查询词典 instability

The following exciting results are derived: 1 When considering the influence of some nonlinear elements such as hard-limit of exciters, the effects of some devices such as Power System Stabilizer, Unified Power Flow Controller and Static Var Compensator as well as using real parameter values of power systems in simulation , the SNB surface and the HB surface on the boundary of small signal stability region will turn close to each other and even coalesce together; 2 Under some conditions, coupling between slow exciters and shunt capacitors will bring negative damping in power system dynamics, which increases the possibility of oscillatory instability, so that a power system with mass shunt compensators is easily subjected to the oscillatory instability.

同时发现：1 系统中的慢速励磁，在某些情况下会与并联补偿电容器组产生负阻尼现象而显著降低系统的动态性能，大大增加系统出现振荡失稳的可能性；2 在采用较多并联电容器组补偿的电力系统中，更容易出现振荡型失稳。

The following exciting results are revealed: 1 When considering the influence of some nonlinear elements such as hard-limit of exciters, the effects of some devices such as Power System Stabilizer and Static Var Compensator which can introduce positive damping in power system, the reasonability of system parameter values in simulation, the SNB surface and HB surface on the boundary of SSSR will turn close to each other and even coalesce together; 2 Under some conditions, coupling between slow exciters and shunt capacitors will bring negative damping in power system dynamics, which increases the possibility of oscillatory instability. So the power system with mass shunt compensators is easily subjected to the oscillatory instability. In recent years, chaotic phenomena of power system have been reported many times. Some simulation studies even found chaos existing inside the power system SSSR. In this dissertation, chaotic phenomena in power systems are thoroughly studied in order to make clear the relation of chaos and SSSR. The following results are derived: 1 Based on Li-Yorke Theorem and their definition on the chaos, the existence of chaos in power system is verified; 2 Three possible routes of causing chaos in power system are found and deeply investigated. They are route of cascading period doubling, route of directly initial energizing and route of torus bifurcation (or quasi-periodicity). The latter two routes are investigated for the first time in power system stability studies; 3 When the stability conditions of chaos are broken, it is found they can lead to voltage collapse, angle divergence, or voltage collapse with angle divergence simultaneously.

针对在电力系统小扰动稳定区域内可能存在混沌吸引域的有关报道，本文深入研究了电力系统混沌现象的出现途径和与系统失稳模式之间的关系：1利用Li-Yorke定理和Li-Yorke的混沌定义，从理论上证明了电力系统混沌现象的存在性；2发现了电力系统中导致混沌出现的三种可能途径：倍周期分岔导致混沌、初始能量直接激发混沌和经由环面分岔导致混沌，并对后两种新发现的途径进行了较为细致的研究；3发现了混沌极限环破裂导致电压崩溃、角度失稳以及电压崩溃和角度失稳同时出现的现象，其中混沌极限环破裂导致系统角度失稳和电压崩溃及角度失稳同时出现的现象均属首次报道；4证明由微分-代数方程描述的系统模型，其小扰动稳定域的边界只包含HB、SNB和SIB三种分岔界面，在SSSR的内部和边界上，均不可能存在会导致混沌的点，从而将混沌现象排除在小扰动稳定域的研究之外，简化了后者的研究工作。

In fact, the process of fuel breakup and atomization is a kind of instability phenomenon of the liquid jet. In order to increasing the oil surface area and promoting efficient combustion, the instability process of the jet is always used to make the fuel atomization in engineering.

燃油的分裂与雾化过程实际上是液体射流的一种失稳现象，在工程上常常利用射流的这种失稳过程来实现燃油的雾化，以增加燃油的表面积提高燃烧效率。

A cusp catastrophe model is presented to describe the behavior of sliding along one deep incompetent structural plane of a gravity dam foundation, and the sufficient conditions leading to instability are discussed. It is found that the instability of sliding relies mainly on the stiffness ratio k, the homogeneity index of the medium m and the geometry-mechanic parameter ξ and that the reliability of the traditional limit analysis method is deficient.

通过建立的模型分析，发现坝基滑动失稳主要取决于软弱面上复杂弹脆性介质和应变软化介质在应变软化拐点处的刚度比k、材料的均匀性指标m及几何－力学参数ξ；并给出了发生突变失稳的充分力学判据，指出传统的刚体极限平衡分析法存在一定的缺陷。

However, the X-ray radiation power increases as the load current. The MARED code is found able to reproduce the primary dynamic characteristics of the Z-pinch implosions, and the development of the instability qualitatively agrees with the simplified instability theoretical analysis and experimental results.

MARED程序能够较好的反映Z箍缩内爆动力学过程，特别是不稳定性发展的二维图像，能够给出与不稳定性简化模型的理论分析及实验结果定性一致的演化规律。

In recent years, the county up and down firmly establish the "animal husbandry instability instability in the whole county, not the rich herders, the county is not rich" ideas, has always been to increase efficiency of agriculture and animal husbandry, farmers and herdsmen in rural incomes and maintain stability as the work of farmers and village enterprise, has invested 2,480 million yuan to build one or two bases and livestock disaster insurance camel, cashmere goats base, completed the demonstration county animal husbandry and the "three" of training works, the new on the restoration and protection of natural vegetation projects, ban works, the completion of 3 million mu of artificial grass, aqueduct built five more than eighty kilometers, 22 kilometers of flood control dams, the new hit 12 motor-pumped wells, construction of the drug bath, flood pool 20, the completion of fencing 41.7 million mu of grassland, built to high standards SHELTER 20, control the "three" of 57.7 million mu of grassland, improved herd face up to 82%, the proportion of school-age dams more than 56%.

近年来，全县上下牢固树立&牧业不稳，全县不稳，牧民不富，全县不富&的思想，始终把农牧业增效、农牧民增收和保持农村稳定作为农牧村工作的重点来抓，先后投资2480余万元，建成了一、二期防灾保畜基地和骆驼、绒山羊基地，完成了畜牧业示范县和&三化&治理工程，新上了天然植被恢复与保护工程、退牧还草工程，完成人工种草3万亩，建成引水渠5条80多公里，防洪堤坝22公里，新打机井12眼，修建药浴池、涝池20座，完成围栏封育草场41.7万亩，建高标准暖棚20座，治理&三化&草场57.7万亩，畜群改良面达82%，适龄母畜比例达到56%以上。

Based on the instability criterion of semi-classical Maxwell -Bloch equations of single-mode optical systems, the global distribution of instability region is depicted in A-6 parameter space (△ detuning of the atoms,θ mistuning of the cavity).

本文艰据半经典Maxwell一Bloeh方程单模光学双稳系统的稳定性判据，在△一日参数平面上描绘该系统不稳定区的整体分布(这里△和日分别正比于原子与腔相对输入场的失谐度)。

Evidence suggests that 1 under more stable stratification, the basic flow, if moving faster at low and high levels (particularly in the presence of jets there), allows a resulting meso-β unsteady wave to propagate eastward with respect to basic flow and even at greater velocity compared with it; 2 vertical windspeed shear of basic flow causes instabilities of the TWT perturbation; 3 considering the second derivative of basic-flow wind with respect to z (denoted by zz≠ 0 which is simply given as β* hereafter) the expression for the phase velocity of vortex Rossby wave is obtained, which is unidirectional in propagation with respect to basic flow; 4 VRoW has its physical origin from β*, i.e., from z-varying heterogeneities of y-direction averaged vorticity of the basic flow field; 5 VRoW phase velocity is associated with zonal wave number k, its energy is dispersive and the group velocity exists in the x direction; 6 when windspeed meets the condition of β*, TWT disturbance instability may be that of mixed VRoW and gravity wave; 7 if basic flow is subject to linear shear but does not meet the condition of β*, the TWT instability is that of inertia-gravity wave.

在大气层结比较稳定的情况下，如果基本气流在低层和高层较大(有可能存在低空急流和高空急流)，此时产生的β中尺度不稳定扰动相对于基流向东传播，甚至于快速向东传播。基本气流在垂直方向上的风速切变对于中尺度横波型的扰动起着不稳定的作用。如果考虑基流的二次切变，可以得到涡旋Rossby波的相速度表达式，涡旋Rossby波相对于基本气流是单向传播的。涡旋Rossby波产生的物理根源是基本流场的风速二次切变，亦即基本流场y方向的平均涡度在空间z方向上的不均匀所致。涡旋Rossby波的相速度与纬向波数也有关，它的能量是频散的，其在纬向x方向也存在群速度。在基本流场的风速存在二次切变时，横波型不稳定可能是混合的涡旋Rossby重力波的不稳定；而在基本流场的风速仅仅存在线性切变，不存在二次切变时，横波型扰动的不稳定则是重力惯性波的不稳定。

It is indicated that the operative and reconstructive effect of the chronic lateral instability of ankle using peroneus brevis tendon is good, and that the treatment way to chronic lateral instability of ankle can consumedly reduce the occurrence of trauma ankle arthritis.

采用腓骨短肌腱重建外侧韧带治疗慢性外踝关节不稳疗效满意，可减少慢性外踝关节不稳导致创伤性关节炎的发生。

The analysis shows that with given grid size higher accurate difference scheme can give higher resolutions with wider range of scales, or with given accuracy large grid size can be used for the higher accurate difference scheme. The second part is the numerical simulation of two-dimensional axisymmetric jet. The simulation results show the structure in the near field and the initial transition. In the near field, Kelvin-Helmholtz instability leads to the formation of vortex ring, and nonlinear growth leads to the merging of vortex ring. This is the main instability form. Under the assumption of axisymmetry and two-dimensional computing conditions, the results are applicable only in the near field.

第二部分采用高精度的差分格式对二维轴对称射流进行了数值模拟，模拟结果显示了射流流场结构和涡结构的发展过程，在射流流场近区，K-H失稳导致涡环的产生以及非线性效应的增长导致涡环的对并是射流失稳的主要形式；分析指出在轴对称假设下的射流数值模拟只适用于射流近区的分析。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。