Isothermal and cyclic oxidation behavior of a sandwiched coating for C/C composites

A ZrC–SiC/TiC–SiC/SiC sandwich-structured coating is prepared on a C/C composite by pack cementation methods. The microstructures of this coating are characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the oxidation resistance is investigated by performing an oxidation test at 1773 K and a cyclic oxidation test. The results show that the mass losses are 7.4% and 3.8% after oxidation for 144 h and 40 cycles, respectively. The sandwich structure relaxes, releases the thermal stress caused by the mismatch in the coefficients of thermal expansion, and absorbs energy to prevent the initiation and propagation of cracks. The ZrC–SiC/TiC–SiC/SiC coating exhibits good isothermal oxidation resistance and excellent cyclic oxidation protection properties.     

Effect of silicon/graphite ratio and temperature on oxidation protective properties of SiC/ZrB2–SiC coatings prepared by pack cementation

To investigate the silicon/graphite ratio and temperature on preparation and properties of ZrB₂–SiC coatings, ZrB₂, silicon, and graphite powders were used as pack powders to prepare ZrB₂–SiC coatings on SiC coated graphite samples at different temperatures by pack cementation method. The composition, microstructure, thermal shock, and oxidation resistance of these coatings were characterized and assessed. High silicon/graphite ratio (in this case, 2) did not guarantee higher coating density, instead could be harmful to coating formation and led to the lump of pack powders, especially at temperatures of 2100 and 2200 °C. But residual silicon in the coating is beneficial for high density and oxidation protection ability. The SiC/ZrB₂–SiC (ZS50-2) coating prepared at 2000 °C showed excellent oxidation protective ability, owing to the residual silicon in the coating and dense coating structure. The weight loss of ZS50-2 after 15 thermal shocks between 1500 °C and room temperature, and oxidation for 19 h at 1500 °C are 6.5% and 2.9%, respectively.     

全尾砂充填性能试验研究

针对拟使用充填法将深部矿产资源采出的某矿山,为研究充填性能,取其尾砂进行试验,通过探索充填料浆性能在灰砂比和质量浓度有差异时的变化情况,判断灰砂比和质量浓度对充填料浆性能的影响。采用极差分析法获取两者影响充填料浆性能的主次关系,明确充填料浆配比的适合范畴,随之建立代表料浆性能参数和两因素之间的回归方程。由试验可得:在灰砂比1∶4～1∶12、料浆浓度66%～74%的情况下,料浆流动性能受质量浓度的影响较灰砂比大,但影响充填体强度的关键要素还是灰砂比。根据该矿山的生产需要及室内试验,再联系灰砂比、浓度与充填料浆性能参数间的回归方程,推荐选择最佳参数,灰砂比1∶8,料浆浓度72%。     

一种锂电池组无损均衡管理系统设计

针对动力锂电池组充放电过程中,各单体电池之间存在的不一致性,设计了超级电容与双向DC-DC变流器相结合的无损均衡管理系统。采用无迹卡尔曼滤波法估算锂电池的荷电状态,与通常采用的扩展卡尔曼滤波器进行了对比研究,经实验验证,本系统能够快速、高效地实现锂电池组的均衡控制,实现精确地锂电池SOC(State of Charge)估计,提高了动力锂电池组的可靠性和安全性。     

春光油田防砂工艺的适用性分析及优化研究

春光油田地处北疆伊犁哈萨克自治州,属特高孔、特高渗储层。油层埋藏浅,胶结疏松,要确保正常开发生产,必须要采取防砂措施。本文通过对春光油田不同砂体区域进行深入研究,对目前采用的防砂工艺进行了适用性分析,并结合实际生产情况和以往的防砂经验,针对不同的开采层位,优化了相应防砂工艺,并根据现场适用情况对改进后的工艺进行分析。研究和优化结果为春光油田的防砂工作提供了科学依据。     

型钢垛型CAD系统开发

提出了实用的型钢垛型ＣＡＤ系统总体方案，建立了由型钢垛型库，型钢标准数据库，规格库和设计方法库，组成了系统数据库和型钢垛型优化模型。描述了系统功能在ＡｕｔｏＣＡＤ Ｒ１２环境下的实现方法。     

A Controlled New Process of Pack Aluminization

IRON ALUMINIDES exhibit excellent corrosionresistance in aggressive atmospheres at elevatedtemperature'1"41,which enables steels or alloys to beprotected by Fe-Al intermetallic coatings.However,itshould be borne in mind that aluminides with a highaluminum content—FeAl3,Fe2Al5—tend to embrittlethe coated layer and reduce its oxidation resistance.Bycontract,iron-rich iron aluminides possess excellentmechanical properties and oxidation resistance15"61.Aluminum diffusion coatings are oft…     

A new method to improve the laser-ablation resistance of Si-SiC coating on C/C composites: Laser cladding

New method to prepare Si-SiC coating on C/C composites by laser cladding (LC-Si-SiC) was established to improve the laser ablation resistance of the coating. Results showed that the LC-Si-SiC coating had lower roughness, better mechanical properties and superior laser-ablation resistance compared with the Si-SiC coating fabricated by the traditional coating preparation process: pack cementation (PC-Si-SiC). Due to the shorter heat treatment and less Si infiltration, the flexural strength of the LC-Si-SiC coated sample was 111.32 MPa, which was 144% higher than that of the PC-Si-SiC coated sample. Confirmed by finite element simulation, the LC-Si-SiC coating exhibited better laser-ablation resistance because of the “sweating cooling” mechanism. Under 23.89 MW?m^?2 ablation for 7 s, the surface temperature of the LC-Si-SiC coated sample was 3046 K, which was 157 K lower than that of the PC-Si-SiC, causing the mass loss rate of the LC-Si-SiC coating (0.10%) was only 45.45% of the PC-Si-SiC coating.     

框架结构填充外墙常见渗漏通病与防治

结合工程实际,就框架结构填充外墙施工中常见的渗漏通病,分析了渗漏通病产生的原因,提出关键的技术处理措施,指出该技术能够有效消除常见的渗漏通病问题.     

Emotional response evoked when looking at and trying a new food product,measured through images and words. A case-study with novel fruit and vegetable smoothies

Little research has been published on emotional responses evoked by completely new, innovative food products. The objectives of the present study were 1) to assess the emotional response to new products (fruit and vegetable smoothies in a drink pouch) in two different scenarios: looking at the smoothie pouch, or tasting the smoothie with the smoothie pouch alongside; 2) to compare the information obtained when the participants use photographs or use words to express emotions. In the Pack-alone scenario, similar emotional spaces and sample configurations were obtained with both images and words. In the Pack-and-tasting scenario, the richness of the emotional response increased when using images. In both scenarios, the participants used a greater number of negative emotions when these were presented as images rather than as words. This could be considered an advantage, as it enables some negative emotional loads to be portrayed. The present results also demonstrate that evaluating the emotional response allows effective discrimination between samples with similar overall liking scores.