A long-lived, quasi-stationary mesoscale convective system （MCS） producing extreme ramtall （maximum of 542 mm） over the eastern coastal area of Guangdong Province on 20 May 2015 is analyzed by using high-resolutio...A long-lived, quasi-stationary mesoscale convective system （MCS） producing extreme ramtall （maximum of 542 mm） over the eastern coastal area of Guangdong Province on 20 May 2015 is analyzed by using high-resolution surface observations, sounding data, and radar measurements. New convective ceils are continuously initiated along a mesoscale boundary at the surface, leading to formation and maintenance of the quasi-linear-shaped MCS from about 2000 BT 19 to 1200 BT 20 May. The boundary is originally formed between a cold dome generated by previous convection and southwesterly flow from the ocean carrying higher equivalent potential temperature （θe） air. The boundary is subsequently maintained and reinforced by the contrast between the MCS-generated cold outflow and the oceanic higher-θe air. The cold outflow is weak （wind speed ≤ 5 m s-1）, which is attributable to the characteristic environmental conditions, i.e., high humidity in the lower troposphere and weak horizontal winds in the middle and lower troposphere. The low speed of the cold outflow is comparable to that of the near surface southerly flow from the ocean, resulting in very slow southward movement of the boundary. The boundary features temperature contrasts of 2-3℃ and is roughly 500-m deep. Despite its shallowness, the boundary appears to exert a profound influence on continuous convection initiation because of the very low level of free convection and small convection inhibition of the near surface oceanic air, building several parallel rainbands （of about 50-kin length） that move slowly eastward along the MCS and produce about 80% of the total rainfall. Another MCS moves into the area from the northwest and merges with the local MCS at about 1200 BT. The cold outflow subsequently strengthens and the boundary moves more rapidly toward the southeast, leading to end of the event in 3 h.展开更多
针对风光互补发电系统并网功率波动问题,在考虑平抑功率波动对储能性能需求的基础上,将蓄电池和超级电容器组成复合储能系统(hybrid energy storage system,HESS)应用到风光互补微电网中,并提出了复合储能的能量管理和控制策略。能量管...针对风光互补发电系统并网功率波动问题,在考虑平抑功率波动对储能性能需求的基础上,将蓄电池和超级电容器组成复合储能系统(hybrid energy storage system,HESS)应用到风光互补微电网中,并提出了复合储能的能量管理和控制策略。能量管理方面,遵循超级电容器优先工作原则,通过判断超级电容器端电压大小来决定复合储能的工作方式;超级电容器用来平抑风光发电并网波动功率的高频部分,蓄电池平抑低频部分,进而减少蓄电池的充放电次数,延长其使用寿命;控制策略方面,蓄电池的双向DC/DC变换器采用恒功率控制,超级电容器的双向DC/DC变换器采用恒母线电压控制,保证了直流母线电压的稳定,实现了复合储能的双向充放电控制。最后,利用PSCAD软件搭建了含复合储能的风光互补微电网仿真模型,仿真结果验证了所提控制策略的有效性和正确性。展开更多
This article reviews the advances in severe convection research and operation in China during the past several decades.The favorable synoptic situations for severe convective weather(SCW),the major organization modes ...This article reviews the advances in severe convection research and operation in China during the past several decades.The favorable synoptic situations for severe convective weather(SCW),the major organization modes of severe convective storms(SCSs),the favorable environmental conditions and characteristics of weather radar echoes and satellite images of SCW and SCSs,and the forecasting and nowcasting techniques of SCW,are emphasized.As a whole,Chinese scientists have achieved a profound understanding of the synoptic patterns,organization,and evolution characteristics of SCW from radar and satellite observations,and the mechanisms of different types of convective weather in China.Specifically,in-depth understanding of the multiple types of convection triggers,along with the environmental conditions,structures and organization modes,and maintenance mechanisms of supercell storms and squall lines,has been obtained.The organization modes and climatological distributions of mesoscale convective systems and different types of SCW,and the multiscale characteristics and formation mechanisms of large hail,tornadoes,downbursts,and damaging convective wind gusts based on radar,satellite,and lightning observations,as well as the related features from damage surveys,are elucidated.In terms of operational applications,different types of identification and mesoanalysis techniques,and various forecasting and nowcasting techniques using methods such as the"ingredients-based"and deep learning algorithms,have been developed.As a result,the performance of operational SCW forecasts in China has been significantly improved.展开更多
To inactivate the potentially pathogenic microorganisms and safely utilize vegetable waste compost, ultra-high temperatures(> 70°C) should be maintained during the composting without having an inhibitory effec...To inactivate the potentially pathogenic microorganisms and safely utilize vegetable waste compost, ultra-high temperatures(> 70°C) should be maintained during the composting without having an inhibitory effect on maturity. This study investigated the influence of bulk density(part 1) and easily-degraded organic matter content(EDOMC, part 2) on temperature evolution during vegetable waste composting: Part 1: corn straw with different particle sizes was used to achieve different bulk densities in the composting material(BD1–BD3); Part 2: partial or total substitution of the corn straw by corn starch was carried out to obtain different EDOMC(ED1–ED4). The composting experiments were conducted in a labscale reactor(1.75 kg material) and lasted for 30 d. Temperature and CO2 emission were recorded daily, and the organic matter, lignocellulose, microbial activity, germination index(GI) and C/N of the samples were measured at different stages. The highest temperature(65.7°C) in part 1 occurred in the treatment with the bulk density of 0.35 g/cm3, which also had the longest thermophilic phase. Bulk density was found to seriously influence the utilization efficiency of O2 and heat transfer through materials, rather than heat production from organic matter degradation. In experiment part 2, the highest temperature was obtained with EDOMC of 45%(71.4°C). Therefore, adjusting the bulk density to 0.35 g/cm3 and the easily-degraded organic matter content of the initial material to 45% was the best combination for reaching temperatures above 70°C during composting, with no inhibitory effect on the maturity of the compost product.展开更多
目的本文通过分析医科达Synergy医用电子直线加速器主接触器CON A的联锁电路,说明主接触器CON A的吸合条件,介绍导致MAIN CON A联锁故障的可能原因及诊断方法,为维修工程师提供借鉴经验。方法当控制软件报MAIN CONA联锁故障时,先在维修...目的本文通过分析医科达Synergy医用电子直线加速器主接触器CON A的联锁电路,说明主接触器CON A的吸合条件,介绍导致MAIN CON A联锁故障的可能原因及诊断方法,为维修工程师提供借鉴经验。方法当控制软件报MAIN CONA联锁故障时,先在维修模式检查主接触器CON A的状态,再通过分析主接触器CON A的联锁电路图,并利用电压表测量相应的测量点,找出故障位置,分析故障原因。结果如果两个测量点之间是断开状态,故障位置即在断开的两个测量点之间。结论根据故障现象,可通过理论分析和实际测量快速查找出MAIN CON A联锁故障的位置及原因,解决问题。展开更多
目的:观察苦参碱对刀豆蛋白A(Con A)性肝损伤小鼠IFN-γ和TNF-α释放及肝组织病理改变的影响. 方法:NIH小鼠48只随机分为5组,分别为正常对照组,模型组,苦参碱大剂量组(25 mg/kg),苦参碱小剂量组(12.5 mg/kg)和联苯双酯治疗组.除正常对...目的:观察苦参碱对刀豆蛋白A(Con A)性肝损伤小鼠IFN-γ和TNF-α释放及肝组织病理改变的影响. 方法:NIH小鼠48只随机分为5组,分别为正常对照组,模型组,苦参碱大剂量组(25 mg/kg),苦参碱小剂量组(12.5 mg/kg)和联苯双酯治疗组.除正常对照组外,其他组于实验首日iv Con A 20 mg/kg,苦参碱大剂量组和小剂量组均采用尾iv给药,联苯双酯组按150 mg/kg 灌胃,每天1次,连续3 d,末次给药后4 h,再次iv Con A 20 mg/kg,8 h采血检测血浆IFN-γ和TNF-α含量、ALT活性,观察肝组织病理学变化. 结果:苦参碱大剂量组、小剂量纽小鼠IFN-γ和TNF-α含量均明显低于模型组(IFN-γ:25.5±6.1 vs 69.3±33.6 ng/L,26.5±2.5 vs 69.3±33.6 ng/L,t=4.0,4.0, P<0.01;TNF-α:49.1±11.9 vs 106.7±64.4 ng/L,52.9±5.2 vs 106.7±64.4 ng/L,t=2.9,2.9,P<0.01),但与联苯双酯组比较,差异无显著性意义(P>0.05);苦参碱大、小剂量组血浆ALT活性明显低于模型组(1 086.9 ±675.8 vs 2 477.2±529.9 nkat/L、1 121.9±957.4 vs 2 477.2±529.9 nkat/L,t=5.1,3.9,P<0.01),且可明显减轻肝细胞坏死及炎性细胞浸润的肝组织病理学改变,与模型组比较差异有显著性意义(P<0.05). 结论:苦参碱对刀豆蛋白A性肝损伤小鼠释放IFN-γ和TNF-α有明显的抑制作用.并可显著减轻肝组织病理改变.展开更多
The electrical conductivities of the dunite from the Qinghai-Xizang (Tibetan) Plateau were measured with the impedance spectra method at 1.0-4.0 GPa and 643-1093 K. The experimental results indicated that activation e...The electrical conductivities of the dunite from the Qinghai-Xizang (Tibetan) Plateau were measured with the impedance spectra method at 1.0-4.0 GPa and 643-1093 K. The experimental results indicated that activation enthalpies of the dunite are smaller than 0.9 eV, the conduction mechanism in dunite may be attributed to the mixed electrical conduction involving grain interiors and boundaries. On the basis of the results of this experiment, we can deduce that there exists cold mantle in the area of Gaize-Lugu in the Qinghai-Xizang (Tibetan) Plateau by reverse methods from the magnetotelluric sounding data (conductivity-depths profile) available for western Tibet. The result provides the present cold mantle viewpoint with strong proof on the basis of high temperature and pressure experiments.展开更多
基金Supported by the China Meteorological Administration Special Public Welfare Research Fund(GYHY201406013 and GYHY201406003)National Natural Science Foundation of China(91437104)National(Key)Basic Research and Development(973)Program of China(2012CB417202)
文摘A long-lived, quasi-stationary mesoscale convective system （MCS） producing extreme ramtall （maximum of 542 mm） over the eastern coastal area of Guangdong Province on 20 May 2015 is analyzed by using high-resolution surface observations, sounding data, and radar measurements. New convective ceils are continuously initiated along a mesoscale boundary at the surface, leading to formation and maintenance of the quasi-linear-shaped MCS from about 2000 BT 19 to 1200 BT 20 May. The boundary is originally formed between a cold dome generated by previous convection and southwesterly flow from the ocean carrying higher equivalent potential temperature （θe） air. The boundary is subsequently maintained and reinforced by the contrast between the MCS-generated cold outflow and the oceanic higher-θe air. The cold outflow is weak （wind speed ≤ 5 m s-1）, which is attributable to the characteristic environmental conditions, i.e., high humidity in the lower troposphere and weak horizontal winds in the middle and lower troposphere. The low speed of the cold outflow is comparable to that of the near surface southerly flow from the ocean, resulting in very slow southward movement of the boundary. The boundary features temperature contrasts of 2-3℃ and is roughly 500-m deep. Despite its shallowness, the boundary appears to exert a profound influence on continuous convection initiation because of the very low level of free convection and small convection inhibition of the near surface oceanic air, building several parallel rainbands （of about 50-kin length） that move slowly eastward along the MCS and produce about 80% of the total rainfall. Another MCS moves into the area from the northwest and merges with the local MCS at about 1200 BT. The cold outflow subsequently strengthens and the boundary moves more rapidly toward the southeast, leading to end of the event in 3 h.
文摘针对风光互补发电系统并网功率波动问题,在考虑平抑功率波动对储能性能需求的基础上,将蓄电池和超级电容器组成复合储能系统(hybrid energy storage system,HESS)应用到风光互补微电网中,并提出了复合储能的能量管理和控制策略。能量管理方面,遵循超级电容器优先工作原则,通过判断超级电容器端电压大小来决定复合储能的工作方式;超级电容器用来平抑风光发电并网波动功率的高频部分,蓄电池平抑低频部分,进而减少蓄电池的充放电次数,延长其使用寿命;控制策略方面,蓄电池的双向DC/DC变换器采用恒功率控制,超级电容器的双向DC/DC变换器采用恒母线电压控制,保证了直流母线电压的稳定,实现了复合储能的双向充放电控制。最后,利用PSCAD软件搭建了含复合储能的风光互补微电网仿真模型,仿真结果验证了所提控制策略的有效性和正确性。
基金Supported by the National Key Research and Development Program of China(2018YFC1507504 and 2017YFC1502000)National Natural Science Foundation of China(41775044 and 41375051)Strategic Research Projects on Medium-and Long-term Development of Chinese Engineering Science and Technology(2019-ZCQ-06)。
文摘This article reviews the advances in severe convection research and operation in China during the past several decades.The favorable synoptic situations for severe convective weather(SCW),the major organization modes of severe convective storms(SCSs),the favorable environmental conditions and characteristics of weather radar echoes and satellite images of SCW and SCSs,and the forecasting and nowcasting techniques of SCW,are emphasized.As a whole,Chinese scientists have achieved a profound understanding of the synoptic patterns,organization,and evolution characteristics of SCW from radar and satellite observations,and the mechanisms of different types of convective weather in China.Specifically,in-depth understanding of the multiple types of convection triggers,along with the environmental conditions,structures and organization modes,and maintenance mechanisms of supercell storms and squall lines,has been obtained.The organization modes and climatological distributions of mesoscale convective systems and different types of SCW,and the multiscale characteristics and formation mechanisms of large hail,tornadoes,downbursts,and damaging convective wind gusts based on radar,satellite,and lightning observations,as well as the related features from damage surveys,are elucidated.In terms of operational applications,different types of identification and mesoanalysis techniques,and various forecasting and nowcasting techniques using methods such as the"ingredients-based"and deep learning algorithms,have been developed.As a result,the performance of operational SCW forecasts in China has been significantly improved.
基金supported by the National Science and Technology Pillar Program in Rural Areas (No. 2013BAD20B01)China Special Fund for Agricultural Research in the Public Interest (No. 201303079)
文摘To inactivate the potentially pathogenic microorganisms and safely utilize vegetable waste compost, ultra-high temperatures(> 70°C) should be maintained during the composting without having an inhibitory effect on maturity. This study investigated the influence of bulk density(part 1) and easily-degraded organic matter content(EDOMC, part 2) on temperature evolution during vegetable waste composting: Part 1: corn straw with different particle sizes was used to achieve different bulk densities in the composting material(BD1–BD3); Part 2: partial or total substitution of the corn straw by corn starch was carried out to obtain different EDOMC(ED1–ED4). The composting experiments were conducted in a labscale reactor(1.75 kg material) and lasted for 30 d. Temperature and CO2 emission were recorded daily, and the organic matter, lignocellulose, microbial activity, germination index(GI) and C/N of the samples were measured at different stages. The highest temperature(65.7°C) in part 1 occurred in the treatment with the bulk density of 0.35 g/cm3, which also had the longest thermophilic phase. Bulk density was found to seriously influence the utilization efficiency of O2 and heat transfer through materials, rather than heat production from organic matter degradation. In experiment part 2, the highest temperature was obtained with EDOMC of 45%(71.4°C). Therefore, adjusting the bulk density to 0.35 g/cm3 and the easily-degraded organic matter content of the initial material to 45% was the best combination for reaching temperatures above 70°C during composting, with no inhibitory effect on the maturity of the compost product.
文摘目的本文通过分析医科达Synergy医用电子直线加速器主接触器CON A的联锁电路,说明主接触器CON A的吸合条件,介绍导致MAIN CON A联锁故障的可能原因及诊断方法,为维修工程师提供借鉴经验。方法当控制软件报MAIN CONA联锁故障时,先在维修模式检查主接触器CON A的状态,再通过分析主接触器CON A的联锁电路图,并利用电压表测量相应的测量点,找出故障位置,分析故障原因。结果如果两个测量点之间是断开状态,故障位置即在断开的两个测量点之间。结论根据故障现象,可通过理论分析和实际测量快速查找出MAIN CON A联锁故障的位置及原因,解决问题。
文摘目的:观察苦参碱对刀豆蛋白A(Con A)性肝损伤小鼠IFN-γ和TNF-α释放及肝组织病理改变的影响. 方法:NIH小鼠48只随机分为5组,分别为正常对照组,模型组,苦参碱大剂量组(25 mg/kg),苦参碱小剂量组(12.5 mg/kg)和联苯双酯治疗组.除正常对照组外,其他组于实验首日iv Con A 20 mg/kg,苦参碱大剂量组和小剂量组均采用尾iv给药,联苯双酯组按150 mg/kg 灌胃,每天1次,连续3 d,末次给药后4 h,再次iv Con A 20 mg/kg,8 h采血检测血浆IFN-γ和TNF-α含量、ALT活性,观察肝组织病理学变化. 结果:苦参碱大剂量组、小剂量纽小鼠IFN-γ和TNF-α含量均明显低于模型组(IFN-γ:25.5±6.1 vs 69.3±33.6 ng/L,26.5±2.5 vs 69.3±33.6 ng/L,t=4.0,4.0, P<0.01;TNF-α:49.1±11.9 vs 106.7±64.4 ng/L,52.9±5.2 vs 106.7±64.4 ng/L,t=2.9,2.9,P<0.01),但与联苯双酯组比较,差异无显著性意义(P>0.05);苦参碱大、小剂量组血浆ALT活性明显低于模型组(1 086.9 ±675.8 vs 2 477.2±529.9 nkat/L、1 121.9±957.4 vs 2 477.2±529.9 nkat/L,t=5.1,3.9,P<0.01),且可明显减轻肝细胞坏死及炎性细胞浸润的肝组织病理学改变,与模型组比较差异有显著性意义(P<0.05). 结论:苦参碱对刀豆蛋白A性肝损伤小鼠释放IFN-γ和TNF-α有明显的抑制作用.并可显著减轻肝组织病理改变.
基金This work was supported by the National Climbing Program (Grant No. 95-P-39) under the auspices of the National Key Project on the Tibetan Plateau (Grant No. G1998040800) the National Natu- ral Science Foundation of China (Grant No. 49674221).
文摘The electrical conductivities of the dunite from the Qinghai-Xizang (Tibetan) Plateau were measured with the impedance spectra method at 1.0-4.0 GPa and 643-1093 K. The experimental results indicated that activation enthalpies of the dunite are smaller than 0.9 eV, the conduction mechanism in dunite may be attributed to the mixed electrical conduction involving grain interiors and boundaries. On the basis of the results of this experiment, we can deduce that there exists cold mantle in the area of Gaize-Lugu in the Qinghai-Xizang (Tibetan) Plateau by reverse methods from the magnetotelluric sounding data (conductivity-depths profile) available for western Tibet. The result provides the present cold mantle viewpoint with strong proof on the basis of high temperature and pressure experiments.
