Modified theoretical stage-discharge relation for circular sharp-crested weirs

A circular sharp-crested weir is a circular control section used for measuring flow in open channels, reservoirs, and tanks. As flow measuring devices in open channels, these weirs are placed perpendicular to the sides and bottoms of straight-approach channels. Considering the complex patterns of flow passing over circular sharp-crested weirs, an equation having experimental correlation coefficients was used to extract a stage-discharge relation for weirs. Assuming the occurrence of critical flow over the weir crest, a theoretical stage-discharge relation was obtained in this study by solving two extracted non-linear equations. To study the precision of the theoretical stage-discharge relation, 58 experiments were performed on six circular weirs with different diameters and crest heights in a 30 cm-wide flume. The results show that, for each stage above the weirs, the theoretically calculated discharge is less than the measured discharge, and this difference increases with the stage. Finally, the theoretical stage-discharge relation was modified by exerting a correction coefficient which is a function of the ratio of the upstream flow depth to the weir crest height. The results show that the modified stage-discharge relation is in good agreement with the measured results.

Novel method for identifying the stages of discharge underwater based on impedance change characteristic

It is difficult to determine the discharge stages in a fixed time of repetitive discharge underwater due to the arc formation process being susceptible to external environmental influences. This paper proposes a novel underwater discharge stage identification method based on the Strong Tracking Filter(STF) and impedance change characteristics. The time-varying equivalent circuit model of the discharge underwater is established based on the plasma theory analysis of the impedance change characteristics and mechanism of the discharge process. The STF is used to reduce the randomness of the impedance of repeated discharges underwater, and then the universal identification resistance data is obtained. Based on the resistance variation characteristics of the discriminating resistance of the pre-breakdown, main, and oscillatory discharge stages, the threshold values for determining the discharge stage are obtained. These include the threshold values for the resistance variation rate(K) and the moment(t).Experimental and error analysis results demonstrate the efficacy of this innovative method in discharge stage determination, with a maximum mean square deviation of Scrless than 1.761.

Predictive model for stage-discharge curve in compound channels with vegetated floodplains

The governing equation of the discharge per unit width, derived from the flow continuity equation and the momentum equation in the vegetated compound chan- nel, is established. The analytical solution to the discharge per unit width is presented, including the effects of bed friction, lateral momentum transfer, drag force, and secondary flows. A simple＇ but available numerical integral method, i.e., the compound trapezoidM formula, is used to calculate the approximate solutions of the sub-area discharge and the total discharge. A comparison with the published experimental data from the U. K. Flood Channel Facility （UK-FCF） demonstrates that this model is capable of predicting not only the stage-discharge curve but also the sub-area discharge in the vegetated com- pound channel. The effects of the two crucial parameters, i.e., the divided number of the integral interval and the secondary flow coefficient, on the total discharge are discussed and analyzed.

Tolerance to Salinity of Sesame Genotypes in Different Phenological Stages

The sesame crop is usually avoided in salt-affected areas because of the various effects of saline stress on plants. Besides varying between species, salinity effects are known to vary for genotypes of the same species as well as plant development stages. Thus, through the irrigation of plants with saline water, this study evaluates tolerance to saline stress of new sesame genotypes in different phenological stages. Three experiments were carried out under greenhouse conditions, using the sesame genotypes BRS Seda, LAG-927561 and LAG-26514. Water with different levels of electrical conductivity (ECw = 0.6, 1.6, 2.6, 3.6 and 4.6 dS m-1) was used to irrigate plants during germination and initial growth stages, as well as the entire crop cycle. Tolerance to saline stress (3.6 dS m-1) during growth and production stages was also studied. Salinity did not affect sesame germination, but seedling growth was hindered from the ECw of 1.6 dS m-1 onwards, and plant height was the most affected growth variable. Seed production is affected by salinity, regardless of the phenological stage in which plants are exposed to salinity. The strains LAG-927561 and LAG-26514 show promising signs in studies on adaptation to saline stress.

A Method for Calculating Oil Field Relative Permeability Curve by Using Water Drive Characteristic Curve in High Water Cut Stage

With the production of strong bottom water reservoir, it will soon enter the ultra-high water cut stage. After entering the ultra-high water cut period, the main means of stable production is liquid extraction. Large liquid volume has a certain impact on the physical property distribution and fluid seepage law of the oilfield. The relative permeability curve measured according to the industry standard is not used for the prediction of development indicators and the understanding of the dynamic law of the oilfield. In order to understand the characteristics of water drive law in high water cut stage of water drive oilfield, starting from the water drive characteristic curve in high water cut stage, the method for calculating the relative permeability curve is deduced. Through numerical simulation verification and fitting the actual production data, it is confirmed that the obtained relative permeability curve is in line with the reality of the oilfield, It can provide some guiding significance for understanding the production law and water drive law of strong bottom water reservoir in ultra-high water cut stage.

Two-Dimensional Numerical Simulation of the DC Glow Discharge in the Normal Mode and with Einstein’s Relation of Electron Diffusivity

This paper presents an investigation of a DC glow discharge at low pressure in the normal mode and with Einstein＇s relation of electron diffusivity. Two-dimensional distributions in Cartesian geometry are presented in the stationary state, including electric potential, electron and ion densities, longitudinal and transverse electrics fields as well as electron temperature. Our results are compared with those obtained in existing literature. The model used in this work is based on the first three moments of Boltzmann＇s equation. They serve as the continuity equation, the momentum transfer and the energy equations. The set of equations for charged particles presented in monatomic argon gas are coupled in a self-consistent way with Poisson＇s equation. A parametric study varying the cathode voltage, gas pressure, and secondary electron emission coefficient predicts many of the well-known features of DC discharges.

STAGE原则指导下的糖尿病足溃疡中医外治方案

糖尿病足是糖尿病患者致残、致死的主要原因之一。业界公认的Wagner和TEXAS分级侧重于病情评估,不能用于指导疮面干预。基于此提出了指导糖尿病足疮面处理的STAGE原则,该原则强调以血供为基础、按足部解剖分层次切开引流以控制感染,感染得到控制后按解剖层次分阶段促愈。在切开引流和分阶段处理糖尿病足疮面过程中,均形成了相应的具有中医特色的理、法、方、药、术,并总结了各个处理阶段临床疗效评价的客观和主观指标,关注全身症状及局部疮面、疮周症状变化。在切开引流阶段,注重观察局部红肿消退情况,全身热退身凉、局部肿消痛减是顺证,反之则提示切开引流层次不到位或存在未切开脓腔。在分层次处理阶段,需及时评估疮面血供,骨(关节)和肌腱的处理关乎愈合和功能康复,需巧妙设计。肉芽组织覆盖疮面是上皮化的关键,需时时评估肉芽组织质量,通过STAGE原则与中医外治的有机结合,为糖尿病足疮面修复提供了系统方案。

Discharge estimation based on machine learning

To overcome the limitations of the traditional stage-discharge models in describing the dynamic characteristics of a river, a machine learning method of non-parametric regression, the locally weighted regression method was used to estimate discharge. With the purpose of improving the precision and efficiency of river discharge estimation, a novel machine learning method is proposed： the clustering-tree weighted regression method. First, the training instances are clustered. Second, the k-nearest neighbor method is used to cluster new stage samples into the best-fit cluster. Finally, the daily discharge is estimated. In the estimation process, the interference of irrelevant information can be avoided, so that the precision and efficiency of daily discharge estimation are improved. Observed data from the Luding Hydrological Station were used for testing. The simulation results demonstrate that the precision of this method is high. This provides a new effective method for discharge estimation.

A Study on Physical Model Test for Cheongpyeong Dam Discharge Recalculation

Cheongpyeong Dam was built in 1943 for the purpose of power generation. Since its construction, discharge flow data based on a theoretical formula have been used to the present times and this leads to a problem of accurate discharge flow information not being available. In particular, Cheongpyeong Dam has been partially repaired and modified to maintain the dam structure over a long period of time and is not being properly reflected with changes at the downstream of the river caused by river improvement projects and sedimentation in reservoir. With a goal to improve Cheongpyeong Dam discharge flow calculation, this study aimed at verifying discharge capability and discharge flow by damper opening in relation to the previously suggested discharge flow through a hydraulic model test based on an accurate reproduction of the dam structure and surrounding topographies as in the present conditions. In this study, a hydraulic model test was conducted to examine the discharge flow of Cheongpyeong Dam. In addition, a comparative examination was carried out against the existing discharge flow proposed using theoretical equations. As a verification of the discharge flow of Cheongpyeong Dam, discharge flows in all sluices and a single sluice were examined. Then, the impact of sluice interference caused by the dam structure consisting with 24 sluices was investigated. As a result of the examination, it was found that the difference between discharge flow calculated using the existing theoretical equations and discharge flow derived from the hydraulic model test was insignificant. Based on the results of hydraulic model test, a formula to estimate stage-discharge flow at a sluice was derived and suggested.

Stage identification and process optimization for fast drilling EDM of film cooling holes using KBSI method

Fast drilling electrical discharge machining(EDM)is widely used in the manufacture of film cooling holes of turbine blades.However,due to the various hole orientations and severe electrode wear,it is relatively intricate to accurately and timely identify the critical moments such as breakout,hole completion in the drilling process,and adjust the machining strategy properly.Existing breakout detection and hole completion determination methods are not suitable for the high-efficiency and fully automatic production of film cooling holes,for they almost all depend on preset thresholds or training data and become less appropriate when machining condition changes.As the breakout and hole completion detection problems can be abstracted to an online stage identification problem,in this paper,a kurtosis-based stage identification(KBSI)method,which uses a novel normalized kurtosis to denote the recent changing trends of gap voltage signals,is developed for online stage identification.The identification accuracy and generalization ability of the KBSI method have been verified in various machining conditions.To improve the overall machining efficiency,the influence of servo control parameters on machining efficiency of each machining stage was analyzed experimentally,and a new stage-wise adaptive control strategy was then proposed to dynamically adjust the servo control parameters according to the online identification results.The performance of the new strategy is evaluated by drilling film cooling holes at different hole orientations.Experimental results show that with the new control strategy,machining efficiency and the machining quality can be significantly improved.

A PROSPECTIVE STUDY TO EVALUATE THE SAFETY AND EFFICACY USING REMOVING BLOOD STASIS HERBALS FOR PATIENTS WITH INTRACRANIAL HEMORRHAGE OF HYPERACUTE STAGE AND RELATIVE FACTORS OF HEMATOMA ENLARGEMENT(A MULTICENTER PROSPECTIVE RANDOMIZED DOUBLE-BLIND PLACEBO

The aim was to investigate whether using a removing blood stasis method in hyperacute intracranial hemorrhage stage can lead to hematoma enlargement and its clinical efficacy.A multicenter retrospective randomized double-blind placebo-controlled clinical study.We recruited patients aged 18 years or older and presenting at less than 6 h from symptom onset in 8 research centers.All the patients

Study of Humidity Effect on Benzene Decomposition by the Dielectric Barrier Discharge Nonthermal Plasma Reactor

The humidity effects on the benzene decomposition process were investigated by the dielectric barrier discharge（DBD） plasma reactor.The results showed that the water vapor played an important role in the benzene oxidation process.It was found that there was an optimum humidity value for the benzene removal efficiency,and at around 60% relative humidity（RH）,the optimum benzene removal efficiency was achieved.At a SIE of 378 J/L,the removal efficiency was 66% at 0% RH,while the removal efficiency reached 75.3% at 60% RH and dropped to 69% at 80% RH.Furthermore,the addition of water inhibited the formation of ozone and NO2 remarkably.Both of the concentrations of ozone and NO2 decreased with increasing of the RH at the same specific input energy.At a SIE of 256 J/L,the concentrations of ozone and NO2 were 5.4 mg/L and 1791 ppm under dry conditions,whereas they were only 3.4 mg/L and 1119 ppm at 63.5%RH,respectively.Finally,the outlet gas after benzene degradation was qualitatively analyzed by FT-IR and GC-MS to determine possible intermediate byproducts.The results suggested that the byproducts in decomposition of benzene primarily consisted of phenol and substitutions of phenol.Based on these byproducts a benzene degradation mechanism was proposed.

Study of partial discharge characteristics in HFO-1234ze(E)/N2 mixtures

HFO-1234 ze(E)(trans-1,3,3,3-tetrafluoropropene,chemical formula:C3H2F4)is an extremely environmentally friendly SF6 alternative gas with high electrical strength.In this paper,the partial discharge(PD)characteristics of HFO-1234 ze(E)/N2 mixtures were studied using the gas insulation test platform.The PD inception voltage of insulating gas under positive and negative half cycles of power frequency was tested.Using SF6/N2 mixtures as a control group,the effects of electrode spacing,mixing ratio and pressure on the insulation performance of HFO-1234 ze(E)/N2 mixtures were explored.The test results show that the PD inception voltage of the negative half-cycle of pure HFO-1234 ze(E)under short electrode spacing can reach 0.96-1.04 times of pure SF6 under different pressures;the PD inception voltage of40%HFO-1234 ze(E)/60%N2 mixtures at 0.3 MPa is 0.67-0.89 times that of SF6/N2 mixtures under the same conditions,which has great application prospect.

Effect of Mirror Magnetic Field on Abnormal Glow Discharge of Four-Anode Device

Abstract In the four-anode device, the mirror magnetic field affects the characteristics of charged particles motion, so that the current-voltage relations of glow discharge are changed. Firstly, the discharge device is introduced, and the distribution of mirror magnetic field generated by the loops surrounding the discharge chamber is presented. Both the discharge current-voltage characteristics and the radial distributions of electron density are measured, respectively, with/without the magnetic field. When the discharge occurs in a 99.99% helium with a pressure ranging from 100 Pa to 800 Pa without magnetic field, the voltage, sustaining a certain abnormal glow discharge current, decreases with the increase in gas pressure. With a mirror magnetic field of certain intensity, the discharge voltage increases with the current in a rate slower than that without the magnetic field. Moreover, when the magnetic field intensity increases, the discharge voltage first decreases then increases. Simultaneously, the mirror magnetic field affects the moving characteristics of charged particles, and causes a more inhomogeneous electron density.

Relative Responses of Noble Gases Using a Pulsed Discharge Helium Photoionization Detector:Theoretical Calculation and Experimental Determination

The relative response factors（RRFs） for noble gas（Ng） were determined on a pulsed discharge helium photoionization detector. Using ab initio method, the atomic orbitals of noble gas were calculated and used to determine the number of ionizable electrons on the basis of the continuous emission of He2. The molar responses of noble gases is well correlated with the number of ionizable electrons.

电容屏破损缺陷局部放电过程规律特征及仿真分析

油纸电容式变压器套管因性能好、成本低而被广泛采用。当电容屏存在边缘破损工艺缺陷时易发生局部放电,进而会改变油纸绝缘性能,缩短套管使用寿命,严重时危及电网设备安全运行。为研究电容屏破损局部放电过程变化规律,明确放电发展阶段,该文搭建了缺陷套管放电实验模型分析局放过程中相位谱图、放电量等参数发展规律,并基于实验规律及流体漂移扩散理论、固体双极电荷传输理论,建立了末屏缺陷针板沿面放电过程仿真模型,结合仿真中电荷形态变化、放电时间及油纸界面电荷密度分布对电容屏破损放电过程进行阶段划分:放电初始阶段,铝箔尖端电荷聚集发生电晕放电;放电发展阶段,尖端处带电粒子在电场作用下向油纸发展,小部分达到油纸界面产生沿面放电;放电破坏阶段,经过长时间沿面放电进入油纸发生预击穿,电场强度更大使带电粒子能量更高,冲击油纸表面造成油纸表面纤维素断裂炭化形成通道。仿真结果与实验结论相对应,证明了仿真的有效性。该文的研究成果进一步阐明了油纸套管电容屏工艺缺陷局部放电的过程及机理。

宣肺降浊清肠汤治疗稳定期支气管扩张症疗效及对肠道微生态的影响

目的观察宣肺降浊清肠汤治疗稳定期支气管扩张患者的效果及对肠道微生态的影响。方法选取2022年1月—2023年1月广州医科大学附属第一医院收治的稳定期支气管扩张症痰湿蕴肺型患者90例为观察对象,随机分为西药组、中药组、中西医结合组,每组各30例;同时于广州医科大学附属第一医院体检中心随机选取30例健康者作为空白组,用于肠道菌群检测的对照。西药组给予氨溴索口服,中药组给予宣肺降浊清肠汤颗粒剂口服,中西医结合组给予宣肺降浊清肠汤联合氨溴索口服。连续治疗6个月后评估3组临床疗效,比较3组治疗前后肺功能指标[第一秒用力呼气容积(FEV_(1))、用力肺活量(FVC)、呼气峰值流速(PEF)]、支气管扩张严重程度指数(BSI)评分、24 h痰量、急性加重次数、咳嗽-咳痰评估问卷(CASA-Q)评分、圣乔治呼吸问卷(SGRQ)评分及粪便标本中直肠真杆菌、多形拟杆菌表达量(采用PCR扩增法测定)。结果治疗结束后,中西医结合组临床总有效率明显高于中药组、西药组[93.3%(28/30)比63.3%(18/30)、76.7%(23/30),P均<0.05]。与治疗前比较,治疗后3组FEV_(1)、FVC、PEF均明显提高,BSI评分、SGRQ评分均明显降低,24 h痰量、急性加重次数均明显减少,CASA-Q评分均明显升高,且中西医结合组各指标改善情况均明显优于中药组及西药组,西药组各指标改善情况均明显优于中药组,差异均有统计学意义(P均<0.05)。治疗后中西医结合组和中药组粪便中直肠真杆菌、多形拟杆菌表达量均较治疗前明显改善(P均<0.05),西药组粪便直肠真杆菌、多形拟杆菌表达量均无明显变化(P均>0.05);治疗后中药组和中西医结合组直肠真杆菌表达量均明显低于西药组(P均<0.05),多形拟杆菌表达量均明显高于西药组(P均<0.05),中药组和中西医结合组直肠真杆菌、多形拟杆菌表达量比较差异均无统计学意义(P均>0.05)。结论宣肺降浊清肠汤联合氨溴索治疗稳定期支气管扩张症痰湿蕴肺型患者效果优于二者单独应用,可有效缓解患者病情,改善肺功能和生活质量,机制可能与宣肺降浊清肠汤可调节肠道菌群微生态相关。

考虑充放电激励机制的电动汽车聚合商参与能量-调频市场多阶段运营策略

完善电动汽车(EV)主动参与充放电双向互动调频的激励机制,综合考虑EV充放电行为在能量-调频市场中的多阶段交互影响,有利于准确评估聚合商参与电力市场的收益。提出了EV聚合商参与多品种市场的多阶段运营策略,以实现聚合商的运营收益最大化。基于充电行为特征的统计数据,建立单体EV的功率及能量响应边界,并考虑用户参与充电和放电控制的差异性,结合用户自身偏好、电池损耗,提出EV集群的充放电激励机制,并在此基础上建立EV集群功率及能量的响应边界约束。基于EV充放电调节控制的时序性和多阶段市场的调频需求,建立考虑多阶段时序交互的多品种市场运营收益优化模型。结合PJM市场的运营案例,验证所提充放电激励机制和运营策略的有效性,结果表明其能在保障用户充电需求的基础上,有效提升聚合商参与能量-调频市场的收益。

山洪灾害雨量预警指标分析方法评述与展望

山洪灾害预警指标是山洪灾害预报预警的核心,我国现阶段主要采用经验法和水位流量反推法确定雨量预警指标,并逐步推广应用复合预警指标法和动态临界雨量法。在系统阐述国内外常用雨量预警指标分析方法及其特点基础上,针对山洪灾害预警指标分析中需考虑的降雨时空分布变化、高含砂水流、泥石流及其他不确定因素影响问题,提出今后雨量预警指标研究方向。

早期分阶段肺康复在肺叶切除术重症肺癌患者中的应用

目的分析早期分阶段肺康复方案对肺叶切除术重症肺癌患者肺功能、癌因性疲乏及身体活动量的影响。方法随机抽样选取2019年6月至2020年5月于新疆医科大学附属肿瘤医院行肺叶切除术的112例重症肺癌患者为研究对象。按照入组先后顺序将其分为对照组和观察组,每组56例,2组患者基线资料比较差异无统计学意义(P>0.05),具有可比性。对照组给予常规康复护理,观察组在对照组基础上添加早期分阶段肺康复方案干预,对2组患者进行为期18个月的随访研究,比较2组患者干预前或术前3 d以及干预后1、6、18个月肺功能指标[第1秒用力呼气容积(FEV1)、第1秒用力呼气容积/用力肺活量(FEV1/FVC)]、癌因性疲乏发生率、每日身体活动时间、焦虑自评量表(SAS)评分和抑郁自评量表(SDS)评分。结果观察组癌因性疲乏发生率(44.64%)低于对照组(64.29%),差异有统计学意义(P=0.037)。重复测量方差分析显示,FEV1、FEV1/FVC、每日身体活动时间、SAS评分、SDS评分主体内效应及主体间效应有统计学意义(P<0.05),FEV1、FEV1/FVC、每日身体活动时间、SAS评分、SDS评分随时间发生变化,且因组别不同而存在差异。干预后1、6、18个月,观察组FEV1、FEV1/FVC、每日身体活动时间高于对照组,SAS评分、SDS评分低于对照组,差异有统计学意义(P<0.05)。结论在常规康复护理基础上添加早期分阶段肺康复干预,能够改善肺叶切除术重症肺癌患者远期肺功能与负性情绪,降低癌因性疲乏发生率,提高身体活动量。