如何在钻孔内水泥浆置换的情况下顺利下放测温管

随着西部大开发的进度日益加快,陕西西部、内蒙古西部的煤炭建设速度也突飞猛进,最明显的特征就是井筒深度越来越深、井径越来越大。以往所采用的普通法掘砌,已经不能适应建井的需要,几乎所有井筒都要采用冻结法施工。水泥置换很好的解决的孔内串水的问题,但是随之而来的是如何解决测温管的下放问题。

基于在线黑体空腔理论的钢水连续测温传感器的研制

基于在线黑体空腔理论的研究成果,设计了一种新型黑体空腔式钢水连续测温传感器,解决了钢水连续测温这一难题。介绍了传感器的结构原理,并对机理进行了详细的分析。实验结果表明,测量误差≤±3℃,测温管寿命可达20～40h,测温成本与现行的快速热电偶实际消耗相当或略低,具有较强实用性,现已成功应用于28家钢铁公司。

基于光流分析法检测钢水液位

在覆盖剂黏着于测温管表面的连铸中包中,基于视觉方法测量钢水液位系统无法通过温度场分析测量钢水液位.为此,本文使用光流分析算法跟踪测温管拔出钢水后表面黏着并向下流动的覆盖剂,检测出覆盖剂在测温管不同位置黏着特性的差异,并从微观角度分析覆盖剂在测温管表面的黏着特性与钢水液位的联系,最终计算出钢水液位.经验证,该方法所测得钢水液位误差在3 mm以内.大量现场试验表明,该方法能较好地解决覆盖剂遮挡测温管表面温度信息的问题,使基于视觉方法的钢水液位测量系统在测温管黏着覆盖剂的异常情况下能准确可靠地测量出钢水液位.

感应炉内钢液温度的连续测定

钢液的温度是炼钢过程的一个重要参数。真空感应炉冶炼钢或高温合金时,一般以电熔镁砂作为坩埚材料。高温下氧化镁在真空下并不稳定,其主要原因是受钢液的温度及熔炼时间的影响。合金的熔炼温度低、时间短,虽可减少由于氧化镁分解所产生的增氧,但又使碳的脱氧能力不能充分发挥。熔炼温度过高、时间过长,虽能使碳的脱氧能力加强,但又促使氧化镁大量分解,使钢液大量增氧。

高原季节性冻土路基处治的现场试验方案研究

为了研究不同路基高度在冻融条件下的稳定性,确定最佳路基高度,确定隔离层最佳厚度和设置方式;分析季节性冻土路基水分迁移机理和途径等,提出现场试验方案,介绍试验设计、器件安装以及器件保护措施等。

降低并联炉海绵钛产品铁含量的研究与实践

对并联炉海绵钛产品含铁高的原因进行了分析，认为反应器中间存在测温管和排氯化镁管是海绵钛含铁高的重要原因，指出实现还原外测温和排氯化镁管外移，是降铁提质的有效途径。

桥梁工程项目大体积混凝土施工及质量控制

为探讨桥梁工程项目大体积混凝土施工及质量控制,结合涪江大桥一期实例,对大体积混凝土施工的要点进行详细分析,并提出选择高性能材料、降低混凝土浇筑温度、减少混凝土内外温差等控制措施。结果表明,在大体积混凝土施工中,最大的难题是如何有效控制温度,以免形成温度裂缝。只有结合桥梁工程的特点,切实做好温度的控制,将混凝土内外温度控制在一定的范围内,并对施工中的质量通病进行合理的防治,才可提升桥梁工程的总体质量。

High-Order Lateral Buckling Analysis of Submarine Pipeline Under Thermal Stress

It is of importance to study and predict the possible buckling of submarine pipeline under thermal stress in pipeline design.Since soil resistance is not strong enough to restrain the large deformation of pipeline,high-order buckling modes occur very easily.Analytical solutions to high-order buckling modes were obtained in this paper.The relationships between buckling temperature and the amplitude or the wavelength of buckling modes were established.Analytical solutions were obtained to predict the occurrence and consequence of in-service buckling of a heated pipeline in an oil field.The effects of temperature difference and properties of subsoil on buckling modes were investigated.The results show that buckling will occur once temperature difference exceeds safe temperature;high-order pipeline buckling occurs very easily;the larger the friction coefficients are,the safer the submarine pipeline will be.

Determining oxygen consumption rate and asphyxiation point in Chanodichthys mongolicus using an improved respirometer chamber

Knowledge of oxygen consumption rates and asphyxiation points in fish is important to determine appropriate stocking and water quality management in aquaculture. The oxygen consumption rate and asphyxiation point in Chanodichthys mongolicus were detected under laboratory conditions using an improved respirometer chamber. The results revealed that more accurate estimates can be obtained by adjusting the volume of the respirometer chamber, which may avoid system errors caused by either repeatedly adjusting fish density or selecting different equipment specifications. The oxygen consumption rate and asphyxiation point of C. mongolicus increased with increasing water temperature and decreasing fish size. Changes in the C. mongolicus oxygen consumption rate were divided into three stages at water temperatures of 11-33~C： （I） a low temperature oxygen consumption rate stage when water temperature was 11-19~C, （2） the optimum temperature oxygen consumption rate stage when water temperature was 19-23~C, and （3） a high temperature oxygen consumption rate stage when water temperature was 〉27~C. The temperature quotients （Q10） obtained suggested that C. mongolicus preferred a temperature range of 19-23~C. At 19~C, C. mongolicus exhibited higher oxygen consumption rates during the day when the maximum values were observed at 10：00 and 14：00 than at night when the minimum occurred at 02：00.

Evaluation of Measurement Accuracy of Underground Thermometers Using Steel-Pipe Piles

For ground source heat utilization systems, pile heat exchangers are sometimes used. In order for these systems to achieve high performance, control of the system dynamics is important, and the underground temperature must he known. Typically, underground temperature is measured using a thermometer in a borehole. However, in the case of pile heat exchangers, a different method is required, making the system expensive to set up. To overcome this problem, the installation of underground thermometers in the heat exchanger piles themselves is proposed in the present study. The proposed thermometer system consists of thermocouples packed in grout such as silica sand within the piles. However, there is a possibility of measurement errors due to vertical thermal conduction in the steel pipes, and it is important to estimate the measurement accuracy before the development of this system. In the present study, the measurement accuracy is estimated using numerical simulations and then confirmed experimentally. The underground temperature profiles inside and outside the pile are compared. The results indicate that the proposed system offers sufficient accuracy for application to pile heat exchangers.

On-Line Life Monitoring Technique for Tube Bundles of Boiler High-Temperature Heating Surface

High-temperature heating surface such as superheater and reheater of large-sized utility boiler all experiences a relatively severe working conditions. The failure of boiler tubes will directly impact the safe and economic operation of boiler. An on-line life monitoring model of high-temperature heating surface was set up according to the well-known L-M formula of the creep damages. The tube wall metal temperature and working stress was measured by on-line monitoring, and with this model, the real-time calculation of the life expenditure of the heating surface tube bundles were realized. Based on the technique the on-line life monitoring and management system of high-temperature heating surface was developed for a 300 MW utility boiler. An effective device was thus suggested for the implementation of the safe operation and the condition-based maintenance of utility boilers.

Influence of Testing Temperature on the Corrosion Behavior of API 5L X70 Pipeline Steel

It is known that localized corrosion attack takes a preponderant role in the onset of stress corrosion cracking of pipeline steels in high pH conditions. Carbonate/bicarbonate solutions can be employed to study the localized corrosion behavior of these materials. In addition to the presence of chloride ions in the electrolyte, the solution temperature is also of prime importance to the onset of pitting corrosion. The aim of this work is to evaluate the influence of the testing temperature on the corrosion behavior of the API 5L X70 pipeline steel which is a standard material for gas pipelines in Brazil. Samples were exposed to a solution consisting of Na2CO3, NaHCO3 and NaCl at three different temperatures： RT （room temperature）, 40 ℃ and 60 ℃. The corrosion morphology was observed using SEM （scanning electron microscopy）. The results showed that pitting corrosion became facilitated when the steel was immersed at higher temperatures.

Evaluation of Heat and Current Characteristics of Bypass Diodes for Fault Detection in Photovoltaic Module

In recent years, PV （photovoltaic） systems have been installed rapidly around the world. However, there is often a delay in the practical application of fault detection in PV systems. In this study, the temperature of BD （bypass diodes） mounted on PV modules was measured for simple and practical fault detection. The temperature of the BD of Module 31 was higher than other modules and a large current passed through one of the BDs. Measuring BD temperatures is easier than other conventional methods of fault detection. From the results of the rise in BD temperature under dark conditions, the increase in temperature increased linearly with increasing current flow. There is a proportional relationship between heat generated and the increasing temperature of the terminal box. The experimental results about surface temperature of the junction box in actual system operation suggested that the electric current through a BD in a terminal box can be known by measuring the surface temperature of the terminal box for PV module fault detection without a system shutdown. Moreover, we tried to evaluate temperature distribution of a terminal box using heat conduction equations. The evaluated results agreed well with the measured results.

Inner wall running state monitoring for the main pipe of nuclear power

The heat conduction equation is solved in this paper under specific boundary conditions.The coefficients of the obtained distribution equation are simplified with the piecewise integral method.Then the associated model for the cylindrical thermal equipment is established.The relationship of the surface temperatures,the material properties and the inner wall state of the cylindrical thermal equipment is described in the associated model.This model is applied to the inner wall running state monitoring of the main pipe.A multi-channel distributed optical fiber temperature measurement system is designed to acquire the external surface temperatures of the main pipe.Then the associated model can be used to analyze the surface temperature data of the main pipe.The location and the physical dimension of the inner wall defect can be got.Therefore,the inner wall defect monitoring of the main pipe can be realized.The feasibility of this method is verified by experiment.This method also provides a theoretical basis for the real-time monitoring of the main pipe’s internal state.

Temperature and Pressure Measurements at Cold Exit of Counter-flow Vortex Tube with Flow Visualization of Reversed Flow

In order to clarify the structure of the cold flow discharged from the counter-flow vortex tube(VT), the temperature and pressure of the cold flow were measured, and the existence and behavior of the reversed flow at the cold exit was studied using a simple flow visualization technique consisting of a 0.75mm-diameter needle, and an oil paint droplet. It is observed through this experiment that the Pitot pressure at the cold exit center can either be lower or higher than atmospheric pressure, depending on the inlet pressure and the cold fraction, and that a reversed flow is observed when the Pitot pressure at the cold exit center is lower than atmospheric pressure. In addition, it is observed that when reducing the cold fraction from unity at any arbitrary inlet pressure, the region of reversed and colder flow in the central part of cold exit extends in the downstream direction.

Stable single-photon detection based on Si-avalanche photodiode in a large temperature variation range

In this paper, we present a stable single-photon detection method based on Si-avalanche photodiode(Si-APD) operating in Geiger mode with a large temperature variation range. By accurate temperature sensing and direct current(DC) bias voltage compensation, the single-photon detector can work stably in Geiger mode from-40 °C to 35 °C with an almost constant avalanche gain. It provides a solution for single-photon detection at outdoor operation in all-weather conditions.

The effect of the boron-ions implantation on the performance of RADFETs

In this work, we studied on the boron-ions implantation, including the implant dose and post-annealing temperature on the performance of PMOS radiation field-effect transistors(RADFETs) in experimental. The possible traps and defects induced by ions implantation in the gate-oxide and their further impacting on the sensitivity and dose range of RADFETs were analyzed qualitatively. Our devices had the dry/wet/dry sandwich gate-oxide of 420 nm thick. Different ion-implanting doses and post-annealing temperatures were carried out during the RADFETs fabrication. We built a real time auto-measurement system to realize the auto-state-switch between irradiation and read-out modes, and in-situ measurement of output voltage for ten devices in turn at once of radiation experiment. The threshold voltage, dose range and sensitivity of RADFETs were extracted and analyzed in detail. The results showed that the highest sensitivity of 229 mV/Gy achieved when the implant dose was2.2×1011 cm.2 and the post-annealing temperature was 1000°C, and the dose range of 34 Gy as well.