对《建设工程工程量清单计价规范》的认识

《清单计价规范》是对工程量清单计价的整个活动进行规范。通过对《清单计价规范》出版前后的计价活动相比较,阐明了《清单计价规范》更适合市场的观点。     

镍市真正短缺就在今年

2003年金属市场价格全面上扬有其基本面的因素,美元兑欧元汇率大幅下降更加突出了有色金属的保值功能。2003年初,欧元对美元的汇率大约在1.06,但是到年底时已升至1.26。2003年12月份,以美元计价的LME镍现货价为14162美元/吨,以欧元计价的镍价为11524欧元/吨。     

工程量清单计价初探

介绍了工程量清单计价的基本概念,总结了实行工程量清单计价的特点;最后,提出了应用工程量清单计价应注意的问题及其解决方案。     

电力工程项目如何应对工程量清单计价

文章介绍T工程童清单计价模式概述及意义分析了清单计价模式在电力工程中存在的问题,提出了电力造价人员做好清单计价工程的结算编制工作     

浅议工程量清单计价模式与施工企业对策

对工程量清单计价模式的定义和作用进行了明确和认定,与传统的定额预算计价模式进行了比较分析,指出了两者之间的异同点,分析了工程量清单计价模式对施工企业产生的影响和意义,对施工企业为适应计价模式的变化提出了几点建议和对策。     

中外工程造价计价差异分析

随着工程国际化步伐越来越大,与国际工程计价接轨的要求越来越高,工程计价模型差异、计价方式的转变与融合是现在国内工程造价领域研究的方向之一,本文就国内工程造价构成及国际上通用计价方法差异进行了基本分析,对计价方式的转变与融合做了简单陈述,希望对于同行开展更深入的研究工作起到抛砖引玉的作用。     

关于采用工程量清单计价模式有效加强工程造价管理的探讨

论述了采用工程量清单计价模式的市场背景及必要性。与传统的定额计价模式进行了比较，并对采用工程量清单计价模式有效加强工程造价管理进行了探讨。     

浅谈工程量清单计价的实践

通过对工程量清单计价与传统预算报价的比较,以及工程量清单计价实践中存在的问题,提出了完善工程量清单计价的改进意见。     

工程量清单计价在冶金项目建设中的应用与思考

论述了传统的计价模式与工程量清单计价在计价性质、形成方式、招投标形式的区别，并根据冶金项目特点阐述了冶金项目分部分项工程量清单、措施项目清单及其它项目清单的编制应用，并结合实际工作提出在工程量清单计价中应注意的问题和解决方法。     

清单计价与定额计价模式并行的思考

分析了现阶段清单计价与定额计价模式并行 (同时存在 )的原因 ,并着重叙述了企业编制内部定额时应注意的问题 ,提出目前清单计价模式的工程投标必须重视清单项目审核工作     

自流耐火材料的流变学机理研究及其在工业炉窑中的应用

自流耐火浇注料以其优异的物理化学性能和施工性能，在各种工业炉窑上得到了日益广泛的应用。本文就自流耐火浇注料的流变学机理、自流性能评价以及自流耐火浇注料在冶金、电力等行业的应用做一简要介绍。     

Turning a patient prone with ARDS

Six patients with hydrocephalus who were treated with cerebrospinal fluid (CSF) shunts became refractory to serosal absorption of CSF. All were subsequently treated with ventriculo-gallbladder shunts. The surgical technique and long-term results were evaluated by retrospective review of the hospital records. Detailed evaluation of 1 of the 6 has suggested a dynamic role for the gallbladder in the function of ventriculo-gallbladder shunts.     

Nerve fibre velocity and refractory period distributions in nerve trunks

With the use of a double stimulus technique, nerve fibre velocity range measurements were performed over a single conduction distance in 13 normal subjects and over two conduction distances in another 12 normal subjects. The velocity ranges were found to be dependent upon the conduction distance, owing to unknown refractory period delays. Refractory period values were calculated for the 12 subjects and also direct refractory period distribution measurements were made on 15 normal subjects using a twin stimulus and automatic subtraction technique. Corrections to the velocity range measurements were made upon differing assumptions as to the correlation between refractory period and fibre conduction velocity. It was concluded that a single median value refractory period obtained from the distribution was the best correction to use, based upon the hypothesis that for group A fibres the random scatter of refractory period values is far greater than any variation due to a correlation between refractory period and fibre conduction velocity. It was found important to recognize that calculated values of velocity range are a function not only of the spread of fibre conduction velocities but also of refractory periods.     

The heat resistance of structural materials in modern engineering

Summary Factors determining heat resistance and refractoriness of primarily metal powder heat-resistant compositions were considered, with special attention to the strength of the interatomic bond and possible methods of its evaluation. On the basis of calculation of the root mean square displacement of atoms in the crystal lattice of heat-resistant metals and compounds, a scheme was proposed for the arrangement of many metals, on the principle of their capacity for use as a base in production of heat-resistant alloys. In estimating heat resistance of refractory compositions, we suggested taking the indices of relaxation capacity as a basis. Technological methods were outlined for producing heat-resistant compositions by use of materials possessing especially high interatomic bond strength. The principal factors characterizing the scale-resistance of refractory compositions were defined.     

Refractoriness and neural precision

The response of a spiking neuron to a stimulus is often characterized by its time-varying firing rate, estimated from a histogram of spike times. If the cell's firing probability in each small time interval depends only on this firing rate, one predicts a highly variable response to repeated trials, whereas many neurons show much greater fidelity. Furthermore, the neuronal membrane is refractory immediately after a spike, so that the firing probability depends not only on the stimulus but also on the preceding spike train. To connect these observations, we investigated the relationship between the refractory period of a neuron and its firing precision. The light response of retinal ganglion cells was modeled as probabilistic firing combined with a refractory period: the instantaneous firing rate is the product of a "free firing rate, " which depends only on the stimulus, and a "recovery function," which depends only on the time since the last spike. This recovery function vanishes for an absolute refractory period and then gradually increases to unity. In simulations, longer refractory periods were found to make the response more reproducible, eventually matching the precision of measured spike trains. Refractoriness, although often thought to limit the performance of neurons, may in fact benefit neuronal reliability. The underlying free firing rate derived by allowing for the refractory period often exceeded the observed firing rate by an order of magnitude and was found to convey information about the stimulus over a much wider dynamic range. Thus, the free firing rate may be the preferred variable for describing the response of a spiking neuron.     

Processing of refractory materials using various magnesium sources derived from Zinelbulak talc-magnesite

Magnesia(MgO)is widely used in the production of refractory materials due to its high melting point,high thermal shock,and excellent slag resistance.The properties of refractory materials depend upon magnesia sources and processing parameters.In this work,three different magnesium sources,namely,magnesium hydroxide concentrate,magnesium carbonate concentrate,and intermediate flotation concentrate,were obtained from the Zinelbulak talc-magnesite,Uzbekistan,by causticization-hydration and flotation processes,respectively.A series of refractory materials were prepared on the basis of these magnesium sources,and their effects on physico-mechanical properties and microstructures were investigated as a function of sintering temperature,molding pressure,and the particle size of magnesium sources.The experimental results showed that a refractory material obtained from the magnesium hydroxide concentrate at 16000C for 4 h demonstrated favorable parameters due mainly to a higher degree of contact among fine particles.The results obtained from X-ray diffraction and optical microscopy confirmed the presence of periclase and forsterite as the predominant phases in refractory specimens.The prepared refractory materials meet the requirements of the State Standards(Nos.4689-94 and 14832-96)for magnesia and forsterite refractories,respectively.It is,therefore,suggested herein that the use of different magnesium sources derived from the Zinelbulak talc-magnesite will offer the potential to provide economic benefits in the refractory industry.     

A new method for estimating spinal cord function. Refractory period of conductive spinal cord evoked potentials

STUDY DESIGN: This study was designed to examine the possibility of a new spinal cord monitoring method using measurement of the refractory period to monitor spinal cord function. OBJECTIVES: To determine whether measuring the refractory period and the recovery rate of conductive spinal cord evoked potential is a useful method for estimating spinal cord function. BACKGROUND: Measuring the refractory period and constructing the recovery curve have been used to investigate peripheral nerve function. Spinal cord evoked potential elicited by the single stimulus usually is used to evaluate spinal cord function, and it has been said that 50% attenuation of the amplitude is the critical alarm level. METHODS: In anesthetized cats, amplitude, area, and latency were measured on a personal computer from subtracted data collected with a paired-stimulation technique. The authors constructed recovery curves of ascending and descending conductive spinal cord evoked potentials and measured the refractory period during spinal cord compression. RESULTS: When the amplitude of the ascending spinal cord evoked potential began to decrease during spinal cord compression, the amplitude of the response elicited by the second stimulus with interstimulus intervals of 0.8 msec and 1.0 msec decreased more significantly. When the amplitude of the ascending spinal cord evoked potential decreased to 50% of the precompression amplitude, the mean value of the absolute refractory periods of the ascending and descending spinal cord evoked potentials became prolonged from 0.40 +/- 0.007 msec to 0.53 +/- 0.014 msec, and the mean values of their amplitude and area recovery rates decreased from 75% +/- 1% to 35% +/- 2% (interstimulus interval, 0.8 msec) and from 81% +/- 1% to 46% +/- 2% (insterstimulus interval, 1.0 msec). CONCLUSIONS: The change of the responses elicited by the paired stimuli is more sensitive than those elicited by the single stimulus in the spinal cord evoked potentials. The absolute refractory periods and the recovery rate during 50% attenuation of the precompression amplitude is the critical alarm level in spinal cord monitoring.     

高发射率涂料在耐火纤维上的应用研究

介绍高发射率涂料对耐火纤维的强化作用。根据试验和检测分析，该涂层对耐火纤维有显著的保护作用。这种涂料已在大型环形炉上应用并取得了巨大的节能效益。     

炼钢用耐火材料的修砌情况与发展方向

炼钢所用耐火材料主要涉及范围有转炉、钢包、连铸中间包、真空处理室等,对这几方面修砌的情况进行介绍,并对在修砌过程中的一些不正常操作状况,造成耐火材料的使用寿命受到影响进行分析;最后对炼钢用耐火材料的发展方向进行探讨。     

熔铜竖炉的设计

结合山东阳谷祥光工程的实践，阐述竖炉的结构形式、燃烧系统、炉体冷却系统、给料系统和耐火材料等，着重论述结构形式与功能的相适应、竖炉的工作原理、烧嘴的布置方式、炉内气氛的控制、炉体冷却方式、耐火材料的选定以及炉体膨胀缝的设置等。