基于催化重整脱氯的轴金属高分子材料制备新工艺

高分子材料是我们在生产以及生活的过程中比较常用的一种化学的合成材料,对我们日常的生产以及生活非常重要,起着不可替代的作用,高分子材料一般为人工的制造,传统的制造的模式往往存在着这样或者那样的不足,所以,近些年,我国的许多的科学家通过积极地学习新工艺以及对高分子材料的研究,创造了许多的新的方法,本文主要的讲述基于催化重整脱氯的轴金属高分子材料制备的新工艺的相关的概念。     

数控机床智能化的主要技术特征

随着时代和科技的不断进步,数控机床技术的发展不断的优化和完善,整体的数控机床的发展趋势逐步向智能化发展。而对于数控机床的技术的开发和应用也逐渐的受到相关的机床生产商和采购者的重视。因而从实际上来讲数控的智能化发展不仅对机床所加工的产品的质量有一定的影响,对于加工的效率的影响也是比较大的。在此基础上,本文将对数控机床智能化的主要技术特征进行有效的分析和研究,从而使得数控机床技术能够更加健康的发展和进步。     

自然铜矿石样品的加工及分析测试方法研究

矿石中含有多种天然物质,矿采对于矿物质的的测定十分重要,有效的开采所需要的矿物质,可以节省大量的人力物力,同时也关系到日后的资金收益。现代社会正处于稳定发展的阶段,所以对矿产的需求比较高,例如电子产业,军事科技等等。有效的利用已开采的矿物质,去除其中的杂质是十分重要的。一块普通的矿石中,往往含有多种杂质,精确的分析其中的化学元素可以更加准确的确定其开采地的矿物质的基本成分。取样是测定的基本前提,铜矿石的元素测定是对矿石本身而言。所以找到有代表性的样品具有重要的意义。本文简述了自然铜矿石的样品加工及其分析的方法。     

浅谈矿产资源的开发与地质环境保护

近年来我国社会的发展过程中,我国的矿产的产值,不断的提升,带来了较大的经济效益,但是随着开采量的不断的增加,给环境带来的污染是不可忽视的。党在十八大提出,要以文明的生态环境,作为宏伟的目标,指出了要将建设生态的文明,放在十分重要的位置上,文章针对矿产资源的开发,地质环境的关系,提出指导性的建议。     

浅谈英语课堂的有效教学

提高课堂教学的有效性,精心设计生动的、富有情趣吸引力的、形式多样的活动。教学的有效性是教学设计的生命,是学校教学活动的一个基本追求,它直接关系到教学的质量和人才的培养。加强教师自身素质的提高是课堂教学的有效性的重要前提,教师本身的能力高低会直接的影响到课堂教学质量。     

马克思主义视域下人性的二重性解读

在人性的问题上,马克思主义之前的哲学往往用静止的、孤立的、片面的、抽象的、形而上学的思维方法来解读人性.马克思主义哲学以实践为出发点,运用辩证的思维方式,对人性作出了全新的二重性的解读,认为人性是全面的、发展的、辩证的,是矛盾的统一体,是能动与受动、客观与主观、具体与抽象、变与不变的统一,是一个系统的、开放的、复杂的有机整体.     

关于端电设备制造和维修的几个问题

整流机组是整流供电的核心设备。对于整流机组而言，合理的方案选择，精良的设计制造，正确的使用操作，以及到位的维护保养是其安全运行的基本保证。方案选择得不合理和设备制造中存在缺陷造成了先天的隐患。不正确的操作和缺乏及时到位的维护会产生后天的祸患。尽可能地排除先天的隐患，避免后天的祸患就是我们要研究的问题和要做的工作。维护检修是其中一项重要的工作。及时到位的维护检修可以发现和排除设备的隐患，保证设备处于良好的状态。即使是很好的设备，缺乏必要的维护保养也是会出问题的。本文重点就供电整流设备的维护和检修问题，结合抚顺铝厂的经验并参照国外公司的产品说明，谈谈个人的粗浅看法。     

部分城市生产资料价格周报

一品名规格条件I北京沈阳天津武汉长沙上海成娜西安白银兰妞广州.曰,朴挂牌26000260的2580026500262的25,502石印02?加O25800,月1,f成交257的256加257002630025?的肠以力舫以冲2650025500自口几n几内内挂称‘168的168的1650016别沁168的1645017加01‘创沁16600下口J、U才、肠月J成文166的164001630016500163的164加17的016右的16200自几1什挂脚6,的72Q0690069的7(期】1即0飞95012的70的,口1,f成交68加‘900680068的69的,1506加069的69的山立,朴挂脚95的9500980097的匀55095509夕00肠阅95的,甲1心宁成交94的9300950096加匀5的95的躺0095的…     

浅谈环境艺术设计中的水景设计

本文从实际操作的层面探讨了环境艺术中重要的一个环节水景的设计工作.丈中已经充分的说明了水景设计是我们人类在生存的地表与其他的一些因素的构成关系所推行的整体性的研判,从这里面找寻出我们人类与大自然和谐共处的发展模式,减少我们人类的行为对于环境的种种破坏,让我们的生态环境能够得到及时的改善,加强我们人类的文明价值,实现人与自然的和平相处.     

马克思感性的自然概念及当代启示

马克思的自然概念是一个具有多重维度的整体性概念.马克思感性的自然概念全面地阐述了人与自然、历史与自然、自然科学与人文科学的辩证统一关系.感性的自然强调的是自然与人的相关性;人化的自然是对人与自然之间认识和实践的对象性关系的概括;历史的自然是对在生产实践基础上历史与自然统一的关系的概括;人本学的自然是对自然科学与人文科学的辩证统一关系的说明;价值的自然是对人与自然之间存在着满足与被满足、需要与被需要的价值关系的概括.马克思的感性自然概念对于理解与建设生态文明具有多方面的启示.     

Drawdown due to Temporally Varying Pumping Discharge: Inversely Estimating Aquifer Parameters

A ramp kernel method is proposed for accurately calculating the drawdown due to any temporal variation in pumping discharge. The use of the ramp kernels assumes the linear variation between the two consecutive measured pumping discharges. The prior studies assume a rectangular variation between the two consecutive measured pumping discharges. In the rectangular variation, a uniform pumping rate is assumed during a time span. An analytical equation for calculating the ramp kernel is derived. An optimization method is used with the proposed ramp kernels for inversely estimating the aquifer parameters from drawdown due to an arbitrary unsteady pumping discharge. Unlike the prior methods, the proposed method accurately identifies the parameters even when the sampling interval for the drawdown and pumping discharge is longer than that needed for assuming a linear variation. The proposed method outperforms the prior method. Application of the proposed method is illustrated using examples.     

New Orleans Levee System Performance during Hurricane Katrina: London Avenue and Orleans Canal South

Hurricane Katrina was one of the worst natural disasters in U.S. history. The effects of the hurricane were particularly devastating in the city of New Orleans. Most of the damage was due to the failure of the levee system that surrounds the city to protect it from flooding. This paper presents the results of centrifuge models conducted at Rensselaer Polytechnic Institute and the U.S. Army Corps of Engineers simulating the behavior of the levees at London Avenue North and South that failed during Hurricane Katrina. Those levees failed without being overtopped by the storm surge. Also included are the results of a centrifuge model of one levee section at Orleans Canal South, which did not fail during the hurricane. The key factor of the failure mechanism of the London Avenue levees was the formation of a gap between the flooded side of the levee and the sheetpile. This gap triggered a reduction of the strength at the foundation of the protected side of the levee. The results are fully consistent with field observations.     

Evaluation, Rehabilitation Planning, and Stay-Cable Replacement Design for the Hale Boggs Bridge in Luling, Louisiana

The Hale Boggs Bridge opened to traffic on October 5, 1983. At the time, it was the first U.S. cable-stayed crossing over the Mississippi River. The PE (polyethylene) protective sheathing was damaged in many of the cables before and during installation, and after the opening of the bridge to traffic. Repairs were attempted to correct the defects in cable sheathing. Many of the repairs performed poorly and failed to protect the main tension element. The condition of 39 out of 72 cables indicated a critical need for repair and timely action was recommended. To address these damages, and to assure the structural integrity of the bridge structure, several strategies involving a range of repair and replacement options were evaluated using life cycle cost analysis. It was concluded that the strategy to replace all cables presents the best value among evaluated alternatives. The design of the complete 72 cable array replacement is the first occasion on which this process is attempted in North America. The final design of the replacement cables is heavily influenced by the geometric restrictions of the existing anchorage locations. The replacement cables are being designed for a 75-year design life and incorporated with the latest advancements in corrosion protection and vibration control. Maintenance of traffic design is an essential part of the project. The bridge is a critical regional link and constitutes a hurricane evacuation route. Traffic maintenance during cable replacement was designed to be as unobtrusive to the public and commerce as practical. This paper describes efforts associated with cable condition assessment, rehabilitation strategy, and design considerations and concepts, undertaken by the writers since 2002 to improve the condition of this major river crossing.     

Case Study of Fluvial Modeling of River Responses to Dam Removal

A plan was made to remove Matilija Dam on the Ventura River. With dam removal, the delta in the reservoir and the downstream channel were expected to undergo major changes in morphology. The FLUVIAL-12 model was employed to simulate reservoir and river channel responses after dam removal. As a first step, the model was calibrated using the Ventura River data to establish its validity. In calibration, the model was used to simulate the fluvial processes starting from the time of dam completion. The simulated sediment deposition above the Matilija Dam matches closely with the deposits measured by the U.S. Bureau of Reclamation. A large amount of sediment was stored in the reservoir; some of the stored sediment would be transported downstream after dam removal. An important consequence of dam removal is the major increase of sediment release to the river channel downstream. The sediment supply to the downstream reach is not only from the stored sediment in the reservoir but also from natural sediment inflow from the upstream watershed. Therefore, sediment supply to the downstream reach will exceed the natural sediment flow before the dam presence. This situation tends to overload the downstream reach with sediment, resulting in excessive deposition. The amount of sediment release from the area above the removed dam is closely related to the changes in reservoir morphology. It is necessary to model changes in the channel bed profile and channel width during erosion in order to determine the amount of sediment removal. The amount of sediment release may not be simulated using an erodible-bed model but it may be determined using an erodible boundary model.     

Below-Average Bidding Method

The low-bid method, typically used for competitive bidding in the United States, may result in a contract with a firm that submits either accidentally or deliberately an unrealistically low-bid price. Such an occurrence hurts both the owner and the contractor by promoting disputes, increased costs, and schedule delays. To address this problem, other countries have adopted bidding methods based on the average of the bids submitted. One such approach is the below-average method where the winning bid is closest to but below the average of all bids. A competitive bidding model for the below-average-bid method is presented and its merits relative to the average-bid method and the low-bid method are explored. The below-average-bid process is investigated analytically and through Monte Carlo simulation. The results of bidding models for the below-average, the average, and the low-bid methods are presented in four easy-to-use nomograms which allow contractors to determine the optimal lump-sum bid price for each method without the need for complicated analysis. A comparison of the three methods provides information and insights to help owners with the difficult choice of a suitable bidding method for the project at hand.     

Reliability-Based Optimal Design of Truss Structures Using Particle Swarm Optimization

In this work, the particle swarm optimization method is employed for the reliability-based optimal design of statically determinate truss structures. Particle swarm optimization is inspired by the social behavior of flocks (swarms) of birds and insects (particles). Every particle’s position represents a specific design. The algorithm searches the design space by adjusting the trajectories of the particles that comprise the swarm. These particles are attracted toward the positions of both their personal best solution and the best solution of the swarm in a stochastic manner. In typical structural optimization problems, safety is dealt with in a yes/no manner fulfilling the set of requirements imposed by codes of practice. Considering uncertainty for the problem parameters offers a measure to quantify safety. This measure provides a rational basis for the estimation of the reliability of the components and of the entire system. Incorporating the reliability into the structural optimization framework one can seek a reliability-based optimal design. For the problems examined herein, the reliability indexes of the structural elements are obtained from analytical expressions. The structure is subsequently analyzed as a series system of correlated elements and the Ditlevsen bounds are used for the calculation of its reliability index. The uncertain-random parameters considered in this work are the load, the yield-critical stress; and the cross sections of the elements. The considered design variables of the optimization problem are the cross-sectional areas of the groups, which control the size of the truss, and the heights and lengths that control the shape of the truss. The results of the optimization are presented for a 25-bar truss and a 30-bar arch and the robustness of the optimization scheme is discussed.     

Bridge Scour and Substructure Deterioration: Case Study

In 1988, the State of Mississippi set up its first statewide underwater bridge inspection program. During this inspection, serious damage was found on the substructure of two parallel bridges on I-10 near Biloxi. Significant scour had occurred, exposing the steel piling. These piles had severe corrosion with cross sections reduced by 50%. Because of the reduced cross section, the web and flanges of the piles had buckled locally. This damage was exacerbated by collisions associated with barge traffic on the waterway. This accumulation of problems resulted in a bridge on the verge of collapse. Two alternatives were used to repair the substructure. The more seriously damaged piles were encased in concrete, and the less seriously damaged ones were dewatered and a concrete seal was placed around the piles. After 10?years, the piers with pile encasements showed no additional scour effects. However, the piers with the large concrete seals had scoured by as much as 3?m (10?ft). Described in this paper is the analysis of damage, design of the repair, and a review of the performance of the two types of repair over a 10-year period.     

Evaluation of Construction Practices That Influence the Bond Strength at the Interface between Pavement Layers

This study investigated the influence of several construction practices on the bond strength at the interface between pavement layers. These practices included the surface treatment, curing time, residual application rate, and equipment tracking. Three tests were performed for estimating the bond strength between an existing hot mix asphalt (HMA) and a newly constructed HMA overlay, namely the Florida Dept. of Transportation shear tester, the University of Texas at El Paso pull off test, and the torque bond test. Testing involved a CSS-1 type emulsion as the tack coat. The results from the three tests were statistically analyzed. Generally, milling provided a significantly better bond at the interface between the existing surface and the new overlay. Curing time had a minimal effect on the bond strength. The results indicated that the absence of tack coat did not significantly affect the bond strength at the interface for the milled sections, whereas it severely decreased the strength for the nonmilled sections. The results also showed that increasing the residual rate of tack coat did not generally affect the bond strength at the interface.     

Bridge Blockage and Overbank Flow Simulations Using HEC–RAS in the Keelung River during the 2001 Nari Typhoon

On September 16, 2001, Typhoon Nari resulted in severe flooding in the Keelung River basin. More than 1,000 shipping containers were swept by the rising water from the floodplain into the river, blocking 14 bridges. A severe overbank flow due to the blockage occurred at the Ba-Tu Railway Bridge. The overbank flow then passed through a railway tunnel and inundated Keelung City, resulting in significant damage. The objective of this study was to determine the influence of the bridge blockage and the Ba-Tu overbank flow on the water stages in the Keelung River during Typhoon Nari. The floating-pier-debris module and the lateral-weir module in the Hydrologic Engineering Center–River Analysis System (HEC-RAS) unsteady-flow routing model were applied to investigate water stage variation due to the bridge blockage and overbank flow. The numerical simulation results provided by this study served as an important reference for authorities who needed to clarify the responsibility of the containers’ owners for the loss of lives and property during this typhoon.     

Influence of the chromium and ytterbium co-doping on the photoluminescence of zinc selenide crystals

The luminescent properties of ZnSe, ZnSe：Cr（0.05 at.% Cr）, ZnSe：Yb（0.03 at.% Yb） and ZnSe：Cr：Yb（0.05 at.% Cr, 0.05 at.% Yb） crystals, doped during the growth process by the chemical vapor transport method, were studied within the temperature interval of 6–300 K. At the 6 K temperature in the visible spectral range 2 bands were observed： a band in the excitonic spectral region and a band of self-activated luminescence. It was shown that co-doping of zinc selenide crystals with the chromium and ytterbium led to the combination of the impurities influence on the photoluminescent properties. At the liquid helium temperature in the middle infrared range of the spectra of the ytterbium and chromium co-doped crystal a band with the maximum localized at 1.7μm was observed, which was overlapped with a complex band in the middle-IR spectral range, characteristic for the chromium doped ZnSe crystals. On the basis of obtained data an interaction mechanism of the chromium and ytterbium co-doping impurities was proposed. Guided by the existent model of the ytterbium ion incorporation in the selenide sublattice of the ZnSe crystals, an assumption about stabilization of single charged chromium ions in the zinc sublattice crystal nodes, by means of formation of the local charge compensating clusters, was made. It was assumed that the resonant energy transfer from one chromium ion to another,which led to the concentration quenching of the IR emission in the ZnSe：Cr PL spectra, would lead to the broadening of the IR emission in the spectra of ytterbium and chromium co-doped zinc selenide crystals.g