流水通道──一种高速的MPP系统互连

传统大规模并行处理机系统中的互连网络及路由器在强同步方式下工作，相邻路由器间消息的传送必须保证一个周期内完成，系统互连长度成为影响网络主频的重要因素，同时也限制了系统的可扩展性．采用流水通道可在一条通道上同时传送多个数据，使得网络的主频独立于线的长度，提高了网络的传输速率，本文介绍了这一思想，并对流水通道互连网络的实现技术进行研究，着重阐述了源同步传输、切换技术、流控策略等几个关键技术问题．

“绿色”流水通道的设计与施工

文章介绍了郑煤集团告成煤矿排水系统存在的安全隐患,针对性地设计并施工了“绿色”流水通道,实践证实了“绿色”流水通道的安全效益和经济效益,具有一定的推广价值。

一种基于EPC编码的货运流水线通道检测系统设计

为解决物联网编码标识应用的问题,实现对EPC的编码和物品的唯一性标识,在EPC编码体系的基础上提出改进方案。即:将SGTIN-96的项目参考字段分成类种品3个字段,实现标识物品的种类信息;将SSCC-96系列化的参考字段分成类种品字段和物品数量字段,用于标识货运单元(1箱货物)。在该方案的基础上,设计一个货运流水线通道检测系统。经验证:该系统设计合理,有效地实现了对贸易项目中单件物品和货运单元的标识,具有高可用性和可靠性。

基于内外两级并行的多通道闪存存储系统设计

针对单片闪存存取速率低、存储容量小的问题,根据对NAND型闪存存取带宽影响因素的分析,提出了一种多通道闪存存储系统结构,同时采用通道间流水和通道内交织两级并行访问方法提高存储系统吞吐量,推导出了通道内外并行多通道存储系统的存取带宽计算公式.此外,通过给出的系统并行加速比公式,对影响系统并行加速性能的原因进行了分析.设计和实现了以该系统模型为核心的多通道闪存存储模块,验证了两级并行方法的可行性和有效性.

行走式软帘堵漏机在抢险堵漏中的应用

1 漏洞险情发生的原因及其危害所谓堤防漏洞就是在洪水期间发生在堤身或堤基的贯通的流水通道。形成漏洞的原因是多方面的,但主要有两个方面,一是由堤防散渗发展形成,汛期堤防在高水位的压力下,尤其是堤坡较陡、堤防偎水时间较长的堤段,堤防本身透水性较大,渗流较为集中,在背河堤坡较为薄弱的地方出逸,起初发生堤坡的散渗,而后渗流逐渐加大集中,形成清水漏洞,随着时间的延长。

基于闪存的大容量高速存储系统的研究

本文提出了一种基于闪存的大容量高速存储系统的设计方案。根据K9K8G08U0M型NAND Flash芯片自身的结构特性,采用位扩展、并行分路及多通道流水线技术,用相对小容量、低速的Flash存储器实现了大容量高速度的存储器。

可重构密码流处理器片外流访存系统的设计

针对可重构密码流处理器和片外存储器之间存在的"访存瓶颈"问题,设计了该处理器的可重构片外流访存系统,它采用多数据通道流水并行化传输结构和利用突发传输方式的流访存调度策略,优化了对外存访问的效率,提高了密码处理器的性能.实验结果表明,相比于常见的密码处理器访存方式,其访存效率最高可提升近5.9倍.

Oblique Water Wave Scattering by Bottom Undulation in a Two-layer Fluid Flowing Through a Channel

The problem of oblique wave （internal wave） propagation over a small deformation in a channel flow consisting of two layers was considered. The upper fluid was assumed to be bounded above by a rigid lid, which is an approximation for the free surface, and the lower one was bounded below by an impermeable bottom surface having a small deformation; the channel was unbounded in the horizontal directions. Assuming irrotational motion, the perturbation technique was employed to calculate the first-order corrections of the velocity potential in the two fluids by using Green＇s integral theorem suitably with the introduction of appropriate Green＇s functions. Those functions help in calculating the reflection and transmission coefficients in terms of integrals involving the shape ftmction c（x） representing the bottom deformation. Three-dimensional linear water wave theory was utilized for formulating the relevant boundary value problem. Two special examples of bottom deformation were considered to validate the results. Consideration of a patch of sinusoidal ripples （having the same wave number） shows that the reflection coefficient is an oscillatory function of the ratio of twice the x-component of the wave number to the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and the interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large. Similar results were observed for a patch of sinusoidal ripples having different wave numbers. It was also observed that for small angles of incidence, the reflected energy is greater compared to other angles of incidence up to π/ 4. These theoretical observations are supported by graphical results.

Wave Scattering by Porous Bottom Undulation in a Two Layered Channel

The scattering of plane surface waves by bottom undulations in channel flow consisting of two layers is investigated by assuming that the bed of the channel is composed of porous material. The upper surface of the fluid is bounded by a rigid lid and the channel is unbounded in the horizontal directions. There exists only one wave mode corresponding to an internal wave. For small undulations, a simplified perturbation analysis is used to obtain first order reflection and transmission coefficients in terms of integrals involving the shape function describing the bottom. For sinusoidal bottom undulations and exponentially decaying bottom topography, the first order coefficients are computed. In the case of sinusoidal bottom the first order transmission coefficient is found to vanish identically. The numerical results are depicted graphically in a number of figures.

Typhoon-dominated Influence on Wood Debris Distribution and Transportation in a High Gradient Headwater Catchment

Wood debris is an important component of mountain streams. It causes serious damage and renders difficulty of water resource management in Taiwan. In this study, the quantity of wood debris and variation of migratory wood debris during flood events were examined. The downstream of Gaoshan Creek and Qijiawan Creek, located at Central Taiwan, was selected as the study area. The distribution and dynamic of wood debris in a high gradient headwater catchment were quantified using field surveys. A formula of critical depth for wood debris entrainment was used to evaluate the wood debris migration during three flooding events. In the study area, wood abundance and unit volume increased downstream, and wood density decreased downstream within a channel network. The channel morphology, riparian vegetation, and wood debris characteristics were found to influence the wood storage. As a result, the wood debris has an irregular accumulative distribution in the steep stream, and it migrates easily in the stream because of a high flow discharge. Strong relationships between the channel width and wood debris variables are discovered. Moreover, wood debris has a tendency to accumulate at sites with low stream power and wood debris dams, topographical notches, and unique geological structures. Our findings assist in the understanding of the effects of channel characteristics on distributions of wood debris in steep stream systems.

Effects of river width changes on flow characteristics based on flume experiment

The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic structures and evolutions of open channel. To better understand the impact of varying width, a flume experiment with adjustable width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in straight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritieal condition to the subcritical condition in diverging sections.

Impact of the Yalong-Yellow River water transfer project on the eco-environment in Yalong River basin

The planning Yalong-River water transfer project will transfer 5.65 billion cubic meters water from the Yalong River into the Yellow River per year.The Yalong River will be dramatically impacted hydrologically and ecologically because more than 60% of the runoff will be diverted.An ecohydrological model was used to evaluate the impacts of the project on river corridor and wetland in this study.Schizothorax is a typical plateau river species and was used as the indicator species for assessment of the impact of water transfer project.The model simulated the habitat area of Schizothorax in the reach between the Reba Dam and the Ganzi Hydrology Station on the Yalong River.The Reba Dam,A'an Dam and Renda Dam will be constructed in the Yalong River for enhancing the water level for water diversion into the Yellow River.The velocity,channel width,runoff,and water depth will be reduced due to the water transfer,especially during flood season.The reduction in the velocity,channel width,runoff and water depth will occur mainly in the reach near the three dams and the reduction will be reduced to a minimum level in a distance about 100 km downstream of the dams.The maximum net water loss of Kasha Lake is only 1197200 m3,only 0.3% of runoff flowing into the lake.The project cannot bring adverse effect on the lake.The habitat area of Schizothorax in the Yalong River might be reduced if the water was transferred from the Reba Dam.The habitat area of this species will be reduced more than 40%.

Experimental study on the characteristics of ventilated cavitation around an underwater navigating body influenced by turbulent drag-reducing additives

In this study, a new control strategy for turbulent drag reduction involving ventilated cavitation is proposed. The configurational and hydrodynamic characteristics of ventilated cavities influenced by turbulent drag-reducing additives were experimentally studied in water tunnel. The test model was fixed in the water tunnel by a strut in the aft-part. Aqueous solutions of CTAC/Na Sal(cetyltrimethyl ammonium chloride/sodium salicylate) with weight concentrations of 100, 200, 400 and 600 ppm(part per million), respectively, were injected into the ventilated air cavity from the edge of the cavitator with accurate control by an injection pump. The cavity configurations were recorded by a high-speed CCD camera. The hydrodynamic characteristics of the test model were measured by a six-component balance. Experimental results show that, within the presently tested cases, the lengths of cavity influenced by drag-reducing solution are smaller than normal condition(ventilated cavity) in water, but the asymmetry of the cavity is improved. The drag resisted by the test model is reduced dramatically(the maximum drag reduction can reach to 80%) and the re-entrant jet is more complex after the CTAC solution is injected into the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitating asymmetry and further drag reduction.