By method of the Laplace transform, this arti- cle presents semi-analytical solutions for transient electro- osmotic and pressure-driven flows （EOF/PDF） of two-layer fluids between microparallel plates. The lineariz...By method of the Laplace transform, this arti- cle presents semi-analytical solutions for transient electro- osmotic and pressure-driven flows （EOF/PDF） of two-layer fluids between microparallel plates. The linearized Poisson- Boltzmann equation and the Cauchy momentum equation have been solved in this article. At the interface, the Maxwell stress is included as the boundary condition. By numerical computations of the inverse Laplace transform, the effects of dielectric constant ratio e, density ratio p, pressure ratio p, viscosity ratioμ of layer II to layer I, interface zeta potential difference △ψ, interface charge density jump Q, the ratios of maximum electro-osmotic velocity to pressure velocity , and the normalized pressure gradient B on transient veloc- ity amplitude are presented.We find the velocity amplitude becomes large with the interface zeta potential difference and becomes small with the increase of the viscosity. The ve- locity will be large with the increases of dielectric constant ratio; the density ratio almost does not influence the EOF ve- locity. Larger interface charge density jump leads to a strong jump of velocity at the interface. Additionally, the effects of the thickness of fluid layers （hi and h2） and pressure gradient on the velocity are also investigated.展开更多
Energy conversion in micro/nano-systems is a subject of current research,among which the electrokinetic energy conversion has attracted extensive attention.However,there exist two different definitions on the electrok...Energy conversion in micro/nano-systems is a subject of current research,among which the electrokinetic energy conversion has attracted extensive attention.However,there exist two different definitions on the electrokinetic energy conversion efficiency in literature.A few researchers defined the efficiency using the pure pressure-driven flow rate,while other groups defined the efficiency based on the flow rate with the inclusion of the effect of the streaming potential field.In this work,both definitions are investigated for different fluid types under the periodic electrokinetic flow condition.For Newtonian fluids,the two definitions give similar results.However,for viscoelastic fluids,these two definitions lead to significant difference.The efficiency defined by the pure pressure-driven flow rate even exceeds 100%in a certain range of the parameters.The result shows that in the case of viscoelastic flow,it is incorrect to define the energy conversion efficiency by pure pressure-driven flow rate.At the same time,the reason for this problem is clarified through comprehensive analysis.展开更多
BACKGROUND Duodenal obstruction is a common clinical scenario that can either be mechanical or a pseudo-obstruction.Clinical management of intestinal obstruction starts from localization and proceeds to histological e...BACKGROUND Duodenal obstruction is a common clinical scenario that can either be mechanical or a pseudo-obstruction.Clinical management of intestinal obstruction starts from localization and proceeds to histological examination of the stenotic intestine.Systemic factors and dysfunction of distant organs might contribute to the development of intestinal obstruction.Here,we report a unique case of idiopathic mechanical duodenal obstruction,which resolved spontaneously after 3 mo of conservative treatment,but was followed by intestinal pseudo-obstruction.CASE SUMMARY An 84-year-old woman presented with worsened postprandial vomiting accompanied by prolonged pneumonia.Thorough noninvasive investigations revealed complete circumferential stenosis in the descending duodenum without known cause.Exploratory surgery was postponed due to septic shock and possible pulmonary fungal infection.Conservative treatment for 3 mo for ileus and control of pulmonary infection resolved the intestinal obstruction completely.Unfortunately,2 wk later,she had regurgitation and postprandial vomiting again,complicated by deteriorating wheezing and dyspnea.Computed tomography revealed a dilated stomach and proximal duodenum without new intestinal stricture or pulmonary infiltration.The patient fully recovered after combined treatment with antireflux agents,enema,prokinetics,and bronchodilators.CONCLUSION This complicated case highlights the inter-relationship of local and systemic contributions to ileus and gut dysfunction,which requires multidisciplinary treatment.展开更多
Flow behavior of transient mixed electro-osmotic and pressure driven flows (EOF/PDF) through a microannulus is investigated based on a linearized Poisson-Boltzmann equation and Navier-Stokes equation. A semi-analytica...Flow behavior of transient mixed electro-osmotic and pressure driven flows (EOF/PDF) through a microannulus is investigated based on a linearized Poisson-Boltzmann equation and Navier-Stokes equation. A semi-analytical solution of EOF velocity distribution as functions of relevant parameters is derived by Laplace transform method. By numerical computations of inverse Laplace transform, the effects of inner to outer wall zeta potential β, the normalized pressure gradient Ω and the inner to outer radius ratio α on transient EOF velocity are presented.展开更多
A high performance 3 inch 0.5 μm InP DHBT technology with three interconnecting layers has been developed.The epitaxial layer structure and geometry parameters of the device were carefully studied to get the required...A high performance 3 inch 0.5 μm InP DHBT technology with three interconnecting layers has been developed.The epitaxial layer structure and geometry parameters of the device were carefully studied to get the required performances.The 0.5 × 5 μm^2 InP DHBTs demonstrated ft = 350 GHz,f（max） = 532 GHz and BV（CEO） = 4.8 V,which were modeled using Agilent-IIBT large signal model.As a benchmark circuit,a dynamic frequency divider operating from 110 to 220 GHz has been designed,fabricated and measured with this technology.The ultra-high-speed 0.5 μm InP DHBT technology offers a combination of ultra-high-speed and high breakdown voltage,which makes it an ideal candidate for next generation 100 GHz＋ mixed signal integrated circuits.展开更多
Developing high activity catalysts for hydrogen oxidation reaction(HOR)under alkaline condition remains a challenge in the exchange membrane fuel cell(AEMFC).Herein,we report that the activity of carbon-supported plat...Developing high activity catalysts for hydrogen oxidation reaction(HOR)under alkaline condition remains a challenge in the exchange membrane fuel cell(AEMFC).Herein,we report that the activity of carbon-supported platinum(Pt/C)towards the hydrogen oxidation reaction(HOR)in alkaline media can be remarkably enhanced by simple immersion of Pt/C in nickel chloride solution.The adsorption of hydrogen on the catalyst surface is weakened by modification of nickel.The HOR activity on the Pt/C after immersion possesses an excellent mass current density of 33.4 A/gmetal,which is 18%higher than that(28.3 A/gmetal)on Pt/C.展开更多
基金supported by the National Natural Science Foundation of China(11062005 and 11202092)Open Fund of State Key Laboratory of Nonlinear Mechanics,the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT-13-A02)+4 种基金the Natural Science Foundation of Inner Mongolia(2010BS0107 and 2012MS0107)the Research Start Up Fund for Excellent Talents at Inner Mongolia University(Z20080211)the support of Natural Science Key Fund of Inner Mongolia(2009ZD01)the Postgraduate Scientific Research Innovation Project of Inner Mongoliathe Enhancing Comprehensive Strength Project of Inner Mongolia University(14020202)
文摘By method of the Laplace transform, this arti- cle presents semi-analytical solutions for transient electro- osmotic and pressure-driven flows （EOF/PDF） of two-layer fluids between microparallel plates. The linearized Poisson- Boltzmann equation and the Cauchy momentum equation have been solved in this article. At the interface, the Maxwell stress is included as the boundary condition. By numerical computations of the inverse Laplace transform, the effects of dielectric constant ratio e, density ratio p, pressure ratio p, viscosity ratioμ of layer II to layer I, interface zeta potential difference △ψ, interface charge density jump Q, the ratios of maximum electro-osmotic velocity to pressure velocity , and the normalized pressure gradient B on transient veloc- ity amplitude are presented.We find the velocity amplitude becomes large with the interface zeta potential difference and becomes small with the increase of the viscosity. The ve- locity will be large with the increases of dielectric constant ratio; the density ratio almost does not influence the EOF ve- locity. Larger interface charge density jump leads to a strong jump of velocity at the interface. Additionally, the effects of the thickness of fluid layers （hi and h2） and pressure gradient on the velocity are also investigated.
基金Project supported by the National Natural Science Foundation of China(Nos.11902165,11772162,and 11862018)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(Nos.2019BS01004 and 2021MS01007)the Inner Mongolia Grassland Talent(No.12000-12102013)。
文摘Energy conversion in micro/nano-systems is a subject of current research,among which the electrokinetic energy conversion has attracted extensive attention.However,there exist two different definitions on the electrokinetic energy conversion efficiency in literature.A few researchers defined the efficiency using the pure pressure-driven flow rate,while other groups defined the efficiency based on the flow rate with the inclusion of the effect of the streaming potential field.In this work,both definitions are investigated for different fluid types under the periodic electrokinetic flow condition.For Newtonian fluids,the two definitions give similar results.However,for viscoelastic fluids,these two definitions lead to significant difference.The efficiency defined by the pure pressure-driven flow rate even exceeds 100%in a certain range of the parameters.The result shows that in the case of viscoelastic flow,it is incorrect to define the energy conversion efficiency by pure pressure-driven flow rate.At the same time,the reason for this problem is clarified through comprehensive analysis.
基金Peking Union Medical College Hospital Science Fund for Junior Faculty,No.pumch-2016-2.13.
文摘BACKGROUND Duodenal obstruction is a common clinical scenario that can either be mechanical or a pseudo-obstruction.Clinical management of intestinal obstruction starts from localization and proceeds to histological examination of the stenotic intestine.Systemic factors and dysfunction of distant organs might contribute to the development of intestinal obstruction.Here,we report a unique case of idiopathic mechanical duodenal obstruction,which resolved spontaneously after 3 mo of conservative treatment,but was followed by intestinal pseudo-obstruction.CASE SUMMARY An 84-year-old woman presented with worsened postprandial vomiting accompanied by prolonged pneumonia.Thorough noninvasive investigations revealed complete circumferential stenosis in the descending duodenum without known cause.Exploratory surgery was postponed due to septic shock and possible pulmonary fungal infection.Conservative treatment for 3 mo for ileus and control of pulmonary infection resolved the intestinal obstruction completely.Unfortunately,2 wk later,she had regurgitation and postprandial vomiting again,complicated by deteriorating wheezing and dyspnea.Computed tomography revealed a dilated stomach and proximal duodenum without new intestinal stricture or pulmonary infiltration.The patient fully recovered after combined treatment with antireflux agents,enema,prokinetics,and bronchodilators.CONCLUSION This complicated case highlights the inter-relationship of local and systemic contributions to ileus and gut dysfunction,which requires multidisciplinary treatment.
文摘Flow behavior of transient mixed electro-osmotic and pressure driven flows (EOF/PDF) through a microannulus is investigated based on a linearized Poisson-Boltzmann equation and Navier-Stokes equation. A semi-analytical solution of EOF velocity distribution as functions of relevant parameters is derived by Laplace transform method. By numerical computations of inverse Laplace transform, the effects of inner to outer wall zeta potential β, the normalized pressure gradient Ω and the inner to outer radius ratio α on transient EOF velocity are presented.
文摘A high performance 3 inch 0.5 μm InP DHBT technology with three interconnecting layers has been developed.The epitaxial layer structure and geometry parameters of the device were carefully studied to get the required performances.The 0.5 × 5 μm^2 InP DHBTs demonstrated ft = 350 GHz,f（max） = 532 GHz and BV（CEO） = 4.8 V,which were modeled using Agilent-IIBT large signal model.As a benchmark circuit,a dynamic frequency divider operating from 110 to 220 GHz has been designed,fabricated and measured with this technology.The ultra-high-speed 0.5 μm InP DHBT technology offers a combination of ultra-high-speed and high breakdown voltage,which makes it an ideal candidate for next generation 100 GHz＋ mixed signal integrated circuits.
基金Supported by the National Key Basic Research Program of China(No.2016YFA0200700)the National Natural Science Foundation of China(Nos.21890381,21721002)+1 种基金the Frontier Science Key Project of Chinese Academy of Sciences(No.QYZDJ-SSW-SLH038)the K.C.Wong Education Foundation.
文摘Developing high activity catalysts for hydrogen oxidation reaction(HOR)under alkaline condition remains a challenge in the exchange membrane fuel cell(AEMFC).Herein,we report that the activity of carbon-supported platinum(Pt/C)towards the hydrogen oxidation reaction(HOR)in alkaline media can be remarkably enhanced by simple immersion of Pt/C in nickel chloride solution.The adsorption of hydrogen on the catalyst surface is weakened by modification of nickel.The HOR activity on the Pt/C after immersion possesses an excellent mass current density of 33.4 A/gmetal,which is 18%higher than that(28.3 A/gmetal)on Pt/C.
