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71.
Yung Ting Liang-Chiang Chen Chun-Chung Li Jeng-Lin Huang 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(4):847-853
A new type of piezoelectric linear motor incorporating a traveling wave has been developed. The linear motor is comprised of a stator and a carriage. The stator design, which consists of a meander-line structure and gear teeth mounted on the meander-line structure, is the focus of this article. The meander-line structure is constructed with bimorph actuators arranged in a line. These actuators are driven by two phased sets of alternating current (ac) in order to generate a traveling wave. The traveling wave is transferred to the gear teeth, by which the carriage is driven. Modeling of the stator is derived by use of a strain energy method. The performance of various materials is evaluated by analytical and experimental methods. The analytical and the experimental results are quite approximate. Modal analysis is investigated using ANSYS. Appropriate modes associated with ultrasonic levels of resonant frequency are selected to obtain desired motion and to enhance the output performance. Surface speed for various applied input voltage are studied and indicate a nearly linear relationship. The stator in combination with the carriage makes up the linear motor. 相似文献
72.
An innovative method for modelling biological processes under anaerobic conditions is presented and discussed. The method is based on titrimetric and off-gas measurements. Titrimetric data is recorded as the addition rate of hydroxyl ions or protons that is required to maintain pH in a bioreactor at a constant level. An off-gas analysis arrangement measures, among other things, the transfer rate of carbon dioxide. The integration of these signals results in a continuous signal which is solely related to the biological reactions. When coupled with a mathematical model of the biological reactions, the signal allows a detailed characterisation of these reactions, which would otherwise be difficult to achieve. Two applications of the method to the enhanced biological phosphorus removal processes are presented and discussed to demonstrate the principle and effectiveness of the method. 相似文献
73.
一、概况南平市种猪场位于延平区浆甲村 ,距市区 13km ,地处 316国道旁 ,面临沙溪口库湾边。年存栏猪760 0头 ,其中母猪 60 0头 ,后备种猪 2 5 0 0头 ,商品猪 4 5 0 0头 ,是闽北集种猪、商品猪生产及科研繁育于一体的副食品基地之一。该场日排猪粪便污水约140t,未建沼气工程前 ,直接排入水库 ,严重污染水体。1999年 ,种猪场采用厌氧发酵技术 ,处理猪粪便污水 ,兴建 4× 2 0 0m3沼气工程 ,技术落后 ,基本属于农村户用水压式沼气池的简单放大 ,猪粪便污水直接进入厌氧发酵池 ,出水直接排入水库。工程设计的主要问题是 :1 不设前处理装置 ,冲洗… 相似文献
74.
本文通过对压电量测系统等效电路图的逐步简化,得出矩形脉冲信号的漏电方程;并对系统在各种情况下的时间常数,漏电相对误差进行了计算,最后就系统在校准和现场测试中经常碰到的几种情况,进行了定量估算,从而解决了压电量测系统在使用中的一些具体问题。 相似文献
75.
高频数字锁相环的研究 总被引:5,自引:0,他引:5
论文阐述了100MHz数字锁相环的设计过程,用10MHz晶体振荡器对100MHz数字压控振荡器进行锁相,使100MHz输出信号指标得到很大改善。论文还分析了各单元电路,关键点时域波形测试,频谱测试。 相似文献
76.
����������̼����������ģʽ����̽ǰ�� 总被引:2,自引:0,他引:2
川东北海相碳酸盐岩所生成的天然气主要聚集在喜山期形成的构造圈闭中。本文针对此特点,划分了背斜圈闭的成因类型,建立了海相碳酸盐岩孔隙、裂缝复合型背斜气藏模式,并指出了当前勘探的三大领域及寻找富集型气藏的前景。 相似文献
77.
The present study determined tumorigenicity, tumor classification and DNA damage induced in infant mice by benzo[a]pyrene (B[a]P) or Manufactured Gas Plant (MGP) residues after a single exposure. Male and female B6C3F1 mice were exposed to B[a]P or MGP residue from a single environmental site (MGP-4) and males were also exposed to MGP residue composite from seven different sites (MGP-M7). At 26, 39 and 52 weeks after exposure tumorigenesis was assessed in lung, forestomach and liver. Formation and persistence of DNA adducts were quantified by 32P-postlabeling. Exposure of males to B[a]P induced liver tumors in a dose and time dependent manner. MGP induced more advanced tumors than B[a]P. Only a single liver tumor was found in MGP-4 treated females. No forestomach and few pulmonary adenomas were induced in males or females. MGP-4, MGP-M7 or B[a]P induced DNA adducts in males and females. Adducts in liver, lung and forestomach peaked on different days and decreased at different rates. At 24 h post-exposure, no significant differences in initial DNA adduct levels occurred in males and females exposed to MGP-4 or B[a]P. Lack of DNA damage (adducted DNA) did not account for non-responsiveness of lung and forestomach in B6C3F1 genders as well as in liver in females. MGP tumorigenicity could not be accounted for solely by B[a]P content nor did it reflect additivity of B[a]P and other carcinogenic polycyclic aromatic hydrocarbons (PAHs) in MGP. Synergy among MGP-PAHs, presence of unidentified carcinogens and/or promoters in MGP may account for MGP potency. The B6C3F1 infant male model is a convenient and rapid assay for assessing MGP liver tumorigenicity and potency. 相似文献
78.
79.
基于争议双地仲裁人的裁决值有不同的概率估计,而这些估计是双方共同知识这一前提分析最终报价中仲裁,把它构造成一个不完全信息的非零和对策模型。然后给出了局部、全局Nash平衡报价策略存在唯一的充分条件,最后探讨了双方认识存在的差异对争议人报价行为的影响。 相似文献
80.
Prof. Dipl.-Ing. Dr.techn. Walter Gretler Prof. Dr. Si-min Zeng 《Forschung im Ingenieurwesen》1996,62(5):105-115
A numerical simulation of unsteady compressible flow induced by two high-speed trains in oncoming traffic within a tunnel
is presented. The computations were carried out by means of a second-order accurate Harten-Yee type upwind TVD scheme. In
order to take the effect of friction into account, a source term is included in the governing flow equations. In the computation,
moving boundary configurations were used to simulate the two trains passing through the tunnel. As geometrical configuration,
the Einmalberg tunnel, where experimental data are available, was selected. The computational results agree reasonably well
with their experimental counter-part. The waves interaction and the waves propagation process at the tunnel entrance and exit
as well as within the tunnel are addressed. Finally, the influence on the transmitted waves at the tunnel exit portal and
the variation of the negative pressure drop during the passage of the two trains are discussed. 相似文献