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61.
依据现代炮兵射击方式对炮兵武器系统机动性的特殊要求,以探索性分析方法为工具,论证保证自身生存之条件下的野战运动速度数量需求.主要结论是:当执行1次射击任务后被敌发现的概率介于0.4和0.65 之间时,炮兵武器系统处于生存的关键期;小于0.4时,野战运动速度的最大需求为9.2km/h;大于0.65时,野战运动速度的最小需求为89km/h,目前牵引火炮、自行火炮和指挥车辆等均不满足这一要求.  相似文献   
62.
While estimating production technology in a primal framework production function, input and output distance functions and input requirement functions are widely used in the empirical literature. This paper shows that these popular primal based models are algebraically equivalent in the sense that they can be derived from the same underlying transformation (production possibility) function. By assuming that producers maximize profit, we show that in all cases, except one, the use of ordinary least squares (OLS) gives inconsistent estimates irrespective of whether the production, input distance and input requirement functions are used. Based on several specifications of the production and input distance function models, we conclude that one can estimate the input elasticities and returns to scale consistently using instruments on only one regressor. No instruments are needed if either it is assumed that producers know the technology entirely (including the so-called error term) or a system approach is used. We used Norwegian timber harvesting data to illustrate workings of various model specifications.  相似文献   
63.
This paper defines an invariant associated to Whitehead's certain exact sequence of a simply connected CW-complex which is much more elementary — and less powerful — than the boundary invariant of Baues. Nevertheless, in good cases, it classifies the homotopy types of CW-complexes.  相似文献   
64.
本文给出一类一般离散型Lurie控制系统绝对稳定的充要条件及充分条件  相似文献   
65.
Biological monitoring is essential for risk assessment in the presence of exposure of workers or the general population to harmful chemical agents. Besides the choice of analytical methods which are fit for purpose and the skills of the analysts, the performance of laboratories, including those working in the field of environmental and occupational medicine, also depends on other technical factors such as frequency of testing, the use of well maintained and properly functioning equipment and the implementation of quality control procedures including the participation in External Quality Assessment Schemes (EQAS). Surveys of laboratory workload have been organized periodically since 1997 within the MeTos Project, an Italian national EQAS for biomarkers of environmental and occupational exposure to chemical agents. In 2001, a more extensive survey, including specific technical issues, was organized as part of the activities of the Thematic Network of European Organizers of External Quality Assessment/Proficiency Testing Schemes Related to Occupational and Environmental Medicine (Network survey). In addition, information on the awareness and implementation of the new requirement for laboratories to estimate the uncertainty of their measurements was collected since 2000. The results of these surveys are reported and compared here. In all surveys, Pb in blood was the biomarker most frequently determined. As for biomarkers of exposure to organic compounds, the data collected in the Network survey indicate that methylhippuric acid, hippuric acid and mandelic acid in urine were the assays most commonly performed. About a third of the participants stated that they estimate the uncertainty of at least some of their measurements. Preliminary analysis of data, limited to Pb in blood, showed that analytical performance improved with continuous participation in EQAS and was positively influenced by a high workload.  相似文献   
66.
The construction of the Bayesian credible (confidence) interval for a Poisson observable including both the signal and background with and without systematic uncertainties is presented.Introducing the conditional probability satisfying the requirement of the background not larger than the observed events to construct the Bayesian credible interval is also discussed.A Fortran routine,BPOCI,has been developed to implement the calculation.  相似文献   
67.
The chamber production and installation of the BESⅢ MUON identifier system have been finished.The cosmic ray test result after installation shows that the average efficiency is bigger than 95% and can meet the requirement of the design report. A database including all the chamber parameters and performance data has been constructed and is accessible online. The quality control procedures during the production and the database are described.  相似文献   
68.
An attempt was made to investigate the possibility of designing and developing a multipurpose, all terrain, 6WD prime mover for the oil palm plantation in Malaysia. Comparisons were made on the engine power requirements of the 6WD prime mover over the 4WD prime mover on four different soil classifications having terrain slopes ranging from 0° to 30° based on the traction equations by ASABE [1]. Generally, the 6WD prime mover showed in the range of 5.27-45.81% reduction in the engine power requirements than the 4WD prime mover having equal size and weight configurations when traversing over the four different soil classifications. Greater percentage reductions in engine power with the 6WD over the 4WD prime mover were found as the terrain changes from concrete to soft or sandy soil classification with prominent percentage reductions at higher terrain slopes. The proposed 6WD prime mover has a single chassis with skid steer drive wheels, oscillating drive axles, and low inflation pressure tires. The 63 kW water-cooled, diesel engine was sufficient to run an hydrostatic main pump at a working pressure of 220 bar and a flow rate of 91 L/min under two drive speeds (i.e. high and low) and two drive modes (i.e. forward and reverse). Proper prime mover wheelbase and proper ground clearance height were employed to give better stability and manoeuvrability for the typical oil palm plantation terrain in Malaysia. Mounting provisions for the seedling transplanting, fertilizer applicator and the in-field fresh fruit bunches (FFB) collection-transportation were made on the prime mover.  相似文献   
69.
超声波电机用摩擦材料的研究进展   总被引:1,自引:1,他引:0  
归纳并探讨超声波电机摩擦材料的基本要求与国内外研究进展.基于行波型超声波电机驱动特点及运行规律,从摩擦学、接触力学和材料学3个方面对超声波电机用摩擦材料的特殊要求进行探讨,初步得出超声波电机摩擦材料应具有优良的摩擦学、一定的接触变形和一定的结构特性3个方面的特殊要求.最后,针对超声波电机摩擦材料研究中存在的问题,提出一些超声波电机摩擦材料值得重视的研究方向,即建立更为完善的接触模型、研制针对多种环境下使用的多种系列摩擦材料、开发考察摩擦材料性能的专门试验设备与测试技术方法和寿命预测技术方法等.  相似文献   
70.
抗滑桩设计推力计算方法研究   总被引:3,自引:0,他引:3  
滑坡推力是抗滑桩设计推力的重要依据,工程中通常使用剩余推力法来计算滑坡推力。为了比较准确合理地计算出抗滑桩的设计推力,提出了在剩余推力法基础上的一种新的抗滑桩设计推力取值方法。分析极限平衡状态下和工程安全要求下各条块的剩余下滑力,选择合理的桩位,使得抗滑桩位于滑坡体的抗滑段;然后调整桩后滑体的剩余下滑力,其调整量一方面保证桩前桩后滑体满足工程安全要求,另一方面则作为抗滑桩设计推力的修正依据,其过程由程序实现。通过实例证明了该方法的合理性。同时对今后抗滑桩设计推力的合理取值提供了参考作用。  相似文献   
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