淀粉胶生物质炭基氮肥制备及其缓释特性分析

以生物质炭为载体,与自制改性淀粉胶黏剂、尿素进行复合,利用万能力学试验机和自制成型模具制备颗粒缓释肥料,研究水分添加量、成型压力、炭肥比及胶黏剂添加量4个因素对颗粒肥料抗压性能和缓释性能的影响。结果表明:对于纯炭粉成型,当水分含量为10%、成型温度为45℃、成型压力为6k N时,成型颗粒的抗压强度达到最大;尿素与炭粉混合后成型可以增加颗粒强度,当稻壳炭-尿素(即炭肥比)为5:1时,在同样成肥条件下,肥料颗粒的抗压强度最大;改性淀粉胶黏剂可进一步增加肥料颗粒强度,当胶黏剂添加量为5%时,肥料颗粒的抗压强度达到最大。不同配比条件下制备的缓释肥料,其氮素累积释放规律符合"S"型释放模型,添加胶黏剂制备的缓释肥的缓释性能明显优于传统的尿素肥料,以胶黏剂添加量为5%时缓释效果最佳。     

利用缸压表对汽缸密封性进行检测与分析

汽缸密封性的好坏关系到汽车的使用性能是否能够得到有效的发挥,对汽车动力性、燃油经济性、环保性能都会产生较大的影响。通过对汽缸压缩压力的检测与分析,判断发动机汽缸的密封状态,确定故障部位并采取手段进行修复,使发动机保持良好的工作状态。     

解决聚丙烯芯钢丝绳生产过程中钢丝“塌陷”（或间隙不均）及绳径超差问题

本文从生产制造角度来分析解决聚丙烯芯钢丝绳生产过程中易出现的钢丝塌陷、钢丝间隙不均及绳径超差等问题。与天然纤维芯相比，聚丙烯芯是一种合成纤维芯，除具有质轻、弹性好、不怕霉蛀等特性外，同时还具有较好的抗挤压性，因此，生产过程中，对聚丙烯芯直径公差的控制比对天然纤维芯直径公差的控制更为严格，如聚丙烯芯直径选择不当，易会出现股中钢丝塌陷(或钢丝间隙不均)、绳径超差等问题。笔者结合生产实际情况，从控制聚丙烯绳芯(股芯)直径公差入手，找出聚丙烯芯直径的计算值与其实测值之间合适的比例范围，对正确选择聚丙烯绳芯(股芯)直径大小，满足钢丝绳生产工艺要求，优化工艺参数，提高钢丝绳结构的稳定性和机台生产作业率有着重要的作用。     

空心刨花板成型挤压机

介绍了成型挤压机的主要结构及工作原理,阐述了均匀下料器部件的改进.     

大型薄壳制件真空辅助树脂传递模塑工艺充模方案仿真分析及优化

针对大型树脂基复合材料制件不适于用实验试错法进行充模方案设计的问题,在分析树脂流动规律的基础上将大型薄壳件的求解区域分解,仿真分析了不同充模方案下树脂在纤维中的流动行为和模腔内压力变化,提出在制件填充面积等分处设置流道的方法,选择和优化大型薄壳制件的充模方案。结果表明:①对于不便进行实验试错法进行真空辅助树脂传递模塑(VARTM)工艺充模方案设计的大型薄壳制件,可以采用数值模拟的方式,以达西定律、能量守恒定律等为计算依据,求解压力场和速度场,对比不同仿真方案的充模时间等数据合理安排注胶方式方法,指导VARTM工艺制备大型复合材料制件合理安排注胶方式,提高生产率、减少因树脂浸润不均匀产生的缺陷。②对于大型薄壳类制件,忽略厚度方向尺寸,影响充模时间的主要因素为流道长度和树脂流动距离。选取尽可能长的注胶流道,合理设置流道位置以减少树脂流动的距离;长流道可以增加树脂瞬时注入量、提高较长时间的压力差;而树脂流程越长,树脂前锋处压力损失越大,流速越慢。③试验提出了制件填充面积等分处设置流道的方法。将大型薄壳工艺制件充模面积等分,注胶流道布置在垂直于制件长度方向的面积等分线上,可缩短充模时间并减少制件两端的树脂富集现象。对于较狭长部分可再次进行面积等分设置流道,以免造成树脂流程过长压力流失过多;而对于较宽阔部分不宜设置过多流道以免树脂前锋稳定前互相接触造成制件充模不均匀。     

Thymic hyperplasia causing right ventricular outflow tract compression following treatment for oesophageal rupture in an Arabian colt

True thymic hyperplasia has been reported sporadically in the human literature as an immunological rebound phenomenon following immunosuppressive treatment or disease. There are limited accounts in domestic species, mainly following vaccination, and thymic hyperplasia has not been a recognised condition in the horse to date. This report details a case of true thymic hyperplasia in a 10-week-old Arabian colt diagnosed by histopathology of core biopsy samples. The colt developed pulmonary stenosis caused by compression due to a space occupying lesion in the cranial mediastinum following a 3-month history of hospitalisation for treatment of traumatic oesophageal rupture with perioesophageal abscess formation. Diagnostic imaging of the cranial mediastinum was indicative of a thymic mass, and histopathology confirmed the mass was normal (hyperplastic) thymic tissue. The colt was treated with a tapering dose of corticosteroids, which led to involution of the hyperplastic tissue and resolution of pulmonary artery compression. Thymic hyperplasia may be an unrecognised sequela to chronic inflammation in horses and was only identified in this case when the size was sufficient to compress right cardiac outflow.     

Factors of affecting the spring back of compressedPaulownia wood

In order to increase its hardness and gravity as well as dimension stability, the technology of hot-compressing onPaulownia wood was studied. The main factors of affecting the spring back of the compressedPaulownia samples were discussed. It was discovered that every factor in the experiment had obvious effects on wood hardness and dimension stability of compressed wood. When the MC (Moisture Content) of experimental specimens was 13.89%, it was useful to spray water on the surface of samples before hot pressing. The best result was the recovery of compression set could decrease from 90.69% of untreated wood to 45.51% of soaking specimens into PF (Phenol Formaldehyde) water solution. The hot pressing time was 8 min at 190°C. Responsible editor: Zhu Hong     

A biomechanical analysis of industrial forest plantation workers in East Kalimantan

The objectives of this study are to clarify physiological work loads and physical loads acting on the lumbar region of workers and to propose a safe work environment in tropical forestry operations. The research was conducted in the industrial forest plantations of East Kalimantan, Indonesia, in 1996. In this study, heart rates and the physical lumbar burden of industrial forest plantation workers were measured for three types of work, that is, weeding, planting and path clearing. In addition, the load moment at the L₅/S₁ and the disc compression force were calculated using low-back biomechanical models. As a result, compression forces at the L₅/S₁ disc during weeding, planting and path clearing were estimated and found to be below the Action Limit (AL) by National Institute for Occupational Safety and Health (NIOSH). However, it was also found that some work posture types during path clearing by chain saw were sometimes above the AL. A part of this paper was orally presented at the 108th Annual Meeting of the Japanese Forestry Society (1997).     

多元羧酸类化合物对木材大压缩量变形的固定作用

以多元羧酸类化合物为酯化剂、以无机盐类为催化剂的交联体系是一类新型的水溶性、无毒害、无污染、木材交联反应未采用过的非甲醛系试剂交联体系。本文研究了这类非甲醛系试剂对木材大压缩量变形的固定作用,结果表明浓度９％的１,２,３,４丁烷基四羧酸处理大青杨试件,干状态的变形恢复率较低,沸水中变形恢复率接近于２７０１％。用１,２,３,４丁烷基四羧酸交联处理木材可以固定压缩变形,适宜的树脂浓度为９％。材色由偏红向偏黄方向转变。     

Experimental Research on the Compressive Strength of the Heated Concrete Tested on the Small Diameter Cores

This paper introduces an experimental research on the compressive strength of the heated concrete tested on the small cores of 45 mm and 70 mm in diameter by compression and transverse cutting methods.By means of mathematical statistics, the test strength equations and regression curves obtained are quantitatively analyzed.