大鼠局灶性脑缺血-再灌注时ε型蛋白激酶与热休克蛋白70表达变化及相关性

目的探讨大鼠脑缺血-再灌注时ε型蛋白激酶C(PKCε)与热休克蛋白70(HSP70)表达间关系。方法60只大鼠,随机分成缺血-再灌注组及假手术组,根据再灌注时间的不同,分别分为再灌注1、6、12、24、48、72h亚组,应用蛋白印迹法观察缺血皮层、基底节区各时间点胞浆内PKCε及HSP70及胞膜PKCε的表达。结果脑缺血后再灌注1h胞浆内PKCε含量开始下降,至再灌注24h达最低点,持续至再灌注72h。而膜内PKCε变化趋势与此相反,含量逐渐上升,于再灌注24h达到最高。再灌注1hHSP70有少量表达,再灌注6h即增高,至再灌注48h达最高,再灌注72h稍有减弱。假手术组各时间点均低含量表达。脑缺血-再灌注时HSP70与胞膜PKCε表达呈正相关,但无差异性,(r=0.55,P>0.05);HSP70与胞浆内PKCε表达间呈显著负相关(r=-0.672,P<0.05)。结论脑缺血再灌注时缺血皮层、基底节区PKCε发生了膜转位激活现象,同时有HSP70的表达,两者间呈一定的相关性。

工程咨询企业知识创造过程的ε型模型研究——以江苏电力设计院为例

在野中郁次郎(Nonaka)描述知识创造过程的SECI模型基础上,针对工程咨询企业知识活动的特征,建构了"ε型"动态知识创造的扩展模型:工程咨询企业知识创造的过程受到分别来自组织目标和组织知识创造现实因素的双向驱动力影响,企业知识创造活动是一个从组织目标出发、经个人知识活动实现组织知识创造的过程;同时,受知识创造现实因素的影响,会在组织实现知识创造的过程中,会对个人、团队、组织层面的目标进行不断的修正。结合江苏电力设计院的案例分析,描述了工程咨询类企业专用知识创造的动态过程。本文的结论可以推广至知识密集型服务企业。

ε型六硝基六氮杂异伍兹烷的结构确证

分别采用紫外光谱、红外光谱、质谱、一维核磁共振光谱及X-射线粉末衍射法对ε型六硝基六氮杂异伍兹烷进行结构确证,并对其核磁共振谱(H谱和C谱)进行了归属判别。根据谱学特征确证了ε型六硝基六氮杂异伍兹烷的结构。

脑慢性低灌注老龄大鼠海马ε型蛋白激酶C及α分泌酶ADAM17表达的变化

目的观察脑慢性低灌注对老龄大鼠海马组织ε型蛋白激酶C(PKCε)及α分泌酶ADAM17蛋白表达的影响。方法将老龄大鼠随机分为假手术组和低灌注组,低灌注组永久性阻断双侧颈总动脉,制作脑慢性低灌注模型;采用Y型电迷宫分别于术后14和28d检测大鼠学习记忆能力;采用免疫组化法和免疫印迹法检测上述时间点海马组织PKCε和ADAM17的表达。结果低灌注组术后14和28d学习记忆能力较假手术组减退(P<0.01);与假手术组比较,低灌注组术后各时间点大鼠海马PKCε和ADAM17表达明显下降(P均<0.01)。结论脑慢性低灌注损害老龄大鼠学习记忆能力,导致痴呆发生,其机制可能与海马PKCε表达下降有关,而PKCε参与调节α分泌酶的表达,推测PKCε表达的下调,导致ADAM17表达减少,间接促进β淀粉样蛋白(Aβ)生成,损伤脑组织形成痴呆。

ε-型铜酞菁的研究

一、前言ε-型铜酞菁在酞菁系颜料中以着色力高、色泽鲜艳、耐热及耐溶剂等优良特性和特殊的光电导性而受到国内外普遍重视,研究日趋深入,在日本和欧美一些国家已有商品出售。ε-型铜酞菁一般用于涂料、塑料及油墨,日本还将其用于静电复印。关于ε-铜酞菁颜料的制备,国外研究较多,但对其核心部分及结晶特性的研究尚未见到详细报导。从多数报导来看,其制备方法不外乎两大类:1)用苯酐、尿素为原料,以有机溶剂法或固相融熔法直接合成获得。ε-型铜酞菁;2)以β-。

新广义V-I致型多目标半无限规划ε-有效解的充分性

对于新广义一致V-I型不变凸函数的推广,借助Minch对称梯度,定义了新广义一致V-I s,ε型不变凸函数,并且得到了涉及这些广义凸性和新广义一致伪V-I s型、新广义一致拟伪V-I s型等非光滑多目标半无限规划的一些最优充分性条件。

鞘内注射瞬时受体电位通道A1 shRNA对部分坐骨神经结扎小鼠神经病理性疼痛的作用及其机制

目的:探讨瞬时受体电位通道A1(TRPA1)在部分坐骨神经结扎(pSNL)小鼠神经病理性疼痛模型中的作用,阐明其作用机制。方法:30只SPF级雄性C57BL/6小鼠随机分为对照组(n=6)、假手术组(n=6)和pSNL组(n=18)。pSNL组小鼠鞘内置管成功后随机分为pSNL组、pSNL+NC shRNA组(于术后第7天鞘内注射NC shRNA)和pSNL+TRPA1 shRNA组(于术后第7天鞘内注射TRPA1 shRNA)。检测注射前和注射后l、7、12和24 h各组小鼠后肢机械缩足反射阈值(MWT)和热阈值(TWL)。最后一次检测后2 h处死小鼠,采用Western blotting法检测各组小鼠术侧背根神经节(DRG)中TRPA1蛋白激酶Cε型(Prkce)和星形胶质细胞激活标记物胶质纤维酸性蛋白(GFAP)的表达,ELISA法检测各组小鼠细胞上清和血清中肿瘤坏死因子α(TNF-α)和单核细胞趋化蛋白1(MCP-1)水平。分离培养pSNL模型小鼠的原代星形胶质细胞,过表达或敲低TRPA1,检测星形胶质细胞中TRPA1、Prkce和GFAP蛋白表达水平以及细胞上清中TNF-α和MCP-1水平。采用STRING数据库和免疫共沉淀(Co-IP)法预测并验证TRPA1和Prkce相互作用。检测过表达或敲低TRPA1后空质粒组、Ad-TRPA1、sh-NC组和sh-TRPA1组星形胶质细胞中Prkce和GFAP蛋白表达水平以及细胞上清中TNF-α和MCP-1水平。将TRPA1 shRNA单独转染或与AdPrkce共转染星形胶质细胞,分为sh-TRPA1+empty vector组(转染空载体)、sh-TRPA1+Ad-Prkce组(转染TRPA1过表达载体)和sh-TRPA1+Ad-Prkce组(转染Prkce过表达载体)。采用Western blotting法检测各组细胞中TRPA1、Prkce和GFAP蛋白表达水平,ELISA法检测细胞上清中TNF-α和MCP-1水平。结果:与对照组比较,pSNL组小鼠MWT和TWL降低(P<0.01);与pSNL+NC中shRNA组比较,pSNL+TRPA1 shRNA组小鼠MWT和TWL升高(P<0.01)。与假手术组比较,术后第7天pSNL组小鼠DRG中TRPA1和GFAP蛋白表达水平升高(P<0.05),血清中TNF-α和MCP-1水平升高(P<0.05)。与pSNL+NC shRNA组比较,pSNL+TRPA1 shRNA组小鼠DRG中TRPA1和GFAP蛋白表达水平及血清中TNF-α和MCP-1水平降低(P<0.05)。与空质粒组比较,Ad-TRPA1组细胞中GFAP蛋白表达水平明显升高(P<0.01),细胞上清中TNF-α和MCP-1水平明显升高(P<0.05);与sh-NC组比较,sh-TRPA1组细胞中GFAP蛋白表达水平明显降低(P<0.05),细胞上清中TNF-α和MCP-1水平明显降低(P<0.05)。与sh-TRPA1+empty vector组比较,sh-TRPA1+Ad-Prkce组细胞中TRPA1、Prkce和GFAP蛋白表达水平升高(P<0.01),细胞上清中TNF-α和MCP-1水平明显升高(P<0.05)。结论:TRPA1通过与Prkce相互作用参与pSNL模型小鼠星形胶质细胞的激活以及神经病理性疼痛发生发展过程。

反溶剂液态CO_2包覆ε-HNIW的工艺研究

为了降低ε型六硝基六氮杂异伍兹烷(ε-HNIW)的感度,提出了一种以液态CO2作为反溶剂的新的包覆方法,该包覆方法解决了水悬浮法对溶剂的选择局限性大的问题。对ε-HNIW包覆前后进行SEM、XRD和FT-IR分析,研究表明:选用这种新的包覆方法,氟橡胶、ESTANE和EPDM包覆剂能均匀包覆于ε-HNIW的表面;偶极矩-极性大的包覆剂溶剂使ε-HNIW包覆后转变为α-HNIW晶体;随着包覆剂添加量的增加、或系统压力的降低、或温度的升高,ε-HNIW复合颗粒的分散性越差,球形造型粉颗粒度越好。对ε-HNIW包覆前后进行撞击感度测试表明,相同包覆剂添加量情况下,3种包覆剂降低ε-HNIW感度的大小顺序为:ESTANE>FE26>EPDM。

Development of an ε-type actuator for enhancing high-speed electro-pneumatic ejector valve performance

A novel ε-type solenoid actuator is proposed to improve the dynamic response of electro-pneumatic ejector valves by reducing moving mass weight. A finite element analysis (FEA) model has been developed to describe the static and dynamic operations of the valves. Compared with a conventional E-type actuator, the proposed ε-type actuator reduced the moving mass weight by almost 65% without significant loss of solenoid force, and reduced the response time (RT) typically by 20%. Prototype valves were designed and fabricated based on the proposed ε-type actuator model. An experimental setup was also established to investigate the dynamic characteristics of valves. The experimental results of the dynamics of valves agreed well with simulations, indicating the validity of the FEA model.

Effects of windbreak width in wind direction on wind velocity reduction

The variations of drag force acting on the windbreak and the bulk drag coefficients for different windbreak widths were studied experimentally in the Eiffel-type non-circulating wind tunnel at the Hydraulic Engineering Laboratory, Saitama University, Japan, to elucidate the effects of windbreak width in the wind direction on wind velocity reduction behind a windbreak. The variations of flow field for different windbreak widths were studied numerically by using the two-dimensional Reynolds-averaged Navier-Stokes (RANS) equation with a k-ε turbulence closure model. Results show that the total drag force to wind increased with increasing windbreak width, but the bulk drag coefficient decreased slightly. The relationship between the bulk drag coefficient Cd and the windbreak width W and height H can be presented by the equation of Cd=kd (W/H)-b (kd, b: constants). The result of the numerical simulation shows that the windbreak width greatly affects the location and the value of the minimum wind velocity. The wind velocity decreased by 15%–22% as the windbreak width increased.

A dual-scale turbulence model for gas–liquid bubbly flows

A dual-scale turbulence model is applied to simulate cocurrent upward gas-liquid bubbly flows and validated with available experimental data. In the model, liquid phase turbulence is split into shear-induced and bubble- induced turbulence. Single-phase standard k-e model is used to compute shear-induced turbulence and another transport equation is added to model bubble-induced turbulence. In the latter transport equation, energy loss due to interface drag is the production term, and the characteristic length of bubble-induced turbulence, simply the bubble diameter in this work, is introduced to model the dissipation term. The simulated results agree well with experimental data of the test cases and it is demonstrated that the proposed dual-scale turbulence model outperforms other models. Analysis of the predicted turbulence shows that the main part of turbulent kinetic en- ergy is the bubble-induced one while the shear-induced turbulent viscosity predominates within turbulent vis- cosity, especially at the pipe center. The underlying reason is the apparently different scales for the two kinds of turbulence production mechanisms： the shear-induced turbulence is on the scale of the whole pipe while the bubble-induced turbulence is on the scale of bubble diameter. Therefore, the model reflects the multi-scale phe- nomenon involved in gas-liquid bubbly flows.

Numerical simulation and analysis of solid-liquid two-phase threedimensional unsteady flow in centrifugal slurry pump

Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of unsteady flow characteristics on solid-liquid two-phase flow and pump performance were researched under design condition. The results show that clocking effect has a significant influence on the flow in pump, and the fluctuation of flow velocity and pressure is obvious, particularly near the volute tongue, at the position of small sections of volute and within diffuser. Clocking effect has a more influence on liquid-phase than on solid-phase, and the wake-jet structure of relative velocity of solid-phase is less obvious than liquid-phase near the volute tongue and the impeller passage outlet. The fluctuation of relative velocity of solid-phase flow is 7.6% smaller than liquid-phase flow at the impeller outlet on circular path. Head and radial forces of the impeller are 8.1% and 85.7% of fluctuation, respectively. The results provide a theoretical basis for further research for turbulence, improving efficient, reducing the hydraulic losses and wear. Finally, field tests were carried out to verify the operation and wear of slurry pump.

Effect of pumping chamber on performance of non-overload centrifugal pump

In order to specify the characteristics of un-overloaded centrifugal pumps, the IH100-65-200 pump was chosen as the model pump. Different calculation models for centrifugal pumps were established under different pumping chamber sectional parameters. In the numerical simulation of the centrifugal pumps flow field, the shaft power, head, efficiency, and the changes of the internal flow field under different sectional areas and sectional shapes were studied with the RNG k-ε turbulence model, and the influence of the pumping chamber section characteristics of the non-overloaded centrifugal pumps were analyzed. The results show that sectional areas have a significant impact on the non-overload characteristics of centrifugal pumps. The shaft power and head of centrifugal pump are increasing with a lager sectional area, by which the gradient of head curves decreases. The efficiency is improved under a large flow rate condition, but the head and the efficiency are reduced at a small flow rate. It is also observed that the sectional shapes have less influence on the shaft power, the hydraulic performance and flow field characteristics of a centrifugal pump.

Numerical simulation of the hydrodynamics within octagonal tanks in recirculating aquaculture systems

A three-dimensional numerical model was established to simulate the hydrodynamics within an octagonal tank of a recirculating aquaculture system. The realizable k-e turbulence model was applied to describe the flow, the discrete phase model （DPM） was applied to generate particle trajectories, and the governing equations are solved using the finite volume method. To validate this model, the numerical results were compared with data obtained from a full-scale physical model. The results show that： （1） the realizable k-e model applied for turbulence modeling describes well the flow pattern in octagonal tanks, giving an average relative error of velocities between simulated and measured values of 18% from contour maps of velocity magnitudes; （2） the DPM was applied to obtain particle trajectories and to simulate the rate of particle removal from the tank. The average relative error of the removal rates between simulated and measured values was 11%. The DPM can be used to assess the self-cleaning capability of an octagonal tank; （3） a comprehensive account of the hydrodynamics within an octagonal tank can be assessed from simulations. The velocity distribution was uniform with an average velocity of 15 cm/s; the velocity reached 0.8 m/s near the inlet pipe, which can result in energy losses and cause wall abrasion; the velocity in tank corners was more than 15 cm/s, which suggests good water mixing, and there was no particle sedimentation. The percentage of particle removal for octagonal tanks was 90% with the exception of a little accumulation of 〈5 mm particle in the area between the inlet pipe and the wall. This study demonstrated a consistent numerical model of the hydrodynamics within octagonal tanks that can be further used in their design and optimization as well as promote the wide use of computational fluid dynamics in aquaculture engineering.

Computational fluid dynamics simulation of gas-liquid two phases flow in 320 m^3 air-blowing mechanical flotation cell using different turbulence models

According to the recently developed single-trough floating machine with the world's largest volume(inflatable mechanical agitation flotation machine with volume of 320 m3) in China, the gas-fluid two-phase flow in flotation cell was simulated using computational fluid dynamics method. It is shown that hexahedral mesh scheme is more suitable for the complex structure of the flotation cell than tetrahedral mesh scheme, and a mesh quality ranging from 0.7 to 1.0 is obtained. Comparative studies of the standard k-ε, k-ω and realizable k-ε turbulence models were carried out. It is indicated that the standard k-ε turbulence model could give a result relatively close to the practice and the liquid phase flow field is well characterized. In addition, two obvious recirculation zones are formed in the mixing zones, and the pressure on the rotor and stator is well characterized. Furthermore, the simulation results using improved standard k-ε turbulence model show that surface tension coefficient of 0.072, drag model of Grace and coefficient of 4, and lift coefficient of 0.001 can be achieved. The research results suggest that gas-fluid two-phase flow in large flotation cell can be well simulated using computational fluid dynamics method.

Numerical Simulation of the Stokes Wave for the Flow around a Ship Hull Coupled with the VOF Model

The surface wave generated by flow around a ship hull moving near free surface of water is simulated numerically in this study. The three-dimensional implicit finite volume method （FVM） is applied to solve Reynolds averaged Navier-Stokes （RANS） equation. The realizable k-e turbulence model has been implemented to capture turbulent flow around the ship hull in the free surface zone. The volume of fluid （VOF） method coupled with the Stokes wave theory has been used to determine the free surface effect of water. By using is a six degrees of freedom model, the ship hull＇s movement is numerically solved with the Stokes wave together. Under the action of Stokes waves on the sea, the interface between the air and water waves at the same regular pattem and so does the pressure and the vertical velocity. The ship hull moves in the same way as the wave. The amplitude of the ship hull＇s heave is less than the wave height because of the viscosity damping. This method could provide an important reference for the study of ships＇ movement, wave and hydrodynamics.

Numerical Simulation and Kinetic Analysis of Turbine Sail

This paper firstly introduces the structure and working principle of turbine sail. Numerical model of a turbine sail is established with Gambit software. The aerodynamic characteristics of the turbine sail are described with RNG k-e turbulence model and the numerical simulation is carded out with Fluent software. The influence of sail＇s structure is analyzed including plate, separation type and height/width ratio. The lift coefficients and drag coefficients of the simulated turbine sail are calculated under different rotation angles, suction intensity and separation plate position. The calculated results are compared with the wind tunnel experimental results, which verifies the feasibility of the numerical results and establishes a foundation for the optimal design of turbine sails.

Numerical simulation of air entrainment and suppression in pump sump

The dynamics of air entrainment and suppression schemes in a pump sump are investigated. Four different turbulence models(standard k-ε model, realizable k-ε model, renormalization group(RNG) k-ε model and shear-stress transport(SST) k-ω model) and the volume of fluid(VOF) multiphase model are employed to simulate the three-dimensional unsteady turbulent flow in a pump sump. The dynamic processes of air entrainment are simulated under conditions of relatively high discharge and low submergence; the mechanism of air entrainment is discussed in detail. Then suppression means for air entrainment is adopted by placing a circular plate on the intake pipe at three different heights. The results show: the position and structure of the free-surface vortices, sidewall-attached vortices, back wall-attached vortices, and floor-attached vortices calculated by SST k-ω turbulence model agree well with the experimental data. The two main contributors for air entrainment are pressure difference and vortex strength. By placing a circular plate in the middle of the intake pipe under water, air entrainment is suppressed because vortex strength is reduced.

A 3D Numerical Study of LO_2/GH_2 Supercritical Combustion in the ONERA-Mascotte Test-rig Configuration

Cryogenic propellants LOx/H2 are used at very high pressure in rocket engine combustion. The description of the combustion process in such application is very complex due essentially to the supercritical regime. Ideal gas law becomes invalid. In order to try to capture the average characteristics of this combustion process, numerical computations are performed using a model based on a one-phase multi-component approach. Such work requires fluid properties and a correct definition of the mixture behavior generally described by cubic equations of state with appropriated thermodynamic relations validated against the NIST data. In this study we consider an alternative way to get the effect of real gas by testing the volume-weighted-mixing-law with association of the component transport properties using directly the NIST library data fitting including the supercritical regime range. The numerical simulations are carried out using 3D RANS approach associated with two tested turbulence models, the standard k-Epsilon model and the realizable k-Epsilon one. The combustion model is also associated with two chemical reaction mechanisms. The first one is a one-step generic chemical reaction and the second one is a two-step chemical reaction. The obtained results like temperature profiles, recirculation zones, visible flame lengths and distributions of OH species are discussed.

Simulation and Experiment Research of Aerodynamic Performance of Small Axial Fans with Struts

Interaction between rotor and struts has great effect on the performance of small axial fan systems. The small axial fan systems are selected as the studied objects in this paper, and four square struts are downstream of the rotor. The cross section of the struts is changed to the cylindrical shapes for the investigation： one is in the same hy- draulic diameter as the square struts and another one is in the same cross section as the square struts. Influence of the shape of the struts on the static pressure characteristics, the internal flow and the sound emission of the small axial fans are studied. Standard K-s turbulence model and SIMPLE algorithm are applied in the calculation of the steady fluid field, and the curves of the pressure rising against the flow rate are obtained, which demonstrates that the simulation results are in nice consistence with the experimental data. The steady calculation results are set as the initial field in the unsteady calculation. Large eddy simulation and PISO algorithm are used in the transient calculation, and the Ffowcs Williams-Hawkings model is introduced to predict the sound level at the eight monitoring points. The research results show that： the static pressure coefficients of the fan with cylindrical struts increase by about 25% compared to the fan with square strum, and the efficiencies increase by about 28.6%. The research provides a theoretical guide for shape optimization and noise reduction of small axial fan with struts.