电流变液在工程中的应用

电流变液是一种在电场下瞬时从液态变为类固态的智能材料。由于它能在瞬时改变材料的力学性能，增加了其表观粘度和强度，又具有可逆性，因而在工业上极具应用前景。本文主要论述了国内外电流变液研究在工程中的应用前景和发展趋向。

Rheological and mechanical properties of wood fiber-PP/PE blend composites

For evaluation of the rheological and mechanical properties of highly filled wood plastic composites （WPCs）, polypropylene/polyethylene （PP/PE） blends were grafted with maleic anhydride （MAH） to enhance the interfacial adhesion between wood fiber and matrix. WPCs were prepared from wood fiber up to 60 wt.% and modified PP/PE was blended by extrusion. The rheological properties were studied by using dynamic measurement. According to the strain sweep test, the linear viscoelastic region of composites in the melt was determined. The result showed that the storage modulus was independent of the strain at low strain region （〈0.1%）. The frequency sweep resuits indicated that all composites exhibited shear thinning behavior, and both the storage modulus and complex viscosity of MAH modified composites were decreased comparing to those unmodified. Flexural properties and impact strength of the prepared WPCs were measured according to the relevant standard specifications. The flexural and impact strength of the manufactured composites significantly increased and reached a maximum when MAH dosage was 1.0 wt%, whereas the flexural modulus after an initial decreased, also increased with MAH dosage. The increase in mechanical properties indicated that the presence of anhydride groups enhanced the interracial adhesion between wood fiber and PP/PE blends.

Effect of electrical current on tribological property of Cu matrix composite reinforced by carbon nanotubes

Cu matrix composite reinforced with 10%（volume fraction） carbon nanotubes（CNTs/Cu） and pure Cu bulk were prepared by powder metallurgy techniques under the same consolidation processing condition.The effect of electrical current on tribological property of the materials was investigated by using a pin-on-disk friction and wear tester.The results show that the friction coefficient and wear rate of CNTs/Cu composite as well as those of pure Cu bulk increase with increasing the electrical current without exception,and the effect of electrical current is more obvious on tribological property of pure Cu bulk than on that of CNTs/Cu composite;the dominant wear mechanisms are arc erosion wear and plastic flow deformation,respectively;CNTs can improve tribological property of Cu matrix composites with electrical current.

Microstructure and mechanical properties of GTA weldments of titanium matrix composites prepared with or without current pulsing

The effects of current pulsing on the microstructure, hardness and tensile properties at different temperatures of gas tungsten arc （GTA） weldments of titanium matrix composites were studied. Full-penetration butt joints were made with or without current pulsing. Optical microscopy, hardness test and scanning electron microscopy were employed to evaluate the metallurgical characteristics of welded joints. Tensile properties of weldments at different temperatures were studied and correlated with the microstructure. The results exhibit that current pulsing leads to the refinement of the weld microstrucmre and TiB whisker and the redistribution of reinforcements resulting in higher hardness, tensile strength and ductility of weldments in the as-welded condition.

Vortex of Fluid Field as Viewed from Curvature

The vortex is a common phenomenon in fluid field. In this paper, vortex can be represented by curvature c, which varies with arc length s. The variance of point (x, y) with arc length in stream line satisfies a 2-order variablecoefficient linear ordinary differential equation. The type vortex can be analyzed qualitatively by this ordinary differential equation.

Hydrodynamic Performance of Flapping-foil Propulsion in the Influence of Vortices

Fish are able to make good use of vortices.In a complex flow field,many fish continue to maintain both efficient cruising and maneuverability.Traditional man-made propulsion systems perform poorly in complex flow fields.With fish-like propulsion systems,it is important to pay more attention to complex flow fields.In this paper,the influence of vortices on the hydrodynamic performance of 2-D flapping-foils was investigated.The flapping-foil heaved and pitched under the influence of inflow vortices generated by an oscillating D-section cylinder.A numerical simulation was run based the finite volume method,using the computational fluid dynamics(CFD) software FLUENT with Reynolds-averaged Navier-Stokes(RANS) equations applied.In addition,dynamic mesh technology and post processing systems were also fully used.The calculations showed four modes of interaction.The hydrodynamic performance of flapping-foils was analyzed and the results compared with experimental data.This validated the numerical simulation,confirming that flapping-foils can increase efficiency by absorbing energy from inflow vortices.

调水工程输水管道建设对沿线景观格局影响的研究

为了了解调水工程输水管道建设对沿线景观格局的影响,选取南水北调中线一期工程河北省易县段调水工程输水管道建设区域为研究对象,以50-3 000 m划分不同宽度研究区,利用Arc GIS和FRAGSTATS软件,研究了施工建设前、中、后期沿线土地利用类型的变化,并且分别计算不同宽度及整体景观的景观指数,分析管道建设对沿线区域景观格局的影响。研究结果表明：管道工程建设期的对区域土地利用方式产生的影响较为明显和强烈,工程建设对施工作业带两侧100 m范围内影响最为明显。

Numerical Analysis of Emergency River Restoration Scheme for Qingping Mega Debris Flow

The mega debris flow occurred on August 13 th 2010 in Qingping town,China(hereafter called '8.13' Debris Flow) have done great damage to the local habitants as well as to the re-construction projects in the quake-hit areas,and the channel-fill deposit problem caused by the debris flow was the most destructive.Moreover,it is of high possibility that an even severe deposit problem would reappear and result in worse consequences.In order to maximize risk reduction of this problem,relevant departments of the government established a series of emergency river restoration schemes,for which the numerical analysis is an important procedure to evaluate and determine the optimized one.This study presents a numerical analysis by applying a twodimensional debris flow model combined with a relevant water-sediment model to simulate the deposit during the progress of the debris flow,and to calculate and analyze the river flow field under both the present condition and different restoration conditions.The results show that the debris flow model,which takes the confluence of the Wenjia Gully to the main river into account,could simulate the deposit process quite well.In the reproduced debris flow from the simulation of the '8.13' Debris Flow,the original river flow path has switched to a relatively lower place just along the right bank with a high speed of near 7m.s-1 after being blocked by the deposit,which is highly hazardous.To prevent this hazard,a recommended scheme is derived through inter-comparison of different restoration conditions.It shows that the recommended scheme is able to reduce the water level and as well to regulate the flow path.Based on the given conditions of the mainstream and the tributary confluence for the simulated '8.13' Debris Flow,when encountering a debris flow with deposit volume less than 0.5 million m3,the river channel can endure a 20-year return flood;however,when the deposit volume increases to 2 million m3,the flood capacity of the river will be greatly impacted and the scheme becomes invalid.The recommended scheme supported by the present study has been applied to the emergency river restoration after this mega-debris flow.

Abdominal aortic aneurysm： Treatment options, image visualizations and follow-up procedures

Abdominal aortic aneurysm is a common vascular disease that affects elderly population.Open surgical repair is regarded as the gold standard technique for treatment of abdominal aortic aneurysm,however,endovaseular aneurysm repair has rapidly expanded since its first introduction in 1990s.As a less invasive technique,endovascular aneurysm repair has been confirmed to be an effective alternative to open surgical repair,especially in patients with co-morbid conditions.Computed tomography （CT） angiography is currently the preferred imaging modality for both preoperative planning and post-operative follow-up.2D CT images are complemented by a number of 3D reconstructions which enhance the diagnostic applications of CT angiography in both planning and follow-up of endovascular repair.CT has the disadvantage of high cummulative radiation dose,of particular concern in younger patients,since patients require regular imaging follow-ups after endovascular repair,thus,exposing patients to repeated radiation exposure for life.There is a trend to change from CT to ultrasound surveillance of endovascular aneurysm repair.Medical image visualizations demonstrate excellent morphological assessment of aneurysm and stent-grafts,but fail to provide hemodynamic changes caused by the complex stent-graft device that is implanted into the aorta.This article reviews the treatment options of abdominal aortic aneurysm,various image visualization tools,and follow-up procedures with use of different modalities including both imaging and computational fluid dynamics methods.Future directions to improve treatment outcomes in the follow-up of endovascular aneurysm repair are outlined.

Effect of preoperative limited fluid resuscitation to the patients with traumatic shock

Objective： To investigate the effect of preoperative limited fluid resuscitation on the patients with traumatic shock. Methods： Eighty-nine patients with multiple injuries complicating with shock were treated in Changhai Hospital Between January 2002 to October 2005 and were divided into 3 groups according to the preoperative levels of systolic blood pressure （SBP）. SBP of group A and group B were about 70 and 80 mmHg, respectively; and the SBP of group C was over 90 mmHg. Results, （1） There was no significant difference in age, gender, and injury severity score （ISS）, initiated resuscitation time and initiated operation time among the 3 groups. Preoperatively, there was significant difference in the amount of fluid resuscitation and infused erythrocyte suspension among group A, B and C （1687 ± 96 ml, 2096 ± 87 ml, 2976±93 ml, P〈0. 05; and 294±110 ml, 404±113 ml, 798±230 ml, P〈0. 05）. （2） The hemoglobin level in group C （94±45 g/L） was lower than that in group A （110±22 g/L） and group B （103±24 g/L） （P〈0.05）. However, there was no significant difference in the level of hemoglobin between group A and B. （3） There was no significant difference in the incidence of acute renal failure （ARF） among the 3 groups. The incidence of acute respiratory distress syndrome （ARDS） of group C （31.2%） was higher than that of group A （16.7%） and group B （18.2%） （P〈0.05）. The mortality of group C （34.4%） was higher than that of group A （12. 5% ） and group B （12. 1% ） （P〈0.05）. Conclusion： Preoperative limited resuscitation applied on patients with traumatic shock can reduce blood loss, incidence of ARDS and mortality.

Rheological properties of magnetorheological fluid prepared by gelatincarbonyl iron composite particles

Gelatincarbonyl iron composite particle was prepared by micro emulsion method. The analysis of scanning electron microscope(SEM) shows that the ultrafine particles are spheroids coated by gelatin, and the average sizes of particles are 310μm. The specific saturation magnetization σ_s is 130.9A·m2/kg, coercivity H_c is 0.823A/m, and residual magnetism r is 4.98Am2/kg for the composite particles. It is shown that the particles possess properties of soft magnetic. The yield stress of magnetorheological fluid(MRF) with composite particle reaches 70kPa at 0.5T magnetic induction. Magnetorheological effects are superior in lower magnetic field intensity and the subsidence stability of the MRF is excellent compared with pure carbonyl iron powder.

Effect of Structural Parameters on the Performance of NS High-efficiency Composite TraysⅠ.The Effect of Aperture and Opening Ratio on NS High-efficiency Composite Trays

In this paper,the structure and characteristics of the NS high-efficiency composite trays based on the doublelayer aperture jet sieve plate and compositely structured packing were investigated.The effect of aperture and opening ratio of plate on the fluid dynamics of the NS high-efficiency composite trays,such as the dry tray pressure drop,the wet tray pressure drop,the entrainment,the froth height,the leakage and mass transfer characteristics,were investigated.As a result, the low pressure drop,the high efficiency and the high capacity are the main advantages of the NS high-efficiency composite trays compared to other types of trays.According to this study,small aperture is useful for reducing the pressure drop and entrainment with a high mass transfer efficiency;while large aperture can achieve high capacity and efficiency in a broader operating range at the same pressure drop and entrainment.

Paste-like self-flowing transportation backfilling technology based on coal gangue

A paste-like self-flowing pipeline transportation backfilling technology with coal gangue as aggregate is proposed to remove the potential damage caused by coal gangue piles. As well, the difficult problems of recovering high quality safety coal pillars and deep mining of the Suncun Coal Mine （SCM）, Xinwen Coal Group, Shandong are resolved. The physical-chemical properties of coal gangue, optimized proportion of materials, backfilling system and craft in the SCM were studied in the laboratory and then an industrial test was carried out on high quality coal pillars under a town. The results show that finely crushed kaolinized and fresh gangue with granularity less than 5 mm can be used as aggregate with fly ash to replace part of the cement and a composite water reducer as an additive, accounting for 1.0%-1.5% of the total amount of cement and fly ash. The recommended proportion is l（cement）：4（fly ash）： 15（coal gangue）, with a mass fraction of 72%-75%, rheoiogical paste-like properties and a strength of more than 0.7 MPa at 7 d. The sequence of adding cement, fly ash, water reducer and then coal gangue ensures that the suspended state of the slurry, reducing the wear and jam of pipelines. The working face is advancing continuously by the alternating craft of building block walls with coal gangue and backfilling mined-out gobs with paste-like slurry. The recovery rate is as high as 90% with a backfilling cost of 36.9 YuarffL good utilization of coal gangue and no subsidence on the surface. This technology provides a good theoretical basis and application experience for coal mines, cement backfilling with paste-like slurry.

Experimental Investigation of the Aerodynamic Flow in the Aircraft Carrier Ski-jump by means of PIV

Computational Fluid Dynamics （CFD） methods have opened a new field to perform aerodynamic studies saving money and time. The difficulties presented by this method to calculate complex flow field problems imply that CFD validation is needed to provide correct results. Experimental data have recently been used to validate the accuracy of CFD predictions. Particle Image Velocimetry （PIV） has shown to be a powerful tool in the investigation of complex flows. The aim of this paper is to present results from PIV experiments that would be interesting for CFD validation. Regarding aircraft operations, the short runway available implies the necessity of equipment which helps to take-off performances. Ski-jump ramp system improves aircraft performances by an increment of lift resulting in successful take-off operations. The ski-jump ramp presence generates a complex flow bounded by a turbulent shear layer and a low velocity recirculation bubble over the end of the flight deck. The adverse effects on the aircraft aerodynamics affect to pilot safe operations, so this region is an interesting problem to be studied by means of wind tunnel experimental tests.

Reducing the Gas Pressure Drop in Suction Mufflers of Hermetic Reciprocating Compressors

The suction muffler of hermetic reciprocating compressors is installed in order to attenuate the noise generated by the gas pulsation of the flow through the suction valve. However, the installation of the suction muffler affects the operation of the compressor owing to gas pressure drop, which causes volumetric and energetic efficiency loss due to the gas specific volume augmentation. Therefore, there is a compromise between sound attenuation and pressure drop increase, which has to be taken into account by compressor designers. In this work, it presents a numerical solution to the flow through a suction muffler in order to analyze the pressure field and point out the main contributions to the overall pressure drop of the flow. A commercial CFD （computational fluid dynamics） code was used to perform the numerical simulations and the results were validated by using experimental data. After analyzing the pressure field, the geometry of the muffler was modified intending to decrease the flow pressure drop. The geometric modification produced a 28% reduction on the overall pressure drop, without influencing the sound attenuation.

Mechanical Properties and Fracture Behavior of Laminated Heterostructured Composites Under Different Current Densities

The mechanical properties and fracture morphologies of Cu/Nb multilayer composites under electric-assisted tension(EAT)were investigated.Results show that the generated Joule-heat leads to obvious stress softening with the increase in current density.However,the elongation decreases,which is closely related to the characteristic fracture behavior of Cu/Nb multilayer composites during EAT.The fracture pattern is gradually transformed from ductile fracture to melt fracture with the increase in current density.

Efficacy observation on cervical spondylosis of vertebral artery type treated with warm needling and rehabilitation physiotherapy therapy

Objective To compare the differences in the efficacy on cervical spondylosis of the vertebral artery type （CSA） treated with the warm needling therapy combined with the rehabilitation physiotherapy, the simple warm needling therapy and the simple rehabilitation physiotherapy separately and observe the impacts of them on the vertebral basilar artery （VBA） in hemodynamics. Methods Ninety cases of CSA patients were randomized divided into an acupuncture plus rehabilitation group, a warm needling group and a rehabilitation group, 30 cases in each. In the acupuncture ＋ rehabilitation group, the warm needling therapy was used at Jiájǐ （夹脊 EX-B 2） from C3 to C7 in combination with the rehabilitation physiotherapy such as traction and magnetic therapy. In the warm needling group, the simple warm needling therapy was applied. In the rehabilitation group, the simple rehabilitation physiotherapy was adopted. The VBA hemodynamic parameters, Vp, Vd, Vm and PI values were detected under the transcranial Doppler and taken as the indexes for the efficacy assessment of the groups. The efficacy of each group was assessed in association with the clinical curative rate. Results After treatment, the VBA hemodynamic parameters, Vp, Vd, Vm and PI values were all remarkably improved as compared with those before treatment in the three groups （P〈0.01, P〈0.05）. The improvement of the indexes in the acupuncture plus rehabilitation group were more significant as compared with either of the other two groups （all P〈0.01）. The clinical curative rate was 70.0% （21/30） in the acupuncture plus rehabilitation group, which was superior to 53.3% （16/30） in the warm needling group and 53.3% （16/30） in the rehabilitation group （all P〈0.01）. Conclusion The warm needling in combination with the rehabilitation physiotherapy significantly improves in VBA hemodynamic parameters for CSA and its clinical efficacy is superior to either the simple warm needling or the rehabilitation physiotherapy. Hence, this combined therapy was highly deserved to be promoted in clinical practice.

THE EFFECT OF TBLT METHODOLOGY ON STUDENTS' ORAL PERFORMANCE IN THE PRIMARY SETTINGS IN GUANGDONG

本文运用对比实验的方式,比较了任务型教学方式与三P教学方式在小学高年级学生英语口语能力发展中所起到的作用。在研究中,实验组实施的是任务型教学途径,而控制组采用的是三P教学方式。经过一个学期的实验研究,最后通过被试完成两个任务的测试成绩,分析了两种不同的教学方式对小学高年级学生在口语的准确性、流利性和复杂性三个方面的实施效果。作者得出结论:任务型教学方式优于三P教学方式。

Existence and Concentration of Ground States of Coupled Nonlinear Schr■dinger Equations with Bounded Potentials

A 2-coupled nonlinear Schrbdinger equations with bounded varying potentials and strongly attractive interactions is considered. When the attractive interaction is strong enough, the existence of a ground state for sufficiently small Planck constant is proved. As the Planck constant approaches zero, it is proved that one of the components concentrates at a minimum point of the ground state energy function which is defined in Section 4.

Epidemiological data on acupuncture and physical and rehabilitation medicine in the European Union

OBJETIVE: To know the prevalence of acupuncturists within physical and rehabilitation medicine specialists in Europe and their characteristics,as well as to analyze the pathologies treated and therapeutic techniques used.METHODS: This is a cross-sectional descriptive study based on a structured and closed questionnaire. The study was carried out from October 2011 to May 2014.RESULTS: A total of 115 specialists from 19 countries completed the questionnaire. The mean characteristics of the physical and rehabilitation medicine(PRM) specialists who are also acupuncturists in Europe were: women(62.6 %); mean age of47.91 years old; 4.20 years of physical and rehabilitation medicine school and 2.00 years of acupuncture training; 15.03 years of mean time of clinical practice as physical and rehabilitation medicine specialists and 10.42 years of experience as acupuncturists; 35.65 % had a doctorate(Ph D) degree,obtained at a mean age of 33.55 years old; working in a public hospital(80%); treating mainly neurological conditions(48.1%) and using mainly techniques such as kinesiotherapy(11.81%),orthosis(10.40%) and electrotherapy(9.92%). Acupuncture was applied by 32.2% of the participants mainly in musculoskeletal conditions(27.38%). A mean number of more than 20 patients a day were treated by47.04% of the specialists,being 41.8% of the patients(adults and children). Significant differences were found between the variables,acupuncture and gender(Pearson's correlation Index = 0.007).However,no differences were observed in relation to acupuncture and age,doctorate degree,years of clinical practice and workplace(all with P values >0.05).CONCLUSION: In the European area,physical and rehabilitation medicine specialists who are also acupuncturists are mainly female,middle-aged,with15 years of professional experience,Ph D holders,working in public hospitals,treating mainly neurological conditions with kinesiotherapy and acupuncture,and treating over 20 patients a day(adults and children) during a 7 h shift. Further epidemiological studies on PRM to provide more information regarding the real situation of this medical specialty and the possibility to open to Chinese traditional medicine techniques such as acupuncture are necessary.