基于评标模式的公路工程造价研究

招标投标是我国工程项目进行施工承包重要的的方式。而评标的是公路工程的建设项目的招标投的标的关键环节。为了保证评标环节的公平、公正、科学、合理,保护招投标双的方的利益的,提高工程的建设的质量,研究科学、合理、有效的评标理论具有十分重的要的意义。     

对低压成套开关设备绝缘配合问题的探讨

电气工业的都配备有低压的成套的开关设备,我国的百分之八十左右的电能供给都是通过低压的成套的开关设备予以供出,低压的成套的开关设备的发展与工业材料制作,工艺产品和加工设备,低压的电器,人们的生活水平和基础的设施建设息息相关,所以它从一个侧面凸显了一个国家的综合国力,而其中的绝缘配合是一个关联到电气产品的安全性的至关重要的问题,应该要有非常的重视     

阐析高速公路路基的路面施工

我国的交通运输行业的发展借助的是我国的经济的高速的发展。我国交通运输业的发展也直接带动了我国的高速公路的发展。在我国的高速公路的建设过程中,关于路基路面的施工还是存在着很多的问题的。本文针对高速公路路基路面施工的问题,来进行相关的讨论和分析,讨论高速公路路基施工中的施工工艺的应用,为高速公路的建设贡献自己的力量。     

220kV变电站主接线运行经济性选择的探讨

变电站的主接线的设计是依据变电站的最高电压以及变电站的性质决定的。通过地区的电网的运行的实际情况出发,对220kv的变电站的主接线的运行进行了详细分析,并对变电站的主接线的设置进行了比较与分析。     

如何进行施工项目的管理和成本的控制工作

随着我国经济的不断发展,我国的基础设施的施工工程越来越多,在施工的过程中,施工项目的管理工作越来越重要。作为现代的企业来讲,施工的项目管理是非常的重要的,这主要是因为施工的企业只有做好施工项目的管理工作才能不断的完善现在的企业管理制度,使企业的管理工作更加的完善。企业只有做好施工项目的管理工作才可以提高企业的经济效益,进行项目施工的时候一定要进行必要的成本控制,这样才能够使企业的社会信誉得到提高,并且可以使企业的发展空间得到更大的提升。     

石化行业的污水处理探析

伴随着世界范围内的资源再利用的步伐,我国的石化行业的从业单位不断的发展壮大,与此同时人们的环保概念不断的在进行加强。石化行业的污水的处理方式已经越来越受到社会的关注。如何处理石化行业的污水已经是一种议题。随着我国的工业化程度的深入,我国石化行业的工业废水已经变化的多种多样,很多的化学污染物掺杂其中,这样就会对我们的化工行业的污水处理带来很多的困难。针对这种现状,我们要做的就是要不断的提升化工行业污水处理的质量和效率。本文就是针对这种问题来进行详细的论述。     

建筑施工中室外照明的接地故障保护和短路保护方法之研究

随着我们国家的经济的迅猛发展,人们的生活水平也是越来越高。人们对周围的环境的要求也是越来越严格。照明系统作为城市道路的一个明显的环节。由于室外的照明的场所的不同,所以室外照明供电系统的供电的方式也是不一样的。本文是通过对室外照明线路的选择以及供电系统的选择进行分析,为以后的室外照明的相关工程提供有利的依据。     

浅析当前公共财政政策存在的问题及对策

随着我国改革开放的不断的深入进行以及社会主义市场经济的建立和不断的完善,极大的改变了我国公共财政所面对的环境。当前我国的财政体制改革起的了很大的成功,极大的促进了我国经济的发展,但是在财政体制改革的过程当中也暴露出我国公共财政存在的一些问题。文章对当前我国公共财政存在的问题进行了深入的分析,并有针对性的提出了改进的建议,促进我国公共财政的发展。     

浅谈信息时代网络环境下的教学模式

网络环境下的教学模式是信息时代的教育所面临的必然选择,从网络环境下的教学模式的特点,网络环境下的教学模式的要求,网络环境下的教学模式的发展的意义等几个方面论述网络环境下的教学模式的重要性和迫切性。     

进行水利工程的工程建设和管理技术的建设

随着经济的不断发展,我国的基础工程的建设也在逐渐的增多,在这些工程中水利工程的建设是十分的重要的,水利工程的建设不但可以促进我国经济的发展,还可以改善当地人们的生活水平和当地农业的发展。但是在水利工程进行建设的时候,要不断的完善水利工程的工程建设以及工程的管理技术,这样才能更好的发展水利工程。     

technical note Linear variable differential transformers — Practical hints

Some years ago, a requirement existed for the development of a transducer of the LVDT type having the greatest possible sensitivity and of the smallest possible size. It was developed by a purely intuitive process and resulted in a series of devices having a variety of practical applications. In particular, its use as an extensometer could be of interest in the field of strain measurement.     

聚醚醚酮的结晶与熔融行为研究

研究了PEEK在高于熔点的温度范围内处理时的结晶行为以及结晶后的熔融行为。发现处理时熔融的PEEK将同时发生交联与结晶,交联使未结晶的部分结晶受阻,结晶使尚存的晶片增厚,从而导致PEEK在DSC上出现对应于不同晶体结构的新的熔融双峰,并在此基础上提出了处理过程中PEEK结构变化的模型。此外,还发现处理后的PEEK的熔点,可高于目前已报导的平衡熔点。     

Epitaxial growth and surface morphology of aluminum films deposited on mica studied by transmission electron microscopy and atomic force microscopy

The bulk structure and epitaxial growth of aluminum films deposited on mica substrates by thermal evaporation in a wide temperature range (16-550 °C) in high vacuum were investigated by transmission electron microscopy and transmission electron diffraction. The surface morphology of the films was observed and analyzed by atomic force microscopy. The films prepared at room temperature consist of single crystals having a diameter of 90 ± 40 nm with (111) planes. The surface of the films comprises spherical grains with morphology that is caused by self-shadowing during the deposition. The surface of the films becomes smoother as the temperature increases, and atomically-smooth surfaces with a root-mean-square roughness of about 0.45 nm over an area of 1 μm² are obtained at 250-350 °C. The crystals are oriented randomly along the [111] direction perpendicular to the substrate. The surface of the films consists of larger (> 300 nm) grains with terraces, and the surface becomes rough above 400 °C. Films with well-oriented single crystals along the [111] direction perpendicular to the substrate are obtained above 520 °C. The films grown epitaxially at 520-550 °C are characterized by the isolated grains with a diameter of 1220 ± 450 nm.     

Enhancement of the lifetime in organic light-emitting devices fabricated utilizing wide-bandgap-impurity-doped emitting layers

The degradation behaviors of the electrical and the optical properties of organic light-emitting devices (OLEDs) fabricated with an emitting layer (EML) doped with or without a wide-bandgap-impurity were investigated. The OLEDs with a wide-bandgap-doped Alq₃ EML were more stable than those with an undoped Alq₃ EML. The existence of the doped wide-bandgap-impurity in the EML decreased the trap-charge density in the EML, resulting in an increase in the number of electrons in the Alq₃ EML. That increases in the number of electron in the Alq₃ EML for the OLEDs with a wide-bandgap-impurity decreased the staying time of the holes in the Alq₃ EML, resulting in an enhanced lifetime for the OLEDs. These results indicate that OLEDs with a wide-bandgap-impurity-doped EML hold promise for potential applications in long-lifetime OLED displays.     

Fabrication and characterization of NiO/ZnO/ITO p-i-n heterostructure

Transparent oxide semiconductors (TOSs) are promising materials for a variety of optoelectronic applications such as UV detectors. While several TOS-based p-n and p-i-n diodes have been recently reported, the high reverse dark current still poses a major issue. In this work, we report on a NiO/ZnO/ITO p-i-n heterostructure with reduced dark current level suitable for practical applications. Ion beam-assisted e-beam evaporation was used to deposit both p-type NiO and intrinsic ZnO layers, while a conventional sputtering system was used to prepare the ITO layer. Samples with sputtered ZnO layer were also fabricated for comparison. The diodes demonstrated clear rectifying I-V characteristics with a current rectification ratio up to 10⁴ at bias voltages of ± 1 V. The lowest level of reverse dark current (∼ 10 nA/cm² at − 5 V) is observed in samples with ZnO deposited by ion beam-assisted e-beam evaporation. In comparison, diodes with sputtered ZnO layer show two orders of magnitude higher dark current. Analysis of the quasi-static J-V characteristics, including time dependence behavior, shows that the dark current can be attributed to thermal generation of charge carriers via deep defects states in the ZnO layer and charge injection from the contacts. Electrical and optical properties of the TOS films are presented and discussed along with deposition conditions and device performance.     

Role of carbon atoms in plasma-enhanced chemical vapor deposition for carbon nanotubes synthesis

The role of carbon atoms in a dc plasma-enhanced chemical vapor deposition for carbon nanotubes (CNTs) synthesis was investigated. It was observed that at 1.33 kPa pressure of CH₄ gas in plasma, a high value of the ratio between the intensities of the graphite peak (G peak) and the disorder peak (D peak) in the Raman spectrum corresponds to the maximum value of the excited C number density in the vicinity of the Si substrate. It was found that a CH₄ gas pressure higher than 1.33 kPa leads to an increase of the relative density of the C₂, C₃ molecules and the clusters, and to a decrease of the C excited atom number density in plasma. The presence of a high amount of sp²-graphite in the composition of CNTs observed in Raman spectrum was also confirmed by the measurement of the IR-active G peak at 1584 cm^- 1 in the transmission spectrum.     

The spectrum of cosmic-ray electrons measured with H.E.S.S.

The measurement of very-high-energy cosmic-ray electrons is intrinsically difficult due to the very steep electron spectrum with low fluxes and an enormous background of hadronic cosmic rays. The large collection areas needed for such a measurement can be provided by ground-based imaging atmospheric Cherenkov telescopes. The High Energy Stereoscopic System (H.E.S.S.) has performed the first ground-based cosmic-ray electron measurement and thereby extended the measured range of the spectrum to several TeV. Here the H.E.S.S. measurement is presented, as well as an extension of the H.E.S.S. spectrum towards lower energies. At these energies, H.E.S.S. can probe recent ATIC measurements, which have been interpreted in terms of dark matter scenarios.     

Optically transparent ZnO-based n-i-p ultraviolet photodetectors

An optically transparent tin-doped indium oxide/ZnO/NiO n-i-p heterostructure photodiode was fabricated by ion beam assisted e-beam evaporation. The diode clearly demonstrates rectifying current-voltage (J-V) characteristics with a current rectification ratio up to 10⁴ at bias ± 2 V and a low reverse current of ∼ 100 nA/cm² at − 5 V. Analysis of J-V characteristics including time dependence of the dark current shows that the leakage current at low biases is attributed to thermal generation via defect states, and at high biases, field-enhanced carrier generation from the ZnO layer dominates. Spectral response and linearity measurements indicate that such a diode is particularly suitable for low level of ultraviolet detection.     

Recent Progress in Studies of Nanostructured Impurity–Helium Solids

Impurity–helium (Im–He) solids are porous materials formed inside superfluid ⁴He by nanoclusters of impurities injected from the gas phase. The results of studies of these materials have relevance to soft condensed matter physics, matrix isolation of free radicals and low temperature chemistry. Recent studies by a variety of experimental techniques, including CW and pulse ESR, X-ray diffraction, ultrasound and Raman spectroscopy allow a better characterization of the properties of Im–He solids. The structure of Im–He solids, the trapping sites of stabilized atoms and the possible energy content of the samples are analyzed on the basis of experimental data. The kinetics of exchange tunneling reactions of hydrogen isotopes in nanoclusters and the changes of environment of the atoms during the course of these reactions are reviewed. Analysis of the ESR data shows that very large fraction of the stabilized atoms in Im–He solids reside on the surfaces of impurity nanoclusters. The future directions for studying Im–He solids are described. Among the most attractive are the studies of Im–He solids with high concentrations of stabilized atoms at ultralow (10–20 mK) temperature for the observation of new collective quantum phenomena, the studies of practical application of Im–He solids as a medium in neutron moderator for efficient production of ultracold (∼1 mK) neutrons, and the possibilities of obtaining high concentration of atomic nitrogen embedded in N₂ clusters for energy storage.     

The influence of structure changes in the properties of TiCxOy decorative thin films

The main purpose of this work consists in the preparation of titanium oxycarbide, TiC_xO_y, thin films, in which the presence of oxygen changed the film properties between those of titanium carbide and those of titanium oxide. Varying the oxide/carbide ratio allowed to tune the structure of the films between titanium oxide and carbide and consequently electronic, mechanical and optical properties of the films. The depositions were carried out from a TiC target by direct current, dc, reactive magnetron sputtering, varying the oxygen flow rate. The obtained results showed that the film's properties can be divided into 3 different regimes — i) carbide, ii) a transition zone and iii) an oxide one. X-ray diffraction results revealed the occurrence of a face-centered cubic phase (TiC-type) for low oxygen content, also obtained in the TiC_1.6(O) film, with a clear tendency towards amorphization with the increase of the oxygen flow rate. For the highest oxygen contents, the results revealed the development of a mixture of poorly crystallized TiO₂ phases. The colour results indicated a strong dependence on the O/Ti ratio. A progressive reduction of hardness and residual stresses with the increase of the O/Ti ratio was also observed. The residual stresses, as well as the film structure, seem to play an important role on the adhesion of the coatings. The static friction coefficient revealed also some correlation with the mechanical properties, but mainly with the surface roughness.