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Na^(+)/K^(+)-ATPase:ion pump,signal transducer,or cytoprotective protein,and novel biological functions 被引量:2
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作者 Songqiang Huang Wanting Dong +1 位作者 Xiaoqian Lin Jinsong Bian 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第12期2684-2697,共14页
Na^(+)/K^(+)-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na^(+)out of and two K^(+)into cells.Additionally,Na^... Na^(+)/K^(+)-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na^(+)out of and two K^(+)into cells.Additionally,Na^(+)/K^(+)-ATPase participates in Ca^(2+)-signaling transduction and neurotransmitter release by coordinating the ion concentration gradient across the cell membrane.Na^(+)/K^(+)-ATPase works synergistically with multiple ion channels in the cell membrane to form a dynamic network of ion homeostatic regulation and affects cellular communication by regulating chemical signals and the ion balance among different types of cells.Therefo re,it is not surprising that Na^(+)/K^(+)-ATPase dysfunction has emerged as a risk factor for a variety of neurological diseases.However,published studies have so far only elucidated the important roles of Na^(+)/K^(+)-ATPase dysfunction in disease development,and we are lacking detailed mechanisms to clarify how Na^(+)/K^(+)-ATPase affects cell function.Our recent studies revealed that membrane loss of Na^(+)/K^(+)-ATPase is a key mechanism in many neurological disorders,particularly stroke and Parkinson's disease.Stabilization of plasma membrane Na^(+)/K^(+)-ATPase with an antibody is a novel strategy to treat these diseases.For this reason,Na^(+)/K^(+)-ATPase acts not only as a simple ion pump but also as a sensor/regulator or cytoprotective protein,participating in signal transduction such as neuronal autophagy and apoptosis,and glial cell migration.Thus,the present review attempts to summarize the novel biological functions of Na^(+)/K^(+)-ATPase and Na^(+)/K^(+)-ATPase-related pathogenesis.The potential for novel strategies to treat Na^(+)/K^(+)-ATPase-related brain diseases will also be discussed. 展开更多
关键词 ANTIBODY biological functions cellular communication electrochemical gradient ion balance ion channels Na^(+)/K^(+)-ATPase neurological diseases neurotransmitter release signal transduction
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Expression levels of K_(ATP)channel subunits and morphological changes in the mouse liver after exposure to radiation
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作者 Ming Zhou Tao-Sheng Li +3 位作者 Hiroshi Abe Hideo Akashi Ryoji Suzuki Yoshio Bando 《World Journal of Experimental Medicine》 2024年第2期103-113,共11页
BACKGROUND ATP sensitive K+(K_(ATP))channels are ubiquitously distributed in various of cells and tissues,including the liver.They play a role in the pathogenesis of myocardial and liver ischemia.AIM To evaluate the r... BACKGROUND ATP sensitive K+(K_(ATP))channels are ubiquitously distributed in various of cells and tissues,including the liver.They play a role in the pathogenesis of myocardial and liver ischemia.AIM To evaluate the radiation-induced changes in the expression of K_(ATP)channel subunits in the mouse liver to understand the potential role of K_(ATP)channels in radiation injury.METHODS Adult C57BL/6 mice were randomly exposed toγ-rays at 0 Gy(control,n=2),0.2 Gy(n=6),1 Gy(n=6),or 5 Gy(n=6).The livers were removed 3 and 24 h after radiation exposure.Hematoxylin and eosin staining was used for morphological observation;immunohistochemical staining was applied to determine the expression of K_(ATP)channel subunits in the liver tissue.RESULTS Compared with the control group,the livers exposed to 0.2 Gyγ-ray showed an initial increase in the expression of Kir6.1 at 3 h,followed by recovery at 24 h after exposure.Exposure to a high dose of 5.0 Gy resulted in decreased expression of Kir6.1 and increased expression of SUR2B at 24 h.However,the expression of Kir6.2,SUR1,or SUR2A had no remarkable changes at 3 and 24 h after exposure to any of these doses.CONCLUSION The expression levels of Kir6.1 and SUR2B in mouse liver changed differently in response to different radiation doses,suggesting a potential role for them in radiation-induced liver injury. 展开更多
关键词 Radiation exposure ATP-sensitive K^(+)channel MOUSE LIVER
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Flake channels construction of hydroxyapatite/gelatin cryogel with excellent flame retardant properties for enhancing the capturing of iodine
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作者 Yanxia Wei Bo Wang +7 位作者 Liyan Cao Xin Cheng Yuhan Qiao Tao Duan Guiqiang He Pingping Ding Yan Zhou Jian Zhou 《Collagen and Leather》 EI CAS 2024年第1期101-112,共12页
Safe and efficient capturing of volatile radioiodine is of extremely important significance in the treatment of spent fuel.Herein,the flake channels in gelatin-hydroxyapatite(HAP@Ge)cryogel with excellent flame retard... Safe and efficient capturing of volatile radioiodine is of extremely important significance in the treatment of spent fuel.Herein,the flake channels in gelatin-hydroxyapatite(HAP@Ge)cryogel with excellent flame retardant properties were constructed by immobilizing hydroxyapatite nanorods(HAP)on Gelatin(Ge)cryogel for enhancing the capturing of iodine.The immobilization of HAP nanorods enhanced thermal stability,provided low rates of dynamic heat transfer and dissipation,and remarkably improved the flame retardant and smoke suppression properties of the Ge cryogel,which can effectively prevent the occurrence of safety incidents caused by further thermal degradation or combustion of this cryogel.More importantly,it was effective in improving the rapid enrichment of iodine,resulting in a high adsorption capacity.The maximum adsorption capacity of HAP@Ge cryogel for iodine vapor reached 2693 mg/g at equilibrium.The high adsorption capacity for iodine was attributed to the multi-scale porous structure in HAP@Ge cryogel,which offered effective channels for iodine diffusion,whereas the numerous complex and irregular flakes provided sufficient number of active sites for iodine capture.The adsorption process was chemical in nature and involved the-PO_(4)^(3-),-OH,-C=O,and-NHR groups on HAP@Ge cryogel.Moreover,the complex porous structure of HAP@Ge cryogel enhanced the physical capturing of iodine.These advantages,such as low-cost raw material,simple preparation method,good flame retardancy,and excellent capturing performance for iodine indicated that HAP@Ge cryogel is a potential candidate for the removal of radioactive iodine in the exhaust gas stream of post-treatment plants. 展开更多
关键词 GELATIN Hydroxyapatite nanorod Flake channel Flame retardancy Iodine capture
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Involvement of leak K^+ channels in neurological disorders 被引量:3
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作者 Hiroki Toyoda 《World Journal of Neurology》 2015年第1期52-56,共5页
TWIK-related acid-sensitive K+(TASK) channels give rise to leak K+ currents which influence the resting membrane potential and input resistance. The wide expression of TASK1 and TASK3 channels in the central nervous s... TWIK-related acid-sensitive K+(TASK) channels give rise to leak K+ currents which influence the resting membrane potential and input resistance. The wide expression of TASK1 and TASK3 channels in the central nervous system suggests that these channels are critically involved in neurological disorders. It has become apparent in the past decade that TASK channels play critical roles for the development of various neurological disorders. In this review, I describe evidence for their roles in ischemia, epilepsy, learning/memory/cognition and apoptosis. 展开更多
关键词 LEAK K^+channel TWIK-related acidsensitive K^+channel NEUROLOGICAL disorder
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Voltage-dependent K^+-channel Responses during Activation and Damage in Alveolar Macrophages Induced by Quartz Particles 被引量:1
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作者 孙敬智 梅勇 +4 位作者 郭翔 殷霄 赵学彬 王正伦 杨磊 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2009年第4期404-408,共5页
The roles of voltage-dependent K^+ channels during activation and damage in alveolar macrophages (AMs) exposed to different silica particles were examined. Rat AMs were collected by means of bronchoalveolar lavage,... The roles of voltage-dependent K^+ channels during activation and damage in alveolar macrophages (AMs) exposed to different silica particles were examined. Rat AMs were collected by means of bronchoalveolar lavage, and were adjusted to 5× 10^5/mL. After AMs were exposed to different concentrations (0, 25, 50, 100, 200 μg/mL) of quartz particles and 100 μg/mL amorphous silica particles for 24 h, the voltage-depended K^+ current in AMs was measured by using patch clamp technique. Meanwhile the leakage of lactate dehydrogenase (LDH) and the viability of AMs were detected respectively. Patch clamp studies demonstrated that AMs possessed outward delayed and inward rectifying K^+ current. Exposure to quartz particles increased the outward delayed K^+ current but it had no effect on inward rectifier K^+ current in AMs. Neither of the two K^+ channels in AMs was affected by amorphous silica particles. Cytotoxicity test showed that both silica particles could damage AM membrane and result in significant leakage of LDH (P〈0.05). MTT studies, however, showed that only quartz particles reduced viability of AMs (P〈0.05). It is concluded that quartz parti- cles can activate the outward delayed K^+ channel in AMs, which may act as an activating signal in AMs to initiate an inflammatory response during damage and necrosis in AMs induced by exposure to quartz particle. K^+ channels do not contribute to the membrane damage of AMs. 展开更多
关键词 QUARTZ alveolar macrophages patch clamp voltage-dependent K^+ channels
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Localization of ATP-sensitive K^+ channel subunits in rat liver 被引量:1
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作者 Ming Zhou Kiwamu Yoshikawa +5 位作者 Hideo Akashi Mitsutaka Miura Ryoji Suzuki Tao-Sheng Li Hiroshi Abe Yoshio Bando 《World Journal of Experimental Medicine》 2019年第2期14-31,共18页
BACKGROUND ATP-sensitive K^+(KATP)channels were originally found in cardiac myocytes by Noma in 1983.KATP channels were formed by potassium ion-passing poreforming subunits(Kir6.1,Kir6.2)and regulatory subunits SUR1,S... BACKGROUND ATP-sensitive K^+(KATP)channels were originally found in cardiac myocytes by Noma in 1983.KATP channels were formed by potassium ion-passing poreforming subunits(Kir6.1,Kir6.2)and regulatory subunits SUR1,SU2A and SUR2B.A number of cells and tissues have been revealed to contain these channels including hepatocytes,but detailed localization of these subunits in different types of liver cells was still uncertain.AIM To investigate the expression of KATP channel subunits in rat liver and their localization in different cells of the liver.METHODS Rabbit anti-rat SUR1 peptide antibody was raised and purified by antigen immunoaffinity column chromatography.Four of Sprague-Dawley rats were used for liver protein extraction for immunoblot analysis,seven of them were used for immunohistochemistry both for the ABC method and immunofluorescence staining.Four of Wistar rats were used for the isolation of hepatic stellate cells(HSCs)and Kupffer cells for both primary culture and immunocytochemistry.RESULTS Immunoblot analysis showed that the five kinds of KATP channel subunits,i.e.Kir6.1,Kir6.2,SUR1,SUR2A,and SUR2B,were detected in liver.Immunohistochemical staining showed that Kir6.1 and Kir6.2 were weakly to moderately expressed in parenchymal cells and sinusoidal lining cells,while SUR1,SUR2A,and SUR2B were mainly localized to sinusoidal lining cells,such as HSCs,Kupffer cells,and sinusoidal endothelial cells.Immunoreactivity for SUR2A and SUR2B was expressed in the hepatocyte membrane.Double immunofluorescence staining further showed that the pore-forming subunits Kir6.1 and/or Kir6.2 colocalized with GFAP in rat liver sections and primary cultured HSCs.These KATP channel subunits also colocalized with CD68 in liver sections and primary cultured Kupffer cells.The SUR subunits colocalized with GFAP in liver sections and colocalized with CD68 both in liver sections and primary cultured Kupffer cells.In addition,five KATP channel subunits colocalized with SE-1 in sinusoidal endothelial cells.CONCLUSION Observations from the present study indicated that KATP channel subunits expressed in rat liver and the diversity of KATP channel subunit composition might form different types of KATP channels.This is applicable to hepatocytes,HSCs,various types of Kupffer cells and sinusoidal endothelial cells. 展开更多
关键词 ATP-sensitive K^+channel LIVER Hepatic stellate cells Kupffer cells Sinusoidal endothelial cells Rat
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Arsenic exposure decreases rhythmic contractions of vascular tone through sodium transporters and K^+ channels
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作者 Javier Palacios Chukwuemeka R Nwokocha Fredi Cifuentes 《World Journal of Pharmacology》 2014年第2期18-23,共6页
Arsenic-contaminated drinking water is a public health problem in countries such as Taiwan, Bangladesh, United States, Mexico, Argentina, and Chile. The chronic ingestion of arsenic-contaminated drinking water increas... Arsenic-contaminated drinking water is a public health problem in countries such as Taiwan, Bangladesh, United States, Mexico, Argentina, and Chile. The chronic ingestion of arsenic-contaminated drinking water increases the risk for ischemic heart disease, cerebrovascular disease, and prevalence of hypertension. Although toxic arsenic effects are controversial, there is evidence that a high concentration of arsenic may induce hypertension through increase in vascular tone and resistance. Vascular tone is regulated by the rhythmic contractions of the blood vessels, generated by calcium oscillations in the cytosol of vascular smooth muscle cells. To regulate the cytosolic calcium oscillations, the membrane oscillator model involves the participation of Ca2+ channels, calcium-activated K+ channels, Na+/Ca2+exchange, plasma membrane Ca2+-ATPase, and the Na+/K+-ATPase. However, little is known about the role of K+ uptake by sodium transporters [Na+/K+-ATPase or Na+-K+-2Cl-(NKCC1)] on the rhythmic contractions.Vascular rhythmic contractions, or vasomotion are a local mechanism to regulate vascular resistance andblood flow. Since vascular rhythmic contractions of blood vessels are involved in modulating the vascular resistance, the blood flow, and the systemic pressure,we suggest a model explaining the participation of the sodium pump and NKCC1 co-transporter in low dose arsenic exposure effects on vasomotion and vascular dysfunction. 展开更多
关键词 Arsenic VASOMOTION Na^+/K^+-ATPase Na^+-K^+-2Cl^- K^+ channels Nitric oxide PROSTAGLANDIN Vascular
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Multi-channel retarding field analyzer for EAST
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作者 M HENKEL D HOSCHEN +8 位作者 Y LIANG Y LI S C LIU D NICOLAI N SANDRI G SATHEESWARAN N YAN H X ZHANG the EAST team 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第5期1-5,共5页
A multi-channel retarding field analyzer(MC-RFA) including two RFA modules and two Langmuir probes to measure the ion and electron temperature profiles within the scrape-off layer was developed for investigations of... A multi-channel retarding field analyzer(MC-RFA) including two RFA modules and two Langmuir probes to measure the ion and electron temperature profiles within the scrape-off layer was developed for investigations of the interplay between magnetic topology and plasma transport at the plasma boundary.The MC-RFA probe for the stellarator W7-X and first measurements at the tokamak EAST was designed.The probe head allows simultaneous multichannel ion temperature as well as for electron temperature measurements.The usability for radial correlation measurements of the measured ion currents is also given. 展开更多
关键词 retarding field analyzer MULTI-channel EAST ion temperature DIAGNOSTIC
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Roles of TRESK,a novel two-pore domain K+channel,in pain pathway and general anesthesia 被引量:1
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作者 黄东越 于布为 范秋维 《Neuroscience Bulletin》 SCIE CAS CSCD 2008年第3期166-172,共7页
TRESK is the most recently reported two-pore domain K^+ channel, and different from other two-pore domain channels in gene, molecular structure, electrophysiological and pharmacological properties. Although the curre... TRESK is the most recently reported two-pore domain K^+ channel, and different from other two-pore domain channels in gene, molecular structure, electrophysiological and pharmacological properties. Although the current knowledge of this potassium channel is inadequate, researches have demonstrated that TRESK is remarkablely linked to acute and chronic pain by activation of calcineurin. The fact that TRESK is sensitive to volatile anesthetics and localization in central nerve system implies that TRESK may play a very important role in the mechanism mediating general anesthesia. The further research of TRESK may contribute to explore the underlying mechanism of some pathological conditions and yield novel treatments for some diseases. 展开更多
关键词 TRESK two-pore domain K^+ channels CALCINEURIN dorsal root ganglion
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缓粘结预应力技术在杭州西站项目中的应用分析
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作者 张树生 胡海芳 樊高冲 《四川建材》 2024年第4期154-155,172,共3页
以浙江省杭州市西站工程项目为例,分析了大型公共建筑工程中,缓粘结预应力筋遇到长期预留施工通道的处理方案,并从缓粘结预应力深化图纸设计和工程实施的角度出发,重点介绍了梁中预应力筋遇型钢骨后钢绞线穿设问题、预应力筋张拉端排布... 以浙江省杭州市西站工程项目为例,分析了大型公共建筑工程中,缓粘结预应力筋遇到长期预留施工通道的处理方案,并从缓粘结预应力深化图纸设计和工程实施的角度出发,重点介绍了梁中预应力筋遇型钢骨后钢绞线穿设问题、预应力筋张拉端排布问题等深化过程中关键问题的处理原则和解决方案,为大型公共建筑工程中缓粘结预应力的深化设计和工程施工提供参考。 展开更多
关键词 缓粘结预应力 深化图纸设计 长期预留施工通道 穿型钢骨 张拉端排布
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Domesticated HERV-W env contributes to the activation of the small conductance Ca^(2+)-activated K^(+)type 2 channels via decreased 5-HT4 receptor in recent-onset schizophrenia 被引量:1
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作者 Xiulin Wua Qiujin Yan +8 位作者 Lianzhong Liu Xing Xue Wei Yao Xuhang Li Wenshi Li Shuang Ding Yaru Xia Dongyan Zhang Fan Zhu 《Virologica Sinica》 SCIE CAS CSCD 2023年第1期9-22,共14页
The human endogenous retroviruses type W family envelope(HERV-W env)gene is located on chromosome 7q21-22.Our previous studies show that HERV-W env is elevated in schizophrenia and HERV-W env can increase cal-cium inf... The human endogenous retroviruses type W family envelope(HERV-W env)gene is located on chromosome 7q21-22.Our previous studies show that HERV-W env is elevated in schizophrenia and HERV-W env can increase cal-cium influx.Additionally,the 5-HTergie system and particularly 5-hydroxytryptamine(5-HT)receptors play a prominent role in the pathogenesis and treatment of schizophrenia.5-hydroxytryptamine receptor 4(5-HT4R)agonist can block calcium channels.However,the underlying relationship between HERV-W env and 5-HT4R in the etiology of schizophrenia has not been revealed.Here,we used enzyme-linked immunosorbent assay to detect the concentration of HERV-W env and 5-HT4R in the plasma of patients with schizophrenia and we found that there were decreased levels of 5-HT4R and a negative correlation between 5-HT4R and HERV-W env in schizophrenia.Overexpression of HERV-W env decreased the transcription and protein levels of 5-HT4R but increased small conductance Ca^(2+)-activated K^(+)type 2 channels(SK2)expression levels.Further studies revealed that HERV-w env could interact with 5-HT4R.Additionally,luciferase assay showed that an essential region(-364 to-176 from the transcription start site)in the SK2 promoter was required for HERV-W env-induced SK2 expression.Importantly,5-HT4R participated in the regulation of SK2 expression and promoter activity.Electrophysiological recordings suggested that HERV-Wenv could increase SK2 channel currents and the increase of SK2 currents was inhibited by 5-HT4R.In condusion,HERV-W env could activate SK2 channels via decreased 5-HT4R,which might exhibit a novel mechanism for HERV-Wenv to influence neuronal activity in schizophrenia. 展开更多
关键词 Human endogenous retroviruses type W(HERV-W) ENV Small conductance Ca^(2+)-activated K^(+)type 2 channels(SK2) 5-Hydroxytryptamine receptor 4(5-HT4R) SCHIZOPHRENIA
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Militarine对离体大鼠胸主动脉环的舒张作用及机制研究 被引量:11
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作者 徐晓雪 徐广涛 +3 位作者 李小鹏 钟旭 韩伟健 许枬 《中华中医药学刊》 CAS 北大核心 2015年第3期617-620,共4页
目的:研究从手掌参中分离的Militarine对离体大鼠胸主动脉环的舒张作用并探讨其可能的机制。方法:记录去甲肾上腺素(NE)和KCl预收缩的离体大鼠主动脉环张力变化,观察Militarine的舒血管作用及不同工具药对其作用的影响。结果:Militarin... 目的:研究从手掌参中分离的Militarine对离体大鼠胸主动脉环的舒张作用并探讨其可能的机制。方法:记录去甲肾上腺素(NE)和KCl预收缩的离体大鼠主动脉环张力变化,观察Militarine的舒血管作用及不同工具药对其作用的影响。结果:Militarine可以抑制去甲肾上腺素(NE,1×10-4mol·L-1)和KCl(1.8 mol·L-1)引起去内皮和内皮完整的离体大鼠胸主动脉环的收缩作用,但二者有明显差别;L-硝基精氨酸甲酯(LNAME,1×10-4mol·L-1)、亚甲蓝(MB,1×10-5mol·L-1)、吲哚美辛(INDO,1×10-5mol·L-1)均能一定程度抑制Militarine对胸主动脉环的舒张作用;钾离子通道阻断剂四乙基胺(TEA,1×10-3mol·L-1)、格列苯脲(glibenclamide,1×10-5mol·L-1)、Ba Cl2(1×10-4mol·L-1)可明显减弱Militarine对血管环的舒张作用;在无钙环境下,预孵育Militarine对去甲肾上腺素引起的血管环收缩有明显抑制作用。结论:Militarine有内皮依赖性和非内皮依赖性的血管舒张作用,其作用机制可能涉及激活内皮细胞中NO/c GMP通路,开放钾离子通道和抑制钙离子内流。 展开更多
关键词 Militarine 手掌参 胸主动脉环 血管舒张 钾通道阻滞剂 钙通道
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液力缓速器瞬态两相流动大涡模拟及性能预测 被引量:9
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作者 李雪松 于秀敏 +1 位作者 程秀生 苗丽颖 《江苏大学学报(自然科学版)》 EI CAS 北大核心 2012年第4期385-389,419,共6页
为了全面掌握液力缓速器各个流动单元内速度场和压力场的分布特性,提取了全流道几何模型作为计算区域,利用CFD平台的大涡模拟法和多流动区域耦合计算的滑动网格法对液力缓速器内部气液两相流动进行了三维瞬态数值模拟,将混合模型与欧拉... 为了全面掌握液力缓速器各个流动单元内速度场和压力场的分布特性,提取了全流道几何模型作为计算区域,利用CFD平台的大涡模拟法和多流动区域耦合计算的滑动网格法对液力缓速器内部气液两相流动进行了三维瞬态数值模拟,将混合模型与欧拉模型交替运用在其多相流模型中,获得了不同充液率下液力缓速器内流场结构的变化及两相体积分数分布情况,分析了流场内二次流、脱流及涡旋的产生机理,并计算了缓速器的外特性.结果表明:数值计算结果与试验结果吻合很好,误差在8%以内;流场计算十分准确,运用的大涡模拟方法可以有效地模拟液力缓速器流场内的真实液流结构,其结果可以用来指导液力缓速器的设计及其结构优化. 展开更多
关键词 液力缓速器 全流道 大涡模拟 瞬态流场 两相流动 性能预测
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液力减速器模型空化特性数值模拟及试验研究 被引量:5
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作者 董亮 肖佳伟 +1 位作者 明加意 刘厚林 《排灌机械工程学报》 EI CSCD 北大核心 2017年第1期1-5,共5页
为了研究液力减速器内部流场空化特性,基于ANSYS CFX软件,采用RNG k-ε湍流模型和Zwart-Gerber-Belamri空化模型,选取液力减速器模型单个流道作为研究对象,对其在泵轮外环壁不同压力时进行数值模拟,并搭建减速器试验台,进行降压性能试验... 为了研究液力减速器内部流场空化特性,基于ANSYS CFX软件,采用RNG k-ε湍流模型和Zwart-Gerber-Belamri空化模型,选取液力减速器模型单个流道作为研究对象,对其在泵轮外环壁不同压力时进行数值模拟,并搭建减速器试验台,进行降压性能试验.将数值模拟结果与试验结果进行对比分析,验证了数值模拟方法对液力减速器空化特性预测是可靠的.研究结果表明:数值模拟方法获得的性能曲线与试验结果变化趋势一致,且可以捕捉到空化初生状态,数值模拟与试验结果平均误差为3.24%,可较好地反映液力减速器内部空化特性;随着泵轮外环壁压力不断降低,空化最先发生在泵轮叶片吸力面靠近轮毂的位置,之后向叶片中部扩大,直至占据叶片吸力面大部分区域;空泡分布在径向存在不均匀性,泵轮外环壁压力为0.25 MPa时,空化区域面积比(Sc/S)随着径向位置(r/R)的增大呈现先增大后减小的趋势,空化现象在流道靠近轮毂位置(r/R=0.3~0.5处)较为严重. 展开更多
关键词 液力减速器 流道 空化 数值模拟 试验研究
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具有行蓄洪区的河道流量演算方法探讨 被引量:17
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作者 李致家 《水科学进展》 EI CAS CSCD 北大核心 1997年第1期65-70,共6页
以马斯京根流量演算法为基础提出了具有行蓄洪区时防洪系统流量演算的一般方法,是马斯京根法在具有行蓄洪区的河道洪水演算的推广应用。对行洪区的入流处理进行了讨论并提出了计算分流比的实用方法。最后以淮河中游王家坝到鲁台子河段... 以马斯京根流量演算法为基础提出了具有行蓄洪区时防洪系统流量演算的一般方法,是马斯京根法在具有行蓄洪区的河道洪水演算的推广应用。对行洪区的入流处理进行了讨论并提出了计算分流比的实用方法。最后以淮河中游王家坝到鲁台子河段为例,根据工程布局、水文站和水位站的分布将该河段分成10段,对12场洪水进行模拟预报计算。 展开更多
关键词 行蓄洪区 河道 河槽演算 流量观测
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胖头泡蓄滞洪区老龙口分洪闸泄洪能力分析 被引量:3
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作者 王志兴 管功勋 +1 位作者 王天祎 丁昌春 《水利水运工程学报》 CSCD 北大核心 2019年第3期51-59,共9页
胖头泡蓄滞洪区位于哈尔滨市上游嫩江干流、松花江干流及第二松花江交汇处,可减轻三江洪水对哈尔滨市的防洪压力。采用数学模型计算和实体模型试验相结合的方法研究老龙口分洪闸的泄流能力及其影响因素,数学模型主要用于分析嫩江干流河... 胖头泡蓄滞洪区位于哈尔滨市上游嫩江干流、松花江干流及第二松花江交汇处,可减轻三江洪水对哈尔滨市的防洪压力。采用数学模型计算和实体模型试验相结合的方法研究老龙口分洪闸的泄流能力及其影响因素,数学模型主要用于分析嫩江干流河道的冲淤演变及水位变化,同时为实体模型提供上下游边界条件;实体模型用于研究不同方案下分洪闸的过流能力。结果表明,老龙口分洪闸的泄流能力主要取决于嫩江干流水位和分洪通道的水位,而且对二者水位差的变化非常敏感。分洪闸过流能力的影响因素主要包括嫩江干流河道冲淤变化、分洪流量、洪水类型及行洪流路走向等。嫩江干流河道冲淤变化幅度很小,对干流水位基本不产生影响;分洪流量对嫩江干流水位影响比较明显,最大分洪流量时水位降幅达0.70m。嫩江干流与第二松花江共发型洪水分洪对蓄滞洪区水位的减小幅度大于嫩江干流型洪水;蓄滞洪区内地形地貌复杂,不同分洪通道对分洪闸闸下水位影响显著,是泄洪闸过流能力的关键影响因素。因此,在蓄滞洪区内设置能快速分散蓄滞洪水的分洪通道非常必要。 展开更多
关键词 蓄滞洪区 分洪闸 泄流能力 行洪通道
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不同出生体重新生大鼠胰腺ghrelin和钙通道表达的研究 被引量:3
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作者 许燕萍 梁黎 +2 位作者 王秀敏 吴亦栋 顾伟忠 《浙江大学学报(医学版)》 CAS CSCD 2008年第3期233-239,共7页
目的:探讨宫内营养环境对大鼠胰腺ghrelin和胰岛细胞团上L型钙通道(Cav1.2、Cav1.3)相对丰度的影响。方法:建立不同出生体重新生大鼠模型,分别取新生第1天大鼠胰腺或分离的胰岛细胞团组织,用实时荧光定量RT-PCR观察不同出生体重组胰腺gh... 目的:探讨宫内营养环境对大鼠胰腺ghrelin和胰岛细胞团上L型钙通道(Cav1.2、Cav1.3)相对丰度的影响。方法:建立不同出生体重新生大鼠模型,分别取新生第1天大鼠胰腺或分离的胰岛细胞团组织,用实时荧光定量RT-PCR观察不同出生体重组胰腺ghrelin mRNA表达的变化和胰岛细胞团上Cav1.2、Cav1.3 mRNA的差异;同时,对胰岛细胞团上ghrelin、Cav1.2、Cav1.3蛋白进行免疫组织化学染色。结果:实时荧光定量RT-PCR显示:新生大鼠小于胎龄儿(SGA)组胰腺ghrelin mRNA水平高于适于胎龄儿(AGA)组的表达(P<0.05)。胰岛细胞团上Cav1.2 mRNA SGA组和大于胎龄儿(LGA)组表达量均小于AGA组,Cav1.3 mRNA SGA组小于AGA组(P<0.05)。免疫组化积分光密度数据显示与实时荧光定量RT-PCR结果呈相同趋势。结论:早期宫内营养状况过剩或缺乏可能导致胰腺分化和成熟障碍,并引起胰岛细胞团上ghrelin和钙通道表达差异。 展开更多
关键词 胎儿生长迟缓/病理生理学 肽类 钙通道 L型 胰岛/细胞学 婴儿 小于胎龄 聚合酶链反应 免疫组织化学
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187 dtex/288 f细旦阻燃涤纶长丝制备工艺 被引量:3
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作者 王延伟 辛长征 《合成纤维》 CAS 2010年第1期41-43,共3页
通过用实验机和在线生产,对用TCS法生产的细旦阻燃涤纶长丝的工艺条件,如切片含水率、纺丝温度、冷却成形、丝条上油率、热管温度及热管位置等工艺参数进行了研究。结果表明:采用合理的干燥工艺可获得含水率稳定在1.8×10-5以内的... 通过用实验机和在线生产,对用TCS法生产的细旦阻燃涤纶长丝的工艺条件,如切片含水率、纺丝温度、冷却成形、丝条上油率、热管温度及热管位置等工艺参数进行了研究。结果表明:采用合理的干燥工艺可获得含水率稳定在1.8×10-5以内的阻燃干切片;1#联苯锅炉温度控制在265~267℃,2#联苯锅炉温度控制在269~271℃;侧吹风风温为(21±1)℃、风速0.45m/s、风湿70%±5%;丝条上油率1%~1.2%;热管温度168~170℃,位置距喷丝板高度910mm时,可生产出质量优良的细旦阻燃涤纶长丝。 展开更多
关键词 涤纶 细旦 阻燃纤维 热管 工艺
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洪泽湖周边滞洪区分区运用研究 被引量:8
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作者 赵一晗 陈长奇 宋轩 《人民长江》 北大核心 2017年第21期15-17,28,共4页
到目前为止,还没有对洪泽湖周边滞洪区的运用方式进行过专门的研究;在现有研究中,只是将其当成单一的一次性全部滞洪来理解,一旦形成滞洪,经济损失将是巨大的。随着淮河入海水道二期等工程的规划实施,淮河下游泄洪能力进一步扩大,为洪... 到目前为止,还没有对洪泽湖周边滞洪区的运用方式进行过专门的研究;在现有研究中,只是将其当成单一的一次性全部滞洪来理解,一旦形成滞洪,经济损失将是巨大的。随着淮河入海水道二期等工程的规划实施,淮河下游泄洪能力进一步扩大,为洪泽湖周边滞洪区的运用方式调整创造了条件。根据洪泽湖周边滞洪区的地形、人口分布特点,提出了分区滞洪的方案,并分别测算了现状和淮河入海水道二期工程建成后两种工况下的运用效果。在此基础上,研究提出了未来滞洪区的面积调整及滞洪区安全工程建设的建议,拟为优化洪泽湖周边滞洪区调度运用方式以及国家172项重大工程洪泽湖周边滞洪区建设工程的前期工作研究提供参考。 展开更多
关键词 分区运用方式 滞洪区 淮河入海水道二期工程 洪泽湖
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缓凝剂对水泥浆静胶凝强度过渡时间的影响 被引量:4
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作者 刘洋 范伟华 +1 位作者 赵常青 冯予淇 《钻井液与完井液》 CAS 北大核心 2013年第6期85-87,90,共4页
静胶凝强度过渡时间是关系水泥浆防窜能力的重要参数,研究静胶凝强度发展规律,对防窜具有积极意义.采用高温高压凝结仪,从水泥水化放热角度,探讨常用的4类典型缓凝剂对静胶凝强度过渡时间的影响规律与作用机理.研究结果表明,中温缓凝剂... 静胶凝强度过渡时间是关系水泥浆防窜能力的重要参数,研究静胶凝强度发展规律,对防窜具有积极意义.采用高温高压凝结仪,从水泥水化放热角度,探讨常用的4类典型缓凝剂对静胶凝强度过渡时间的影响规律与作用机理.研究结果表明,中温缓凝剂对阳离子的络合作用或对水泥颗粒的吸附作用较弱易破坏,对静胶凝强度负面作用不明显;而在90~105 ℃时,高温缓凝剂HNG-1对阳离子有极强的螯合能力,大幅度延缓了静胶凝强度的发展,温度更高时负面作用则不明显,建议在设计防窜水泥浆体系时,应重视缓凝剂对静胶凝强度过渡时间的影响. 展开更多
关键词 气窜 静胶凝强度 过渡时间 水化 缓凝剂
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