微流道交流电水力泵的数值模拟及优化

描述了微通道内交流电水力泵(EHD)的工作原理,并用IntelliSuite的Microfluidic模块对电水力泵进行数值模拟.并分析了影响电水力泵速度场分布的因素,包括流体电导率、驱动交流电频率和相位、电极维度以及电极间隙和数量等.通过数值模拟不同参数下的电水力泵,比较驱动压力大小,最后给出优化的设计结果,为给电水力泵设计参数的选择提供依据.本文对流道长度为5mm,宽0.4mm,厚度0.4mm的电水力泵做了优化设计的数值模拟,最后得到驱动电极宽度为0.01mm,电极间距为0.02mm.

谈小水电输、配电变压器的接地措施

对农村小水电站输、配电变压器的接地措施作了介绍，并叙述了接地的目的和要求。

EHD喷雾电晕放电现象研究

通过水滴在电流波形中形成的明显规律性波谷来研究水滴在直流电场作用下的快慢情况、雾化场强和放电电流等 ,并对正负极性作了比较 。

Activating d^(10)electronic configuration to regulate p-band centers as efficient active sites for solar energy conversion into H_(2)by surface atomic arrangement

Relationship between the activity for photocatalytic H_(2)O overall splitting(HOS)and the electron occupancy on d orbits of the active component in photocatalysts shows volcanic diagram,and specially the d^(10)electronic configuration in valley bottom exhibits inert activity,which seriously fetters the development of catalytic materials with great potentials.Herein,In d^(10)electronic configuration of In_(2)O_(3)was activated by phosphorus atoms replacing its lattice oxygen to regulate the collocation of the ascended In 5p-band(Inɛ5p)and descended O 2p-band(Oɛ2p)centers as efficient active sites for chemisorption to*OH and*H during forward HOS,respectively,along with a declined In 4d-band center(Inɛ4d)to inhibit its backward reaction.A stable STH efficiency of 2.23%under AM 1.5 G irradiation at 65°C has been obtained over the activated d^(10)electronic configuration with a lowered activation energy for H_(2)evolution,verified by femtosecond transient absorption spectroscopy,in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations of dynamics.These findings devote to activating d^(10)electronic configuration for resolving the reaction energy barrier and dynamical bottleneck of forward HOS,which expands the exploration of high-efficiency catalytic materials.

Towards the Integrating Wind Power into Power Grid in China

With abundant wind resources and high pressure imposed on en-vironmental protection, wind power development has a promising future. Butdue to intermittent nature, wind power can bring into full play only if being con-nected into power grid to ensure its supply reliability and continuity, aswell as operational economy. However, technical and market barriers haveprevented wind power from integrating into power grid. To foster wind powerdevelopment, these barriers should be removed by both government incentivepolicies and sophisticated technologies.

The Small Hydropower in China-A Focus of World Attention

This paper describes the present situation, construction experiences, existing problems and the principal tasks in the development of small hydropower in China.

关于森林生态功能评价的探讨

森林生态功能是无形的，无法通过市场交换实现其价值，但是森林生态功能既有营林成本，又是营林收入，需要对其进行正确评价．该文就森林生态功能评价的意义、评价指标和评价方法做扼要论述，以朱亭小流域为例对森林涵养水源、保护土壤、纳碳释氧等生态功能进行评价，并对森林生态功能评价存在的问题提出几点看法。

龚嘴水力发电总厂On-Call系统的设计与应用

结合On-Call系统的发展趋势和新需求,介绍了南瑞集团公司On-Call系统在龚嘴水力发电总厂的设计和应用。强调了On-Call系统在今后流域梯级电站运行管理和设备维护中所起的重要作用。

Friction characteristics of a new type of continuous rotary electro-hydraulic servomotor applied to simulator

The principle of a new type of no-pulsation continuous rotary electro-hydraulic servomotor applied to simulators is introduced. LuGre friction model was analyzed. The identification method of LuGre parameters was proposed, and the measures to compensate the effect of friction forces were given. A friction torque model for the new rotary motor was proposed. The low-speed response and step response of the motor were studied experimentally. Experimental results proved that using friction compensation could eliminate stick-slip motion at the low speed, which makes the servomotor applicable to simulators.

Characteristics of a magnetic fluid seal and its motion in an axial variable seal gap

With suitable assumptions a hydrodynamic model for the magnetic fluid motion in an axial variable gap seal was con- structed, and the solution to the equations of the model was deduced. The characteristics of a magnetic fluid seal and its motion, including the speed and pressure distribution, and the seal capacity of a magnetic fluid rotating seal were systematically described. The factors affecting seal capacity and ways to improve seal capacity based on the hydrodynamic model are discussed. The basic condition for dynamic seal availability is presented. The rotating speed and radius of the shafts should be decreased. The work can provide proof of a seal design or suggest ways to improve the seal capacity of magnetic fluid seals.

Design and Application of Automatic Test System of Soil Water Characteristic Curve

[Objective] In order to better meet the requirement of crops on a more and more accurate water content under various planting environment of modern agri-culture, an automatic test system of soil water characteristic curve was designed by combining the conceptions of soil moisture content and soil water potential. [Method] Electronic soil moisture tension meter was used to determine the real-time tension value of soil moisture in the tested container, and the electronic Weigh sensor was used to determine soil Weigh. Minusing method was used to calculate soil moisture content, based on which the soil water characteristic curve was plotted. [Result] Through the filed survey of 2 different kinds of soil in Jiangsu Province, the results were as fol ows： soil of different composition showed different trend in soil water characteristic curve that the soil water characteristic relation of the sandy soil in the old course of the Yel ow River in Xuzhou was Y=-0.000 2X3＋0.027 7X2-1.644 5X＋38.161, R2=0.991 9; while the soil water characteristic relation of the saline-alkali soil in Jinhai Farm of Dafeng was Y=-0.00 2X2-0.426X＋39.905, R2=0.991 3. [Con-clusion] The automatic test system of soil water characteristic curve soil water char-acteristics curve could reflect soil moisture content and soil water potential, as wel as reflect the effectiveness of soil water to plant growth, providing basis for the sci-entific irrigation.

A column study of the hydro-mechanical behavior of mature fine tailings under atmospheric drying

In this paper, the hydro-mechanical behavior and physical properties of mature fine tailings(MFT) under atmospheric drying are investigated through a column study. In the study, evaporation takes place in the development of suction in the upper parts of the column and increasing suction leads to higher strength in the tailings. After 5 days, the suction in the first lift is around 17 k Pa in the upper part of the column.When a second lift is added, the first lift initially loses strength but over a 30 days' period, the strength is recovered to its prior value and suction in the second lift reaches 500 k Pa. The vane shear strength values show a substantial increase in the strength of the MFT after 30 days under atmospheric drying and drainage. The 90% strength found in the column exceeds the threshold(5 k Pa). The hydraulic-mechanical properties of the deposited tailings are closely coupled due to several mechanisms, such as evaporation,drainage, self-consolidation, suction and crack development. The findings of this study will provide a better understanding of the placement behavior of multiple lifts of MFT and thus contribute to reclamation design standards and reduce the use of dedicated disposal areas.

Long-term kinematics and mechanism of a deep-seated slow-moving debris slide near Wudongde hydropower station in Southwest China

Long-term kinematic research of slow- moving debris slide is rare despite of the widespread global distribution of this kind. This paper presents a study of the kinematics and mechanism of the Jinpingzi debris slide located on the Jinsha river bank in southwest China. This debris slide is known to have a volume of 27×106 ms in active state for at least one century. Field survey and geotechnical investigation were carried out to define the structure of the landslide. The physical and mechanical properties of the landslide materials were obtained by in-situ and laboratory tests. Additionally, surface and subsurface displacements, as well as groundwater level fluctuations, were monitored since 2005. Movement features, especially the response of the landslide movement to rainfall, were analysed. Relationships between resisting forces and driving forces were analysed by using the limit equilibrium method assuming rigid-plastic frictional slip. The results confirmed a viscous comoonent in the long-term continuous movement resulting in the quasioverconsolidated state of the slip zone with higher strength parameters than some other types of slowmoving landslides. Both surface and subsurface displacements showed an advancing pattern by the straight outwardly inclined （rather than gently or reversely inclined） slip zone, which resulted in low resistance to the entire sliding mass. The average surface displacement rate from 2005 to 2016 was estimated to be 0.19-0.87 mm/d. Basal sliding on the silty clay seam accounted for most of the deformation with different degrees of internal deformation in different parts. Rainfall was the predominant factor affecting the kinematics of Jinpingzi landslide while the role of groundwater level, though positive, was not significant. The response of the groundwater level to rainfall infiltration was not apparent. Unlike some shallow slow-moving earth flows or mudslides, whose behaviors are directly related to the phreatic groundwater level, the mechanism for Jinpingzi landslide kinematics is more likely related to the changing weight of the sliding mass and the downslope seepage pressure in the shallow soil mass resulting from rainfall events.

Hydraulic Resistance and Capacitance in the Soil-Plant System

In this paper, the hydraulic resistances and capacitances were evaluated. based on the development of non-(?) model of water flow in the soil-plant system and the simulating experiment work.The results show that the mean hydraulic resistance in the soil-plant system is 6.79×109 MPa·S·m-3; the mean hydraulic capacitance in the system is 5.2×107m3·MPa-1. In the components of hydraulic capacitance in the system, the capacitance in soil (81.8×10-6m3·MPa ) is the biggest and its variability with suii water potential is extremely strong, the capacitance in plant (5.3×10-7m3·MPa-1) is much smaller than that in soil, and the capacitance in shoots (15.5×10-7m3·2MPa-1) is bigger than that in roots (8.4×10-7m3·2MPa-1). An interesting result is that the capacitance in plant is almost equivalent to that in the soil-plant system.

Quo Vadis Archimedean Turbines Nowadays in Greece, in the Era of Transition？

According to recent hydropower inventories, the first aim of this paper is to prove that Greece is a real ＂Archimedean Soft Small Hydro Development Terra Incognita＂. It is a country in the Era of Transition of nowadays, having an important unexploited hydropower potential of several TWh and thousands of MW. The second goal is to present the results of rediscovering the old screw pumps and the always-modern Archimedean cochlear screw ideas as a series of soft hydropower turbines with inclined axis rotors and floating spiral screw devices. By following the similarity methodology, a few small-scale models of cochlear rotors were designed, developed and tested in an Armfield hydraulic channel. The conventional and unconventional, low or zero-head screw turbines, could efficiently harness the important and unexploited Greek small potential and kinetic hydraulic energy of all the natural watercourses, the man-made open urban or rural channels and the most important tidal or sea currents, producing useful green electricity. The very promising low-head hydropower inventory of Greece, the preliminary experimental results and the research studies of cochlear projects in watercourses, hydraulic works, tidal conditions of Euripus Strait and in the mysterious ＂Sea River Current of Cephalonia＂, seems to give a good answer to the question ＂Quo Vadis Archimedes nowadays in Greece, in the Era of Transition？＂.

Development of hydraulic power unit and accumulator charging circuit for electricity generation,storage and distribution

It is the purpose of the present paper to convert hydraulic energy to electric energy and saves both the pressure and electrical energy for re - use during the next system upstroke using two secondary units coupled to induction motor to drive cylinder loads. During upstroke operation, the variable pump/motor （P/M） driven by both electric motor and the second （P/M） works as hydraulic pump and output flow to the cylinders which drive the load. During load deceleration, the cylinders work as pump while the operation of the two secondary units are reversed, the variable （P/M） works as a motor generating a torque with the electric motor to drive the other （P/M） which transforms mechanical energy to hydraulic energy that is saved in the accumulator. When the energy storage capacity of the accumulator is attained as the operation continues, energy storage to the accumulator is thermostatically stopped while the induction motor begins to work as a generator and generates electricity that is stored in the power distribution unit. Simulations were performed using a limited PT2 Block, i.e. 2nd-order transfer function with limitation of slope and signal output to determine suitable velocity of the cylinder which will match high performance and system stability. A mathematical model suited to the simulation of the hydraulic accumulator both in an open-or close-loop system is presented. The quest for improvement of lower energy capacity storage, saving and re-utilization of the conventional accumulator resulting in the short cycle time usage of hydraulic accumulators both in domestic and industrial purposes necessitates this research. The outcome of the research appears to be very efficient for generating fluctuation free electricity, power quality and reliability, energy saving/reutilization and system noise reduction.

Involvement of cyclic electron flow in irradiance stress responding and its potential regulation of the mechanisms in Pyropia yezoensis

Pyropia yezoensis, belongs to the genus of P orphyra before 2011, inhabit on intertidal zone rocks where irradiation changes dramatically, implying that the seaweed has gained certain mechanisms to survive a harsh environment. Based on the photosynthetic parameters with or without the inhibitors determined by a Dual-PAM-100 apparatus, we investigated the photosynthetic performance and the changes in electron fl ow that occurred during the algae were stressed with dif ferent light intensities previously. When the irradiation saturation was approaching, the CEF around PS I became crucial since the addition of inhibitors usually led to an increase in non-photochemical quenching. The inhibitor experiments showed that there were at least three dif ferent CEF pathways in Py. yezoensis and these pathways compensated each other. In addition to maintaining a proper ratio of ATP/NAD(P)H to support effi cient photosynthesis, the potential roles of CEF might also include the regulation of dif ferent photoprotective mechanisms in Py. yezoensis. Under the regulation of CEF, chlororespiration is thought to transport electrons from the reduced plastoquinone(PQ) pool to oxygen in order to mitigate the reduction in the electron transfer chain. When irradiation was up to the high-grade stress conditions, the relative value of CEF began to decrease, which implied that the NADP+ pool or PQ + pool was very small and that the electrons were transferred from reduced PS I to oxygen. The scavenging enzymes might be activated and the water-water cycle probably became an ef fective means of removing the active oxygen produced by the irradiation stressed Py. yezoensis. We believe that the dif ferent mechanisms could make up the photoprotective network to allow Py. yezoensis for survival in a highly variable light stress habitat, which may enlighten scientists in future studies on irradiance stress in other algae species.

Experimental assessment of two-phase bubble pump for solar water heating

The research goal is to develop a new solar water heater system(SWHS) that uses a solar bubble pump instead of an electric pump.The pump is powered by the steam produced from an evacuated tube collector.Therefore,heat could be transferred downward from the collector to a hot water storage tank.The designed system consists of two sets of heat-pipe evacuated tube collectors,a solar bubble pump installed at an upper level and a water storage tank with a heat exchanger at a lower level.Discharge heads of 1 and 5 m were tested.The bubble pump could operate at the collector temperature of about 90-100 ℃ and vapor gage pressure of 80-90 kPa.It is found that water circulation within the SWHS depends on the incident solar intensity and system discharge head.Experimental investigations are conducted to obtain the system thermal efficiencies from the hourly,daily and long-term performance tests.The thermal performance of the proposed system is compared with conventional solar water heaters.The results show that the proposed system achieves system characteristic efficiency of 10% higher than that of the conventional systems using electric pump if taking the consumption of electric power into account.And the former is a zero carbon system.

Crack initiation rate of brittle rock under thermal-hydro-mechanical coupling condition

A calculation formula of thermal-hydro-mechanical(THM)coupling crack initiation rate for brittle rock was derived based on the energy conservation law.The self-designed THM coupling fracture test with conductive adhesive electrical measurement method was applied to measuring the THM coupling crack propagation rate of brittle rock continuously.Research results show that both calculation and test results of crack initiation rate increased with increase of the temperature and the hydraulic pressure.They are almost in good agreement,which can prove validity of the calculation formula of THM coupling crack initiation rate.

Effect of ageing temperature on precipitation of A1-Cu-Li-Mn-Zr alloy

The precipitation behaviors of an A1-Cu-Li-Mn-Zr alloy at different ageing temperatures （120, 160 and 200 ~C） were investigated using Vickers hardness measurements and transmission electron microscopy （TEM） characterization. Age hardening curves show an increase in precipitation kinetics with increasing ageing temperature. The results of TEM show that for the samples peak aged at 120 ~C, the amount of g＇ （A13Li）, GP zones/0＇ （A12Cu） and Z （A15Cu6Li2） phases is obviously higher than that of T1 （A12CuLi） precipitates; while the samples peak aged at 160 and 200 ~C are usually dominated by T1 phase with a minor fraction of GP zones/0＇ and g＇, and the Z phase almost does not form. In addition, quantitative analysis on the T1 platelets demonstrates that the samples peak aged at 200 ~C have larger plate diameter and smaller area fraction of T1, as compared to the samples peak aged at 160 ~C. Correspondingly, the possible reasons for such phenomena are discussed.