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1.
给出了通货膨胀影响企业所得税及投资效果的分析计算方法,弥补了一般项目投资技术经济分析不考虑通货膨胀因素影响的不足。  相似文献   
2.
Spatial fisheries ecology: Recent progress and future prospects   总被引:1,自引:0,他引:1  
We review recent progresses made in the study of fish distribution and survival over space — i.e., fisheries spatial ecology. This is achieved by first surveying the most common statistical approaches and relative challenges associated with the analysis of fisheries spatial data, loosely grouped in geostatistical and regression approaches. Then we review a selected number of case-studies implementing the discussed techniques. We conclude by proposing new areas of statistical and ecological research to further our understanding of how fish distribute and survive in space. This review serves a dual purpose by emphasizing the scientific importance of studying spatial interactions to better understand the temporal dynamics of fish abundance, and by promoting the development of new analytical and ecological approaches for the analysis of spatial data. Through our survey we cover different statistical techniques, marine ecosystems and life stages. This analytical, geographic and ontogenetic variety is also purposely selected to highlight the importance of comparative and multidisciplinary studies across diverging ecological disciplines, ecosystems and life stages. Besides having a general ecological relevance this review also bears a more applied significance, owing to the increasing need for protecting renewable marine resources along with their primary habitat.  相似文献   
3.
浅谈中央充放气系统充放时间计算   总被引:1,自引:0,他引:1  
本文针对不同容积轮胎及充气压力下充放气系统所需充放时间进行计算,使其根据气温,路面状况的不同,自动调节控制轮胎气压,产生最大附着力而又不至于产生过大阻力,保证汽车始终保持最合理的运动状态,提高车辆的地面通过性和工作效率。  相似文献   
4.
1概述随着建筑市场投标竞争的日趋激烈,承包商中标项目所能取得的利润空间越来越小,市场竞争下的微利经营是市场经济发展的必然结果。由于诸多不确定因素的存在,投标报价存在潜在的风险,特别是近两年,由于材料价格的大幅上涨,施工成本加大,给中标项目带来巨大的风险,在投标报价  相似文献   
5.
In-plane tyre modal behaviour determines the response of tyres to ride excitations and braking/traction manoeuvres. In many studies, the interest is limited to relatively low frequencies and a detailed investigation into the ability of models to accurately simulate higher-order responses is unnecessary. In cases where an in-plane model is to be used for the generation of the contact deformation and stresses, or where modal reduction methods are implemented, a detailed knowledge of the modal response is desirable. The present work forms a study on the ability of a number of frequently used modelling approaches to generate realistic modal data throughout a wide frequency range. The analytical ring on elastic foundation model is used as a benchmark throughout the paper. Its predictions are compared with those of two discretised models, namely a truss- and a beam-based model. The sensitivity of the ring’s response to a number of physical parameters is discussed. The results are used to inform the comparison between the analytical ring and the discretised models, providing explanations for any discrepancies observed. The limited applicability of the truss model is pointed out, while the accuracy of the beam-based model is enhanced by a circumferential inextensible string element. Both the ring and the enhanced beam models are further improved with the addition of a nonlinear string-based sidewall that accounts for the change in sidewall stiffness with inflation pressure. The findings may offer a reference when setting up in-plane models, including the stage of planning modal tests for parameter identification.  相似文献   
6.
基于轮胎压实的揉搓作用以及能使被压实材料具有良好的封闭性等特点,提出可以利用轮胎充气压力的变化来改变压实度,获取最佳压实效果。介绍了一种能根据被压实材料密实度的变化状况,自动调节轮胎充气压力的智能型轮胎压路机,并且分析了该设备的关键技术、控制原理和创新点。  相似文献   
7.
通货膨胀是一种经常发生的现象,长期地影响各国的经济发展.如何反映和消除合并报表中的通货膨胀的综合影响成为理论界和实务界面临的一大难题.本文尝试就此问题的解决方案提出了自己的看法.  相似文献   
8.
避振穴是一种减小船舶尾部振动的重要装置,本文采用基于橡胶材料超弹性和空气压缩性的非线性有限元方法对其进行数值模拟和隔振特性分析。选取Mooney-Rivlin模型对橡胶材料非线性特性进行模拟,建立气体单元模拟加压空气,对一个独立密闭气室结构进行充气过程模拟和振动响应计算,分析气室深度、初始气压和橡胶板厚度等参数对其隔振特性的影响。将避振穴应用于实船尾部模型,验证其对螺旋桨激振力的隔振效果。计算结果表明,避振穴对于船舶尾部减振具有显著效果,但需要留意其在低频共振区引起的响应增大情况。  相似文献   
9.
土工膜焊缝剥离强度是整个防渗结构可靠性保障的关键因素之一。为了分析充气时间和充气压力对土工膜焊缝剥离强度质量的影响,选择7种不同厚度的HDPE土工膜在不同充气时间和充气压力条件下进行焊缝剥离强度试验。试验结果表明:在相同土工膜厚度和充气时间(3 min或10 min)条件下充气压力越大,焊缝剥离强度越小,土工膜厚度在0.25~1.00 mm范围内影响较大,在土工膜厚度1.00~2.00 mm范围影响较小;相同土工膜厚度和充气压力(0.1 MPa或0.2 MPa)条件下在土工膜厚度较薄范围0.25~1.00 mm内随着充气时间的增加剥离强度在减小,影响较小,在土工膜厚度较厚范围内1.00~2.00 mm范围内充气时间对剥离强度影响很小,可以忽略不计;相同充气时间和充气压力条件下,土工膜焊缝剥离强度随着土工膜厚度的增加而增大;土工膜焊缝工艺在土工膜厚度小于1.0 mm时,充气压力宜选择0.1 MPa;土工膜厚度大于1.0 mm时,充气压力宜选择0.2 MPa,充气时间可统一选择为10 min。  相似文献   
10.
This paper presents an econometric model for the behaviour of carsharing users. The econometric model is developed to jointly forecast membership duration, the decision to become an active member in a particular month, and the frequency of monthly usage of active members. The model is estimated using the membership directory and monthly transaction data of a carsharing program, ‘Communauto Inc.’, based in Montréal, Canada. The model shows a high degree of fit to the observed dataset and provides many behavioural details of carsharing users. The results are instructive to carsharing planners in devising efficient policies.  相似文献   
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