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.

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.

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.

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.

明渠非标准断面法测流水位流量关系的率定及影响因素分析

为探究明渠非标准断面法测流的水位流量关系曲线的率定问题,以新疆第三师某团场25处渠道量水断面为研究对象,利用FlowTracker 2手持式声学多普勒流速仪进行了水位流量关系率定工作.根据实测结果,率定了各渠道量水断面的水位流量关系曲线,并对所率定出的曲线进行了符号检验、适线检验和偏离数值检验及误差分析,在此基础上,对流量拟合参数的影响因素进行了分析.结果表明:所率定的25处渠道量水断面中,14处具有稳定的水位流量关系,5处受回水影响、6处受渠道淤积影响为不稳定的水位流量关系;在渠道粗糙系数Ra、边坡系数m及坡降i相同的条件下,流量拟合参数与渠道底宽b总体上呈正相关;在渠道粗糙系数Ra、边坡系数m及底宽b相同的条件下,流量拟合参数与渠道坡降i总体上呈负相关.研究结果可以为灌区自动化量水设备测流准确性的校核提供参考依据.

水下等离子体声源放电特性和声特性实测与分析

在小型消声水池中,同步测量水下等离子体脉冲声源的放电特性和声特性,实验分析研究了其在单电极和多电极下负载注入峰值功率和放电能量对声特性的影响。结果表明,在相同的电极数和间距下,直达波脉冲声源级仅与负载注入峰值功率有关,气泡脉冲声源级和气泡周期则主要受放电能量影响,多电极放电通过减小单根电极放的电能量来减小气泡脉冲声源级和气泡周期。此外,在相同的充电电压下,减小充电电容对电极数的比,可以增大直达波脉冲声源级并压制气泡脉冲;负载注入峰值功率对放电能量的比对声特性的影响也呈现出类似规律。实测及其分析结果可为进一步优化水下等离子体脉冲声源的声特性提供参考。

水位流量关系单值化方法的研究历程和展望

水位流量关系单值化方法是实现水文监测体系创新发展的重要基础。为此,系统阐述了水位流量关系单值化方法的基本原理,回顾了水位流量关系单值化方法在过去50 a的发展与创新历程,以及目前在整个水文领域的实际应用情况,展望了水位流量关系单值化方法在整编系统、站网规划、相应流量报汛等方面的作用。研究表明:水位流量关系单值化方法推动了“驻巡结合,巡测优先,测报自动,应急补充”水文现代化发展模式的形成;提高了水文测站单值化方案的效率,投产后的流量测次比历年平均流量测次减少50%~73%以上。研究成果可为现代化水文监测体系建设提供参考。

基于灰色关联分析的纵扭超声辅助对电火花微孔加工影响评价

TC4钛合金是航空航天领域经常加工的材料,由于其难切削的特点通常使用电火花进行加工,但存在加工效率与废屑排除的问题。纵扭超声振动可以有效优化如上弊端,但目前没有严谨定量的科学分析证明纵扭超声辅助对电火花加工的优化程度。因此提出纵扭超声辅助电火花放电能量模型,阐明放电机制以及放电能量的影响因素;设置单因素试验和正交试验,通过显著性T检验探索纵扭超声振动对电火花加工的影响程度,通过建立灰色关联分析模型分析电参数的影响权重并选出最优参数组,最后通过打孔试验验证了选优结果的正确性。研究结果表明:峰值电流和脉冲宽度对加工效率和质量的影响较为明显,引入纵扭超声振动明显改善了电火花加工性能,最优峰值电流从2 A提升至3 A,脉冲宽度从125μs提升至150μs,材料去除率提升了83.8%,相对电极损耗率、孔锥度和表面粗糙度分别降低了33.7%、22.3%和16.4%。

基于Peplau人际关系理论的出院计划对甲状腺癌手术患者心理健康、社会功能及生存质量的影响

目的:探讨基于Peplau人际关系理论的出院计划对甲状腺癌手术患者心理健康、社会功能及生存质量的影响。方法:将2022年1月—2023年6月在大冶市人民医院甲乳胸外科接受治疗的186例患者作为研究对象,按随机数表法将患者分为对照组和观察组,各93例。对照组接受常规院外护理,观察组接受基于Peplau人际关系理论的出院计划干预,比较两组心理健康、社会功能、生存质量和护理满意度的差异。结果:护理前,两组心理健康测试问卷(DCL-90)评分比较,差异无统计学意义(P>0.05);护理后,两组DCL-90评分较护理前降低,且观察组低于对照组,差异有统计学意义(P<0.05)。护理前,两组生活质量综合评价量表(GQOLI-74)各维度评分比较,差异无统计学意义(P>0.05);护理后,两组躯体功能、社会功能、心理功能、角色功能评分较护理前升高,且观察组高于对照组,差异有统计学意义(P<0.05)。观察组服务态度、护理技能、沟通情况、疾病相关知识掌握情况评分高于对照组,差异有统计学意义(P<0.05)。结论:基于Peplau人际关系理论的出院计划应用于甲状腺手术患者,能改善心理健康状态,提高社会功能和生存质量,还可提高护理满意度。

基于多导睡眠图的抗癫痫发作药物与偏侧化发作间期癫痫样放电对癫痫患者睡眠的影响

目的通过多导睡眠图(PSG)探讨抗癫痫发作药物(ASM)及偏侧化发作间期癫痫样放电(IED)对癫痫患者睡眠结构及睡眠期相关事件的影响。方法选取2018年3月至2022年12月在福建省级机关医院神经内科、睡眠医学中心门诊或病房治疗的癫痫患者75例,其中32例服用ASM、43例未服用ASM,对两组患者进行PSG(含视频及16个导联的脑电图)+动态脑电图监测,比较两组患者的睡眠结构及睡眠期相关事件。并对两组患者单、双侧IED的睡眠结构及睡眠期相关事件的不同结果进行分析。结果两组患者的睡眠结构比较差异无统计学意义(P>0.05);而服药癫痫组的血氧饱和度高于未服药癫痫组[95(94,96)%vs 94(93,95)%],在未服药癫痫组中,单、双侧IED组的睡眠结构及睡眠期相关事件比较差异均无统计学意义(P>0.05);在服药癫痫组中,单侧IED组的非快速眼动睡眠1期比例(N1%)[(21.48±15.61)%vs(12.06±6.55%)]、觉醒指数[12.9(7.75,18.3)次/h vs 8.8(6.5,10.9)次/h]均高于双侧IED组,差异有统计学意义(P<0.05)。结论ASM对IED患者的睡眠结构影响不大,服药癫痫组的血氧饱和度高于未服药癫痫组。服用ASM的患者单侧IED对睡眠期各结构的影响更大,主要表现为N1%及觉醒指数增高。

嫩江干流江桥站近年来水文特征变化分析

江桥站为嫩江干流控制站,文中通过统计整理该站近年来的降水、径流、泥沙、水位流量关系等水文特征资料,分析各水文特征参数的变化情况,有利于进一步了解掌握流域水文特征变化趋势,为流域水资源管理和水旱灾害防御提供有力的基础技术支撑。

长江下游干流八里江水文站水位流量关系分析

长江下游干流八里江水文站是鄱阳湖入汇长江后的重要控制站。该站流量测验方式为巡测,且实测资料主要集中在高水时期。为适应今后的流量在线监测要求,需要对该站水位流量关系进行分析。通过合理的试算与分析获取较为连续且可靠的数据,开展了关系定线和各项检验验算。结果表明:单一曲线法可适用于八里江站水位流量关系,且满足现行水文整编规范要求。研究成果可今后流量测次布置、报汛精度及流量在线监测实施提供参考。

多项式拟合水位流量关系曲线

依据实测资料采用多项式结合最小二乘法数学原理对水位流量关系曲线进行拟合。对于测站控制分时段或者各级水位流量关系曲线趋势不一致的测站采用分段拟合,人工对节点稍加修正即可通过三项检验,经采用黄梨树等站多站多年实测资料验证,工定线推流和拟合定线推流年平均流量误差为0~0.007之间;最大流量误差为0~0.01之间;最小流量误差为0~0.03之间;误差全部小于±5%,其精度满足SL247-2012《水文资料整编规范》要求。多项式拟合水位流量关系曲线可代替传统的人工定线,工作效率大幅提升。

基于回归分析的龙泉港出海闸高淹没度下水位流量关系率定

龙泉港出海闸排水受外海潮汐影响显著,不适宜采用堰闸流量系数法进行推流。结合龙泉港出海闸水文过程试验的实测资料,以水力学公式为基础,采用回归分析法率定得到了高淹没度状态下的水位流量关系式,并对关系式进行了符号检验、适线检验、偏离检验和精度分析。结果表明:回归分析法率定得到的出海闸高淹没度状态下的水位流量关系成功通过了3项检验,定线精度能够达到一类精度标准,可以在受潮汐影响的出海闸水位流量关系率定中推广使用。

柴庄水文站测站特性分析

通过1994-2016年水文资料分析柴庄站测站特性,结果表明,汾河上游赵城站与支流东庄站控制了柴庄站81.8%的径流量,柴庄站多年平均径流量主要分布在7~10月,占全年60.6%。柴庄站断面年际间冲淤变化较大,1994-2016年间总趋势为逐年下切,至2011年断面已接近基岩,2011年以前断面年内冲淤变化较大,以涨冲落淤为主,但全年总趋势为冲刷,2011年后年内冲淤基本平衡,年际变化较小。1994~2016年间柴庄站水位流量关系线逐渐由全年多条发展为全年1条。柴庄站2011~2016年水位流量关系曲线符合合并定线要求。

电火花微小孔加工工艺参数的优化研究

由于目前对电火花放电机理认识的有限性而使参数优化成为电火花加工中的难点之一,特别是多项工艺指标要求下的参数优化问题更是缺乏理论指导和具体应用方法。因此,在用正交试验法研究了电火花微小孔加工中放电参数和非放电参数对加工速度、电极损耗和孔径间隙等各单项工艺指标的影响规律的基础上,采用灰色相关性理论,重点解决了多项工艺指标下的参数优化这一难点问题,简化了优化过程,得出了优化的参数组合方案。

托吡酯对青霉素诱发大鼠痫性放电和海马区相关递质含量的影响

目的 观察托吡酯对大鼠皮层定位注射青霉素诱发惊厥模型的对抗作用,并探讨其作用机制。方法 建立大鼠皮层定位注射青霉素诱发惊厥模型,观察两种剂量托吡酯ig给药对青霉素诱发痫性发作的程度和海马区痫性放电的潜伏期、痫波发放频率及痫波最高波幅的影响;采用HPLC法测定惊厥大鼠海马区Glu、Asp、Gly、GABA含量的变化。结果 两种剂量托吡酯(110, 440mg·kg-1,ig)均可减轻大鼠惊厥发作的程度,延长痫性放电的潜伏期,减少痫波发放频率,减小放电最高波幅,与模型组比较,差异均具有显著性(P<0 05或P<0 01)。同时,均可使大鼠海马区Glu含量降低,GABA含量升高,与模型组比较差异均有显著性 (P<0 05或P<0 01)。结论 托吡酯可明显抑制皮层定位注射青霉素诱发的痫性发作和痫性放电, 产生抗惊厥作用。其作用机制可能与加强GABA抑制功能和限制Glu兴奋功能有关。

西大亚湾海水中^3H浓度与大亚湾核电站液态^3H排放的相关性分析

通过对广东省环境辐射研究监测中心 (GERC)在西大亚湾海水中 3 H的浓度将近 6年的监测结果与广东大亚湾核电站 (GNPS)液态3 H排放的相关性分析和拟合计算 ,找出海水中全部 (13～ 18个 )采样点的3 H平均浓度与核电站液态3 H排放量的函数关系。利用这一函数 ,根据液态 3 H的年排放量 ,按照瞬时排放 (实际排放方式 )或准连续排放 (水动力方程计算的假设排放方式 )可以简便地估算出湾内海水中3 H平均浓度的瞬时值和年均值。结果表明 ,GNPS液态 3 H瞬时排放与连续排放在西大亚湾海水中产生的平均效果基本相同 ,这一结果与水动力方程计算的结果也基本相符。