Generation characteristics of vacuum discharge plasma are very important for the applied research of metal plasma. The vacuum discharge electrode configuration and the cathode material affect the generation characteri...Generation characteristics of vacuum discharge plasma are very important for the applied research of metal plasma. The vacuum discharge electrode configuration and the cathode material affect the generation characteristics of the metal plasma which consists of metal ions coming from cathode and generated by vacuum discharge. In this research, the generation characteristics of the metal plasma generated by vacuum discharge are discussed for four patterns of electrode configurations, i.e. cone-mesh electrode setup, cone-cross line electrode setup, cone-line electrode setup and cone-ring electrode setup. Characteristics of the metal plasma, such as elec- tron density, electron temperature, space potential, ion energy, are measured by the probe method for discussing the impacts of different electrode configurations on the density of generated metal plasma. Moreover, the diffusion velocities of the metal plasma are measured for cathode materials of Pb, Al, and Cu, respectively. The experimental results indicate that the plasma generated by the discharge of cone-ring electrode configuration possesses the maximum density and the metal plasma generated by the Al cathode possesses the fastest diffusion velocity and the highest kinetic energy.展开更多
An experimental system of AC arc discharge in water was designed with pole-pole electrodes and a peak voltage of 1500 V and a test circuit was set up using virtual instrument technology. The mechanism of an AC plasma ...An experimental system of AC arc discharge in water was designed with pole-pole electrodes and a peak voltage of 1500 V and a test circuit was set up using virtual instrument technology. The mechanism of an AC plasma arc generated in water was analyzed. The voltage- current characteristic of the AC plasma are was obtained from the waveform. The temperature characteristic was tested with a spectrum diagnosis system, and the effect of different electrode materials on the striking voltage and peak current was analyzed. The results show that when a power supply of 6 kW is applied on electrodes with a gap of 2 mm in water, the striking voltage is from 900 V to 1300 V, the arc voltage is from 40 V to 100 V, the arc current is from 2 A to 7 A, and the zero rest period is from 1 ms to 2 ms. In addition, the arc voltage and current are different for electrodes in aluminum, copper and stainless steel. The arc voltage is lower and the current is higher for an aluminum electrode than those for copper and stainless steel ones. The highest temperature of the arc is 7643 K.展开更多
混合物的联合毒性评估是环境安全领域研究热点。前期研究发现,特性参数k·EC_(x)可以预测二元混合物(等毒性配比)的联合毒性。本研究进一步探明k·EC_(x)在不同浓度比二元混合物中的预测能力。本研究以盐酸苯海拉明(diphenhydra...混合物的联合毒性评估是环境安全领域研究热点。前期研究发现,特性参数k·EC_(x)可以预测二元混合物(等毒性配比)的联合毒性。本研究进一步探明k·EC_(x)在不同浓度比二元混合物中的预测能力。本研究以盐酸苯海拉明(diphenhydramine hydrochloride,DPH)、氯霉素(chloramphenicol,CAP)、多黏菌B硫酸盐(polymyxin B sulfate,PLB)、盐酸四环素(tetracycline hydrochloride,TC)、1-十二烷基-3-甲基咪唑氯盐(1-dodecyl-3-methylimidazolium chloride,IL)及其二元混合物体系DPH-PLB、DPH-IL、DPH-CAP和TC-DPH为研究对象,采用直接均分射线法设计二元混合物,通过微孔板法测定研究对象对费氏弧菌的急性毒性,借助独立作用模型(independent action,IA)和相对模型偏差百分比(relative model deviation ratio,rMDR)评价混合物的联合作用。结果表明,前期二元混合物的分类法具有普遍适用性;不同浓度比二元混合物的联合毒性具有浓度水平和浓度比依赖性。组合DPH-PLB、TC-DPH的参数k·EC_(x)的相对差异(Δ(k·EC_(x))%)的值域跨度分别为99.78%、61.94%,随着浓度配比的变化,混合物类型发生转变,而DPH-IL和DPH-CAP对应参数的值域跨度为52.37%和39.85%,随着浓度配比的变化,混合物类型未发生转变。简言之,Δ(k·EC_(x))%的值域跨度较大时,同一体系不同浓度比的二元混合物的类型/联合作用易发生转变,Δ(k·EC_(x))%的值域跨度较小时,同一体系不同浓度比的二元混合物的类型/联合作用不易发生转变。展开更多
The different physical states of saturated sand, including shear elasticity, positive dilatancy, and negative dilatancy (preliminary negative dilatancy, secondary negative dilatancy and reversal negative dilatancy) ar...The different physical states of saturated sand, including shear elasticity, positive dilatancy, and negative dilatancy (preliminary negative dilatancy, secondary negative dilatancy and reversal negative dilatancy) are revealed based on the pore water pressure response of saturated sand in undrained dynamic torsional tests of thin cylinder samples and also checked by the drained cyclic triaxial tests under a given mean effective normal stress. According to the effective stress path of different physical states under the undrained cyclic torsional tests the physical state transformation surface, stress history boundary and yield surface are determined, and the state boundary surface is also determined by the range of effective frictional stress state movement. Based on the moving yield surface without rotation, and the expanding stress history boundary surface relevant to the stress path variations under different physical states in 3D stress space, a physical state model is proposed to provide a new approach to calculating the transient pore water pressure under the undrained condition, and the volume strain of dilatation under drained condition in this paper.展开更多
文摘Generation characteristics of vacuum discharge plasma are very important for the applied research of metal plasma. The vacuum discharge electrode configuration and the cathode material affect the generation characteristics of the metal plasma which consists of metal ions coming from cathode and generated by vacuum discharge. In this research, the generation characteristics of the metal plasma generated by vacuum discharge are discussed for four patterns of electrode configurations, i.e. cone-mesh electrode setup, cone-cross line electrode setup, cone-line electrode setup and cone-ring electrode setup. Characteristics of the metal plasma, such as elec- tron density, electron temperature, space potential, ion energy, are measured by the probe method for discussing the impacts of different electrode configurations on the density of generated metal plasma. Moreover, the diffusion velocities of the metal plasma are measured for cathode materials of Pb, Al, and Cu, respectively. The experimental results indicate that the plasma generated by the discharge of cone-ring electrode configuration possesses the maximum density and the metal plasma generated by the Al cathode possesses the fastest diffusion velocity and the highest kinetic energy.
基金supported by National Natural Science Foundation of China (No. 50777014)
文摘An experimental system of AC arc discharge in water was designed with pole-pole electrodes and a peak voltage of 1500 V and a test circuit was set up using virtual instrument technology. The mechanism of an AC plasma arc generated in water was analyzed. The voltage- current characteristic of the AC plasma are was obtained from the waveform. The temperature characteristic was tested with a spectrum diagnosis system, and the effect of different electrode materials on the striking voltage and peak current was analyzed. The results show that when a power supply of 6 kW is applied on electrodes with a gap of 2 mm in water, the striking voltage is from 900 V to 1300 V, the arc voltage is from 40 V to 100 V, the arc current is from 2 A to 7 A, and the zero rest period is from 1 ms to 2 ms. In addition, the arc voltage and current are different for electrodes in aluminum, copper and stainless steel. The arc voltage is lower and the current is higher for an aluminum electrode than those for copper and stainless steel ones. The highest temperature of the arc is 7643 K.
文摘混合物的联合毒性评估是环境安全领域研究热点。前期研究发现,特性参数k·EC_(x)可以预测二元混合物(等毒性配比)的联合毒性。本研究进一步探明k·EC_(x)在不同浓度比二元混合物中的预测能力。本研究以盐酸苯海拉明(diphenhydramine hydrochloride,DPH)、氯霉素(chloramphenicol,CAP)、多黏菌B硫酸盐(polymyxin B sulfate,PLB)、盐酸四环素(tetracycline hydrochloride,TC)、1-十二烷基-3-甲基咪唑氯盐(1-dodecyl-3-methylimidazolium chloride,IL)及其二元混合物体系DPH-PLB、DPH-IL、DPH-CAP和TC-DPH为研究对象,采用直接均分射线法设计二元混合物,通过微孔板法测定研究对象对费氏弧菌的急性毒性,借助独立作用模型(independent action,IA)和相对模型偏差百分比(relative model deviation ratio,rMDR)评价混合物的联合作用。结果表明,前期二元混合物的分类法具有普遍适用性;不同浓度比二元混合物的联合毒性具有浓度水平和浓度比依赖性。组合DPH-PLB、TC-DPH的参数k·EC_(x)的相对差异(Δ(k·EC_(x))%)的值域跨度分别为99.78%、61.94%,随着浓度配比的变化,混合物类型发生转变,而DPH-IL和DPH-CAP对应参数的值域跨度为52.37%和39.85%,随着浓度配比的变化,混合物类型未发生转变。简言之,Δ(k·EC_(x))%的值域跨度较大时,同一体系不同浓度比的二元混合物的类型/联合作用易发生转变,Δ(k·EC_(x))%的值域跨度较小时,同一体系不同浓度比的二元混合物的类型/联合作用不易发生转变。
基金Project supported by the National Natural Science Foundation of China (No.10172071) the Natural Science Foundation of Shaanxi Province.
文摘The different physical states of saturated sand, including shear elasticity, positive dilatancy, and negative dilatancy (preliminary negative dilatancy, secondary negative dilatancy and reversal negative dilatancy) are revealed based on the pore water pressure response of saturated sand in undrained dynamic torsional tests of thin cylinder samples and also checked by the drained cyclic triaxial tests under a given mean effective normal stress. According to the effective stress path of different physical states under the undrained cyclic torsional tests the physical state transformation surface, stress history boundary and yield surface are determined, and the state boundary surface is also determined by the range of effective frictional stress state movement. Based on the moving yield surface without rotation, and the expanding stress history boundary surface relevant to the stress path variations under different physical states in 3D stress space, a physical state model is proposed to provide a new approach to calculating the transient pore water pressure under the undrained condition, and the volume strain of dilatation under drained condition in this paper.
