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1.
为提高钢铁生产中浇铸的命中率,需对钢包内钢液温度进行测量,传统方法是用热电偶直接测量,但热电偶易损坏、成本高,且测点数目有限,不能完全反应钢液温度分布情况。针对上述问题,提出使用共轭梯度法(CGM)反演钢液温度分布。建立钢包的二维稳态传热模型,采用有限元法对钢包传热模型进行离散,获得钢包传热系统温度场;通过构建误差信息最小化函数,建立反演模型,利用CGM对刚包内钢液温度分布情况进行反演。并对某80t钢包模型仿真试验。试验证明,利用上述传热学反问题能够有效的对钢包内钢液的温度分布情况进行辨识,证实了通过传热学反问题方法辨识钢包内钢液温度分布的有效性,为钢包内钢液温度的准确识别提供新的技术手段。  相似文献   

2.
高校产学研一体化发展的实践与前瞻   总被引:11,自引:0,他引:11  
本文探讨我国高校产学研一体化发展的必要性、可行性及其前景。从人类社会发展的历史特点入手,并借鉴了美国硅谷发展的经验和我国改革开放推进社会主义市场发展的需求,对高校产学研一体化发展的道路作了论述。针对目前高校产学研一体化中存在的问题,作者提出了加速高校产学研一体化发展的四条建议:1,高校产学研一体化发展必须转变观念,积极参与社会大循环;2,推进高校产学研一体化要有过硬的产品和准确的市场定位;3,高校产学研一体化发展要依托高科技园区,切实解决经费投入问题;4,高校产学研一体化发展要突出以人为本的思想,努力造就发明家和企业家。  相似文献   

3.
针对某大型直线振动筛频繁出现横梁断裂问题,应用ANSYS软件,对横梁结构进行了模态分析和谐响应分析,指出结构设计中存在问题。提出横梁结构改进方案,对改进后结构动力学性能进行分析,并与原设计横梁结构的动力学性能进行比较。结果表明:横梁断裂属于低应力断裂;横梁结构静力分析与动力分析的应力值差异较大,采用静力准则的结构设计不能保证结构可靠性;改进后的横梁结构应力状态得到改善,疲劳寿命提高。  相似文献   

4.
双向中继X网络相对于传统无线通信网络可以实现更高的自由度.然而,基于迫零算法的中继处理算法仅考虑了消除干扰成分,忽略了对期望信号的影响,从而使得网络的和速率有待提高.特别地,当用户发送功率越低,其和速率劣势越明显.针对上述问题研究其干扰对齐方案,并给出了优化的联合考虑期望信号和干扰信号的中继处理算法.首先,通过利用用户矢量信号之间的空间关系,给出网络和速率的数学模型;其次,通过矩阵分析及数值分析理论将最大化网络和速率的中继预编码设计问题转化为线性搜索最优值问题,并用极限值方法近似网络目标函数;再次,进一步将双向网络的目标函数近似为单向网络用户参数的线性组合,大大降低算法复杂度;最后,基于优化的线性搜索最优值问题,得到最大化网络和速率的中继预编码矩阵.仿真结果表明:相较于现有的中继处理方案,本文方案明显改善了网络和速率,同时还简化了最大化网络和速率带来的算法复杂度.  相似文献   

5.
This study attempts to apply the general equilibrium model of stock index futures with both stochastic market volatility and stochastic interest rates to the TAIFEX and the SGX Taiwan stock index futures data, and compares the predictive power of the cost of carry and the general equilibrium models. This study also represents the first attempt to investigate which of the five volatility estimators can enhance the forecasting performance of the general equilibrium model. Additionally, the impact of the up‐tick rule and other various explanatory factors on mispricing is also tested using a regression framework. Overall, the general equilibrium model outperforms the cost of carry model in forecasting prices of the TAIFEX and the SGX futures. This finding indicates that in the higher volatility of the Taiwan stock market incorporating stochastic market volatility into the pricing model helps in predicting the prices of these two futures. Furthermore, the comparison results of different volatility estimators support the conclusion that the power EWMA and the GARCH(1,1) estimators can enhance the forecasting performance of the general equilibrium model compared to the other estimators. Additionally, the relaxation of the up‐tick rule helps reduce the degree of mispricing. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

6.
The problem of integration and control of the various processes of the metazoan organism is a major challenge to the physiologist. The traditional research strategy in dealing with the problem is neuron-oriented and its roots extend back into the last century when knowledge of hormones was lacking. In the present article, the traditional strategy is analyzed in the light of available data and its logical basis is questioned. Different levels of communication are supposed to occur in the animal or human body. Circulating hormones are responsible for the highest level of communication that occurs between organs or tissues. The central concept in the article is that regulation of circulating hormones constitutes a higher level of control relative to regulation of intercellular hormones. This is regardless of whether the latter occurs in the nervous system or elsewhere. The approach is utilized in defining the mechanism that integrates and controls the part processes of the body. The mechanism is defined as endothelial; the vascular endothelial system is the controlling part and the nervous system is one of the subordinate parts. Thanks to the new approach, meaningful biological explanations of major psychiatric disorders are now possible.  相似文献   

7.
Normally the pacemaker of the mammalian heart is located in the sinus node. In the rabbit the sinus node can be subdivided into two regions, the center of the node where the impulse originates and the border zone through which the impulse is conducted towards the atrium. Conduction properties of both regions were investigated. It appeared that conduction velocity increases and refractoriness decreases when one goes from the nodal center towards the atrium. The tissue mass of the atrium is large in comparison to the sinus node and normally the resting membrane potential of atrial fibers is more negative than that of nodal fibers; consequently, a potential difference exists causing a current flow between both areas. Evidently this hyperpolarizing current flow depresses impulse formation in the border zone fibers which have better intrinsic pacemaker properties than fibers in the nodal center. If the impulse has reached the atrium it is conducted with a relatively high safety factor and will reach the AV node in principle without difficulty. The AV node, if deprived of sinus nodal dominance, develops spontaneous activity originating from the lower nodal fibers. Also in this structure, electrotonic depression by surrounding tissue causes deceleration of the pacemaker.  相似文献   

8.
An anti-Ia immune serum (A . TL anti-A . TH) directed to the antigens of the stimulating cell, blocked the MLR-II. A significant correlation was observed between the anti-Ia reactivity of the immune serum, studied against a panel of eleven original H-2 haplotypes and the reactivity against the same panel of the in vitro primed responding cells (A . TL anti-A . TH). These results confirm the hypothesis that Ia antigens are the structures stimulating the MLR-II.  相似文献   

9.
Primary open-angle glaucoma is a multifactorial disease that affects the retinal ganglion cells, but currently its therapy is to lower the eye pressure. This indicates a definite involvement of the trabecular meshwork, key region in the pathogenesis of glaucoma. This is the first target of glaucoma, and its functional complexity is a real challenge to search. Its functions are those to allow the outflow of aqueous humor and not the reflux. This article describes the morphological and functional changes that happen in anterior chamber. The “primus movens” is oxidative stress that affects trabecular meshwork, particularly its endothelial cells. In these develops a real mitochondriopaty. This leads to functional impotence, the trabecular meshwork altering both motility and cytoarchitecture. Its cells die by apoptosis, losing barrier functions and altering the aqueous humor outflow. All the morphological alterations occur that can be observed under a microscope. Intraocular pressure rises and the malfunctioning trabecular meshwork endotelial cells express proteins that completely alter the aqueous humor. This is a liquid whose functional proteomics complies with the conditions of the trabecular meshwork. Indeed, in glaucoma, it is possible detect the presence of proteins which testify to what occurs in the anterior chamber. There are six classes of proteins which confirm the vascular endothelium nature of the anterior chamber and are the result of the morphofunctional trabecular meshwork decay. It is possible that, all or in part, these proteins can be used as a signal to the posterior pole.  相似文献   

10.
Historiographical analyses of the development of genetics in the first decade of the 20th century have been to a great extent framed in the context of the Mendelian-Biometrician controversy. Much has been discussed on the nature, origin, development, and legacy of the controversy. However, such a framework is becoming less useful and fruitful. This paper challenges the traditional historiography framed by the Mendelian-Biometrician distinction. It argues that the Mendelian-Biometrician distinction fails to reflect the theoretical and methodological diversity in the controversy. It also argues that the Mendelian-Biometrician distinction is not helpful to make a full understanding of the development of genetics in the first decade of the twentieth century.  相似文献   

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