Mechanical characteristics of fused cast basalt tube encased in steel pipe for protecting steel surface

Because of the various excellent characteristics of cast basalt materials, such as, anti-corrosion, anti-wearing, good hardness, high chemical stability, of which steel may not possess, the steel-basalt composite pipes are used in severe environments for compensating the defects of steel. The limit of bending moment with which steel-basalt composite pipe may safely endure was calculated and the limit curvature of the composite pipe in the safe range was presented. The application temperature of steel-basalt pipe was examined due to a different coefficient among basalt, mortar and mild steel.     

Dielectric breakdown of an unpoled piezoelectric material with a conductive channel

The dielectric breakdown of an unpoled piezoelectric ceramic, PZT807, with a conductive channel, is investigated. Cylindrical bar specimens with a conductive channel are used for breakdown tests of the unpoled piezoelectric ceramic under purely electrical loads. Narrow tubular channels emanating from the head of the initial channel are observed in the specimens after breakdown occurs. The radius of the tubular channel that is created at the surface of the initial channel head is insensitive to various types of channel formation. The problem of a fine tubular channel that emanates from the initial channel head is numerically solved to evaluate the three-dimensional J integral, which is directly related to the energy that is available at breakdown, at the initiation of a new channel in the specimen. The critical J integral at the onset of breakdown is obtained.     

远程分布式光纤温度传感系统的设计和制造

为了测量长距离大范围空间分布温度场,设计制造出30km远程光纤温度传感器。基于光纤放大的反斯托克斯背向拉曼自发散射测温原理,对系统进行了优化设计。用1550nm掺铒光纤激光器作为抽运源,采用高速瞬态波形采样技术,累加平均等信号处理技术,解决了远处背向反斯托克斯弱信号的检测问题。采用了智能化恒温技术,使主要元器件在恒温条件下工作,解决了工程应用中环境的适应性。远程分布光纤拉曼温度传感器系统已达到的主要技术指标如下:光纤长度31km,测温范围0-100℃(可扩展),温度测量不确定度为±2℃,温度分辨力为0.1℃,测量时间为432s,空间分辨力为4m。     

OXIDATIVE STABILITY AND VITAMIN ELEVELS INCREASED IN RESTRUCTURED BEEF ROASTS WITH ADDED RICE BRAN OIL1

Crude rice bran oil 0, 1%, and 2% (w/w), was added to restructured beef roasts that were stored at 4C and analyzed at 0, 7, and 14 days to determine nutritional properties and oxidative stability. The saturated fatty acid to unsaturatedfatty acid (SFA/UFA) ratio and the content of 7‐ketocholesterol decreased (p < 0.05) whereas vitamin E vitamers increased (p < 0.05) in the product with 2% rice bran oil. TBARs numbers were lower (p < 0.05) in roasts with rice bran oil after 7 days of storage. The addition of 2% rice bran oil (w/w) was effective in improving both oxidative stability and vitamin E levels.     

Enhanced MAC Protocol and Scheduling Algorithm for High Rate WPANs

The demands for higher data rate in Wireless personal area network （WPAN） than one in Bluetooth has been completed with IEEE 802.15.3 standard. The standard, named High-rate WPAN （HR-WPAN）, adopts TDMA-based Medium access control （MAC） protocol. In this paper, we propose novel MAC protocol and scheduling algorithm to achieve efficient time-slots allocation. Time slots for data transmissions are allocated by two steps. In the first step, the time slots are initially allocated using a proposed allocation algorithm based on statistical packet inter-arrival time. Then, the initial allocation is dynamically adjusted by utilizing feedback information coming from each device. Performance evaluations are carried out through extensive simulations and significant performance enhancements are observed.     

PFQ-OS： A Packet Fair Queueing Based Opportunistic Scheduler in Wireless Networks

In this paper, we investigate the issues of extending the Packet fair queueing （PFQ） algorithms into continuous channel model. We present a PFQ-based Opportunistic scheduler （PFQ-OS）, which can improve user throughput while satisfying strict short-term fairness. We decouple the conflicting design objectives of fairness and user throughput improvement by introducing a Search radius （SR） into the framework of PFQ. We develop an analytical model and derive the fairness properties of PFQ-OS, which are related to the SR. Thereby system operators can focus on opportunistic scheduling for the users within the SR without violating the fairness guarantee. We further investigate the designing of scheduling policy under the strict fairness constraints, and propose that in order to utilize the opportunistic scheduling all the time, the selection rule should provide all the users with equal chance in being scheduled at each selection. Accordingly, we present Maximum relative SNR （Max-rSNR） selection rule for PFQ-OS. We derive the bounds in terms of user throughput under Rayleigh fading channel. An extensive set of simulations testifies our derived theoretical properties that PFQ-OS can significantly improve user throughput while providing excellent short-term fairness guarantee.