纤维增强MDF水泥的性能

研究了玻璃纤维和碳纤维作为MDF水泥增强材料的可行性及其增强效果，考察了二种纤维的长径比、体积掺量对MDF水泥材料的抗弯强度、断裂韧性、浸水体积膨胀率等性能的影响。研究结果表明，碳纤维和玻璃纤维作为MDF水泥的增强材料均能够显著提高MDF水泥的力学性能和耐水性、玻璃纤维的效果优于碳纤维。纤维增强MDF水泥的微观结构特征是纤维在复合材料中呈三维均匀分布，形成空间网络结构，这是纤维增强MDF水泥的主要原因。     

Urinary exposure marker discovery for toxicants using ultra-high pressure liquid chromatography coupled with Orbitrap high resolution mass spectrometry and three untargeted metabolomics approaches

Human biomonitoring is the assessment of actual internal contamination of chemicals by measuring exposure markers, chemicals or their metabolites, in human urine, blood, serum, and other body fluids. However, the metabolism of chemicals within an organism is extremely complex. Therefore, the identification of metabolites is often difficult and laborious. Several untargeted metabolomics methods have been developed to perform objective searching/filtering of accurate-mass-based LC-MS data to facilitate metabolite identification. In this study, three metabolomics data processing approaches were used for chemical exposure marker discovery in urine with an LTQ-Orbitrap high-resolution mass spectrometry (HRMS) dataset; di-isononyl phthalate (DINP) was used as an example. The data processing techniques included the SMAIT, mass defect filtering (MDF), and XCMS Online. Sixteen, 83, and 139 probable DINP metabolite signals were obtained using the SMAIT, MDF, and XCMS procedures, respectively. Fourteen probable metabolite signals mined simultaneously by the three metabolomics approaches were confirmed as DINP metabolites by structural information provided by LC-MS/MS. Among them, 13 probable metabolite signals were validated as exposure-related markers in a rat model. Six (m/z 319.155, 361.127, 373.126, 389.157, 437.112 and 443.130) of the 13 exposure-related DINP metabolite signals have not previously been reported in the literature. Our data indicate that SMAIT provided an efficient method to discover effectively and systematically urinary exposure markers of toxicant. The DINP metabolism information can provide valuable information for further investigations of DINP toxicity, toxicokinetics, exposure assessment, and human health effects.     

CO2 laser cutting of MDF: 1. Determination of process parameter settings

This paper details an investigation into the laser processing of medium-density fibreboard (MDF). Part 1 reports on the determination of process parameter settings for the effective cutting of MDF by CO₂ laser, using an established experimental methodology developed to study the interrelationship between and effects of varying laser set-up parameters. Results are presented for both continuous wave (CW) and pulse mode (PM) cutting, and the associated cut quality effects have been commented on.     

铁炭微电解法预处理中纤板热磨废水的研究

采用铁炭微电解预处理法对中纤板热磨废水进行处理,研究铁炭微电解法预处理对废水中COD、木质 素等去除率的影响。单因素实验研究结果表明,最佳中纤板热磨废水处理工艺条件如下：原水pH为3,铁炭 体积比为1∶1,填料投加量为300 mL/L,反应时间为80 min,混凝pH为85,混凝沉淀时间为120 min。在 此条件下,COD、木质素和SS的去除率分别为74.24 %、89.77 %和91.27 %,且重现性良好。对比实验表明 ,混凝沉淀过程在热磨废水处理中所起的作用要比电化学过程大,是影响中纤板热磨废水处理效果的关键 因素。     

MDF cements

The applicability of MDF synthesis procedure, the coincidence of the interfacial cross-linking and the moisture resistance of MDF-related mixes based on two industrial Portland cements (CEM I, CEM II) and poly-P are reported. The knowledge of the moisture resistance of synthesized material is of paramount importance; two independent experimental methods confirmed that the moisture resistance of MDF cements based on CEM I (or CEM II) with 5% of poly-P achieves sufficient levels at 50% RH and at ambient values of RH. The results of thermal analysis are directly related to the former knowledge on the appearance and role of cross-links in the interfacial zone of MDF cements. This revised version was published online in August 2006 with corrections to the Cover Date.     

Processing-Moisture Resistance and Thermal Analysis of Macro-Defect-Free Materials

The system of sulfoaluminate ferrite belite (SAFB) clinkers premixed with Portland cement (PC) in mass ratio 85:15 in combination with hydroxypropylmethyl cellulose (HPMC) or polyphosphates(poly-P) was used for the syntheses of Macro-Defect-Free (MDF) materials. The subsequent moisture treatment and thermal stability of these MDF materials were investigated. The effect of individual humidity upon the evolution of mass is more intensive than the effects of composition of MDF materials or duration of the original MDF material synthesis. Detailed values of mass changes at 100% relative humidity (RH) and under ambient conditions are strongly affected by the nature of polymer used. A significant improvement of moisture resistance of MDF materials is achieved when the materials are dried after 24 h of finishing the pressure application. In the inter-phase section of MDF material samples, the content ofC-(A,F)-S hydraulic phases, mainly tetracalcium aluminate ferrite monosulphatehydrate (AFm) decomposing by 250°C and CaCO₃ decomposing at 600–700°C increase after the moisture attack, while cross-links in AFm-like section with typical thermoanalytical traces in temperature region 250–550°C remain intact. This revised version was published online in July 2006 with corrections to the Cover Date.     

中密度纤维板热压机模糊控制器的设计

针对中密度纤维板生产过程中,热压时间控制存在的强非线性和滞后问题,提出了具体的解决方法.采用模糊控制理论,建立中密度纤维板热压机模糊控制器模型,运用M amdan i推理合成算法,进行离线编程,得到热压时间模糊控制查询表,将模糊规则的推理合成运算简化为直接查模糊控制查询表来实现,达到控制任务的要求.从M atlab的仿真结果和具体应用可见,模糊控制具有稳定性好、超调量少、震荡现象减少等优势.     

MDF甲醛释放流变性的研究

在MDF甲醛释放蠕变过程中,MDF甲醛释放驱动力保持不变时,MDF甲醛释放量随时间延长而变化。马克斯韦模型可在甲醛释放驱动力为恒定条件下,较好地模拟MDF的甲醛释放流变性的规律;凯尔文模型较好地模拟了MDF甲醛延时释放特征;勃格模型是描述MDF甲醛释放蠕变的重要公式,它较好地模拟了MDF甲醛常规释放蠕变特征,换算得到的公式可较好地描述锯切后试件放置时间对MDF甲醛释放量的影响规律,是描述和预测MDF甲醛释放松弛特性的有价值模型;也可较好地描述干燥器测试时间对MDF甲醛释放量的影响规律,是描述和预测MDF甲醛释放蠕变特性的有价值模型。     

MDF老化过程中甲醛释放量的研究

将MDF放在气候箱中按设定的条件进行快速老化，同时在室内环境中作对比试验，比较两种条件下MDP甲醛释放量与力学性能的变化。MDF甲醛释放量随着加速老化周期增加而不断减少，与循环周期呈显著指数关系。加速老化对木材纤维与树脂之间的结合有较大的影响，UF在高温高湿下体形结构受到破坏。MDF加速老化后甲醛释放量与放置室内每10d的MDF的甲醛释放量具有显著的指数关系。     

高铝水泥基MDF材料的介电性能研究

本文报导了某些因素对高铝水泥基ＭＤＦ材料介电常数和介电损耗的影响。实验结果表明：ＭＤＦ材料的介电常数和介电损耗均与交电电频率有关；当聚合物掺量增加时，介电常及介电损耗均减小；采用热压成型的ＭＤＦ材料比雾室养护的ＭＤＦ材料具有较低的介电常数及介电损耗；用硅灰改性可使介电常数和介电损耗进一步降低。