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Osmotic pressure of serum and cerebrospinal fluid in patients with suspected neurological conditions 预览
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作者 Tetsuya Akaishi Toshiyuki Takahashi +3 位作者 Ichiro Nakashima Michiaki Abe Masashi Aoki Tadashi Ishii 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第5期944-947,共4页
Interstitial fluid movement in the brain parenchyma has been suggested to contribute to sustaining the metabolism in brain parenchyma and maintaining the function of neurons and glial cells.The pulsatile hydrostatic p... Interstitial fluid movement in the brain parenchyma has been suggested to contribute to sustaining the metabolism in brain parenchyma and maintaining the function of neurons and glial cells.The pulsatile hydrostatic pressure gradient may be one of the driving forces of this bulk flow.However,osmotic pressure- related factors have not been studied until now.In this prospective observational study,to elucidate the relationship between osmolality (mOsm/kg) in the serum and that in the cerebrospinal fluid (CSF),we simultaneously measured the serum and CSF osmolality of 179 subjects with suspected neurological conditions.Serum osmolality was 283.6 ± 6.5 mOsm/kg and CSF osmolality was 289.5 ± 6.6 mOsm/kg.Because the specific gravity of serum and CSF is known to be 1.024–1.028 and 1.004–1.007,respectively,the estimated average of osmolarity (mOsm/L) in the serum and CSF covered exactly the same range (i.e.,290.5–291.5 mOsm/L).There was strong correlation between CSF osmolality and serum osmolality,but the difference in osmolality between serum and CSF was not correlated with serum osmolality,serum electrolyte levels,protein levels,or quotient of albumin.In conclusion,CSF osmolarity was suggested to be equal to serum osmolarity.Osmolarity is not one of the driving forces of this bulk flow.Other factors such as hydrostatic pressure gradient should be used to explain the mechanism of bulk flow in the brain parenchyma.This study was approved by the Institutional Review Board of the Tohoku University Hospital (approval No.IRB No.2015-1-257) on July 29,2015. 展开更多
关键词 brain PARENCHYMA bulk flow CEREBROSPINAL FLUID hydrostatic PRESSURE interstitial FLUID OSMOLARITY OSMOTIC PRESSURE
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The Schlager mouse as a model of altered retinal phenotype 预览
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作者 Lakshini Y.Herat Aaron L.Magno +5 位作者 Márcio G.Kiuchi Kristy L.Jackson Revathy Carnagarin Geoffrey A.Head Markus P.Schlaich Vance B.Matthews 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第3期512-518,共7页
Hypertension is a risk factor for a large number of vision-threatening eye disorders.In this study,we investigated for the first time the retinal neural structure of the hypertensive BPH/2J mouse(Schlager mouse)and co... Hypertension is a risk factor for a large number of vision-threatening eye disorders.In this study,we investigated for the first time the retinal neural structure of the hypertensive BPH/2J mouse(Schlager mouse)and compared it to its control counterpart,the normotensive BPN/3J strain.The BPH/2J mouse is a selectively inbred mouse strain that develops chronic hypertension due to elevated sympathetic nervous system activity.When compared to the BPN/3J strain,the hypertensive BPH/2J mice showed a complete loss of outer layers of the neural retina at 21 weeks of age,which was indicative of a severe vision-threatening disease potentially caused by hypertension.To elucidate whether the retinal neural phenotype in the BPH/2J strain was attributed to increased BP,we investigated the neural retina of both BPN/3J and BPH/2J mice at 4 weeks of age.Our preliminary results showed for the first time that the BPH/2J strain develops severe retinal neural damage at a young age.Our findings suggest that the retinal phenotype in the BPH/2J mouse is possibly due to elevated blood pressure and may be contributed by an early onset spontaneous mutation which is yet to be identified or a congenital defect occurring in this strain.Further characterization of the BPH/2J mouse strain is likely to i)elucidate gene defects underlying retinal disease;ii)understand mechanisms leading to neural retinal disease and iii)permit testing of molecules for translational research to interfere with the progression of retinal disease.The animal experiments were performed with the approval of the Royal Perth Hospital Animal Ethics Committee(R535/17-18)on June 1,2017. 展开更多
关键词 blood pressure eye hypertension mice neural regeneration RETINA Schlager MOUSE SYMPATHETIC nervous system
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压力流场中含炭黑聚对苯二甲酸乙二醇酯熔体的流变特性 预览
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作者 郭增革 张斌 +4 位作者 姜兆辉 贾曌 丁作伟 程博闻 李鑫 《材料导报》 EI CAS CSCD 北大核心 2020年第2期2159-2162,2168,共5页
利用毛细管流变仪及反向压力腔组件研究了压力流场中含炭黑聚对苯二甲酸乙二醇酯(PET)熔体的流变行为,并与普通PET熔体的流变行为进行对比。结果表明:随剪切速率的增加,含炭黑PET熔体的“剪切变稀”行为比普通PET更显著;在相同温度和相... 利用毛细管流变仪及反向压力腔组件研究了压力流场中含炭黑聚对苯二甲酸乙二醇酯(PET)熔体的流变行为,并与普通PET熔体的流变行为进行对比。结果表明:随剪切速率的增加,含炭黑PET熔体的“剪切变稀”行为比普通PET更显著;在相同温度和相同剪切速率下,含炭黑PET的剪切黏度随着压力的增加而增加;在相同剪切速率和相同压力下,随着温度的升高,含炭黑PET熔体的剪切黏度逐渐减小;压力增加ΔP与温度下降ΔT对剪切黏度的贡献是等效的;在相同剪切速率下,含炭黑PET熔体的黏-温依赖性随压力的升高而增强;在相同压力下,含炭黑PET熔体的黏-温依赖性随剪切速率的增加而减弱;随着温度的升高,普通PET和含炭黑PET熔体的结构粘度(Δη)降低,可纺性提高;当温度为290~295℃时,普通PET和含炭黑PET熔体的可纺性最优。 展开更多
关键词 聚对苯二甲酸乙二醇酯 炭黑 流变行为 压力 黏流活化能 结构黏度指数
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Pressure characteristics of landslide-generated impulse waves
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作者 TAN Jian-min HUANG Bo-lin ZHAO Yong-bo 《山地科学学报:英文版》 SCIE CSCD 2019年第8期1774-1787,共14页
The destructiveness of impulse waves generated by landslides(IWL) originates from the wave’s movement and load, wherein the impulse wave’s load is the major cause of sub-aerial building damage and casualties. In thi... The destructiveness of impulse waves generated by landslides(IWL) originates from the wave’s movement and load, wherein the impulse wave’s load is the major cause of sub-aerial building damage and casualties. In this study, an experiment involving 16 groups of physical tests for the wave pressure generated by a landslide was designed, consisting of 4 sets of IWL and 4 opposite bank slope angles. A high-frequency strain system was used to measure the total pressure of the impulse wave in a water tank. The tests showed that the dynamic pressure caused by the IWL can be divided into two types: impact pressure generated by the jetflow and the pulsating pressure caused by the wave. Under the same impulse wave conditions, the maximum run-up becomes smaller as the opposite bank’s slope angle increases, and the jetflow maximum impact pressure experienced by the opposite bank increases, while the maximum pulsating pressure caused by the impulse wave is slightly decreased. Different from previous studies, the spatial maximum pressure distributions of the wave generated by landslide were concluded that the position of the maximum pulsating pressure appears adjacent to the still water surface, and the overall spatial distribution pattern of maximum wave pressure is presented as an inclined 'M' shape.Meanwhile, this study is the first to quantitatively analyzed that impact pressure has a very short action time, is even 7 times of the pulse pressure value, and there is a simple mathematical linear relationship between the two. Currently, some wave-load formulas for wind waves and tides are not applicable to calculating the loads of IWL. Research on the load of IWL will explain the hazard of impulse wave very clearly, and will greatly contribute to hazard prevention, mitigation and risk assessment work associated with IWL. 展开更多
关键词 LANDSLIDE IMPULSE WAVE WAVE PRESSURE Impact PRESSURE Pulsating PRESSURE PRESSURE distribution
用变压吸附法提纯氢气,如何通过压力曲线变化分析和判断故障程控阀 预览
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作者 庞新胜 《广东化工》 CAS 2019年第3期118-119,共2页
变压吸附法是现代石油化工普遍使用的从气体中提取氢气的一种方法。其中的压力变化影响着氢气的质量和产量,而控制压力变化的程控阀门又是整个装置生产氢气的主要部件,故程控阀的故障影响着氢气的产量和质量;用何种方法迅速的判断和检... 变压吸附法是现代石油化工普遍使用的从气体中提取氢气的一种方法。其中的压力变化影响着氢气的质量和产量,而控制压力变化的程控阀门又是整个装置生产氢气的主要部件,故程控阀的故障影响着氢气的产量和质量;用何种方法迅速的判断和检验故障程控阀是提高生产效率的关键。 展开更多
关键词 吸附罐 程控阀 压力 压力曲线 压力被拉升 压力被降低 闸阀
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Comparison of walking quality variables between incomplete spinal cord injury patients and healthy subjects by using a footscan plantar pressure system 预览
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作者 Xiang-Nan Yuan Wei-Di Liang +4 位作者 Feng-Hua Zhou Han-Ting Li Li-Xin Zhang Zhi-Qiang Zhang Jian-Jun Li 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第2期354-360,共7页
The main goal of spinal cord rehabilitation is to restore walking ability and improve walking quality after spinal cord injury (SCI). The spatiotemporal parameters of walking and the parameters of plantar pressure can... The main goal of spinal cord rehabilitation is to restore walking ability and improve walking quality after spinal cord injury (SCI). The spatiotemporal parameters of walking and the parameters of plantar pressure can be obtained using a plantar pressure analysis system. Previous studies have reported step asymmetry in patients with bilateral SCI. However, the asymmetry of other parameters in patients with SCI has not been reported. This was a prospective, cross-sectional study, which included 23 patients with SCI, aged 48.1 ± 14.5 years, and 28 healthy subjects, aged 47.1 ± 9.8 years. All subjects underwent bare foot walking on a plantar pressure measurement device to measure walking speed and spatiotemporal parameters. Compared with healthy subjects, SCI patients had slower walking speed, longer stride time and stance time, larger stance phase percentage, and shorter stride length. The peak pressures under the metatarsal heads and toe were lower in SCI patients than in healthy subjects. In the heel, regional impulse and the contact area percentage in SCI patients were higher than those in healthy subjects. The symmetry indexes of stance time, step length, maximum force, impulse and contact area were increased in SCI patients, indicating a decline in symmetry. The results confirm that the gait quality, including spatiotemporal variables and plantar pressure parameters, and symmetry index were lower in SCI patients compared with healthy subjects. Plantar pressure parameters and symmetry index could be sensitive quantitative parameters to improve gait quality of SCI patients. The protocols were approved by the Clinical Research Ethics Committee of Shengjing Hospital of China Medical University (approval No. 2015PS54J) on August 13, 2015. This trial was registered in the ISRCTN Registry (ISRCTN42544587) on August 22, 2018. Protocol version: 1.0. 展开更多
关键词 nerve REGENERATION spinal cord injury WALKING gait QUALITY PLANTAR PRESSURE SYSTEM PLANTAR PRESSURE distribution speed PLANTAR PRESSURE impulse contact area symmetry index neural REGENERATION
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导管压装过程及压装力影响因素探析 预览
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作者 熊强强 孙庆 +1 位作者 柳佳深 雷冲 《汽车科技》 2019年第1期96-99,共4页
用伺服压机进行缸盖导管阀座压装,可以采集整个压装过程中的压装力-位移曲线。压装力是导管压装工序中重要监控参数,在压装过程中,异常情况都会伴随出现压装力过大或者过小的现象,所以利用压装力位移曲线监控压装过程中压装力变化是保... 用伺服压机进行缸盖导管阀座压装,可以采集整个压装过程中的压装力-位移曲线。压装力是导管压装工序中重要监控参数,在压装过程中,异常情况都会伴随出现压装力过大或者过小的现象,所以利用压装力位移曲线监控压装过程中压装力变化是保证导管压装质量的关键。本论文结合压力位移曲线对导管压装过程中各阶段进行分析,并通过在不同条件下进行导管压装实验,得出不同条件下最大压装力变化情况,总结出过盈量、压装前润滑、压装速度对导管压装的影响。 展开更多
关键词 导管 压装力 压力位移曲线 过盈量 压装前润滑 压装速度
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不对称花键啮合齿对锁环式同步器换挡平顺改善分析 预览
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作者 魏小强 《汽车科技》 2019年第1期100-104,共5页
目前锁环式同步器对称结构的花键啮合齿存在换挡二次冲击问题,BP在同歩器同步结束滑套与结合齿圈啮合时会产生过大的换挡冲击,在变速器上反映出挂档有顿挫、卡滞等不顺畅感觉,造成换挡舒适性降低,增加了司机驾驶换挡强度。并且锁环式同... 目前锁环式同步器对称结构的花键啮合齿存在换挡二次冲击问题,BP在同歩器同步结束滑套与结合齿圈啮合时会产生过大的换挡冲击,在变速器上反映出挂档有顿挫、卡滞等不顺畅感觉,造成换挡舒适性降低,增加了司机驾驶换挡强度。并且锁环式同步器二次冲击较大会产生噪音,影响变速器的整体性能。本文是在锁环式同歩器的基础上,改变锁环式同步器滑套、同步环、结合齿圈的花键啮合齿,将花键两侧的啮合齿面设计成不对称结构,并根据同步器在变速器中使用的情况,考虑工作原理将不对称度适当增加,在不影响使用寿命和可靠性的基础上,可显著提高锁止可靠性,保证同步器具有的同步传扭功能。另外在啮合齿与倒锥齿连接位置增加过渡圆角或倒角,这为换档力的逐步过渡提供了结构基础,可保证换档的平稳顺畅。 展开更多
关键词 不对称花键 啮合齿 二次冲击 锁环式 同步器
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Predictive Value of Resting Pd/Pa for Fractional Flow Reserve Assessed with Monorail Pressure Microcatheter in Real-World Practice 预览
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作者 Keng Tat Koh Asri Said +11 位作者 Khaw Chee Sin Oon Yen Yee Erwin Mulia Tan Chen Ting Francis Shu Eng Pbeng Ho Kian Hui Voon Chi Yen Cham Yee Ling Khiew Ning Zan Nor Hanim Mohd Amin Alan Fong Yean Yip Ong Tiong Kiam 《心血管创新与应用》 2019年第B07期113-120,共8页
Background and Objectives:The aims of this study were(1)to examine the diagnostic accuracy of resting timeaveraged distal coronary pressure(Pd)to mean aortic pressure(Pa)ratio to predict hyperemic fractional flow rese... Background and Objectives:The aims of this study were(1)to examine the diagnostic accuracy of resting timeaveraged distal coronary pressure(Pd)to mean aortic pressure(Pa)ratio to predict hyperemic fractional flow reserve(FFR)and(2)to identify a resting Pd/Pa value that can preclude the need for hyperemic FFR assessed with use of a monorail pressure catheter.Methods:A total of 191 stenoses were assessed.After exclusions,157 FFR data sets from 103 patients were analyzed.Results:Resting Pd/Pa showed poor agreement with hyperemic FFR(r=0.619,P<0.001).The receiver operating characteristic curve for resting Pd/Pa with reference to hyperemic FFR of 0.80 or less showed an area under the curve of 0.800(95%confi dence interval 0.732– 0.868,P<0.001),with the greatest diagnostic accuracy of 74.5%for resting Pd/Pa of less than 0.85.Resting Pd/Pa of 0.96 or greater had a sensitivity of 100%and a negative predictive value of 100%,and resting Pd/Pa of 0.82 or less had a specifi city of 98.9%and a positive predictive value of 94.1%to predict abnormal FFR of 0.80 or less.These results were consistent regardless of the vessels studied,the location of lesions,and the severity of stenosis.Conclusions:Resting Pd/Pa showed poor agreement with hyperemic FFR assessed with use of a monorail pressure microcatheter.However,resting Pd/Pa of 0.96 or greater had excellent sensitivity and negative predictive value to predict normal hyperemic FFR,and resting Pd/Pa of 0.82 or less had excellent specifi city and positive predictive value to predict abnormal hyperemic FFR. 展开更多
关键词 fractional fl ow reserve MONORAIL PRESSURE CATHETER RESTING time-averaged DISTAL coronary PRESSURE to mean aortic PRESSURE ratio
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Analysis and verification of gas content and pressure change rate characteristics in hydraulic system 预览
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作者 韩贺永 Liu Yuan +2 位作者 Qin Lixia Wang Kai Peng Huayu 《高技术通讯:英文版》 CAS 2019年第3期326-333,共8页
Gas content of the hydraulic system directly affects the rate of pressure change of the hydraulic system. The purpose of this paper is to establish a mathematical model of oil gas content, hydraulic system pressure an... Gas content of the hydraulic system directly affects the rate of pressure change of the hydraulic system. The purpose of this paper is to establish a mathematical model of oil gas content, hydraulic system pressure and pressure rise rate, obtain corresponding oil pressure value when the pressure rise rate of different gas content is maximum, and verify the accuracy of this conclusion by the FLUENT simulation software. On this basis, a rapid pressure building device of the hydraulic system is developed and designed. The above oil pressure value is used as the working cut-off pressure of the rapid pressure building device, and then the hydraulic oil pump continues to pressurize to the highest working pressure required by the system. The research content can replace the hydraulic system from the initial low pressure to the rapid pressure build-up of the oil, thus increasing the construction pressure of the hydraulic system. The research results show that the rapid pressure building device effectively reduces the time for the hydraulic system to establish pressure. Through the analysis of theoretical derivation and the collected experimental data, the error is about 5.9%, which verifies the correctness of the theoretical formula. 展开更多
关键词 HYDRAULIC system gas content ESTABLISHMENT of PRESSURE rate RAPID PRESSURE BUILDING device PRESSURE BUILDING time
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球形空腔内的粒子对内壁作用力的讨论 预览
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作者 石凤良 李敬林 《大学物理》 2019年第7期23-25,共3页
指出了一道量子力学习题解答的错误,并给出合理的解答,探讨了处于束缚定态的粒子对空腔内壁的平均作用力。
关键词 束缚定态 压力 压强 力的平均值 力的方向
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简析锅炉启动系统疏水扩容器的运行故障 预览
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作者 杨威 邓科 季敏东 《电站辅机》 2019年第1期12-14,27共4页
进入锅炉启动系统扩容器的疏水,存在多样性和疏水时机具有阶段性等特点,而且,设备的排汽环境复杂多变。当疏水扩容器的运行出现异常时,无法快速确定扩容器出现运行异常的原因。针对排大气式启动系统疏水扩容器在电厂运行中常见的扩容器... 进入锅炉启动系统扩容器的疏水,存在多样性和疏水时机具有阶段性等特点,而且,设备的排汽环境复杂多变。当疏水扩容器的运行出现异常时,无法快速确定扩容器出现运行异常的原因。针对排大气式启动系统疏水扩容器在电厂运行中常见的扩容器排汽管道振动、嚣叫、排汽大量带水等问题,提出在扩容器设备顶部进入排汽管道处增加一远传压力信号测点,通过分析计算准确快速的判断扩容器故障产生的原因,并能针对问题提出解决方案和措施,进一步保障电厂启动系统的安全有效运行。 展开更多
关键词 锅炉 启动 疏水 扩容器 故障 压力 排汽 远传信号
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Screening for Human Immunodeficiency Virus, Hepatitis B, High Blood Pressure, and Diabetes Mellitus in the General Population of South Kivu<br/>—Results of World AIDS Day 2016 预览
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作者 Richard Bahizire Riziki Sylvie Mutonda Mwangaza +6 位作者 Théo Mitima Kashosi Bienfait Mitima Misuka Freud Muciza Bayunvanye Tharcisse Mateso Kakulibo Jean Paul N’Sibula Bisimwa Jean Lambert Mandjo Aholoma Philippe Bianga Katchunga 《艾滋病(英文)》 2019年第1期11-22,共12页
Background: It has been well-established that a program to fight HIV can accomplish the same results with noncommunicable diseases (NCDs). Such a strategy has not yet been the subject of a trial in the Democratic Repu... Background: It has been well-established that a program to fight HIV can accomplish the same results with noncommunicable diseases (NCDs). Such a strategy has not yet been the subject of a trial in the Democratic Republic of the Congo (DRC). The aim of this study was to test the feasibility of HIV concurrent and respectively other chronic infectious and NCDs in the general population of South Kivu. Methods: Between 1 December 2016 and 15 January 2017, HIV, hepatitis B, high blood pressure (HBP) and diabetes mellitus (DM) were tested in the general adult population ≥ 15 years, respectively, in the towns of Bukavu and Uvira, and the rural areas Nyangezi and Walungu, on World AIDS Day 2016. Previous screening of these diseases has been sought, but the association between them was modeled in a multiple logistic regression. Results: Among the three thousand eight hundred and sixty-three (3863) adult subjects > 15 years (52.1% of men) tested voluntarily, the previous screening and prevalence were 33.8% and 1.2% respectively for HIV, 1.3% and 8.3% for hepatitis B, 18.2% and 25.1% for HBP and 9.5% and 4.8% for DM. The acceptance rate for current screening was significantly higher (p Conclusion: This study did more HIV testing than screens for other diseases. Finally, these problems can be managed (at a reasonable cost) with a view similar to the objectives of the World Health Organization (WHO). 展开更多
关键词 SCREENING HIV Pressure DIABETES Aids Kivu
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Bubble formation and evolution behavior from vertical wall orifice 预览
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作者 Zhao-Wei Ma Xiao-Ling Wu +4 位作者 Qin Zhang Guo Yang Gui-Min Liu Hua Li Wei Liu 《核技术:英文版》 SCIE CAS CSCD 2019年第12期94-102,共9页
Bubble formation is an integral part of the twophase flow science.Through numerical simulation and experiments using different air flow rates and orifice diameters,the present study aims at investigating the behavior ... Bubble formation is an integral part of the twophase flow science.Through numerical simulation and experiments using different air flow rates and orifice diameters,the present study aims at investigating the behavior of bubble formation and evolution from vertical wall orifice in quiescent pure water.For the experiments,the images of the bubble formation process under different working conditions were recorded using a high-speed camera and analyzed the entire process.The bubble formation process can be divided into three stages,namely nucleation,stable growth,and necking.According to the obtained results,bubble forms only when the air-phase pressure exceeds the threshold pressure at wall orifice.Due to the influence of the threshold pressure and buoyancy,the bubble volume decreases with an increase in the wall orifice diameter for the same flow rate.Moreover,the volume of fluid method is applied to simulate bubble formation in a three-dimensional model and the"buffer volume"is considered in the simulation model.The simulation results matched well with the experimental data,which proves the existence of threshold pressure and the periodic pressure fluctuation at the wall orifice. 展开更多
关键词 Bubble formation Vertical wall orifice Threshold pressure Pressure fluctuation
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Analytical analysis of single-stage pressure relief valves
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作者 Sven Osterland Jurgen Weber 《机电液工程学报》 2019年第1期1-2,共2页
The article presents an explicitly straightforward formulation of the stationary and dynamic behaviour of a pressure relief valve (PRV). This includes an analytical solution for the static p-Q-characteristic, the step... The article presents an explicitly straightforward formulation of the stationary and dynamic behaviour of a pressure relief valve (PRV). This includes an analytical solution for the static p-Q-characteristic, the step and harmonic response and a stability criterion using elementary operations only. It also mathematically proves the intrinsic connection between the gradient of the static p-Q-characteristic and the stability. Thus, the new method offers four main advantages. 展开更多
关键词 SINGLE-STAGE PRESSURE RELIEF valves PRESSURE RELIEF VALVE (PRV) STATIC p-Q-characteristic
一种新型上销的设计与研发 预览
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作者 罗斌 《纺织器材》 2019年第1期16-17,43共3页
为提高纺纱质量,分析现有金属上销和碳纤上销的结构及缺点,研发出SX200型上销,将压力源由片弹簧改为螺旋弹簧,利用旋转调压块等方式实现两档压力可调;通过与SX2-6833型压力棒上销进行试纺C 9.7tex纱对比,说明SX200型上销改善成纱质量较... 为提高纺纱质量,分析现有金属上销和碳纤上销的结构及缺点,研发出SX200型上销,将压力源由片弹簧改为螺旋弹簧,利用旋转调压块等方式实现两档压力可调;通过与SX2-6833型压力棒上销进行试纺C 9.7tex纱对比,说明SX200型上销改善成纱质量较明显。结果表明:SX200型上销钳口压力稳定、可调,使用寿命长,能满足棉纺高端用户的纺纱工艺要求;但其压力档位选择及相应最优化纺纱数据须进一步探索。 展开更多
关键词 上销 钳口 压力 片弹簧 杠杆比原理 螺旋弹簧 调压块
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气压疑异时的观测处置
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作者 陈建德 冯燕 +1 位作者 邓建华 张洋飞 《民航学报》 2019年第3期79-81,共3页
修正海平面气压时时对航空器的离地速度和滑跑距离以及飞行高度直接影响,甚至造成飞行事故。而近年来由于气压数据疑异产生的不安全事件却时有发生。为降低差错风险更好地保障飞行安全,本文对工作中常见的气压疑异情况进行分类,逐一分... 修正海平面气压时时对航空器的离地速度和滑跑距离以及飞行高度直接影响,甚至造成飞行事故。而近年来由于气压数据疑异产生的不安全事件却时有发生。为降低差错风险更好地保障飞行安全,本文对工作中常见的气压疑异情况进行分类,逐一分析原因,探讨正确的处置方法。 展开更多
关键词 气压 疑异原因 处置方法
Oxidation Kinetics of Aluminum Powders in a Gas Fluidized Bed Reactor in the Potential Application of Surge Arresting Materials 预览
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作者 Hong Shih 《材料科学与应用期刊(英文)》 2019年第3期253-292,共40页
In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arre... In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switc 展开更多
关键词 Aluminum Spherical Power GAS FLUIDIZATION Bed Oxidation Mechanism Oxide Growth Rate Gibbs Free Energy Ellingham Diagram Mathematical Modeling Dynamic System Plasma DIFFUSION DIFFUSION Coefficient Crystallographic Defect Vacancy Pressure Temperature Flow Laplace Transform Equation Boundary Condition Fick’s Second Law Software Experimental Theoretical SURGE ARRESTING MATERIALS Analytical Solution
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Characteristics of DBD micro-discharge at different pressure and its effect on the performance of oxygen plasma reactor
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作者 刘蕊 俞哲 +2 位作者 曹慧娟 刘璞 张芝涛 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第5期5-13,共9页
The oxygen plasma reactor based on dielectric barrier discharge principle can produce a high concentration of reactive oxygen species,which can cooperate with hydraulic cavitation gas-liquid mixer to realize the appli... The oxygen plasma reactor based on dielectric barrier discharge principle can produce a high concentration of reactive oxygen species,which can cooperate with hydraulic cavitation gas-liquid mixer to realize the application of advanced oxidation technology in water treatment.In this technology,the work pressure of the oxygen plasma reactor is decreased by the vacuum suction effect generated in the snap-back section of the gas-liquid mixed container.In this paper,the characteristics of single micro-discharge at different pressures were investigated with the methods of discharge image,electrical characteristics and spectral diagnosis,in order to analyze the electrical characteristics and reactive oxygen species generation efficiency of oxygen plasma reactor at the pressure range from 60 kPa to 100 kPa.The study indicated that,when the pressure decreases,the duty ratio of ionization in the discharge gap and number of electrons with high energy increases,leading to a rise in reactive oxygen species production.When the oxygen reaches the maximum ionization,the concentration of reactive oxygen species is the highest.Then,the discharge intensity continues to increase,producing more heat,which will decompose the ozone and lower the production of reactive oxygen species.The oxygen plasma reactor has an optimum working pressure at different input powers,which makes the oxygen plasma reactor the most efficient in generating reactive oxygen species. 展开更多
关键词 atmospheric PRESSURE plasma REACTOR PRESSURE active oxygen particle dielectric BARRIER DISCHARGE
Buckling of Cassini Oval Pressure Hulls Subjected to External Pressure 预览
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作者 TANG Wen-xian WANG Wei-min +1 位作者 ZHANG Jian WANG Shu-yan 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第4期503-508,共6页
The paper focuses on Cassini oval pressure hulls under uniform external pressure. The Cassini oval pressure hull is proposed based on the shape index of Cassini oval. The buckling of a series of Cassini oval pressure ... The paper focuses on Cassini oval pressure hulls under uniform external pressure. The Cassini oval pressure hull is proposed based on the shape index of Cassini oval. The buckling of a series of Cassini oval pressure hulls with the shape index of 0.09–0.30 and one spherical pressure hull with the diameter of 2 m is devoted. Such hulls are numerically studied in the case of constant volume, material properties, and wall thickness. The results show that Cassini oval pressure hulls with the shape index of 0.10–0.11 can resist about 4% more external pressure than the spherical one. This deviates from the classical mechanics conclusion that spherical shell is the optimal shape for underwater pressure resistant structures. 展开更多
关键词 PRESSURE HULL CASSINI OVAL SHELL shape index BUCKLING behaviour external PRESSURE
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