风力灭火与爆炸灭火技术在秦岭林区救火中的应用

风力灭火和爆炸灭火是秦岭林区常用的灭火方法,而风力灭火机和灭火弹是秦岭林区灭火最常采用的工具。分析其灭火原理,熟练掌握灭火技术,对指导森林防火有很大的作用。     

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。     

A malware analysis method based on symbolic execution tree

In the malware analysis, it is a common method to monitor malware dynamically in a virtual environment. However, with so many branches of executable pathes, path explosion problem will probably occur, leaving some executable pathes uncovered, and hence harming the comprehensiveness of analysis. To solve this problem, we propose a malware analysis method based on symbolic execution tree. This method introduces sinknode and solves the execution of malicious code path by constructing the symbolic execution tree, so improves the analysis of comprehensive. Experiments to analyze the samples of malware show that the method can enhance the efficiency of the analysis with lower time complexity.     

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。     

不同处理方式对八角莽草酸和茴香油含量的影响

为研究不同处理方式对八角莽草酸和茴香油含量的影响,以广西壮族自治区国有六万林场的八角果为原料,莽草酸和茴香油含量为指标,采用水蒸气蒸馏法提取莽草酸和茴香油,高效液相色谱法（HPLC）检测莽草酸含量,气相色谱法检测茴香油中主要成分含量。研究结果表明,不同处理方式对莽草酸和茴香油含量影响不同。莽草酸含量最高的处理方式是100℃开水杀青后晒干,为9.64%;含量最低的处理方式是微波杀青后烘干,为7.35%。茴香油含量最高的处理方式是薄膜包住杀青后晒干,为4.23%;含量最低的处理方式是100℃开水杀青后烘干,为3.12%。不同方式处理八角所提取茴香油中茴脑含量均在90%以上。     

Thermal weed control technologies for conservation agriculture—a review

Research and development activities on non-chemical weed control methods to date have mainly focused on mechanical and thermal applications. Selectivity in mechanical weed control is obtained using dynamically actuated harrows. Selectivity in thermal weed control is obtained through a certain heat tolerance of the crop. In conservation agriculture (CA), weed emergence is partially suppressed by constant soil cover with crops or cover crops. Large amounts of plant residues therefore remain on the soil, which make mechanical methods inefficient or difficult to implement. And thermal methods need to prevent not only crop damage but also fire from situationally dry plant residues. In this review, technologies that can potentially be used for in-crop weed control in CA are discussed. The technologies reviewed include spot-flaming, electric resistance heating, electromagnetic irradiation and steam/hot water application. Their evaluation focuses on efficiency and specificity (spatial precision). This review indicates that existing equipment does not fulfil the spatial precision required in CA and that further research and development is required on this topic. In particular, the authors suggest further research on the use of laser diodes, micro-flames and capacitive coupling of electric fields. It seems that the use of automated imaging systems for weed/crop differentiation is a prerequisite in CA to enable automatisation of weed control.     

纸盒无菌灌装包装材料灭菌工艺优化

为解决屋顶纸盒无菌灌装中包装材料灭菌工艺和灭菌效率问题,该研究进行工艺优化及提出微生物挑战测试方法.通过单因素试验研究过氧化氢溶液浓度、汽化过氧化氢蒸汽温度、汽化热空气压力和紫外线照射时间对灭菌效率的影响;并在此基础上,依据Box-Behnken原理设计响应面试验,建立包装材料灭菌效率二次多项式回归模型,获得灭菌工艺优...     

汽爆系统中进料密封阀门的结构设计及稳定性分析

针对汽爆系统中进料口阀门进料效率低,容易漏气等问题,设计了一种集进料、密封和开启为一体的进料密封阀门。根据阀门的材质和使用环境,对阀门中的阀芯进行了理论分析,并利用ANSYS Workbench软件对其进行强度分析,得到了阀芯的最大变形量发生位置以及能够满足其稳定进料和密封时螺旋轴的最佳直径和最佳转速,经理论计算和强度校核,阀门在正常工作环境下,其阀芯的强度完全满足设计要求。对不同进料时间和转速对阀门的进料稳定性影响进行试验研究,确定150 kg玉米秸秆完成进料时的最佳转速为200 r·min-1,最佳进料时间为5 min。