Concurrent transmission with minimal SR-pair interference in WiMAX mesh networks

Performance of wireless mesh networks can be greatly improved by spatial reuse (SR), therefore, lots of algorithms have been proposed to maximize the number of concurrent transmissions. However, most methods only considered the interference brought by the sender nodes. In this paper, we study the interference model in WiMAX mesh networks and propose a minimal SR-pair interference model to perform concurrent transmissions in both uplink and downlink directions. Simulation results show that our model is more efficient and stable, i.e., it increases the number of concurrent transmissions and its performance is constant and independent of transmission directions. Biography: XIONG Qing(1978–), male, Ph. D., research direction: wireless mesh networks.     

Features of intervertebral disc degeneration in rat’s aging process

Objective: The age-related change is important part of degenerative disc disease. However, no appropriate animal model or objective evaluation index is available. This study aimed to investigate the features of intervertebral disc degeneration in aging process of rats. Methods: 22-month-old Sprague-Dawley (SD) rats were used as spontaneously occurring intervertebral disc degeneration models and 6-month-old rats as young controls. Expression of collagen types II and X was measured by immunohistochemistry. Degenerations of intervertebral discs were scored according to Miyamoto’s method. Numbers and areas of afferent vascular buds were measured. The thicknesses of non-calcified and calcified layers were measured and statistically analyzed. Results: There were less collagen type II expression and more collagen type X expression in the calcified layer of the cartilage endplates and nucleus pulposus in the rats of the aged group than in the young control. There were fewer and smaller afferent vascular buds in the rats of the aged group than in the young control group. The ratio of the non-calcified to the calcified layers in the rats of the aged group significantly decreased, compared with that of the young control group (P<0.01). Conclusion: Rats can spontaneously establish intervertebral disc age-related degeneration. The expression of collagen types II and X, numbers and areas of afferent vascular buds, the ratio of the non-calcified to the calcified layers, and water and glycosaminoglycan contents in the nucleus pulposus are sensitive indexes of intervertebral disc degeneration.     

Sikkema-Kantorovitch算子在B_α空间的逼近

研究了Sikkema－kantorovitch算子在Bα空间的逼近估计．     

Rapid Prototyping and Manufacturing Technology: Principle,Representative Technics,Applications, and Development Trends

The rapid prototyping and manufacturing technology (RPM), is an integration of many different disciplines. It is based on an advanced dispersed-accumulated forming principle and originated from 1980s. It generates an entity by first forming a series of layers according to the dispersed section information of the digital model, and then piling the formed layers sequentially together. It is capable of forming parts with complicated structures and non-homogeneous materials. Traditional RPM techniques are mainly used as prototypes in product invention process, such as stereolithography, three-dimensional printing, laminated object manufacturing, and fused deposition modeling. Later, with the progress of material and enabling technology, many new RPM techniques emerged out and have been already applied in the fields such as rapid tooling/moulding, direct formed usable part, nano-/micro-RPM, and biomanufacturing. This high flexible digital manufacturing method has a likely ability to become an almighty forming technology.     

东濮凹陷轴向重力流水道沉积研究

利用地质、测井和地震等多种资料进行的综合研究表明,东濮凹陷桥口和新霍地区沙三段中发育轴向重力流水道沉积,它们主要由灰黑色块状泥岩与平行层理砂岩、块状层理砂岩、递变层理砂岩及合卵石砂岩构成,在垂向上组合成鲍玛序列的AE、BE、ACE、BCE和CE等。依据研究区轴向重力流水道沉积特征,将其划分成近源和远源水道、近源和远源水道侧源等4个微相,并描述了这4个微相的沉积特征,建立了沉积模式。油气勘探实践表明,重力流水道砂体是我国东部陆相断陷湖盆中重要的油气勘探新目标,它具有良好的储集物性,并含有丰富的油气。     

生物质能源开发——Ⅲ.甘蔗渣的湿式裂解气化

对文题内容研究表明,Na_2CO_3对生物质的湿式裂解是良好的催化剂。Ni-Mo催化剂有利于甲烷生成,Ni-Mo和Na_2CO_3混合催化剂效果最好。可使气体转化率达55%以上。生物质的湿式裂解气化可得气体、液体和焦三种产品。其中气体产品主要含CO_2、CO、H_2、CH_4和少量的C_mH_n。脱(?)CO_2后可得热值为12500～16700kJ/m~3左右的中热值煤气。对液体产品的组分用荧光光谱法进行了分析,发现有菲、(?)醌等几十种物质。湿式裂解气化的最佳反应时间为150min、反应温度380℃以上。若以液体产品为主,则反应时间为80min较佳,反应温度相对降低。讨论了不同催化剂及Na_2CO_3用量对甘蔗渣湿式裂解气化的影响。     

Evans图法研究SbO_Zn置换体系的反应速度

本文采用旋转电极上的动电位扫描法以及旋转杯盘电极技术研究了硫酸钠溶液中(pH=4.0)的SbO~+/Zn置换反应,并根据Evans图法,计算了SbO~+/Zn置换反应的速度常数(k).900rpm时;k=(1.7±0.2)×10~(-5)m·s~(-1).Evans图表明,SbO~+离子可被金属锌还原至SbH_3,其反应过程受SbO~+离子向电极表面的扩散过程控制.     

关于图的顶点划分数

该文讨论了无爪图的顶点划分数,给出了完全n部图的顶点划分数的计算公式,最后证明了任意图的点线荫度不大于它的边线荫度且不等式是精确的.     

加强民主党派自身建设发挥民主党派民主监督职能

统一战线中的民主监督不仅是我国监督机制中不可缺少的组成部分，而且是民主党派的基本职能之一。笔者论述了加强民主党派自身建设的必要性以及民主党派的民主监督对我们党的事业及社会主义建设所起到的重要作用。     

夫琅和费圆缝衍射的分析

论述由两个贝塞尔函数之差表示的圆缝衍射的光强分布公式，并以此分析三种情况的衍射斑的各级极值光强位置，进而讨论艾里斑随ε的值接近于１而收缩的规律。