with unlicensed frequencies, like IEEE 802.11 in the 2.4 GHz band. Moreover, none of the previous studies have considered frame aggregation, a major improvement in transmission efficiency introduced and widely deployed with the IEEE 802.11n standard. In this paper, we propose a new AP selection algorithm based on the estimation of available throughput calculated with a model based on the IEEE 802.11 distributed coordination function in consideration of hidden terminal problems and frame aggregation. The proposed algorithm is evaluated through extensive simulation, and the results show that the nMN with the proposed AP selection algorithm can achieve up to 55.84% and 22.31% higher throughput compared to the traditional RSSI-based approach and the selection algorithm solely based on the network load, respectively.     

Coastal trapped waves in the southern Caspian Sea

Previous studies reported coastal trapped waves (CTWs) in the Caspian Sea (CS). This study deals with the generation mechanisms, the temporal and spatial variability of CTWs in this area, and their transformations during propagation from the origin to the destination using recent measurements and high-resolution numerical simulations. CTWs are observed at all stations with periods of 2–6 days after northerly storms. The Absheron Peninsula, old Sefidrud delta, and Nur coasts were identified as the CTWs prone regions. The generation of CTWs in these locations was confirmed using numerical experiments. The propagation away from the generating location of CTWs was analyzed using a representative real wind storm. In the west part of the CS, the generation mechanism of CTWs is mainly similar to the barotropic Kelvin waves; in contrast, it is similar to the continental shelf waves in the southern shelves. The results can be used to study the contribution of generated CTWs to the transport of sediment and biological materials in all large lakes.     

AP1000安注箱球壳压制成形的厚度超差分析

文章通过对成形后壳体厚度数据的分析,找出了压制成形后的壳体厚度变化分布规律。基于核安全和经济性两方面,分别从设计、制造的角度,分析了AP1000安注箱复合板球壳压制成形厚度超差的原因;还介绍了厚度超差对安注箱安全性影响的评价方法,提出了防止超差可采取的技术措施：一方面,可通过试验和模拟计算,优化成形工艺;另一方面,可在设计计算中,优选出壳体名义厚度。     

AP1000次级汽水分离器分离性能及结构优化的数值研究

建立AP1000次级波纹板汽水分离器内两相流动的数学模型,随后数值模拟波纹板内的两相流动,并分析其分离性能。进而对波纹板结构进行优化,得到具有较高分离效率和较低流动阻力的新型波纹板。首先分别建立波纹板内部蒸汽相和液滴相运动的数学模型。然后通过自编程序与Fluent软件耦合对该两相流动模型数值求解。随后得到波纹板进出口总压降,并通过模拟液滴在波纹板内的运动轨迹,得到波纹板的分离效率和内部液滴湿度分布。进而以分离效率和流动压降为目标优化波纹板结构,设计得到具有较高分离效率和较低流动阻力的新型波纹板。本文提出的数值模拟方法对汽水分离器结构的设计和优化具有较强的指导意义。     

Verification and validation of explicit moving particle simulation method for application to internal flooding analysis in nuclear reactor building

The Fukushima nuclear accident raised the importance of flooding study in nuclear reactor buildings. It is known that the external flooding can be attributed to natural causes, while the internal flooding is caused by the piping ruptures, tank failure or the actuation of fire suppression systems. The building flooding process can damage the safety-related components and systems, which needs to study carefully. In order to simulate this phenomenon which is accompanied by complex flow with free surface, a particle method based on Lagrangian approach named explicit moving particle simulation (EMPS) method, is employed in this analysis. Verification and validation analyses are carried out. The verification problems are a hydrostatic analysis and a water spreading to investigate the differences of the particle wall and polygon wall boundary models, while the validation studies of two experiments of dam-break induced flooding show good agreements. Afterwards, the internal flooding process in AP1000 is simulated by assuming a break of the in-containment refueling water storage tank as an example. The results achieved so far indicate that the EMPS method is capable to simulate the internal flooding process in the nuclear reactor buildings.     

溶胀/溶解法回收HTPB推进剂中AP组分的实验研究

采用溶胀/溶解法回收报废HTPB推进剂中的AP。研究了浸取时间、浸取温度、四氢呋喃质量分数、液料比(四氢呋喃溶液体积与HTPB推进剂的质量比)、试样厚度及搅拌速率对AP回收率的影响。通过扫描电镜、X射线能谱仪对回收得到的AP进行表征,并对其纯度进行了检测。结果表明,AP的最佳回收工艺参数为:浸取时间6h、浸取温度60℃、四氢呋喃质量分数80%、液料比10∶1(mL/g)、试样厚度3mm、搅拌速率500r/min。其中,浸取时间、浸取温度和四氢呋喃质量分数对AP回收率的影响较大。在最佳工艺条件下,AP的回收率为95.0%,纯度为96.1%,表明此方法可用于报废HTPB推进剂中AP组分的回收。