Finite element numerical calculation is widely used in hydraulic engineering.Its accuracy and error is one of the important problems that need to be considered and controlled.Studies on this issue can provide technical support for the FEM in the design and check of hydraulic engineering.Gravity dam was used as the object of research.The factors influencing the error in finite element stress calculation were analyzed by comparing the resultant load value of the gravity dam with the internal force value of the dam base surface from finite element calculation (integral value of stress of dam base surface).The results showed that extracting the stress from different objects results in different finite element calculation error,even under the same stress state.It is necessary to select the proper object to extract the stress from according to the research goal and error control requirements.The error can be greatly reduced by making the thin-layer foundation adjacent to the dam the same size and in the same constraint condition as the dam body.Proper determination on mesh size,simulation range of foundation,number of paths to extract the stress,and spacing of extracting points can meet the required precision without overly consuming resources or time.The results can provide reference for controlling the finite element calculation error in similar projects.

The operation safety of spillway structure can be influenced by anti-sliding stability of spillway sidewall .To study the stability of spillway sidewall ,the three-dimensional finite element calculation model of the spillway sidewall in complex stepped foundation surface was established by using ANSYS software ,which based on one project ,the normal stress and shear stress of the complex stepped foundation surface was calculated in this paper .It obtained the total effect and total resistance by integral ,and the stability against sliding of the spillway sidewall was discriminated by partial coef-ficient under limit state .The calculation results show that the maximum compressive stress of spillway sidewall surface is less than 3 .9 MPa while the maximum tensile stress is less than 0 .5 MPa ,and the results meet the foundation bearing capacity .The trends of safety margin of sidewall section from upstream to downstream are similar to sine curve and the anti-sliding stability of each section during operation period meets the requirement .It provides important reference for practical engineering design and safety assessment .

In order to study influences of force attenuation and cable failure of prestressed anchor on the stability of the right guide wall, taking the actual situation of a project as an example, the ANSYS finite element software was used to simulate the spillway right guide wall and to validate the scheme feasibility of the given anchor reinforcement, also to study impacts of the constant decrease of prestressed anchor ca-ble and the failure of single row anchor on the structure stability of the right guide wall. The results showed that the given anchor cable reinforcement scheme is feasible. The structure stability of the right guide wall continues to decrease with the attenuation of the prestressed anchor cable, the structure stabili-ty of the right guide wall reaches ultimate bearing state when the prestressed anchor cable attenuation de-creased from 3000kN to 500kN, the top anchor rope failure has the greatest effect on the structure stabili-ty of the right guide wall.

为了改善预应力闸墩受力状态,同时在节约成本的基础上,保证其结构的安全运行,从锚块与闸墩接触方式、锚索吨位和次锚索位置三个方面进行优化研究,对预应力闸墩进行优化分析,进而改善闸墩颈部、锚块和锚固洞的应力状态.结果表明:锚块底部与闸墩采用分离式接触方式,可以大大降低锚块下游面与闸墩交界处的拉应力.预应力锚索的拉锚系数的增大有利于减小闸墩颈部的拉应力,但同时锚块和锚固洞周围的拉应力会有所增大.次锚索靠近锚块下游面,可以更好地抵消主锚索对锚块产生的局部拉应力,但对闸墩颈部和锚固洞的影响很小.此算例推荐锚块底部与闸墩采用分离式接触方式;拉锚系数采用1.95,即主锚索永存吨位为3 200 kN,次锚索永存吨位为1 900 kN;水平次锚索尽量靠近锚块下游面布置.

This paper mainly studies the relative navigation between two navigation modules, and realizes the real-time measurement of the relative position between the two navigation module. Location result in different coordinate system conversion was been discussed. The navigation module output data was analyzed. The use of C# language procedures realize the extraction of the positioning data in the Visual Studio compiler environment. The two module positioning information was been processed, it calculates the relative position information of two navigation module.

T he research in decoding the raw binary data of navigation receiver has impor-tant significance for improving receiver positioning .In this paper ,the original binary format of Huaxun GPS/BD dual-mode receiver output were discussed ,a method of using matlab to decode its output binary data was presented ,in order to extract the observation value ,e-phemeris ,and other information which are required for GPS data processing .This method be able to decode the observational data concisely and rapidly .These information has the vital significance in research of navigation principle ,pseudo-range differential and carrier phase differential .

The classification and synthesis are the effective ways to solve the time-varying problem in electrical load,as well as the key link in load modeling utilization.Based on the weighted average synthesis method of induced motor parameters and in combination with the principle of standard measured samples synthesis,this paper suggests the comprehensive modeling method of model parameter clustering center by means of the model parameter clustering center as the characteristics of similar loads.The results from the actual example tests,comparative and analysis indicate that this synthesis method is effective and feasible.

Since the traditional load model can not overcome the problems such as nonlinear and discontinuous in load modeling effectively,a load modeling method based on general regression neural networks(GRNN) is proposed.The capacity of universal approximation and the best approximation as well as the merits of steady networks,fast convergence is used in GRNN to establish a new comprehensive load model in power system.Then it is compared with two improved back propagation neural networks.The simulation results prove its effectiveness and accuracy when the proposed model is adopted in power system load identification.

<正>彩色喷墨打印机在家庭与商业应用中的普及,已经是大势所趋。数码时代的到来也让更多用户开始关注这一大输出设备。家庭对于数码技术的应用需求已经不单单只是局限在使

<正>彩色喷墨打印机在家庭与商业用户应用的普及已是大势所趋,数字时代的到来也让更多用户开始关注这一输出设备。彩色喷墨打印墨水等打印材料的社会需求呈稳步上升的趋势。喷墨打印用器水分颜料型墨水和染料型墨水,颜料型墨水中的颜料不能溶解于水,墨水的粒度较大,易堵塞喷墨头：而染料型果水的染料呈溶解状态,不存在粒度问题,只要添加其它组分以满足墨水系统一定的基本性能,就可方便地使用。本文试图通过对黑色染料型墨水基本性能指标的测试,研究墨水中染料、黏度调节剂及表面活性剂等主要组分对墨

Water solubility and function of the three direct black dyestuffs were tested.The optimal proportion of solvent and percentage of other auxiliary agents was determined by orthogonal experiment.The prepared ink was poured into the hollow ink box;and the printing result was proved to be good through probation.

The basic formula of four-colors ink through plenty of experiments,then test color density,liquidity,continuity and intermittence to confecting inks,confecting inks formula improved by testing result.As a result,make sure the proportion of black dye is 4.2%,and the formula of the dyestuff C.I.Direct Black 19 ∶C.I.Direct Black 168 ∶DyestuffⅠ=3∶1∶1,and when using two surfactants,printing liquidity is better,at same time compare to printing result with national inks,and the result is that confecting inks excels national inks in soaking paper,curliness and edge definition.

<正>与颜料着色剂相比,染料着色剂的主要优点是色谱齐全,具有优良的水溶性,配制方便,成本低廉,易于制成高浓度的墨水,墨水稳定性好,不易堵塞喷墨头,故打印

To produce pause flow in surge irrigation and solve the key technique problems of surge flow irrigation, a new water-saving irrigation technique-the siphon surge flow irrigation with low pressure pipes was put forward based on the principle of siphon. The surge irrigation is realized by using an intermittent flow generating device and a regulating pond to form automatically intermittent flow in the outlet low distribution pressure pipeline. The technique combines surge flow with low-pressure pipeline harmoniously, exerting each advantage fully to attain the best water-saving result. The constitution and each part's function of the system were introduced, and the principle to form intermittent flow was analyzed. Moreover, indoor experiments have been carried out to test the feasibility of the new system which laid the foundation for further field experiment.

<正>1实验内容及方法1)实验仪器DNJ-8S数字显示粘度计、JK99B型全自动界面张力仪、PHS-3C酸度计、DDS-12数字电导率仪、电子天平、烧杯、玻璃棒、胶头滴管、量筒、大中小勺以及300目和600目的标准筛。2)实验药品去离子水、有机溶剂、活性红染料、表面活性剂、粘度调解剂、消泡剂、催干剂和pH值调节剂。