目的:探讨成人和儿童术前乳酸林格氏液液体动力学的差别。方法:本研究是随机,双盲前瞻性研究。择期盆腔、肛肠或者下肢小手术患者28例,美国麻醉医师协会(ASA)I级,其中儿童14例,成人14例。所有患者给予镇静药后在20 min内恒速输入10 m L...目的:探讨成人和儿童术前乳酸林格氏液液体动力学的差别。方法:本研究是随机,双盲前瞻性研究。择期盆腔、肛肠或者下肢小手术患者28例,美国麻醉医师协会(ASA)I级,其中儿童14例,成人14例。所有患者给予镇静药后在20 min内恒速输入10 m L/kg的乳酸林格氏液体,通过血红蛋白(Hb)稀释-时间曲线和尿量采用Matlab 4.2软件包计算液体动力学参数。结果:一级动力学模型拟合结果显示,与成人相比,在输入林格氏液体后90 min内儿童的血浆稀释程度明显降低(0.16 vs 0.07,P=0.000),儿童将输入液体的43%通过肾脏排出,显著高于成人(18%)(P=0.011)。按公斤体重计算儿童和成人对乳酸林格氏液的血浆清除率分别是2.2 m L·min-1·kg-1和0.5 m L·min-1·kg-1(P=0.016),而肾脏对乳酸林格氏液体的清除率两组分别是0.76 m L·min-1·kg-1和0.10 m L·min-1·kg-1,(P=0.000)。结论:儿童对乳酸林格氏液体血浆和肾脏清除率分别是成人的4倍和7倍,术前给儿童输液,按照体重计算量可以参照成人的剂量。展开更多
The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this wo...The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.展开更多
目的骨陷窝-骨小管系统(LCS)是一种微米级复杂管网结构,维持了骨细胞信号分子、营养物质和废物的有效传输。在太空飞行的宇航员和老年骨质疏松的机理中,LCS的独特传输方式可能发挥着关键作用。这一研究为深入理解LCS传质规律、骨质疏松...目的骨陷窝-骨小管系统(LCS)是一种微米级复杂管网结构,维持了骨细胞信号分子、营养物质和废物的有效传输。在太空飞行的宇航员和老年骨质疏松的机理中,LCS的独特传输方式可能发挥着关键作用。这一研究为深入理解LCS传质规律、骨质疏松治疗提供了新思路。方法以天然的LCS结构为研究对象,采用分子量分别为376 Da、20 k Da和150 k Da的小、中、大3种示踪剂,用骨细胞处荧光量表述传质效果,系统研究了这3种分子在正常和超重力环境下的传质效果。结果骨陷窝的荧光强度随着距离哈弗氏管的增加而逐渐减弱。对比不同分子的传质情况,小分子示踪剂表现出较高的传输速率,而大分子示踪剂传输速率较低。在超重力条件下,示踪剂向深层传质的荧光量增加,中分子示踪剂的变化最显著;此外延长传质时间也被证明能够促进大分子示踪剂向更深层陷窝传质。结论超重力促进了不同大小分子的LCS传质。反之,随着重力场的大小的降低,尤其是微重力时,骨细胞周围的液体动力学变化,LCS的传质会受到很大程度的抑制。导致深层骨细胞缺乏营养,刺激了破骨细胞的吸收,加剧了骨丢失,进而发生骨质疏松。展开更多
Based on the population balance equation in a batch crystallizer characteristic of seeded precipitation, a model to calculate the rate of apparent crystal growth of aluminum hydroxide from the size distribution was de...Based on the population balance equation in a batch crystallizer characteristic of seeded precipitation, a model to calculate the rate of apparent crystal growth of aluminum hydroxide from the size distribution was deve- loped. The simulation results indicate that the rate of apparent crystal growth during seeded precipitation exhibits a manifest dependence on the crystal size. In general, there is an obvious increase in the apparent crystal growth rate with the augment in crystal size. The apparent activation energy increases with the increase of characteristic crystal size, which indicates that the growth of small crystals is controlled by surface chemical reaction; it is gradually controlled by both the surface reaction and diffusion with the augment in crystal size.展开更多
A new electro-hydraulic exciter that consists of rotary valve and micro-displacement double-functioned hydraulic cylinder was proposed to realize different kinds of waveforms.Calculated fluid dynamics(CFD) simulation ...A new electro-hydraulic exciter that consists of rotary valve and micro-displacement double-functioned hydraulic cylinder was proposed to realize different kinds of waveforms.Calculated fluid dynamics(CFD) simulation of rotary valve orifice reveals that orifice exists the two-throttle phenomenon.According to the finding,the revised flow area model was established.Vibration waveforms analysis was carried out by means of mathematic model and the related experiments were validated.Furthermore,as a new analysis indicator,saturation percentage was introduced first.The experimental results indicate that the revised flow area model is more accurate compared to the original one,and vibration waveforms can be optimized through suitable spool parameters and the revised cylinder structure.展开更多
The dissolution property of high-ferrite gibbsitic bauxite and the effect of ferrite content on the dissolution kinetics of gibbsitic bauxites in sodium hydroxide solution under atmospheric pressure from 50 to 90 ...The dissolution property of high-ferrite gibbsitic bauxite and the effect of ferrite content on the dissolution kinetics of gibbsitic bauxites in sodium hydroxide solution under atmospheric pressure from 50 to 90 °C were systematically investigated.The dissolution property of high-ferrite gibbsitic bauxite is increased by increasing the dissolution temperature and the Na OH concentration or decreasing the particle size of bauxite,which is easy to dissolve under atmospheric pressure.The kinetic equations of gibbsitic bauxites with different ferrite contents during the dissolution process at different temperatures for different times were established,and the corresponding activation energies were calculated.The ferrite in the gibbsitic bauxite reduces the dissolution speed and increases the activation energy of dissolution,the diffusion process of which is the rate-controlling step.展开更多
文摘目的:探讨成人和儿童术前乳酸林格氏液液体动力学的差别。方法:本研究是随机,双盲前瞻性研究。择期盆腔、肛肠或者下肢小手术患者28例,美国麻醉医师协会(ASA)I级,其中儿童14例,成人14例。所有患者给予镇静药后在20 min内恒速输入10 m L/kg的乳酸林格氏液体,通过血红蛋白(Hb)稀释-时间曲线和尿量采用Matlab 4.2软件包计算液体动力学参数。结果:一级动力学模型拟合结果显示,与成人相比,在输入林格氏液体后90 min内儿童的血浆稀释程度明显降低(0.16 vs 0.07,P=0.000),儿童将输入液体的43%通过肾脏排出,显著高于成人(18%)(P=0.011)。按公斤体重计算儿童和成人对乳酸林格氏液的血浆清除率分别是2.2 m L·min-1·kg-1和0.5 m L·min-1·kg-1(P=0.016),而肾脏对乳酸林格氏液体的清除率两组分别是0.76 m L·min-1·kg-1和0.10 m L·min-1·kg-1,(P=0.000)。结论:儿童对乳酸林格氏液体血浆和肾脏清除率分别是成人的4倍和7倍,术前给儿童输液,按照体重计算量可以参照成人的剂量。
文摘The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.
文摘目的骨陷窝-骨小管系统(LCS)是一种微米级复杂管网结构,维持了骨细胞信号分子、营养物质和废物的有效传输。在太空飞行的宇航员和老年骨质疏松的机理中,LCS的独特传输方式可能发挥着关键作用。这一研究为深入理解LCS传质规律、骨质疏松治疗提供了新思路。方法以天然的LCS结构为研究对象,采用分子量分别为376 Da、20 k Da和150 k Da的小、中、大3种示踪剂,用骨细胞处荧光量表述传质效果,系统研究了这3种分子在正常和超重力环境下的传质效果。结果骨陷窝的荧光强度随着距离哈弗氏管的增加而逐渐减弱。对比不同分子的传质情况,小分子示踪剂表现出较高的传输速率,而大分子示踪剂传输速率较低。在超重力条件下,示踪剂向深层传质的荧光量增加,中分子示踪剂的变化最显著;此外延长传质时间也被证明能够促进大分子示踪剂向更深层陷窝传质。结论超重力促进了不同大小分子的LCS传质。反之,随着重力场的大小的降低,尤其是微重力时,骨细胞周围的液体动力学变化,LCS的传质会受到很大程度的抑制。导致深层骨细胞缺乏营养,刺激了破骨细胞的吸收,加剧了骨丢失,进而发生骨质疏松。
文摘Based on the population balance equation in a batch crystallizer characteristic of seeded precipitation, a model to calculate the rate of apparent crystal growth of aluminum hydroxide from the size distribution was deve- loped. The simulation results indicate that the rate of apparent crystal growth during seeded precipitation exhibits a manifest dependence on the crystal size. In general, there is an obvious increase in the apparent crystal growth rate with the augment in crystal size. The apparent activation energy increases with the increase of characteristic crystal size, which indicates that the growth of small crystals is controlled by surface chemical reaction; it is gradually controlled by both the surface reaction and diffusion with the augment in crystal size.
基金Project(51275499)supported by the National Natural Science Foundation of ChinaProject(2013CB035404)supported by the National Basic Research Program("973" Program)of ChinaProject(51221004)supported by the Science Fund for Creative Research Groups,National Natural Science Foundation of China
文摘A new electro-hydraulic exciter that consists of rotary valve and micro-displacement double-functioned hydraulic cylinder was proposed to realize different kinds of waveforms.Calculated fluid dynamics(CFD) simulation of rotary valve orifice reveals that orifice exists the two-throttle phenomenon.According to the finding,the revised flow area model was established.Vibration waveforms analysis was carried out by means of mathematic model and the related experiments were validated.Furthermore,as a new analysis indicator,saturation percentage was introduced first.The experimental results indicate that the revised flow area model is more accurate compared to the original one,and vibration waveforms can be optimized through suitable spool parameters and the revised cylinder structure.
基金Projects(51104041,51174054,51374065)supported by the National Natural Science Foundation of ChinaProject(N130402010)supported by the Fundamental Research Funds for the Central Universities of China
文摘The dissolution property of high-ferrite gibbsitic bauxite and the effect of ferrite content on the dissolution kinetics of gibbsitic bauxites in sodium hydroxide solution under atmospheric pressure from 50 to 90 °C were systematically investigated.The dissolution property of high-ferrite gibbsitic bauxite is increased by increasing the dissolution temperature and the Na OH concentration or decreasing the particle size of bauxite,which is easy to dissolve under atmospheric pressure.The kinetic equations of gibbsitic bauxites with different ferrite contents during the dissolution process at different temperatures for different times were established,and the corresponding activation energies were calculated.The ferrite in the gibbsitic bauxite reduces the dissolution speed and increases the activation energy of dissolution,the diffusion process of which is the rate-controlling step.
