从招投标角度谈对电力工程造价的控制

许多电力企业要求投标商在保证安全和质量的同时不断降低工程成本.在整个工程建设中,招投标对电力工程造价有着极其重要的影响.从招投标的角度分析了其对控制工程造价的影响,以及相关解决措施.     

从招投标角度谈对电力工程造价的控制

许多电力企业要求投标商在保证安全和质量的同时不断降低工程成本。在整个工程建设中,招投标对电力工程造价有着极其重要的影响。从招投标的角度分析了其对控制工程造价的影响,以及相关解决措施。     

电力工程实施勘察设计与施工监理招投标的探讨

目前,广西电网的电力工程施工和物资采购已经普遍实行了招投标,但电力工程的勘察设计、施工监理尚未实行招投标。下面就电力工程如何加快实施勘察设计与施工监理招标进行探讨。     

电力工程施工招投标阶段的造价控制

电力工程通过招投标制,不仅有效的确保了工程质量及工期,鞭策施工单位改进技术、装备与管理水平以适应竞争,而且能对电力工程造价进行良好的控制。,通过加强工程招投标的技术与管理水平,电力工程造价能在有效范围得到控制,同时满足施工单位的合理利润。浅要分析了招投标制对电力工程造价控制的意义、措施,旨在提供实操参坚.     

对电力工程低价竞标的探讨

针对当前电力工程招投标中所出现的低价竞标问题分析了产生的主要原因,进一步论述电力工程低价竞标的可行性,最后提出电力工程低价竞标的基本对策。     

参加审查电力工程设计招投标管理规定的几点体会

原电力工业部于 1998年颁发的《电力工程设计招标投标管理规定》 ,在新形势下有不少需要修改之处。为了适应我国加入WTO新形势的要求 ,以《中华人民共和国招投标法》为依据制订《新规定》 ,它是国家经贸委颁发的有关电力工程设计招投标工作的行政法规 ,是与《招投标法》配套的实施办法。     

从招投标角度谈对电力工程造价的控制

从实际工作出发,分析了招投标对电力工程造价的影响,并从招投标角度提出了控制工程造价的对策和通过招投标实现工程造价控制应防范的几个问题。     

工程项目招投标机制与风险研究

<正>1工程项目招投标机制1.1工程项目招投标的基本内容招投标的基本内容主要由招标、投标、开标、评标及中标等几个方面组成。1.2招投标存在的问题我国招投标主要存在以下问题:①投标方片面追求利润最大化,在投标时挂靠资质更高的企业参加资格预审,临时组建项目管理班子并招募劳动力素质底下的劳务队伍,采用低价中标或故意抬高部分单价的办法竞标,一旦中标后,很     

浅谈招投标

本语文介绍了广西电力工程建设项目中招投标的情况及现状，探讨实行招标的优越性、对招投标荼提出几点建议。     

我国电力工程造价管理探析

随着经济的不断发展,我国电力工程造价管理面临着新的问题。电力工程造价容易受到自然条件、物价、人为等各方面的影响。主要分析了电力工程建设造价在新时代下的变化趋势,以及存在的一些问题,并有针对性地提出了一些措施,包括改善电力工程造价管理的决策、改善电力工程造价管理的设计、改善电力工程造价管理的招投标、改善电力工程造价管理的施工、改善电力工程造价管理中的审计。从而对电力工程造价进行管理,实现电力工程造价管理的节约型、合理性、科学性。     

Methods for controlling a linear asynchronous motor

This article describes the case of one of possible method of controlling a linear asynchronous motor (LAM) with a controlled normal component of the force of interaction between an inductor and a reactive bus. It is shown that the normal force in a unilateral linear asynchronous motor can affect significantly the operation of devices and systems on which a motor is installed. This normal force can attract an inductor to a reactive bus or repel it from a reactive bus. For the model of a motor, which is represented by four zones, namely, an inductor, an air gap, a conductive bus, and a steel core of a reactive bus, the analytical expressions for the calculation of the components of a magnetic field in an air gap were obtained. The effect of the longitudinal and transverse edge effects in the considered plane model of a motor is not considered. The expressions for the determination of the specific tangential and normal forces per area unit were found. It is shown that, under a change in the slide from negative to positive values, the tangential force changes similarly to the electromagnetic torque of a conventional asynchronous motor with a rotating rotor. Under a change in the slide, the normal force can attract an inductor to a reactive bus or repel it from a reactive bus. The force of attraction reaches the highest values under a zero slide. The slide under which the normal force is equal to zero is determined only by the pole pitch and the conductivity of material of a reactive bus and provides the operation of a motor at the highest power factor. It is proposed to use the measured normal force value as a parameter for the construction of a traction linear asynchronous motor-control system.     

水利工程模糊多模式工期-成本-质量均衡优化

针对不确定环境下水利工程建设项目的工期-成本-质量均衡优化问题,采用双指数函数和二次函数分段模拟工程质量和工期之间的关系,构建了水利工程模糊多模式离散工期-成本-质量均衡优化模型。运用微粒群算法对其进行求解,并将优化结果与相关文献进行对比分析,验证了模型的合理性和计算方法的有效性。最后,将该模型应用于水利工程实例,为决策者进行目标计划和控制提供理论依据。     

Teleoperation via computer network

In a teleoperation system, providing force information to a human operator can improve task performance. When a communication block between a master and a slave has a transmission delay, the system is easily destabilized. Anderson and Spong guaranteed passivity in the communication block by using scattering transformation and overcame this instability caused by the time delay. But this method can be applied to the communication block with a constant time delay. In a traditional teleoperation system, its communication block has a constant time delay. But time delay irregularly changes in a computer network because many users share telecommunication lines. This paper shows that the variable time delay destabilizes bilateral master-slave manipulator with scattering transformation and a new compensation method which keeps the time delay constant. This new compensation method has been implemented in a single-axis master-slave manipulator.     

Negotiating expert status: who gets taken seriously

A lay person may listen puzzled as a specialist in a public hearing discusses a technical point. Similarly, a challenging question from a technically knowledgeable member of the audience may be difficult to fathom. Failure to understand what a speaker discusses-despite one's interest in a topic-can cause frustration, anger and despair. It makes a listener wonder why they are there trying to engage, and why technical specialists persist in such a style of presentation. Breakdowns in communication between technical and nontechnical people are linked to the concept of “expert”. This link involves the process of the “negotiation of expert status”; this refers to the social construction of the role of the “expert” by the participants in a conversation. The term “negotiation” refers to the sometimes subtle and sometimes overtly contentious nature of a debate about who deserves to be listened to as a voice of authority on a particular topic     

Unit commitment using Lagrangian relaxation and particle swarm optimization

Unit commitment (UC) is a NP-hard nonlinear mixed-integer optimization problem. This paper proposes ELRPSO, an algorithm to solve the UC problem using Lagrangian relaxation (LR) and particle swarm optimization (PSO). ELRPSO employs a state-of-the-art powerful PSO variant called comprehensive learning PSO to find a feasible near-optimal UC schedule. Each particle represents Lagrangian multipliers. The PSO uses a low level LR procedure, a reserve repairing heuristic, a unit decommitment heuristic, and an economic dispatch heuristic to obtain a feasible UC schedule for each particle. The reserve repairing heuristic addresses the spinning reserve and minimum up/down time constraints simultaneously. Moreover, the reserve repairing and unit decommitment heuristics consider committing/decommitting a unit for a consecutive period of hours at a time in order to reduce the total startup cost. Each particle is initialized using the Lagrangian multipliers obtained from a LR that iteratively updates the multipliers through an adaptive subgradient heuristic, because the multipliers obtained from the LR tend to be close to the optimal multipliers and have a high potential to lead to a feasible near-optimal UC schedule. Numerical results on test thermal power systems of 10, 20, 40, 60, 80, and 100 units demonstrate that ELRPSO is able to find a low-cost UC schedule in a short time and is robust in performance.     

Evaluation of the Lorentz law by using a Barlow wheel

In this work, an evaluation of the Lorentz law has been carried out by a Barlow wheel. Basically, a Barlow wheel is a primitive dynamo-electric machine (invented by P. Barlow in 1828) which consists of a metallic cogwheel, which moves around a horizontal axis. The theoretical analysis includes the Lorentz law and the Petroff law, which characterizes the friction between the axis and the bearing. In the stationary state (when the angular velocity is constant), a simple formula can be obtained which relates the current intensity and the angular velocity. Experimental data approximately confirms this formula, and this device can be used as a simple and classical laboratory experiment in basic electromagnetism courses. Some modern complements were used for the acquisition of data, as a light barrier connected to a counter, a voltammeter and a direct-current power supply Therefore, the Barlow wheel, originally designed for qualitative demonstrations, can be used as a quantitative and useful assembly in a laboratory of General Physics     

Development of a web-based laboratory for control experiments on acoupled tank apparatus

The Internet provides a new environment for developing a variety of applications for educational and research purposes. This paper presents the implementation of a web-based laboratory experiment on a coupled tank apparatus, a multi-input-multi-output (MIMO) system. The web-based laboratory has been developed to serve students and staff in the Department of Electrical Engineering at the National University of Singapore (NUS). The laboratory is an educational tool for teaching students the basic principles and methodology in performing a series of experiments on a coupled tank apparatus at any time and from any location through the Internet. With the capability to implement strategies for manual, proportional integral derivative (PID), general state-space, and fuzzy logic control, the laboratory also provides a platform for research staff to test control algorithms. Video conferencing has been used to provide audio and video feedback, with a camera mounted on a movable platform so that the user can control both the zooming and viewing angle     

换热器管壁圆形泄漏口空间辐射声场分布特征数值研究

根据可分离辐射源的声辐射，利用叠加原理和无穷级数迭代求和，建立了换热器管道壁面圆形口非分离泄漏声辐射源的空间声场分布数学模型。计算了圆形口均匀幅度非分离声辐射源的空间声场远场分布，给出了其远场相对声压级和位相的空间分布图案。与方形口均匀可分离辐射源的空间声场分布特征相比，发现两种情况具有相同的空间指向性特征，在较高频率时辐射声场空间分布出现盲区，在x—y平面内声场分布与泄漏口形状无关，但与辐射频率有密切关系。