模形式

The economic and social benefits of reforming air steam forging hammer with the power head are analysed.

介绍了25kJ电液模锻锤动力头的形式、用途，分析了25kJ电液模锻锤动力头改造1t蒸空模锻锤所带来的经济效益。

In the CAD system for progressive dies, the method is introduced to automatically generate geometric models of stampings through inputting the product drawings by AutoCAD and picking-up the entity information from DXF files and programming with ObjectARX and C＋＋ language, at the same time, generating algorithm of close contour lines and unidirectional chain-table structure are used to express the models of stampings, the class and direct judgment of contour lines are realized and the entity existing side is judged by analytical geometry, which efficiently solves the problem of automatic input of drawings of stamping and providing information of process planning and mold design.

在级进模CAD系统中，将产品的图形信息以AutoCAD直接绘图形式输入到计算机中，从AutoCAD的图形交换文件中提取信息，采用面向对象的二次开发工具ObjectARX和C＋＋语言编写接口程序，并通过封闭轮廓的生成算法自动生成冲裁零件的几何模型，且用单向链表的形式加以表达，同时对冲裁零件图形的轮廓进行分类与走向判定，采用简单的解析几何方法对实体存在侧进行判定，有效地实现了零件图形的自动输入，为级进模CAD系统的工艺计算和模具工作部分的设计等提供了必要的信息。

The general infinite dimensional modal system describing liquid nonlinear sloshing is derived first by pressure integral variational principle. After selecting two dominating modes and three secondary modes based on the Narimanov-Moiseev third order asymptotic hypothesis, the infinite dimensional modal system is reduced to a five dimensional asymptotic modal system.

首先通过压力积分变分原理推导出描述液体作非线性晃动的一般形式无穷维模态系统，然后根据 Narimanov-Moiseev三阶渐近假设关系，通过选取二阶主模态和三阶次模态，将无穷维模态系统降为五维渐近模态系统。

According to the demand of high magnetic field power supply, reference is increased with a set ramp rate and stops at a set stable value, so reference system is composed of digital setting and digit to analog converting circuit. But the stability of reference is mostly guaranteed by the performance of D/A circuit, so D/A circuit is particularly studied in reference system. The scheme of D/A circuit, the selection of DAC and its voltage reference, hardware anti-jamming design and PCB design are discussed in detail, and software of remote control and PLC are discussed in brief. Zero-flux DC current transformer well satisfies the demands of the high stability of Load current detection unit, so the principle of zero-flux DC current transformer is analyzed; in the mean time a project which detects the long term stability is designed. During 8 hours, analog signal which is detected with high precision digit multimeter is recorded in computer at 1HZ frequency by GPIB communication. The drift error source and related parameters are explained in the compare-amplify part. Detailed subtraction circuit is designed; also amplifier chip and periphery components are selected and verified according to the theory of error analysis.

根据强磁场电源的需求，参考源应按照软件设定的斜率逐渐上升到设定稳态值，则参考源系统应由数字给定和数模转换电路两大部分组成，而参考源的稳定度主要依靠完成数模转换功能的模拟电路的性能来保证，因此本文对参考源系统的研究以数模转换电路为重点，分别从电路方案的确定、数模转换芯片及其基准电压源的选取和验证、电路板硬件抗干扰和PCB设计几方面进行了论述，然后对数字给定部分的远控组态和PLC程序设计作了简要介绍；采用零磁通原理的直流电流转换器很好地满足了对负载电流检测单元高稳定度的需求，本文详细分析了零磁通检测的原理，并在选定此种类型电流转换器的基础上设计了一套检测长期稳定度的方案，8小时内以1秒为采样周期，通过计算机Labview程序和高精度数字电压表的GPIB通讯，将被高精度数字电压表数字化后的模拟信号采样值连续记录至计算机中；比较放大环节简要阐述了漂移产生的原因和相关参数指标，确定了具体的减法电路形式，并根据误差分析理论对运算放大器和外围元器件进行了选取和验证。

By using the modal superposition method for the dynamic responses calculation of the linear oscillation system, a judging indictor in the energy norm form is given to determine the number of dominant modes on mode truncation .

针对用模态叠加法计算结构线性振动系统的响应，作模态截断的截尾模态阶数的取值，给出了能量范数形式的判断指标。

By using the modal superposition method for the dynamic responses calculation of the linear oscillation system, a judging indictor in the energy norm form is given to determine the number of dominant modes on mode truncation.

针对用模态叠加法计算结构线性振动系统的响应，作模态截断的截尾模态阶数的取值，给出了能量范数形式的判断指标。用于小湾拱坝结构的动力分析表明，需取 10阶以上的模态进行叠加

Uncertain singular systems are transformed into the form of restricted equivalence by a nonsingular linear transformation. By the method of Lyapunov function, a new terminal sliding mode control strategy based on the form of restricted equivalence is proposed for the first time, and the hypersurface of a special terminal sliding mode is given. A terminal sliding mode controller is designed correspondingly such that the motion of sliding mode can be guaranteed and the systems state variables can converge to the equilibrium point in a finite time.

通过非奇异线性变换把不确定奇异系统变换成受限等价形式，利用Lyapunov函数方法，首次提出了一种新的Terminal滑模控制策略，给出了特殊的Terminal滑模超曲面，设计了相应的滑模控制器，实现了滑模运动，保证了系统状态变量在有限时间内收敛到平衡点。

In this article,we mainly study the space-like submanifolds with parallel mean curva-ture vector,constant scalar curvature or constant square length of the second fundamental form,respectively.We obtain some pinching theorems and rigidity results by estimating Laplace of the square length of the second fundamental form of the such submanifolds and using yaus maximum principle or Stokes Theorem.

本论文主要研究de Sitter空间中具有平行平均曲率向量、常数量曲率或第二基本形式模长平方是常数的三类类空子流形，并通过分别估计三种情形下子流形的第二基本形式模长平方的Laplace，利用Yau的极大值原理和Stokes定理，获得了这些子流形的一些拼挤定理和刚性定理。

The compression process CAD mainly included primary contents as following: compression part process judging, shaping force calculation, hydropress selection, opening die force and knockout press calculation, checking the worki...

模具结构CAD主要包括：总装设计、凸模设计、凹模设计、加料室的设计计算、凸模与加料室及凹模的配合形式、侧向抽芯机构设计、标准件的管理、非标准件的管理、工程图生成。

We use eigenvalue analysis todetermine the instability of the target pattern under control condition,and find a four-mixing-wave mode,which has never been mentionedin previous works,serving as the eigenfunctions of the CGLE system.

从中我们首次发现了受控系统的不稳定模可以写成四波混合的形式，这种不稳定模的形式成功地描述了受控CGLE在临界点的失稳状态。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。