提高深凹露天矿汽车运输掘沟工程速度的途径

在露天开采中,为使采矿场保持正常持续生产,需及时开拓新的工作水平.新水平开拓最首要的是掘进出入沟,而出入沟掘进的速度则是露天矿掘沟工程的关键所在,它直接影响着整个水平开掘速度、开拓矿量的及时补充和采掘设备的作业效率,特别进入深凹开采以后,普遍遇到地下含水量剧增,不断使牙轮钻废孔率急剧加大,还必须配置排水设施,从而增加了掘沟工程工艺技术和生产组织的复杂性.因此,如何提高深凹露天矿山汽车掘沟速度,不但是当前和今后采矿生产亟待解决的关键环节,也是广大采矿工作者关注的课题之一.本文仅根据笔者组织深凹露天掘沟工程的点滴体会,将矿山广大采矿工作者多年来在掘沟工程中积累的提高掘沟速度的经验做一个概括介绍,供矿山采掘工作者今后组织深凹掘沟工程施工时参考.

土方填筑筑堤施工技术在水利工程中的应用与优化

水利工程建设中,土工筑堤技术扮演着重要角色。本文深入研究和探讨了土方填筑筑堤施工技术在水利工程中的应用及其优化方法。通过运用现代工程技术和土壤力学理论,对合理选材、土方耙车运行方式、土壤碾压次数和循环频次等方面进行了系统研究。研究结果表明,这些优化措施不仅能缩短工期、提高工作效率,还能显著提升土坝的质量和稳定性,为水利工程建设提供了有力的技术支持。同时,结合实际工程案例,分析了在施工过程中采用优化土方填筑技术带来的具体经济效益和社会效益。得出的结论是,适当地优化土方筑堤施工流程和技术,可显著提高水利工程建设的速度与质量,进而产生更大的社会经济效益。此研究成果对于推动我国水利工程建设发展有着重要的理论与实践指导意义。

SCDI Flash Memory Device Ⅱ:Experiments and Characteristics

Step channel direct injection(SCDI) flash memory device is successfully achieved by 1 2μm CMOS technology,moreover good performance is obtained.At the bias condition of V g=6V, V d=5V,the programming speed of SCDI device is 42μs.Under the condition of V g=-8V, V s=8V,the erasing speed is 24ms.Compared with the same size of conventional flash memory device whose corresponding parameters are 500μs and 24ms,respectively,the performance of SCDI device is remarkably improved.During manufacturing of SCDI device,the key technologies are to make the shallow step with appropriate depth and angle,along with eliminating the etch damage during the process of Si 3N 4 spacer.

求“最”——江苏射阳新坍轧花厂技改扩建“四最”纪实

1994年射阳县新坍轧花厂实施“上规模创名牌”工程,对棉纺车间进行技改,增扩两万纱锭。整个项目的投入总量、筹资总额、工程速度、设备工艺创全县工业史上“四最”:项目总投入最大,共投入3000万元;自筹资金最多,所有投入90％以上依靠企业自筹、融通;工程速度最快,将一个从开工到投产近两年工期的工程,仅用9个月时间就保质保量地完成;设备工艺水平最高,所有机械设备全部采用国家部委定点生产厂家的最新产品,具有90年代国内先进水平。大投入带来大效益。

勇于创新 促进企业快速发展

简要介绍中煤四十九工程处近年来的企业管理经验。机制创新、依法治处、科技兴处 ,使该处的工程施工速度和质量。

The First Forty Years of a Technosol

Soil formation is often a very slow process that requires thousands and even millions of years. Human influence, occasionally on a par with the function of climate or geological forces, can accelerate the process and can be viewed as a distinct soil forming factor. This paper describes a soil, Haplic Regosol, in which anthrosolization dominates the soil forming process. Man-made soils, Technosols, were stabilized with techniques of ecological engineering (crib walls). We measured the main soil properties and focused on the movement of water (the reduction of soil weight is the key factor in stabilizing these calcschists). The newly deposited debris, sheltered by anthropic interventions, after four years differentiated an A/C profile while after forty years differentiated an O/A/AB/Bw/BC/C profile. Our results indicate that colonization by plants and the consequent success of vegetation establishment is influenced mainly by control of the factor of pedogenesis 'topography' and by the ability of these Technosols to retain nutrients.

Relationship between speed and traffic accident and speed limit on freeway

To develop an equation between discrete degree of speed and traffic accident on freeway in China and give reasonable suggestions of speed management, the relation model was established between speed standard deviation and accident rate per 100,000,000 vehicle kilometers by regression analysis. The model shows that the more discrete is the speed distribution, the higher is the accident rate, which provides theoretical gist for speed limit on freeway. It is suggested that speed limit should be set according to 85th percentile speed obtained by the relationship between 85th percentile speed and RCCs (curvature change rate of single circular curve), and different speed limits should be set for cars and trucks. Through analyzing spot speed data of eight freeways in China, regression models were established between 85th percentile speed and RCCs and 15th percentile speed and RCCs. Reasonable speed limit suggestion values are put forward through these models.

Prediction of preheating conditions for inclined laser assisted machining

For laser assisted machining,shape of preheating laser heat source is changed irregularly because of complexity of material shape.So,the preheating temperature should be controlled by adjusting the feed rate or the laser power.Thermal analyses of the laser assisted machining process for inclination planes were performed.By analyzing the obtained temperature profile,a proper feed rate control method was proposed according to the inclination angles.In addition,the temperature distribution of the cross section after feed rate control was predicted.The correlation equation between inclination angles and adjusted proper feed rate was proposed.The results of this analysis can be used to predict the preheating effect on workpiece and can be applied as a preheating temperature control method in laser assisted machining processes.

An improved multidirectional velocity model for micro-seismic monitoring in rock engineering

An improved multidirectional velocity model was proposed for more accurately locating micro-seismic events in rock engineering. It was assumed that the stress wave propagation velocities from a micro-seismic source to three nearest monitoring sensors in a sensor's array arrangement were the same. Since the defined objective function does not require pre-measurement of the stress wave propagation velocity in the field, errors from the velocity measurement can be avoided in comparison to three traditional velocity models. By analyzing 24 different cases, the proposed multidirectional velocity model iterated by the Simplex method is found to be the best option no matter the source is within the region of the sensor's array or not. The proposed model and the adopted iterative algorithm are verified by field data and it is concluded that it can significantly reduce the error of the estimated source location.

Inproved grade length limitation of freeways

A method of ascertaining grade length limitation of freeways in mountain terrain is presented. The relationship models between 15 th percentile speeds and grades were built through the surveys and analyses of operation speeds on 7 typical sections of 3 freeways in mountain terrain. Using 15 thpercentile and 85 th percentile as speed limitations, the methods of determining admitted velocities were put forward according to the grades. Deceleration distances of longitudinal slopeways were analyzed utilizing the theories of vehicle. According to the results of analysis, grade length limitation was loosed. Finally the values of grade length limitation for freeways were put forward. The results could be used as references for freeway design.

Optimization of Resource in the Industry of Construction

Time and cost are two of the most important factors to consider in each construction project. In order to maximize performance, both the client and the contractor will work to optimize both the duration of the project and its cost. We show a model of linear entire mixed programming to solve the considered problem. The aim is to minimize the project total time, by means of the assignment of equipments of work to the different production lines of the activities to realizing. The fundamental beginning is to support the same production （rate of production in meters/day of the activity in view of the equipment of work） for tbe different equipments to achieve the maximum efficiency in each period of time. With the limited availability of resources, the work must be continuous and the period of time between operations and final must be kept. However, this paper also presents the bibliographical study on methodologies of the optimization of construction processes in response to the two objectives： time and cost. This will consider the use of recta-heuristic techniques, such as population based algorithms.

Biomechanism of impact resistance in the woodpecker's head and its application

The woodpecker does not suffer head/eye impact injuries while drumming on a tree trunk with high acceleration （more than 1000xg） and high frequency. The mechanism that protects the woodpecker＇s head has aroused the interest of ornithologists, biologists and scientists in the areas of mechanical engineering, material science and electronics engineering. This article reviews the literature on the biomechanisms and materials responsible for protecting the woodpecker from head impact injury and their applications in engineering and human protection.

Dynamic response of gravity dam model with crack and damage detection

Gravity dam is a typical structure that has been frequently used in the fields of water conservancy engineering, and the safety of the structure has received widespread attention recently. Due to earthquakes or other reasons, gravity dams normally have damage such as cracks in practical service. Damage in the structures can alter the structural dynamic behavior and seriously affect structural performance. Maintaining safety and integrity of the gravity dam structures requires a better understanding of dynamic response of structure with damage and associated damage detection method. In order to study thoroughly the dynamic behavior of gravity dam with damage, the sweep vibration responses of the gravity dam with and without damage are investigated. The experimental results show that the peak-peak acceleration responses all increase for the structure is with crack. At the same time, a structural damage detection method, i.e., the local damage factor (LDF) method, is considered in the study of gravity dam damage detection when the dam is subjected to the base excitation. It is shown that the LDF method can be used as a damage index and is capable of evaluating both the presence and relative severity of structural damage, and it can be used as a viable condition assessment and damage identification technique to detect and quantify the damage in the gravity dam.

Design of an Enhanced Sensitivity FBG Strain Sensor and Application in Highway Bridge Engineering

The theoretical design method of enhanced sensitivity fiber grating （FBG） strain sensors was given, and moreover high qualified strain sensors were developed and fabricated, whose sensing properties were good for practical applications. The strain sensor with cylindrical shell encapsulation contained three tubular structures, due to the uneven surface structure, in the area of the strain concentration, improving the sensitivity. It could achieve the embedment strain measurement and surface measurement and had the advantages of the easy installation. The good agreement was obtained between the measurements and theoretical simulation results. After each calibration test, twenty-four FBG strain sensors and six FBG temperature compensation sensors have been installed on the undersurface of the box girder of Diaoshuiyan bridge in Yongtaiwen highway. Finally, we built up a long-term structure health system for the highway bridge.