Research on Design Method of the Full Form Ship with Minimum Thrust Deduction Factor

In the preliminary design stage of the full form ships, in order to obtain a hull form with low resistance and maximum propulsion efficiency, an optimization design program for a full form ship with the minimum thrust deduction factor has been developed, which combined the potential flow theory and boundary layer theory with the optimization technique. In the optimization process, the Sequential Unconstrained Minimization Technique（SUMT） interior point method of Nonlinear Programming（NLP） was proposed with the minimum thrust deduction factor as the objective function. An appropriate displacement is a basic constraint condition, and the boundary layer separation is an additional one. The parameters of the hull form modification function are used as design variables. At last, the numerical optimization example for lines of after-body of 50000 DWT product oil tanker was provided, which indicated that the propulsion efficiency was improved distinctly by this optimal design method.

INVESTIGATION ON THE APPLICATION OF THE BOUNDARY ELEMENT METHOD TO THE SPILL GROOVED THRUST BEARING

An application of the boundary element method (BEM) is presented to calculate the behaviors of a spiral grooved thrust bearing (SGTB). The basic reason is that the SGTB has very complex boundary conditions that can hinder the effective or sufficient applications of the finite difference method (FDM) and the finite element method (FEM), despite some existing work based on the FDM and the FEM. In other to apply the BEM, the pressure control equation, i. e., Reynolds' equation, is first transformed into Laplace's and Poisson's form of the equations. Discretization of the SGTB with a set of boundary elements is thus explained in detail, which also includes the handling of boundary conditions. The Archimedean SGTB is chosen as an example of the application Of BEM, and the relationship between the behaviors and structure parameters of the bearing are found and discussed through this calculation. The obtained results lay a solid foundation for a further work of the design of the SGTB.

Aerodynamics of indirect thrust measurement by the impulse method

The aerodynamic aspects of indirect thrust measurement by the impulse method have been studied both experimentally and numerically. The underlying basic aerodynamic principle is outlined, the phenomena in subsonic, supersonic and arc-heated jets are explored, and factors affecting the accuracy of the method are studied and discussed. Results show that the impulse method is reliable for indirect thrust measurement if certain basic requirements are met, and a simple guideline for its proper application is given.

INVESTIGATION OF FLIGHT DYNAMICS OF THRUST VECTORING AIRCRAFT USING EXTENDED CONTINUATION METHODS

This paper presents the flight dynamical behavior of the thrust vectoring aircraft with extended bifurcation and continuation methods. In contrast to the standard bifurcation and continuation methods, the extended methods are capable of calculating the continuation curves of the equilibrium points for the particular type of trimming flight. Therefore, these methods can not only give the performance measures of aircraft, but also determine the stability of trimming points. In this paper, the methods are used to verify the effectiveness of the thrust vectoring control law, to define the flight envelope boundary, to analyze the stability and controllability of trimming flight, and to predict the departures of the instable flight. The result shows that the extended methods provide more flight dynamic information and are useful in preliminary design of the thrust vectoring aircraft.

Orthogonal design to sift the optimal parameter of Neiguan acupuncture for cerebral infarction

The individual difference and non-repeatability in acupuncture have not only restricted the devel- opment of acupuncture, but have also affected the specificity of acupoints. The present study used instruments to control needle depth, lifting and thrusting frequency, and the duration of acupuncture. Effects of the quantified acupuncture were observed at Neiguan （PC6） with different stimulation parameters. A frequency of 1, 2, or 3 Hz and duration of 5, 60, or 180 seconds were used to observe cerebral blood flow and ratio of infarct volume recovery. Results showed that stimulation at Neiguan with a frequency of 1 Hz and long duration of 180 seconds or 2/3 Hz and long duration of 5/60 seconds significantly increased cerebral blood flow and decreased the ratio of infarct volume. In- teractions between frequency and duration play a critical role in quantified acupuncture therapy.

Dynamic simulation of a flexible spinning vehicle with the periodic varying thrust

The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.

Systematic improvement in Tong's B-type water drive method

Tong's B-type water drive method was proposed as early as the 1970s and has been widely applied in the dynamic prediction and effective evaluation of oilfield development.Through extensive applications and studies,many researchers found that the statistical constants in the formula of the Tong's B-type water drive method(also referred to as the Tong's B-type formula)are not applicable to multiple types of reservoirs,especially low-permeability ones,due to the limited range of reservoir types when the formula was conceived.Moreover,they put forward suggestions to improve the Tong's B-type formula,most of which focused on the research and calculation of the first constant in the formula.For oilfields in the development stages of high or ultra-high water cuts,it is widely accepted that different types of reservoirs have different limit water cuts.This understanding naturally makes it necessary to further modify the Tong's B-type formula.It is practically significant to establish the water drive formula and cross plot considering that the two constants in the formula vary with reservoir type.By analyzing the derivation process and conditions of the Tong's B-type formula,this study points out two key problems,i.e.,the two constants 7.5 and 1.69 in the formula are not applicable to all types of reservoir.Given this,this study establishes a function between key reservoir parameters and the first constant and another function between key reservoir parameters and recovery efficiency.Based on the established two functions and considering that different types of oil reservoir have different limit water cuts,this study develops an improved Tong's B-type formula and prepares the corresponding improved cross plot.The results of this study will improve the applicability and accuracy of Tong's B-type water drive method in predicting the trend of water cut increasing for different types of oil reservoirs.

Numerical simulation on the stability of rock slope based on an improved SPH Method

The presence of random fissures has a great impact on rock slope stability.To investigate the failure modes and stability of rock slopes containing different types of pre-existing fissures,the fracture mark ξ was introduced to improve the kernel function in the traditional smoothed particle dynamics(SPH) method,and a novel numerical method,the improved kernel of smoothed particle hydrodynamics(IKSPH),was proposed to realise the microscopic damage characteristics of particles.The ‘random fissure generating method' has been proposed for random fissure generation,and the gravity increase method has been embedded into the IKSPH program,thereby realising the stability analysis of rock slopes considering crack propagation processes.A typical steep rock slope is taken as a numerical simulation example considering the random distributions of preexisting fissures,and its failure modes as well as the stability under different conditions were simulated.The results show that the failure processes of the rock slope contain propagations of microcracks and then macrocrack penetrations.When the fissure length is short,shallow collapse failure modes can be observed;when the fissure length is long,the deep layer slide occurs,and the slope stability decreases with an increase in fissure length.The micro and macrocrack surfaces are basically consistent with pre-existing fissure angles,and the safety factor is the least at a fissure angle of 30°.The greater the fissure density,the greater the number of macrocracks,and the stability decreases with an increase in the number of pre-existing fissures.The research results can provide some references for disaster protection and understanding the failure laws of rock slopes.Meanwhile,combining the geological survey results with the numerical simulations and developing a high-performance IKSPH program will be a future research direction.

The Scientific Outlook on Development：New and Modern form of Historical Resultant Theory

The Historical Resultant Theory and The Scientific Outlook on Development are consistent in essence,with the former serving as the philosophical foundation of the latter,and the latter being the new and modern form of the former.Thorough analysis and deep understanding of the dialectical relationship of the two theories contributes a lot to promoting China's localization of Marxism and to building a harmonious socialist society,both theoretically and practically.

Application of homotopy perturbation method to the radial thrust problem

The dynamics of a spacecraft propelled by a continuous radial thrust resembles that of a nonlinear oscillator.This is analyzed in this work with a novel method that combines the definition of a suitable homotopy with a classical perturbation approach,in which the low thrust is assumed to be a perturbation of the nominal Keplerian motion.The homotopy perturbation method provides the analytical(approximate)solution of the dynamical equations in polar form to estimate the corresponding spacecraft propelled trajectory with a short computational time.The accuracy of the analytical results was tested in an orbital-targeting mission scenario.

LOW-THRUST ORBIT TRANSFER BY COMBINING GENETIC ALGORITHM WITH REFINED Q-LAW METHOD

A new orbit transfer method is presented by combining the genetic algorithm（GA）with the refined Q-law method.Considering the energy consumption,the relative thrust efficiency is introduced as a threshold deciding whether to thrust or coast.GA is used to achieve the global time-optimal orbit transfer.The trajectory optimization problem is transformed into the constraint parameter optimization problem,thus the nonlinear two-point boundary value problem is avoided.The refined Q-law method integrated with the fuzzy logic control is adopted for the end course,the vibration is avoided and the high precision is achieved.The numerical simulation of satellite orbit transfer is implemented.Results show that the new method can achieve the time-optimal orbit transfer and the low energy consumption,thus improving the transfer precision.

Mathematica软件在非线性回归方法中的应用

将非线性模型线性化．然后用加权线性回归模型的方法去估计参数，并通过 Ｍａｔｈｍａｔｉｃａ软件实现计算．

Optimization of Permanent Magnet Skew in Permanent Magnet Linear Synchronous Motors Using Finite Element and Statistical Method

The permanent magnet skew is one of the techniques mostly used on the Permanent Magnet Linear Syn-chronous Motors (PMLSMs) to reduce the thrust ripple;even though there is a reduction in the amplitude of ripple and at the same time a significantly decrease of the motor’s thrust. This article proposes a combined technique between the Finite Elements Method (FEM) and statistical regression, to obtain an objective function that will allow the achievement of the optimal Permanent Magnet (PM) skew angle, so that there is a greater reduction of ripple with the minimum thrust diminishment.

Calculation methods of lubricant film pressure distribution of radial grooved thrust bearings

In order to calculate the pressure distribution of radial grooved thrust bearing, analytical and numerical methods were applied respectively. Grooved region and land region were linked by u- sing the mass conservations principle at the groove/land boundary in each method. The block-weight approach was implemented to deal with the non-coincidence of mesh and radial groove pattern in nu- merical method. It was observed that the numerical solutions had higher precision as mesh number exceed 70 x 70, and the relaxation iteration of differential scheme presented the fastest convergence speed when relaxation factor was close to 1.94.

Variation Characteristics of Ultraviolet Radiation over the North China Plain

In situ measured data of broadband solar radiation （Rs） and ultraviolet （Uv） radiation were used to investigate the spa- tiotemporal variation properties of Uv radiation and the ratio of Uv radiation to Rs over the North China Plain （NCP）. Based on the analysis, an empirical model for estimating Uv radiation under all weather conditions in this region was developed. The results showed that the annual Uv radiation over the NCP ranges from 0.38-0.52 MJ m^-2 d^-1. The highest value during the study period was recorded at the Changwu site, which is located near the margin of the Loess Plateau, while the lowest value appeared at the station in Beijing. The seasonal variation pattern of the ratio of Uv radiation to Rs is similar to that of Uv radiation; namely, the highest value appears in August and then decreases gradually until the lowest value appears in November. A small increasing trend in the Uv radiation levels and the ratio of Uv radiation to Rs was observed over the NCP. The evaluation results showed that the empirical estimation model can be widely used to estimate Uv radiation under all atmospheric conditions. The relative error between the modeled and measured daily values were within ± 15%.

可倾瓦推力轴承惰转过程的最小膜厚预测方法

为建立可倾瓦推力轴承惰转过程中最小油膜厚度的预测方法,依据核主泵推力轴承的实际工作情况,基于雷诺方程的自编程序,分别进行热态和冷态下主、副轴瓦润滑性能参数的计算与数值模拟分析,提出可倾瓦推力轴承的最小油膜厚度的理论拟合公式,并对最小膜厚的计算值和拟合值进行对比和分析。结果表明:随着转速降低,主轴瓦的最小膜厚单调减小,副轴瓦的最小膜厚先增加后减小;主、副轴瓦最小膜厚的计算值可以和拟合值较好地对应,验证了理论拟合公式的可靠性。提出的理论拟合公式可以通过额定转速下的最小膜厚计算结果预测多种工作条件下的最小油膜厚度,为主泵惰转的安全性提供重要参考。

基于融合特征ADRMFCC的语音识别方法

针对在复杂噪声环境下语音识别准确率低和鲁棒性差的问题,提出一种基于增减残差Mel倒谱融合特征的语音识别方法.该方法首先利用增减分量法筛选关键语音特征,然后将其映射到Mel域-残差域空间坐标系中生成增减残差Mel倒谱系数,最后将这些融合特征用于训练端到端模型.实验结果表明,该方法在不同噪声类型和信噪比条件下均显著提高了语音识别准确率及性能,在-5 dB低信噪比条件下,语音识别准确率达73.13%,而在其他噪声条件下的平均语音识别准确率达88.67%,充分证明了该方法的有效性和鲁棒性.

露天矿含弱层边坡三维危险滑面构建及稳定性计算

露天矿含弱层边坡稳定性分析是露天开采领域中的一个重要研究内容,实际工程问题复杂多样,基于二维计算会导致结果偏于保守,有时无法满足复杂工程的需要,因此,开展含弱层边坡三维稳定性分析的研究是很有必要的。基于标准椭球,对其进行空间几何变换,与边坡插值生成一种由x_(a)等6个参数控制的椭球危险滑面,将椭球滑面与弱层结构面进行组合插值,构建含弱层边坡三维危险滑面;使用三维剩余推力法和遗传算法计算边坡稳定性系数并进行最危险滑面搜索,使用经典算例对方法进行验证,发现含弱层边坡随着滑体宽度增加稳定性系数逐渐降低。以锡林浩特某露天矿为应用实例,对东北帮含弱层边坡进行三维稳定性计算,验证了方法在实际工程中的适应性。

种植方式对寒地水稻抗倒伏性状的影响

为了探索不同种植方式对寒地水稻抗倒伏能力的影响,以‘龙粳21’和‘龙稻18’为试材,比较研究了水直播、旱直播和插秧栽培模式下水稻的抗倒伏特性。种植方式对寒地水稻的抗倒伏特性有显著影响,但两品种表现不一致。其中,‘龙粳21’N1至N4节间的倒伏指数为插秧>水直播>旱直播,单茎抗推力为旱直播>插秧>水直播。‘龙稻18’N1、N3和N4节间的倒伏指数为插秧>旱直播>水直播,N2节间为旱直播>插秧>水直播,单茎抗推力均为水直播>插秧>旱直播。相关分析表明,提高寒地水稻抗倒伏能力应适当降低株高、重心高度和N1、N2节间的长度,不宜攻大穗。在寒地稻区,通过选择适宜的品种及合理地构建多穗和小穗的群体结构,既利于直播稻获得较高的产量,也有利于提高抗倒伏性。

某在建商业建筑满足承载力要求的消能减震加固设计与分析

本文以新疆某商业楼加固工程为背景,针对该建筑工程施工时一、二层梁柱纵向钢筋等级选择与设计要求不符,造成多数框架梁、柱配筋不满足抗震承载力要求的问题,提出了传统加固技术与消能减震技术相结合的加固方案。基于PKPM和ETABS软件,通过大量数据分析对加固方案进行了优化和调整,同时采用PERFORM-3D软件分析了罕遇地震作用下结构的时程响应。得到结论:(1)减震加固后,结构满足“小震不坏、大震不倒”的设防目标;(2)通过合理布置黏滞阻尼墙,降低了地震作用,大幅度减小了传统加固的用量。