气液螺旋环状流压降特性研究

考虑旋流衰减的影响,对气液螺旋环状流的压降特性进行研究并推导出了螺旋环状流压降预测模型。定义压降旋-直比系数为气液两相螺旋环状流和气液两相直流的压降之比,以此来表征旋流衰减对压降的影响。基于量纲分析的方法对压降旋-直比系数进行分析,推导出其表达式,压降旋-直比系数依赖于Lockhart-Martinelli 参数和气相Froude数变化。最终,得出了气液两相螺旋环状流的压降预测模型。在50 mm内径的水平管内对螺旋环状流的压降特性进行了实验研究,其中气相表观流速变化范围为10~16 m/s,体积含液率（LVF）变化范围为0.6%~4.8%。通过与实验数据进行对比,压降预测模型的相对误差在±15%以内,为工程应用提供了参考。     

新疆哈图金矿成矿流体组分与同位素地球化学特征分析

哈图金矿床位于新疆西准噶尔地区南部,是哈图金矿带中重要的金矿床之一。通过对金矿石英脉样品中的石英开展流体包裹体成分分析,结合矿石样品中的毒砂和黄铁矿的硫同位素以及方解石中的碳、氧同位素特征,分析可知:包裹体气相成分以H_2O为主,CO_2和N_2含量次之。液相成分中阳离子以Na~+、Ca~(2+)为主,阴离子以Cl~-和SO_4~(2-)为主,成矿流体属SO_4~(2-)-Cl~--Na~+-Ca~(2+)型。从早阶段至晚阶段,H_2O含量增加,CO_2及Na~+、Cl~-等离子含量降低。硫化物中硫同位素组成为-2.9‰～+0.8‰,集中在0±3‰范围,成矿物质的硫来自岩浆流体或赋矿围岩。方解石中的碳、氧同位素组成中δ13 CPDB值为-11.4‰～-9.2‰,δ18 OSMOW值为+8.5‰～+17.4‰,认为成矿流体属大气降水和岩浆水混合流体。哈图金矿与穆龙套型金矿有相似的含矿地层和成矿时间,因此可以考虑哈图地区寻找穆龙套型金矿的可能性。     

基于作物需水的灌溉用水量核算方法及应用

用水量核算方法是最严格水资源管理制度实施的一项技术支撑。以山东济宁市梁山县为研究区,采用FAO(国际粮农组织)推荐的Penman-Monteith公式,计算了该县3种主要农作物的逐日作物需水量及净灌溉需水量。研究中考虑到研究区的作物种植面积、灌溉水利用系数等因素提出理论需水量和折算系数的概念,通过推求理论需水量与实际用水量的折算系数,对2011年和2012年梁山县灌溉用水量统计数据进行核算,核算的相对误差分别为0.08%和-1.52%,核算结果较好。     

Energy-Efficient Redundant Execution of Processes in a Fault-Tolerant Cluster of Servers

This paper investigates into fault tolerance of cluster of servers and their energy efficiency to realize a reliable and energy aware server cluster system. A client issues a request to one server in a server cluster and the server sends a reply to the client in information systems. Once the server stops by fault, the client does not receive a reply of the request. Even if the request is performed on another server on detection of fault of the server, some QoS requirements like response time may not be satisfied. Hence, each request has to be redundantly performed on multiple servers to be tolerant of server faults. The redundant power consumption laxity-based (RPCLB) algorithm is discussed where multiple servers are selected to redundantly and energy-efficiently perform a request process in our previous studies. Since each application process is redundantly performed on more than one server, the larger amount of electric power is consumed. In this paper, we propose a novel and improved RPCLB (IRPCLB) algorithm to reduce the power consumption of servers, where once a process successfully terminates on one server, meaningless redundant processes are forced to terminate on the other servers. In the evaluation, we show the total power consumption of servers and total execution time of processes are reduced in homogeneous and heterogeneous types of clusters by the IRPCLB algorithm than the RPCLB and RR algorithms.     

High-temperature thermoelectric properties of non-stoichiometric Ag1 − xInTe2 with chalcopyrite structure

Our group has revealed that AgGaTe₂ with the chalcopyrite structure exhibits relatively high thermoelectric (TE) figure of merit (ZT) when it has a deviation of Ag content from the stoichiometry. The maximum ZT value of 0.77 was obtained for Ag_0.95GaTe₂ at 850 K. On the other hand, the TE properties of AgInTe₂ with the same chalcopyrite structure with AgGaTe₂ have not been investigated. In the present study, we examined the high-temperature TE properties of AgInTe₂ with the composition of Ag_1 − xInTe₂ (x = 0, 0.01, 0.03, and 0.05). The deviation of Ag content from stoichiometry slightly enhanced the ZT value. The maximum ZT value was 0.07 at 600 K obtained in the samples of x = 0.03 and 0.05.     

Study on pressure drop characteristics of gas-liquid swirl annular flow

Considering the influence of swirl attenuation, the pressure drop characteristics of gas-liquid spiral annular flow are studied, and the pressure drop prediction model of spiral annular flow is deduced. The swirl-straight ratio of pressure drop is defined as the ratio of pressure drop of swirl flow to straight flow, used to characterize the effect of swirl decay on pressure drop. The expression of swirl-straight ratio of pressure drop is derived by the method of dimensional analysis, and it has a strongly dependence on Lockhart-Martinelli coefficient and gas phase Froude number. Finally, the prediction model of pressure drop for gas-liquid swirl annular flow is obtained. The pressure drop characteristics of the swirl annular flow are experimentally studied in a horizontal tube with an inner diameter of 50 mm. The range of the gas superficial velocity is 10—16 m/s and the range of the liquid volume fraction (LVF) is 0.6%—4.8%. Through comparison with experimental data, the relative error of the pressure drop prediction model is within ±15%, which provides a method reference for engineering applications.     

响应曲面法优化新疆药桑桑皮总多酚提取工艺

采用响应曲面法对新疆药桑桑皮中多酚类化合物的提取工艺进行优化。在单因素试验的基础上,选择乙醇体积分数、提取温度、提取时间,进行三因素三水平的Box-Behnken 中心组合试验设计,采用响应曲面法(RSM)分析3 个因素对响应值的影响。结果表明：最佳提取工艺条件为溶剂中乙醇体积分数78%、提取温度70℃、提取时间240min、液料比30:1(mL/g),在此条件下,总多酚的得率达到0.793%。该工艺稳定可靠,可在生产中应用。     

基于Mask R-CNN的马匹烙印号提取方法研究及应用

马匹烙印号提取是鉴定工作不可缺少的环节.针对传统的鉴定工作需人工进行标记,且存在工作量大、效率低、人工成本较高等问题,采用了Mask R-CNN算法对马匹烙印号进行分割提取.通过Labelme标注出马匹躯干及烙印号制作数据集标签,结合主干网络(ResNet-101-FPN)进行特征提取,区域建议网络(RPN)生成感兴趣...     

Glacier changes in Glacier Bay,Alaska, during 2000–2012

This article presents measurements of glacier surface areas, mean snow line altitude (MSLA) values, mean snow accumulation area ratio (MAAR) values, and elevation changes in the Glacier Bay, Alaska, using Landsat Thematic Mapper (TM)/Landsat Enhanced Thematic Mapper Plus (ETM+) images and digital elevation models (DEMs) from Shuttle Radar Topography Mission (SRTM) and interferometric synthetic aperture radar (IFSAR) data during 2000–2012. Glacier area estimation results showed that Desolation glacier and Fairweather glacier have lost 2.6% and 2.2% of the glacier area, respectively. Only minor surface area changes were seen in Cascade glacier, Crillon glacier, and Lituya glacier during the study period. The results of MSLA and MAAR showed that the MSLA of Fairweather glacier, Lituya glacier, and Desolation glacier increased by about 120–289 m and the MAAR of Fairweather glacier, Lituya glacier, and Desolation glacier decreased by about 3–6%. In contrast, MSLA and MAAR of Crillon glacier decreased by about 70 m and increased by about 1%, respectively. Glacier elevation change results showed that 7.7 m, 4.6 m and 1.5 m of mean thinning change were observed, respectively, on Fairweather glacier, Lituya glacier, and Desolation glacier. However, 7 m and 0.65 m of mean thickening were, respectively, experienced on Cascade glacier and Crillon glacier in the same period. Results from the study indicated that glacier retreat (Fairweather glacier, Lituya glacier, and Desolation glacier) affected by higher temperatures probably dominates with over-increased precipitation. However, increasing debris cover on the glacier surface can also modify the glacier dynamic, resulting in a different response to global warming.     

Energy-Efficient Server Clusters to Perform Communication Type Application Processes

In energy-aware systems, it is critical to discuss how to reduce the total electric power consumption of information systems. In this paper, we consider communication type applications where a server transmits a large volume of data to clients. A client first selects a server in a cluster of servers and issues a file transmission request to the server. In our previous studies, the transmission power consumption (TPC) model and the extended TPC (ETPC) model of a server to transmit files to clients are proposed. In this paper, we newly propose the transmission power consumption laxity-based (TPCLB) algorithm for a cluster of servers, which are based on the TPC and ETPC models so that the total power consumption in a cluster of servers can be reduced. We evaluate the TPCLB algorithm in terms of the total power consumption and elapse time compared with the round-robin (RR) algorithm.