CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposit...CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.展开更多
A copper vapor laser with active medium length of 60 cm and bore of 16 mm has been operated and optimized using different buffer gases to investigate the effect of the gas flow rates on the output power. It is found t...A copper vapor laser with active medium length of 60 cm and bore of 16 mm has been operated and optimized using different buffer gases to investigate the effect of the gas flow rates on the output power. It is found that there is a special optimum gas flow rate associated with the type of buffer gas.展开更多
Experimental results are presented for superfluid (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. ...Experimental results are presented for superfluid (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. The temperature was measured from 1.5K to 1.9K. Two flow regions were observed in small and large pressure and temperature differences regions respectively. The experimental data are compared with theoretical predictions.The performance and applicability of the basic theory are discussed. Hysteresis of the flow rate is also observed and discussed.展开更多
为研究气相抽提技术(SVE)现场去污效果及影响因素,在北京市某化工厂搬迁遗留场地,以苯系物为目标污染物,应用气相抽提法进行场地污染修复现场小试,考察了气相抽提真空度、气体抽排流量、空气渗透率及温度变化等的影响。试验结果表明,抽...为研究气相抽提技术(SVE)现场去污效果及影响因素,在北京市某化工厂搬迁遗留场地,以苯系物为目标污染物,应用气相抽提法进行场地污染修复现场小试,考察了气相抽提真空度、气体抽排流量、空气渗透率及温度变化等的影响。试验结果表明,抽提真空度存在最优值(试验场地在30 k Pa左右),在该值附近,抽取的气体流量最大(流量为13.5 m3/h);抽出气体的污染物浓度及去污速率随流量增大而提高,在不考虑污染物由土壤中迁移过程的限制时,去污速率基本正比于抽气流量;土壤的透气性越强,气相抽提的影响半径越大,抽气流量以及去除污染物的速率也越高;抽出气体的污染物浓度及去除速率总体随温度的升高而增大。展开更多
空分设备下塔、上塔、粗氩塔的不同精馏工况影响氩馏分流量的因素不同,使得氩馏分流量的调节方法也不同。以马钢20000 m 3/h液氧内压缩流程空分设备与35000 m 3/h氧气外压缩流程空分设备为例,详细分析空分设备下塔、上塔、粗氩塔不同精...空分设备下塔、上塔、粗氩塔的不同精馏工况影响氩馏分流量的因素不同,使得氩馏分流量的调节方法也不同。以马钢20000 m 3/h液氧内压缩流程空分设备与35000 m 3/h氧气外压缩流程空分设备为例,详细分析空分设备下塔、上塔、粗氩塔不同精馏工况对氩馏分流量的不同影响因素,介绍20000 m 3/h空分设备热开车粗氩塔投运阶段、35000 m 3/h空分设备正常运行变负荷状态的氩馏分流量调节方法运用实例。展开更多
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No 61334009the National High Technology Research and Development Program of China under Grant No 2014AA032604
文摘CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.
文摘A copper vapor laser with active medium length of 60 cm and bore of 16 mm has been operated and optimized using different buffer gases to investigate the effect of the gas flow rates on the output power. It is found that there is a special optimum gas flow rate associated with the type of buffer gas.
文摘Experimental results are presented for superfluid (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. The temperature was measured from 1.5K to 1.9K. Two flow regions were observed in small and large pressure and temperature differences regions respectively. The experimental data are compared with theoretical predictions.The performance and applicability of the basic theory are discussed. Hysteresis of the flow rate is also observed and discussed.
文摘为研究气相抽提技术(SVE)现场去污效果及影响因素,在北京市某化工厂搬迁遗留场地,以苯系物为目标污染物,应用气相抽提法进行场地污染修复现场小试,考察了气相抽提真空度、气体抽排流量、空气渗透率及温度变化等的影响。试验结果表明,抽提真空度存在最优值(试验场地在30 k Pa左右),在该值附近,抽取的气体流量最大(流量为13.5 m3/h);抽出气体的污染物浓度及去污速率随流量增大而提高,在不考虑污染物由土壤中迁移过程的限制时,去污速率基本正比于抽气流量;土壤的透气性越强,气相抽提的影响半径越大,抽气流量以及去除污染物的速率也越高;抽出气体的污染物浓度及去除速率总体随温度的升高而增大。
文摘空分设备下塔、上塔、粗氩塔的不同精馏工况影响氩馏分流量的因素不同,使得氩馏分流量的调节方法也不同。以马钢20000 m 3/h液氧内压缩流程空分设备与35000 m 3/h氧气外压缩流程空分设备为例,详细分析空分设备下塔、上塔、粗氩塔不同精馏工况对氩馏分流量的不同影响因素,介绍20000 m 3/h空分设备热开车粗氩塔投运阶段、35000 m 3/h空分设备正常运行变负荷状态的氩馏分流量调节方法运用实例。
