饱和蒸气密度、焓和蒸发潜热的通用对比态推算式

本文提出了新的饱和蒸气密度的通用对比态推算式,并分别以标准沸点下的蒸发潜热和临界温度与标准沸点温度之差为基准,对蒸发潜热和温度无量纲化导出了工质蒸发潜热通用对比态方程,结合饱和液体焓通用对比态方程导出了饱和蒸气焓通用对比态方程,揭示出饱和蒸气焓通用对比态方程为双变量函数,除有温度变量外还包含有表示物质差异的变量。对多种物质的文献值计算比较,以上方程的总的平均绝对偏差分别为0.43％、0.87％和O.35％。

有机液体导热系数的新推算式——通用相关式和醇、烷、芳香族的具体推算式

本研究用相关法给出了有机液体导热系数的通用相关式和醇、烷、芳香族的液体导热系数的具体推算式,经比对,22种液体的计算值与TPRC 及其他权威参考文献的推荐值之间的平均偏差约为-1.5%,本推算式具有相关参数少和精度高的优点.

斜拉桥弯曲及扭转的一次固有周期的简易推算式

斜拉桥弯曲及扭转的一次固有周期的简易推算式（日）长井亚嗣，川治为了研究斜拉桥的抗风稳定性，进行了对弯曲及扭转一次振动次数的简单研究。虽然只凭这些不可能完成稳定性研究，但至少是在初步计划时做为一种简略的方法，而且目前斜拉桥的修建规模逐渐向长大方向发展，...

饱和液体密度的推算法和通用算式

本文选出了可构成饱和液体密度通用对比方程的参数△ρｒ和△Ｔｒ，给出了饱和液体密度的一般推算法和具体通用算式，该算式除水以外，适用于包括氨在内的各种制冷剂，也适用于氮、氧等液体。通用算式精度约０．３１％，满足工程所需精度。本文还给出了计算水饱和密度的高精度算式。

顶管法施工计算的差异分析

对顶管法施工国内规范、标准与日本下水道协会《下水道推进工法的指针和解说》中推算式的差异进行分析。对比发现,对顶管施工计算结果和顶管设备选用影响较大的计算参数,在编制顶管施工计算书和顶管施工方案时应谨慎取值,确保施工方案可行。

Prediction of Planing Craft Motion Based on Grey System Theory

In order to minimize the harm caused by the instability of a planing craft, a motion prediction model is essential. This paper analyzed the feasibility of using an MGM（1,N） model in grey system theory to predict planing craft motion and carried out the numerical simulation experiment. According to the characteristics of planing craft motion, a recurrence formula was proposed of the parameter matrix of an MGMfl,N） model. Using this formula, data can be updated in real-time without increasing computational complexity significantly. The results of numerical simulation show that using an MGM（1,N） model to predict planing motion is feasible and useful for prediction. So the method proposed in this study can reflect the planing craft motion mechanism successfully, and has rational and effective functions of forecasting and analyzing trends.

Rock burst induced by roof breakage and its prevention

Based on the research on rock burst phenomenon induced by the breakage of thick and hard roof around roadways and working faces in coal mines, a criterion of rock burst induced by roof breakage （RBRB） was proposed and the model was built. Through the model, a method calculating the varied stresses induced by roof breakage in support objects and coal body was proposed and a unified formula was derived for the calculation of stress increment on support objects and coal body under different breaking forms of roof. Whilst the formula for calculating dynamic load was derived by introducing dynamic index Kd. The formula was verified in Huating Mine by stress measurement. According to the formula for stress increment calculating, the sensitivities of dynamic load parameters were further studied. The results show that the thickness and breaking depth of roof, width of support objeet are the sensitive factors. Based on the discussion of the model, six associated effective methods for rock burst prevention are obtained.

Numerical simulation of bubble chaotic motion in a cavitating water jet

A computational fluid dynamics (CFD) method is developed to investigate the radical motion of single cavitating bubble in the oscillating pressure field of a cavitating water jet. Regarding water as a compressible fluid, the simulation is performed at different oscillating frequencies. It is found that the bubble motion presents obvious nonlinear feature, and bifurcation and chaos appear on some conditions. The results manifest the indetermination of the cavitating bubble motion in the oscillating pressure field of the cavitating water jet.

Design of dead reckoning system for mobile robot

A dead reckoning system for a wheeled mobile robot was designed, and the method for robot’s pose estimation in the 3D environments was presented on the basis of its rigid-body kinematic equations. After analyzing the locomotion architecture of mobile robot and the principle of proprioceptive sensors, the kinematics model of mobile robot was built to realize the relative localization. Considering that the research on dead reckoning of mobile robot was confined to the 2 dimensional planes, the locomotion of mobile robot in the 3 coordinate axis direction was thought over in order to estimate its pose on uneven terrain. Because the computing method in a plane is rather mature, the calculation in height direction is emphatically represented as a key issue. With experimental results obtained by simulation program and robot platform, the position of mobile robot can be reliably estimated and the localization precision can be effectively improved, so the effectiveness of this dead reckoning system is demonstrated.

THE MIGRATION SCHEME BASED ON SCHEMA THEOREM OF PGAs

Genetic Algorithms (GAs) are efficient non-gradient stochastic search methods and Parallel GAs (PGAs) are proposed to overcome the deficiencies of the sequential GAs, such as low speed, aptness to local convergence, etc. However, the tremendous increase in the communication costs accompanied with the parallelization stunts the further improvements of PGAs. This letter takes the decrease of the communication costs as the key to this problem and advances a new Migration Scheme based on Schema Theorem (MSST). MSST distills schemata from the populations and then proportionately disseminates them to other populations, which decreases the total communication cost among the populations and arms the multiple-population model with higher speed and better scalability.

On Recursion Operator of the q-KP Hierarchy

It is the aim of the present article to give a general expression of flow equations of the q-KP hierarchy.The distinct difference between the q-KP hierarchy and the KP hierarchy is due to q-binomial and the action of q-shift operator θ, which originates from the Leibnitz rule of the quantum calculus. We further show that the n-reduction leads to a recursive scheme for these flow equations. The recursion operator for the flow equations of the q-KP hierarchy under the n-reduction is also derived.

New fundamental quantum mechanical operator-ordering identities for the coordinate and momentum operators

In quantum mechanics theory one of the basic operator orderings is Q-P and P-Q ordering,where Q and P are the coordinate operator and the momentum operator,respectively.We derive some new fundamental operator identities about their mutual reordering.The technique of integration within Q-P ordering and P-Q ordering is introduced.The Q-P ordered and P-Q ordered formulas of the Wigner operator are also deduced which makes arranging the operators in either Q-P or P-Q ordering much more convenient.

One Hair Postulate for Hawking Radiation as Tunneling Process

For Hawking radiation, treated as a tunneling process, the no-hair theorem of black hole together with the law of energy conservation is utilized to postulate that the tunneling rate only depends on the external qualities(e.g., the mass for the Schwarzschild black hole) and the energy of the radiated particle. This postulate is justified by the WKB approximation for calculating the tunneling probability. Based on this postulate, a general formula for the tunneling probability is derived without referring to the concrete form of black hole metric. This formula implies an intrinsic correlation between the successive processes of the black hole radiation of two or more particles. It also suggests a kind of entropy conservation and thus resolves the puzzle of black hole information loss in some sense.

Flow rate limitation in open wedge channel under microgravity

A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of the liquid free surface. A maximum flow rate is achieved when the curvature cannot balance the pressure difference leading to a collapse of the free surface. A 1-dimensional theoretical model is used to predict the critical flow rate and calculate the shape of the free surface. Computa- tional Fluid Dynamics tool is also used to simulate the phenomenon. Results show that the 1-dimensional model overestimates the critical flow rate because extra pressure loss is not included in the governing equation. Good agreement is found in 3-dim- ensional simulation results. Parametric study with different wedge angles and channel lengths show that the critical flow rate increases with increasing the cross section area; and decreases with increasing the channel length. The work in this paper can help understand the surface collapsing without gravity and for the design in propellant management devices in satellite tanks.