基于网络流量水平等级预测的自适应随机早期检测算法

针对随机早期检测及其变体算法中平均队列长度和数据包最大丢弃概率的计算对网络流量的变化反应迟缓的问题,提出了一种基于网络流量水平等级预测的自适应随机早期检测算法。基于自相似网络流量的统计特性,建立了网络流量水平等级转移概率表,设计了自相似网络流量水平等级预测方法,该方法复杂度较低且精度较高。进一步,将预测结果应用于等间隔平均队列长度计算及数据包最大丢弃概率调整中,在固定和可变瓶颈链路容量2种情况下的仿真发现,无论自相似程度如何,所提算法在丢包率和吞吐量方面都有提升,特别在Hurst参数较大且流量负载较低时,吞吐量性能提升较大。

奖状XLS飞机双水平流量活门失效原因研究

研究奖状XLS飞机双水平流量活门失效原因，提出解决方法。

海上超长水平段MRC井钻完井关键技术研究与应用

对于高含水、低渗透、非常规超薄致密性碳酸盐油气藏以及浅海油田和新能源开发项目,MRC井是一项具有针对性的创新技术,通过最大化储层接触面积,并配合一系列配套钻完井工艺,能有效提高单井产量并降低桶油成本。随着MRC技术在阿布扎比海上项目的投入使用,与MRC井配套的钻井技术和完井技术也在飞速发展。超薄低渗致密性碳酸盐储层MRC井眼轨迹精确控制技术、超长MRC井一趟钻优快高效钻井技术等钻井相关的关键技术,以及MRC长水平段均衡流量控制技术、MRC井高效储层改造酸化技术等完井相关的关键技术被成功应用在阿布扎比海上项目。截至2020年,共计9口MRC井在阿布扎比海上项目投产作业,其平均产量约是常规水平井的2.5倍,每口井大概节约成本1200万美元。MRC井技术在最大化单井产能、实现高效的项目资本支出上取得显著成果。

江西兴国侵蚀荒山森林小流域的降水流出特性分析

用小流域和量水堰方法6a 多的观测资料,分析了江西兴国一个面积为2.9hm^2的侵蚀荒山森林小流域的降水流出特性。年流量(Q)随年降水量(P)的增多而增加,Q/P 为48.0%～63.7%。P-Q 的差数在737mm～1128mm 之间,大体上是稳定的。由于表面水占流出量的主要部分,因而流量水平的变化极大。观测期间的流量水平最高为93.3mm/h,持续5min,最低为0.01mm/h。月流量与月降水量、日流量与日雨量、以及小时流量与小时雨量之间都基本上是线性关系。

企业财务风险的管理与控制措施

随着我国市场经济体制改革和经济全球化进程的不断发展,企业在生产经营过程中遇到的风险将越来越多,而财务风险作为一种信号,能及时、全面地反映企业的财务状况、经营成果和现金流量水平.因此,企业有必要建立完善的风险评估和内部控制体系,以进一步识别、评估、预防和控制风险,将其可能带来的损失降至最小.本文通过分析企业财务风险的类型及来源,进一步探讨如何建立有效的财务管理方法及内部控制系统,以防范、降低和化解企业的财务风险.

九连山常绿阔叶林小流域的流出特性

用量水堰法研究了九连山常绿阔叶林小流域的流出特性。3个小流域的特性是相似的。年流量(Q)随年降水量(P)的增多而增加,Q/P 为38.3%～64.6%。P-Q 的差数在718mm～1125mm 之间,大体上是稳定的。根据流量曲线推定,小流域的滞容水能力在流量水平0.04mm/h～2mm/h 之间不少于255mm～285mm。在雨季观测到的暴雨最大流量水平为8.9mm/h。仅在雨季骤性暴雨时才可能产生小的表面流出峰,其流量约占暴雨雨量的1%～2%。从10月至翌年1月共4个月的旱季流量合计一般在124mm～164mm 之间,基本上是稳定的。旱季流出主要是深层的基底(地下水)流出,因而与旱季的降水量无明显关系。

这样推导直立式毛细管黏度计的黏度计算公式是错误的

目的:不知道从何时起,医学院校物理学实验教材中用泊肃叶定律推导直立毛细管黏度计的黏度计算公式。这种推导是错误的。它已经蒙骗了几代人。本文力图揭示其错误,指出正确的推导方法。方法:首先,论文借助人们的生活经验揭示非水平管包括直立管中的液体流量不遵从泊肃叶定律,从而可知不能用泊肃叶定律计算非水平管中液体流量。然后阐明直立黏度计毛细管两端的压强近似等于大气压,毛细管两端的压强差△P=0,从而可知△P=ρgl是错误的。结果:由以上两点证明:用泊肃叶定律是推导不出直立毛细管黏度计的黏度计算公式的。结论:直立毛细管黏度计的黏度计算公式只能用非水平管的液体流量公式推导,这才是正确的。

Creation method for bi-level positive airway pressure based on pressure and flow feedback

An airway pressure and flow data acquisition system is developed to investigate the approach to building the bi-level positive airway pressure BiPAP in a ventilator.A number of experiments under different breathing situations and states are conducted and the experimental data are recorded.According to the data from these experiments the variation characteristics of the pressure and flow are analyzed using Matlab. The data analysis results show that the pressure increases while the flow decreases in the expiratory phase contrarily the pressure decreases while the flow increases in the inspiratory phase during the apnea state both the pressure and the flow remain unchanged. According to the above variation characteristics of breath a feedback-based method for creating bi-level positive airway pressure is proposed. Experiments are implemented to verify the BiPAP model. Results demonstrate that the proposed method works effectively in following respiration and caters well to most polypnea and apnea events.

道路平面交叉口中环形交叉口设计

着重阐述了常规环形交叉口的适用条件、计算行车速度、进出口车道宽及车道数、环道机动车道数、交织段长度及交织角、环道通行能力、流量比和服务水平评价等。

Effectiveness of Soil Conservation Methods in Preventing Red Soil Erosion in Southern China

Rainfall, runoff(surface runoff and interflow) and soil loss were recorded from 2002 to2005 in an experiment with four treatments on sloping red soil land in southern China. Treatments consisted of bare sloping ground(control check, CK),interplanting with soybean in spring or radish in autumn(I), level terrace(i.e., grass planted on the riser and bunds built at the edge of a bench terrace)(II), and level terraces of orchards with Bahia grass planted on the riser(III). The surface runoff and erosion in treatment II and III during the four years were low despite the occurrence of potentially erosive rains. By contrast, the CK plot had both the highest surface runoff coefficient and the highest sediment yield among all the plots. The surface runoff and soil erosion of the CK plot significantly differed from that of the treatment plots(p < 0.05). Additionally,Significant differences between the interflow of the CK plot and that of the treatment plots was found from April to August(p < 0.05). However, no significant differences between the CK and treatment plots were found from January to March and September to December. The order of the plots in terms of surface runoff coefficients and soil losses was: CK > I > III > II, whereas their order in terms of interflow was II > III > I > CK. The effects of treatment II were excellent, indicating that level terrace(i.e., grass planted on the riser and bunds built at the edge of a bench terrace) can be an excellent practice for soil and water conservation on sloping red soil land. Soil loss in southern China can be reduced through the widespread use of this approach.

Impact of Climate Change on Regional Hydroclimate Projection in Peninsular Malaysia

For the assessment of the impact of future climate change on the hydrologic regime and water resources of Peninsular Malaysia, it is necessary to downscale the climate change simulations of a coarse scale General Circulation Model to the region of Peninsular Malaysia at fine grid resolution. This paper presents a desktop review of the state of climate change parameters, namely rainfall and river flow over the Peninsular Malaysia for the 2041-2050 projection period. Analysis of the results from the models shows there will be a substantial increase in mean monthly precipitation over the North East Coastal region from historical 259.5 mm to 281.5 mm, from 289.0 mm to 299.0 mm and 221.8 mm to 239.5 mm over Terengganu and Kelantan, respectively. Meanwhile, for river flow projection, it will be an expected increase in interannual and intraseasonal variability with increased hydrologic extremes （higher high flows, and lower low flows） at Kelantan, Pahang, Terengganu, and Kedah watersheds in the future.

Role of Downward Momentum Transport in the Formation of Severe Surface Winds

The Weather Research and Forecasting (WRF) model was used to investigate the role of downward momentum transport in the formation of severe surface winds for a squall line on 3-4 June 2009 across regions of the Henan and Shandong Provinces of China. The results show that there was a strong westerly jet belt with a wind speed greater than 30 m s 1 and a thickness of 5 km at an altitude of 11-16 km. The jet belt was accelerated, and it descended while the squall line convective system occurred. It was found that the appearance of strong negative perturbation pressure accompanied by the squall line caused the acceleration of the upper-level westerly jet and increased the horizontal wind speed by a maximum of 18%. Meanwhile, the negative buoyancy due to the loading, melting, and evaporation of cloud hydrometeors induced the downward momentum transport from the upper levels. The downward momentum transport contributed approximately 70% and the surface cold pool 30% to the formation of severe surface winds.

Quantum Computation with Two-Level Systems in Current-Biased Josephson Junction

We present a feasible scheme that realizes quantum computation using the two-level systems （TLSs） in Current-biased Josephson junction （CBJJ） under the present experimental technology. Effective manipulation of the TLSs by CBJJ serving as register qubit can be obtained, such as initialization, single-qubit rotations, two-qubit gates, entanglement generation, and read out, etc. In addition, we also discuss the experimental feasibility and efficiency of the scheme.

Climate Change and its Impact on Water Resources in the Huai River Basin

Rainfall and air temperature data from six meteorological stations above the Bengbu Sluice and hydrological and water resources evaluation data from the Bengbu Hydrological Station in the Huai River Basin from 1961 to 2008 are used to analyze the impact of changes in climatic factors on the amount of water resources in the Basin. There was a general trend of rise in its average annual air temperature, with the highest increase of 0.289℃/10a recorded at Bengbu in Anhui Province. Rising rainfall was mainly observed in the western part of the study area, while rainfall actually declined in the eastern part, i.e. the middle reaches of the Huai River. The Average rainfall in the study area was in a vaguely declining trend. In other words, the rainfall in the Basin is still much affected by natural fluctuations. On the whole, there was a trend of gradual decrease in the quantity of the Basin＇s water resources for the period under study. Water resources quantity is found to fall with decreasing rainfall and rising air temperature. Regression analysis is used to establish a mathematical model between water resources quantity and climatic factors （i.e. air temperature and rainfall） in order to explore the impact of climate change on water resources in the Basin. Moreover, various scenarios are set to quantitatively analyze the response of water resources to climate change. Sensitivity analysis shows that changes in rainfall have a much bigger impact on its water resources quantity than changes in its air temperature.

The Extent of Land Use Impact on Water Regime in the Vseminka Catchment

The paper deals with the impact of land use changes on water regime. An assessment was carried out in order to determine the extent to which the main components of the water balance on the experimental catchment Vseminka have been influenced by land use changes （region Vsetinske Hills, the Czech Republic）. For this reason, the water balance model WBCM-5 was implemented for the period of 30 years in a daily step, with particular focus on the simulation of the components of direct runoff and of subsurface water recharge. In the selected years of the period 1980-2009, major changes were made in land use and significant fluctuation of rainfall-runoff regimes were observed （e.g. dry year 1992, flood year 1997 and normal year 2009）. After WBCM-5 parameter calibration it was observed that some water balance components can change in relation to substantial land use changes, even up to dozens of percent in a balance-consideration, i.e. in daily, monthly and yearly or decadal values, specifically as far as the components of interception and also of direct runoff and of subsurface water recharge are concerned. However, a different situation appeared during the investigation of significant short-term rainfall-runoff processes. There were about seven real flood events during the same period on the same catchment which were analysed using the KINFIL-2 model （time step 0.5 hr）. Land use change, positive or negative scenarios, were also analysed during this period. As opposed to long-term water balance analyses, only a 10% difference in the hydrograph peak and volume was observed. In summary, the authors have shown that it is always important to distinguish a possible land use change impact on either long-term balance or short-term runoff. Otherwise, as often found in over simplified commentaries on flood events in the mass media, the actual impact of land use changes on water regime may be misunderstood.

Evolution of Nitrogen, Phosphorus and Potassium Fertilizer Application Rates in Cotton Fields and Its Influences on Cotton Yield in the Yangtze River Valley

[Objective] The historical evolution pattern of nitrogen （N）, phosphorus （P） and potassium （K） fertilizer application rate and its effects on lint cotton yield were explored to provide the theoretical basis for reasonable fertilizer management strate-gy in the cotton planting region of the Yangtze River Val ey. [Method] GGE biplot analysis method was adopted to analyze the correlation among N, P and K fertilizer application rate and lint cotton yield with the dataset of national cotton regional trials of the Yangtze River Val ey during 1991-2013. The linear and nonlinear regression analysis method was used to reveal the evolution of the fertilizer applying patterns, and analyze the effects of N, P, K application rates on cotton lint yield. [Result] The application rates of N, P and K fertilizer presented highly significant positive corre-lation with lint cotton yield, among which the potassium fertilizer was the strongest relative factor with lint cotton yield, fol owed by phosphorus fertilizer, while nitrogen fertilizer was the weakest factor. The application rate of nitrogen fertilizer was relat-ed with the test year in the pattern of a quadratic function, while phosphate and potassium had progressive increase linear relation with the test year in the cotton planting region of the Yangtze River Val ey. Meanwhile, cotton lint yield was in re-sponse to nitrogen fertilizer content increase with a quadratic parabola function, and increased with the applying phosphate fertilizer and potassium fertilizer content with linearly increasing function. [Conclusion] The increasing application amount of N, P and K fertilizer was general y beneficial to cotton yield improvements, however, ex-orbitant applying nitrogen fertilizer was unfavorable for cotton production, and a reasonable mixture formula of N, P and K fertilizer was better in terms of cotton yield-increasing effect.

Exploring Solutions of Nonlinear Rossby Waves with Complete Coriolis Force

Nonlinear Rossby waves in a Boussinesq fluid model which includes both the vertical and horizontalcomponents of Coriolis force are studied by using the semi-geostrophic approximation and the method of travelling-wavesolution.Taylor series expansion has been employed to isolate the characteristics of the linear Rossby waves and identifythe Rossby cnoidal and solitary waves.Qualitative analysis indicates that if the disturbances are independent of latitude,the effect of horizontal components of Coriolis force disappears.

Study on Blade Surface Flow around Wind Turbine by Using LDV Measurements

This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine(HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade is a challenging endeavor. In this research, the HAWT model with 2.4 m diameter was tested in the large wind tunnel. The flow around the rotating blade surface was measured simultaneously for three velocity components, and two probes were used for the synchronized measurement of three-dimensional flow components. The local velocity was detected for the single seeding particle measured in the point where three pairs of laser beams intersected. Blade sections of interest in this study are composed of radial positions r/R = 0.3, 0.5 and 0.7. Optimum and low tip speed ratio flow characteristics were also compared. The velocity flow vector, skin friction coefficient and bound circulation were calculated from LDV measurements, and the experimental research showed reasonably and clearly the experimental results.

Distribution of fatty acids in the alpine grassland soils of the Qinghai-Tibetan Plateau

As an important biomarker, fatty acids(FAs) have been extensively used to trace the origin of organic matter in sediments and soils. However, studies of the distribution and abundance of FAs in alpine grassland soils are still rare, especially on the Qinghai-Tibetan Plateau(QTP), the highest plateau in the world, which contributes sediments to many large rivers in Asia. This study investigates the composition, distribution and source of FAs with increasing soil depths from 17 typical alpine grassland sites in the QTP. The most abundant FAs included the ubiquitous C16 FA and even-numbered long-chain FAs(C20–C30), indicating mixed inputs from microbial and higher plant sources. Source apportionment showed that higher plants were the dominant contributor of FAs(approximately 40%) in QTP soils. The abundance of FAs decreased with soil depth, with the highest value(1.08±0.09 mg/g C) at a 0–10 cm depth and the lowest value(0.46±0.12 mg/g C) at a 50–70 cm depth, due to much lower plant inputs into the deeper horizons. The total concentration of FAs was negatively correlated to the mean annual temperature(MAT; P<0.05) and soil p H(P<0.01), suggesting that the preservation of FAs was favored in low-MAT and low-p H soils on the QTP. The abundance of fresh C source FAs increased significantly with the mean annual precipitation(MAP; P<0.05), indicating that high MAP facilitates the accumulation of fresh FAs in QTP soils. Other environmental parameters, such as the soil mineral content(aluminum and iron oxide), microbial community composition as well as litter quality and quantity, may also exert a strong control on the preservation of FAs in QTP soils and warrant further research to better understand the mechanisms responsible for the preservation of FAs in QTP soils.