共查询到20条相似文献，搜索用时 15 毫秒
1.
The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. The simulation of the flow field characteristics was conducted via the FLUENT computational fluid dynamics package. Effects of the inlet conditions and the nozzle dimensions on the reaction thrust of a water jet were addressed particularly. The reaction thrust experiments were performed on a custom-designed test apparatus. The experimental results reveal that a） the nozzle diameter and the inlet conditions exert great influence on the water jet reaction thrust; and b） for L≤4d0, where the nozzle is treated as a thin plate-orifice, the reaction thrust is independent of nozzle length; for L〉4d0, where the nozzle is treated as a long orifice, the reaction thrust can reach maximum under the condition of a certain flow rate. These findings lay a theoretical foundation for the design of nozzles and have significant value, especially for the future development of high-oressure water-let orooulsion technology. 相似文献
2.
A laboratory-scale trickling biofilter column,filled with Raschig rings and inoculated with Pseudomonas putida (ATCC 1785)was used to purify chlorobenzene contained waste gases.Sodium dodecyl sulfonate(SDS)was used to enhance the performance of trickling biofllter.Purification performance of the trickling biofilter was examined for chlorobenzene inlet concentration of 1.20～5.04 g/m~3 at different EBRTs between 76～153 s.Without SDS addition,with simultaneous increase in chlorobenzene inlet loading rate and gas flow rate,100% removal efficiency was achieved at EBRT of 109 s and inlet loadings below 5120 mg/m~3.Addition of SDS to nutrient solution led to improvement of trickling biofilter purification performance. By introducing 25 mg/L SDS,the removal efficiency was increased by 21% and elimination capacity up to 234 g/(m~3.h)was achieved at chlorobenzene inlet loading of 241 g/(m~3.h).Although SDS concentration experienced a low rate reduction after continuous nutrient solution recirculation,this result has little influence on trickling biofilter's removal efficiency in monitoring period. 相似文献
3.
In this paper, we discuss a class of piecewise linear hyperbolic maps on the 2-torus. These maps arise in the second-order digital fdter with two＇ s complement arithmetic. By introducing codings underlying the map operations, we give some admissibility conditions for symbolic sequences and find some periodic properties of these symbolic sequences. Then we use these conditions to check the admissibility of periodic symbol sequences. 相似文献
4.
This paper aims to investigate exact solutions for a second-grade fluid flow with the inverse method. By assuming the relation
between the vorticity field and the streamfunction, the exact solutions of the motion of plane second-grade fluids are investigated
and obtained. The solutions obtained include simple Couette flows, slit jet flows and uniform flows over a series of distributed
obstacles.
Project supported by the National Natural Science Foundation of China (Grant No.10472063) 相似文献
5.
In this paper, dynamics in the oscillations of the relative atomic population in two periodically driven and weakly coupled Bose-Einstein eondensates (BECs) was qualitatively studied. Using the well-known Melnikov method, the conditions of existence of the periodic and chaotic coherent atomic tunnellings were given in the model. Our results indicate the typical route from bifurcation of the limited circles to chaos, and are in agreement with the previous numerical results. 相似文献
6.
WANG Xiao jing ZHANG Zhi ming ZHANG Guo xian 《上海大学学报(英文版)》1999,3(3):234-237
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｗｉｔｈｔｈｅｉｎｃｒｅａｓｉｎｇｃａｐａｃｉｔｙｏｆｈｙｄｒｏｇｅｎｅｒａｔｏｒｓａｎｄｔｈｅｒｅｌｅｖａｎｔｌｙｉｎｃｒｅａｓｉｎｇｓｉｚｅａｎｄｌｏａｄｉｎｇｏｆｔｈｒｕｓｔｂｅａｒｉｎｇｓ,ｔｈｅｃｏｎｆｉｇｕｒａｔｉｏｎｏｆｐａｄｓｕｐｐｏｒｔｅｄｏｎａｓｉｎｇｌｅｐｉｖｏｔｈａｓｍｏｒｅａｎｄｍｏｒｅｄｉｆｆｉｃｕｌｔｙｉｎｍｅｅｔｉｎｇａｌｌｔｈｅｄｅｍａｎｄｓｉｎｒｅａｌｏｐｅｒａｔｉｏｎｃｏｎｄｉｔｉｏｎｓ．Ｔｈｅｃｏｎｆｉｇｕｒａｔｉｏｎ… 相似文献
7.
A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed.
Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain the variation of the elastic
linkage deformation, an experimental platform mainly based on the device of micro aerial vehicles (MAVs) and a new control
system mounted on TMS320LF2407 are designed. This control system has its compacted configuration and reliability. Finally,
using this system to control the MAV for simulating the flying forward, experimental results show the MAV’s flight attitude
can be controlled based on the variation of the elastic linkage.
Project supported by the National Natural Science Foundation of China (Grant No.60605028), the National High-Technology Research
and Development Program of China (Grant No.2007AA04Z225), the Shanghai Rising-Star Program (Grant Nos.07QA14024, 07QH14006),
the Shanghai Shuguang Program (Grant No.07SG47), and the Shanghai Leading Key Laboratory of Mechanical Automation and Robotics
Science Foundation (Grant No.ZZ0805) 相似文献
8.
Absorption of NO2 into Na2S solution in a stirred tank reactor 总被引：1，自引：1，他引：0
To understand the absorption mechanism of nitrogen dioxide into a sodium sulfide solution, a stirred tank reactor with a plane gas-liquid interface was used to measure the chemical absorption rate of diluted nitrogen dioxide into sodium sulfide solution. The absorption rates under various experimental conditions were measured and the effects of experimental conditions on nitrogen dioxide absorption rate were discussed. The results show that, in the range of this study, nitrogen dioxide absorption rate increases with increasing sodium sulfide concentration, nitrogen dioxide inlet concentration, and flue gas flow rate, but decreases with increasing reaction temperature and oxygen content in flue gas. 相似文献
9.
1 Introduction Microactuators are the key devices of micro-electro-mechanical system( MEMS) . For many MEMS devicessuch as switches , optical attenuators , pumps andvalves to function, microactuators are required . Mo-tion of microactuators can be achieved by several kindsof actuation mechanisms . Electrostatic ,piezoelectric ,magnetostrictive, magnetic ,thermomechanical actua-tors have been reported[1-5].Among the different actu-ation principles ,the electrostatic actuationis predomi-nant… 相似文献
10.
喷嘴是水射流切割系统的关键元件，通过研究一级喷嘴直径、二级喷嘴直径、混合腔直径和喉管距、系统工作压力、磨料直径大小等对轴向射流速度的影响，为水切割喷嘴的优化设计奠定了基础，其结果可为高压水切割工具的设计提供参考依据。 相似文献
11.
1IntroductionIn recent years,there are many papers published ontoluene oxidation to benzaldehyde.The most i mpor-tant research works of these papers are electric oxida-tion and toluene oxidizied by using air in gas phase orin liquid phase.A novel technology for benzaldehydeproduction is developed,with which manganese sul-fate reacts with ammonium carbonate to yield manga-nese carbonate and ammoniun sulfate.Manganese car-bonate is baked for being changed into manganese ses-quioxide,which can ox… 相似文献
12.
Stabilization for a class of second-order switched systems with saturation constrains 总被引：1，自引：0，他引：1
This paper proposes a global stabilization method for a class of planar switched systems with input saturation constrains
by using a state feedback and switching strategy. This method is proved to be effective by analyzing the characteristics of
the trajectory of second-order linear systems with input saturation.
Project supported by the China Postdoctoral Science Foundation (Grant No.20070420643), the National Natural Science Foundation
of China (Grant No.60774059), and the Innovation Program of the Shanghai Municipal Science and Technology Commission (Grant
No.08DZ2272400) 相似文献
13.
LetB(X)andS(X)standfortheunitballandunitsphereofanormedspaceX ,respectively .x∈S(X)iscalledanextremepointofB(X) providedthatfory ,z∈B(X) ,x =y z2 implies y =z .DenotethesetofallextremepointsofB(X)byExtB(X) .XiscalledrotundprovidedthatS(X) =ExtB(X) .Therotundspacesarerelatedtotheoperationresearch ,thecontroltheory ,etc[1] . LetΦbeaevenconvexfunctionwithΦ(0 ) =0 ;Φ(u) >0 (u≠ 0 ) ;limu→ ∞ Φ (u) = ∞ .LetXbeanormedspace ,G Rnbeaboundedmeasurableset ,and (G ,∑ ,μ)beameasur… 相似文献
14.
卢义玉 《重庆大学学报(英文版)》2002,1(1):11-15
A new type jet, the oscillating & deflecting jet, is put forward and its oscillating and deflecting characteristics are investigated. The nozzle of the self-oscillating & deflecting water jet consists of an upstream nozzle, a downstream nozzle, an oscillating chamber and two switches. It is experimentally shown that the deflective angle may reach 9.53 degree. The generated pressure fluctuation is very regular and the jet can efficiently increase the ability for breaking and cutting by eliminating the water cushion effect associated with a continuous jet. 相似文献
15.
蒋易强 《十堰职业技术学院学报》2011,24(4):106-110
机耕船驱动轮入土深度不仅影响驱动轮的最大水平推力、驱动轮和船体的支承反力、滚动阻力以及船体的行驶阻力等,而且影响机耕船的滑转率、牵引效率、燃油经济性等。增加入土深度,虽然增大了剪切面积,可使最大水平推力增加,牵引附着性能增强,滑转损失功率减小,但会使滚动阻力增加,功率损耗增大。因此,在保证牵引性能的前提下,入土深度必须可调,而且应尽量减小。入土深度有驱动轴、船体和驱动轮半径可调等三种方式。通过对关于机耕船驱动轮入土深度的文献进行研究,为研制更加方便地调节入土深度的装置提供借鉴意义。 相似文献
16.
The choice of self-concordant functions is the key to efficient algorithms for linear and quadratic convex optimizations,
which provide a method with polynomial-time iterations to solve linear and quadratic convex optimization problems. The parameters
of a self-concordant barrier function can be used to compute the complexity bound of the proposed algorithm. In this paper,
it is proved that the finite barrier function is a local self-concordant barrier function. By deriving the local values of
parameters of this barrier function, the desired complexity bound of an interior-point algorithm based on this local self-concordant
function for linear optimization problem is obtained. The bound matches the best known bound for small-update methods.
Project supported by the National Natural Science Foundation of China (Grant No.10771133), the Shanghai Leading Academic Discipline
Project (Grant No.S30101), and the Research Foundation for the Doctoral Program of Higher Education (Grant No.200802800010) 相似文献
17.
n-soliton-like solutions of three non-isospectral equations, the non-isospectral mKdV equation, the non-isospectral sine-Gordon equation and the non-isospeetral nonlinear Schroedinger equation were obtained by using the Hirota method. 相似文献
18.
通过以恒温恒速浇注为中心的生产组织方式,控制钢水成分;通过提高连铸机结晶器制作质量及强化检查制度,调整结晶器振动参数,控制结晶器液面波动;改善结晶器水质及降低进水温度,改善二冷水质,减少喷嘴堵塞;使用稀土包芯线.通过以上措施使2003年中厚析裂纹发生率控制在2%以下,同时中厚板轧后废品量比2002年降低了53%. 相似文献
19.
Network based data management is the backup/restore mechanism used in a data storage center. This paper presents a new network based data management-NDMP-Plus, a revision of network data management protocol. Components and the working mechanism of the NDMP-Plus architecture are first discussed. Two new techniques in NDMP-Plus-virtual storage layer （VSL） and negotiation mechanism are then studied. VSL is a crucial component to achieve flexibility, and the negotiation mechanism is a key to improve performance. Furthermore, experiments are carried out to evaluate the performance of NDMP-Plus. The result suggests that NDMP-Plus has stronger flexibility and better performance than NDMP. 相似文献
20.
建立了浮环式推力轴承的数学模型，分析了轴承的承载能力、摩擦功耗、温升、浮环－转子的转速比等静态特性及结构参数．实验验证了理论计算的正确性． 相似文献