室温离子交联苯丙乳液合成及性能研究

以苯乙烯(St)、丙烯酸丁酯(BA)和丙烯酸(AA)为单体,过硫酸钾(KPS)为引发剂,采用乳液聚合方法通过离子交联合成了室温交联型苯丙乳液。考查了聚合温度、引发剂用量、乳化剂用量对聚合稳定性和乳液性能的影响,同时研究了Zn~(2+)/AA配比和软硬单体配比对胶膜性能的影响。结果显示,在80℃、KPS用量为0.4%、乳化剂用量为2.0%~3.5%时,乳液具有较好聚合稳定性以及粒径单分散性;随配比中醋酸锌用量增加,胶膜的干燥时间缩短,吸水性减小,而拉伸强度有适当提高;随体系中硬单体含量增加,胶膜的干燥时间增加,而硬度和拉伸强度则逐渐提高,吸水性变小。     

变换低变催化剂二次升温硫化总结

我公司生产能力为合成氨 8万 t/a、尿素 1 0万 t/a,近年来随着能力的增加 ,变换系统能力明显不足。 2 0 0 0年 8月 ,中、低变炉新添加了部分催化剂 ,并一直运行到 2 0 0 2年 4月 ,在此期间 ,变换系统极不稳定 ,阻力上升 ,蒸汽消耗增加 ,CO跑高。基于以上情况 ,我公司决定对低变炉催化剂重新进行硫化。下面 ,笔者将对本次硫化工作及处理后的效果作一总结。1　变换催化剂的基本情况中变催化剂 B1 1 7,棕褐色圆柱片剂 ,堆密度1 .5～ 1 .6kg/L ,其主要成分 Fe2 O365 %～ 75 %、Cr2 O33%～ 6%。低变催化剂 B30 1 Q,浅兰色球形颗粒 ,粒度 3～ …     

耐高温输送带运行过程温度场的模拟

利用大型非线性有限元分析软件MSC．MARC／MENTAT 2001对耐高温输送带运行过程温度场进行模拟。通过对任意时刻带体断面温度场的分析，得到一定长度输送线上耐高温输送带在输送高温炉渣过程中带体传热达到平衡时的时间及相应的温度分布。     

高温碳化温度对碳纤维性能的影响

对经过相同预氧化、低温碳化和不同高温碳化处理的碳纤维样品进行了拉伸强度、拉伸模量、密度的分析,找出了2种原丝在经过碳化工艺处理后拉伸强度、拉伸模量、密度与高温碳化温度的相关性,并对其影响机理进行了研究。研究结果表明:在一定的温度范围内碳纤维拉伸强度随着高温碳化温度的提高而增加,在高温碳化温度达到一定值时,碳纤维拉伸强度将下降;碳纤维拉伸模量均随着高温碳化温度的提高而增加;碳纤维密度均随着高温碳化温度的提高而降低。     

Optimal temperature of fixed-bed reactor for high temperature removal of hydrogen sulfide

To find optimal temperature of the reaction between H₂S gas and ZnO-5 at% Fe₂O₃ sorbent, the effluent gas from a fixed-bed reactor was analyzed by gas chromatography. The experimental results showed that H₂S removal efficiency of sorbent was maximum at 650°C and EDX data were in accordance with this feature. XRD analysis exhibited intriguing phenomenon in that different mechanisms were observed at different temperatures. Chemisorption and chemical reaction was considered to be the main mechanism of H₂S removal at 600 C and 650°C, respectively. SEM photographs supported this interesting phenomenon, but unfortunately TGA and DTA results could not distinguish it. To investigate the effect of sorbent deactivation on the reaction rate, deactivating factor was considered.     

红外测温技术在滚动轮胎表面温度场测试中的应用

介绍了红外测温技术的特点及其在滚动轮胎表面温度场测试中的应用。红外测温技术是依据物体发出的红外辐射能量与物体温度之间的关系进行温度测量的,它具有快速、非接触、不破坏被测温度场及测量精度高等优点。应用双向红外测温系统进行了载重轮胎9.00-2014PR滚动表面温度场分布的测定,其数据表面,轮胎各部位温升大小不同;胎冠最大、胎侧次之、胎圈较小、胎肩最小,与实际情况基本符合。     

Ultra-high temperature ceramics melting temperature prediction via machine learning

Melting temperature has great influence on the high temperature properties and working temperature limits of ultra-high temperature ceramics (UHTCs) In order to bypass the challenge in the measurement of ultra-high melting points, this paper proposed a novel method to predict UHTCs melting temperature via machine learning. A dataset including more than ten thousand melting temperature data has been established, which covers 8 elements and most of the known non-oxide UHTCs. We built up an element to ceramic system framework by back propagation artificial neural network (BPANN) with the accuracy approaching to 90% and the correlation coefficients approaching to 0.95. Our work provides a probability to get the high accuracy melting temperature of UHTCs, and a more convenient way to develop novel materials with higher working temperature. The given case of melting temperature prediction of Hf-C-N ceramics proves the generality of the artificial neural network (ANN). An inter-validation of melting temperature prediction using our network with materials thermodynamics and density functional theory (DFT) has been demonstrated, indicating that our network is of powerful prediction ability.     

Improving low temperature degradation of 3Y-TZP ceramics via high temperature carburizing

3Y-TZP ceramics are prepared by solid state method and surface carburization process, and the effect of surface carburization on its the low temperature degradation is studied. The conventional sintered samples completely lost its mechanical properties after aging for 15 h, while the failure time of the surface carburized samples are 300 h. In addition, the nuclear growth rate of the surface carburized samples (αd) and the nucleation rate (Nr) is lower than that of sintered samples, αd plays a dominant role in the degradation process at low temperature and is the key factor determining the aging rate. At the same time, it is found that carbon is dissolved in zirconia lattice in the form of electrically neutral atoms, which will not destroy the original charge balance and produce new oxygen vacancies when entering the interstitial site. More importantly, the precipitation rate of Y³⁺ from zirconia lattice is the key factor to determine the low-temperature phase transition of tetragonal-monoclinic(T-M). The treatment method of surface carburization has significantly improved the low-temperature degradation performance of 3Y-TZP ceramics, which provides a basis for the application of zirconia ceramics in low-temperature and humid environment.     

中低低和全低变变换工艺的设计与选择

介绍了中低低工艺及其流程和全低变工艺及其流程的特点和适用范围,从设计方面对工艺中出现的问题进行了分析和探讨,并提出了解决途径.     

蒸发温度和冷凝温度变化对制冷机性能的影响

分析了蒸发温度和冷凝温度的相互关系及其对制冷机性能的影响     

Positive temperature coefficient behavior of polymer composites having a high melting temperature

The positive temperature coefficient (PTC) behavior of polymers having a high melting temperature, such as nylon, polyvinylidene fluoride, polyester, and polyacetal, was investigated. Carbon black and nickel powder were used to investigate the influence of their conductive fillers on PTC intensity. The polymer/filler composite was irradiated with gamma rays at dosages of 50, 100, and 150 kGy for the purpose of reducing the negative temperature coefficient (NTC) of a conductive composite. It was found that the PTC temperature depended on the melting point of the polymer matrix. The crosslinking structure enhanced the electrical stability and decreased the NTC effect of the composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 394–401, 2004     

声波测温技术在水泥厂高温区段中的应用

分析了水泥生产中传统热电偶测温方法存在的问题，介绍了声波测温技术的基本原理、系统构成，并结合工况分析了声波测温技术在水泥生产中的应用情况，总结得出声波测温技术在水泥生产工艺中是适用的。     

室温固化耐高温胶粘剂的研究

以环氧氯丙烷和对氨基苯酚为主要原料制备了多官能度的环氧树脂(EP-005),并采用自制的复配固化剂、纳米SiO2、特殊的增韧剂和特种填料等进行改性,制得了一种结构加固用的建筑耐温结构胶。实验结果表明,该胶粘剂可常温固化,加固后的构件可在常温与高温(150℃)环境中长期使用;该胶粘剂在150℃时的剪切强度为17.28 MPa,常温拉伸强度为42.60 MPa,常温压缩强度为90.63 MPa;该胶粘剂具有卓越的综合性能,并已成功用于建筑工程等领域中。     

High temperature electrodialysis

New components, spacers and membranes, have been developed for electrodialysis at temperatures up to 80°C. The performance of a sea water plant using these components is examined. Total water costs depend on membrane cost and membrane life. Even with conservative assumptions with regard to membrane cost and life, it appears possible to desalt sea water for less than 28ø per cubic meter (< $1.05/1000 gallons). The current status of the development and testing program is described.     

藻类与煤低温共炭化对低温煤焦油的影响

将不同配比的藻类与煤以低温干馏的方法进行低温共炭化,研究煤焦油的变化.结果表明,煤焦油中轻质油含量增加29.55％,萘类化合物含量增加9.15％,酚类化合物含量增加23.93％,实现一定程度的轻质化.     

非恒温状态下时间和温度对NR锥型减震器挠度的影响

探讨了非恒温状态下时间和温度对DF4型内燃机车柴油机减震系统的NR锥型减震器（简称减震器）挠度的影响。在非恒温状态下,减震器存放时间越长,挠度值越大;考察减震器挠度变化（挠度值与基准值的差值）的温度宜采用累计平均温度,不宜采用测试当日温度;减震挠度变化 与累计平均温度有对应关系,温度高于1℃时,减震器挠度变化的幅度较小,温度低于1℃时,减震器挠度变化的幅度较大;温度对减震器挠度的影响存在时间效应。