喷蒸热压法和传统热压法生产杨木刨花板的比较(Ⅰ)喷蒸热压对刨花板力学强度的影响(英文)

该研究以杂种毛白杨无性系（ＰｏｐｕｌｕｓｔｏｍｅｎｔｏｓａＢＬ）４年生幼龄格为原料，应用喷蒸坟和传统热压两种方法来生产杨木刨花板．刨花板内施胶量为１０％的脲醛树脂胶（ＵＦ），目标厚度分别取１０，１５，２０，２５ｍｍ，热压温度固定在１８０℃．喷蒸热压时所用饱和蒸汽的压力为０３～０５ＭＰａ，每种厚度下喷时间一定，取两个压时间；传统热压时每种厚度下各取４个热压时间．然后测定刨花板试件的力学强度和物理性能．在这部分里，主要讨论了责任中热压法生产的刨花板的静曲强度和内结合强度．结论为：相对于传统热压法，喷蒸热压可以明显缩短杨木刨花板生产所需的热压时间，而且使刨花板具有优异的内结合强度；但是，它对饱花板的静曲强度并没有显著影响     

组合预处理对橡实壳组成及酶解转化的影响

为脱除果壳类原料中的半纤维素和木质素,减少其对纤维素酶的无效吸附,提高酶解转化率。采用蒸汽爆破、Na OH、碱性H2O2及其组合预处理方法,研究不同方法对橡实(蒙古栎种子)壳组成及酶解转化的影响。结果表明,经过2.25 MPa蒸汽爆破预处理后,橡实壳半纤维素由26.81%降低至5.79%,半纤维素脱除率达87.28%,酶水解120 h后葡萄糖得率由10.32%提高至38.36%。橡实壳蒸汽爆破组合氢氧化钠处理后,木质素脱除率可达54.29%。而蒸汽爆破组合碱性H2O2处理后,酶解120 h葡萄糖得率可达76.65%,是未处理橡实壳的7.4倍。     

RESERCH ON THE COLD START OF 200MW CHINESS-BUILT STEAM TURBINES

In this paper, the temperature field, stress, critical crack size and expenditure rate of life of HP and IP rotors of 200MW Chinese-built steam turbines in eight typital patterns of cold start of Chongqing Power Plant was calculated by finite element method. Some problems in speed-up process have been discussed, and advanced that it is better to appraise start-up process by Fracture Mechanics Mechod in the period when the temperature of rotor is low. The discussion are useful for the start of steam turbines.     

THE FREQUENCY DOMAIN DISCRIMINATIONS OF SEVERAL VIBRATIONS ON THE TURBOGENERATOR

The frequency spectrum analyses of several vibration on No. 4 Unit in a power plant are made and the experience of the future failure diagnosis on turbogenerator is collected in this paper.     

锯木屑蒸汽爆破预处理制备糠醛的研究

以锯木屑为原料,采用蒸汽爆破进行预处理,然后酸催化提取糠醛。探讨了预处理温度、爆破压力、预处理时间及液料比等因素对糠醛得率的影响。采用响应面法建立二次回归模型,并对预处理工艺进行了优化。研究结果表明:预处理能有效的促进锯木屑的降解,提高糠醛的得率。在预处理温度为216℃、爆破压力1.8 MPa、预处理时间6 min、液料比3∶1(mL∶g)时,糠醛的得率(79.13%)比相同条件下未进行蒸汽爆破预处理的试样(55.35%)提高了23.78个百分点。     

Lignin Characteristics of Steam Exploded Bamboo Residue during Hot Pressing

bamboo(Phyllostachys edulis) residue was subjected to steam explosion treatment to produce superior fibers for binderless boards.Then,lignin was isolated from extract-free bamboo meal,steam exploded pulp,and binderless boards with characteristics being determined by thermo-gravimetry (TG),differential scanning calorimetry (DSC),and fourier transform infrared spectroscopy (FTIR).Results showed that:1) the yield of lignin directly extracted with dioxane-water from steam exploded bamboo pulp(SEBPL) and binderless board (SEBBL) was higher than that of milled bamboo lignin (MBL).Also,the yield of SEBBL was lower than that of SEBPL.2) FTIR results showed cleavage of ester and ether bonds between lignin and p-coumaric acid during steam explosion treatment.3) SEBBL showed two glass transitions at 115℃and 200℃, while MBL gave one glass transitions at 155℃.And 4) the modulus of rupture(MOR) and modulus of elasticity(MOE) decreased with an increase in steaming time;whereas internal bonding(IB) increased.In all cases the dimensional stability of boards did not exceed the maximum requirements for type GB/T 11718- 1999.     

一种利用电站乏汽余热供暖方式的新方案

提出了一种基于常规供暖模式下采用吸收式热泵吸收汽轮机做功后乏汽和汽水换热器将热网循环回水进行二次加热的新方案。以某2×300MW热电厂机组为例,对新方案进行了可行性分析,并与常规方式进行了对比,结果表明:新方案更加节能环保,供暖成本降低,效果更好。     

过热蒸汽膨化番茄的预干燥条件及干燥模型

热风干燥温度对经甘油溶液处理的番茄的干燥特性、色泽以及过热蒸汽膨化后番茄的比容和复水性均有较大影响,过热蒸汽膨化的预干燥温度为70℃时,干燥速率较大,预干燥番茄色泽好,膨化充分,且复水性好.建立的基于Page方程的预干燥模型可以有效模拟和预测不同热风干燥温度条件下任意时刻番茄的干燥速率及含水率.     

油田热电厂200MW机组调峰运行安全经济性分析

分析了油田热电厂200MW机组变负荷调峰运行时,对锅炉燃烧稳定性、汽轮机主辅机及锅炉安全性的影响,以及机组效率下降的原因。并对采用复合变压运行方式来提高机炉安全经济运行的可行性进行了分析。     

Modification of protein structure and dough rheological properties of wheat flour through superheated steam treatment

Native (NF, 13.5% w.b) and moistened (MF, 27% w.b) wheat flours were treated with superheated steam (SS) at 170 °C for 1, 2 and 4 min, and their protein structure as well as dough rheological properties were analyzed. Confocal laser scanning microscopy (CLSM) and SDS-PAGE patterns indicated the formation of protein aggregates with reduced SDS extractability after treatment. Farinograph and dynamic rheometry measurements showed that the strength as well as elastic and viscous moduli of the dough made from SS-treated flours progressively increased with SS treatment time. And both the improvements were more pronounced for superheated steam-treated moistened flours (SS-MF) than for superheated steam-treated native flours (SS-NF). Size-exclusion high performance liquid chromatography (SE-HPLC) analysis demonstrated that dough rheological parameters have positive correlations with SDS unextractable polymeric proteins (UPP) contents. SS treatment on flours led to a transition of protein secondary structures to more ordered form (α-helix and β-sheet). Additionally, free sulfhydryl (SH) contents decreased after treatment, which implied that disulfide bonds accounted for protein extractability loss and dough rheological properties improvement. Elevated moisture level promoted the modification of both protein structure and dough behaviors of flours during SS treatment.