高温高压蒸汽改性落叶松木材力学性能预测模型的建立

利用RBF神经网络和支持向量机两种算法建模,分析落叶松高温高压蒸汽改性工艺参数与其力学性能关系;以落叶松热处理的温度、相对湿度、处理时间3个主要工艺参数作为网络输入,建立了RBF神经网络和支持向量机预测模型,并对两者进行比较。结果表明:支持向量机模型,在网络建立结构、收敛速度和泛化能力上更具优势。     

高温蒸汽松木颗粒富氢气化试验

采用自制下吸式气化炉试验系统平台,以松木颗粒为原料,进行不同蒸汽流量及气化温度条件下的高温蒸汽气化试验。试验表明:随着气化温度升高,气化反应程度加剧,碳氢化合物与高温蒸汽的重整反应亦更剧烈。气化气中H2体积分数从气化温度为700℃时的23.38%升高到950℃时的44.79%,提高了近一倍,但由于CO和蒸汽的变换反应在900℃后受到抑制,H2体积分数略微下降,CO随温度升高先减少后增加,CO2呈缓慢减少趋势;蒸汽流量是高温蒸汽气化技术重要影响指标,在气化温度为850~950℃范围内,蒸汽流量由0.3增加到0.9 kg/h时,气化气中H2体积分数由37.06%增长到47.67%,CO变化较为稳定,CO2的含量先降低后上升,CnHm的体积分数呈下降趋势,气化气产率和氢气产率均随蒸汽流量的增加先增大后减小;特别是当蒸汽流量为0.6 kg/h,气化温度为900℃时,气化气产率和氢气产率分别为2.69 m3/kg和101.8 g/kg,达到试验工况条件下的最大值,此时反应加入的蒸汽量与生物质量的比值约为0.95,为试验较佳工况。     

A simple method for determination of ammonium in semimicro‐Kjeldahl analysis of soils and plant materials using a block digester

Abstract

A simple method for determination of ammonium in semimicro‐Kjeldahl analysis of soils and plant materials using a Tecator or Technicon 40‐tube block digester is described. It involves use of an inexpensive steam distillation apparatus that permits direct distillation of ammonium from the tubes used for Kjeldahl digestion in 40‐tube block digesters. The method is rapid and precise, and it gives results that agree closely with those obtained by the customary method of ammonium N analysis involving transfer of the Kjeldahl digest before distillation.     

水溶性酚醛树脂游离苯酚水蒸汽蒸馏测定方法的研究

本文研究了用水蒸汽蒸馏法测定水溶性酚醛树脂中的游离苯酚,酸碱度、游离甲醛和树脂对苯酚蒸出率的影响。实验结果表明,我国林业部部标准和苏联国家标准,即在碱性和强酸条件下对水溶性酚醛树脂试液进行水蒸汽蒸馏,苯酚蒸出率低,游离苯酚测定结果偏低。树脂试液的最佳水蒸汽蒸馏条件是:试液体积控制在150—200ml,试液的pH=4.0—5.0。     

添加剂对汽爆玉米秸秆养分和发酵特性的影响

为解决饲料短缺问题,提高收获籽实后玉米秸秆的利用效率。本试验以经汽爆处理的玉米秸秆进行厌氧发酵,设对照（CK）、分别添加乳酸菌制剂Sila-Max（MAX）,Sila-Mix（MIX）及纤维活性菌（活性菌）4个处理,发酵60 d后测定营养成分及发酵品质。结果表明：不同处理间常规营养成分无显著差异;康奈尔净碳水化合物-蛋白质体系（Cornell Net Carbohydrate and Protein System,CNCPS）评价结果表明,活性菌组乳酸、MAX组总挥发性脂肪酸含量显著高于其他处理（P<0.05）;从发酵品质来看,活性菌组pH、NH₃-N/TN显著低于其他处理（P<0.05）,乳酸显著高于其他处理组（P<0.05）,MAX组乙酸、丙酸含量显著高于其他处理组（P<0.05）,MAX,MIX组干物质损失率显著低于其他处理组（P<0.05）。综上,纤维活性菌可以改善秸秆发酵品质;Sila-Max可以增加乙酸、丙酸含量,减少干物质损失,具有提高秸秆有氧稳定性、抑制饲料二次发酵的潜力;Sila-Mix可以减少秸秆干物质损失。     

植物秸秆纤维素物理化学改性及其吸附机理研究

采用植物秸秆为原料，借助高压蒸汽闪爆技术、稀碱蒸煮等方法得到具有一定α-纤维素含量的秸秆基纤维素，在此基础上进行碱化、醚化和胺基亲核取代反应，制备出对Cu^2＋和Cd^2＋等重金属离子具有优良吸附性能的乙二胺螯合植物秸秆纤维素，并对其吸附机理进行研究。结果表明，用蒸汽闪爆物理方法可以纯化天然植物秸秆纤维素，制备的吸附材料对金属铜离子、镉离子吸附规律基本符合Freundlish等温吸附式，其等温式中lgC系数分别为0.997和1.159。     

Original Papers: Manganese toxicity of melon plants growing on an isolated soil bed after steam sterilization

(Jpn. J. Soil Sci.Plant Nutr., 77, 257–263, 2006)

The symptom of blighted leaves was observed for the melon plants grown on an isolated soil bed after steam sterilization (SS) in a greenhouse in Kochi Prefecture, Japan. To clarify the causes of this symptom, soil and plant analyses were conducted in the first experiment. Manganese concentrations in the leaves with the symptom were higher than 1,000 mg kg?1and exchangeable Mn in the soil was higher than 30 mg kg?1, which indicated the observed symptom was due to Mn excess. In the second experiment, formation of Mn oxide-dissolving substances after SS was examined for several organic amendments, because large amounts of palm chips had been supplied to the soil before SS in the first experiment. As a treatment similar to SS, palm chips, bark compost, and cattle feces manure were autoclaved. The water extracts were collected before and after the autoclave treatment and the Mn oxide-dissolving capacities of the extracts were evaluated. The Mn oxide-dissolving capacity of the water extracts after SS was remarkably higher than before SS, and the value was highest in palm chips, and followed by bark compost, and cattle feces manure. Fractionation and HPLC analysis of the water extracts after SS revealed that the main substance behind Mn oxide reduction in palm tips was arabinose and that in bark manure was malic acid. Further, Mn oxide-dissolving capacities of the water extracts were almost completely explained by the amounts of arabinose or malic acid found in these materials. From these results, it was considered that reducing substances such as arabinose were released by SS from the palm chips which had been applied in large quantity before SS and these reducing substances dissolved the soil Mn oxides and increased the amounts of available Mn, which led to the occurrence of Mn toxicity to the plants.     

两种物理加工方式对西洋参加工副产物粉体性质的影响

为明确西洋参加工副产物粉体的适宜加工方式,扩大西洋参加工副产物粉体在食品与保健品加工中的应用范围,丰富西洋参产品种类,分别采用蒸汽爆破、超微粉碎两种物理加工方式处理西洋参加工副产物粉体,评价其物理指标和营养指标,以期为生产西洋参片剂、粉剂、胶囊剂等产品提供一定的理论参考。结果表明：超微西洋参粉体与对照和汽爆相比色泽保持效果好,休止角小,比表面积大,可满足加工成片剂和胶囊剂的需求,也适宜作为功能性食品原料吸附或包裹于食品表面;其膨胀力大,持油力强,有利于吸附肠道中的脂类,适合加工为固体饮料。汽爆西洋参粉体滑动角小,堆积密度大,吸湿率小,更利于压片成型以及产品的短期保存;同时,汽爆西洋参粉体粗多糖含量大幅度增加,是对照粗多糖的4.107倍,更适合加工成功能性固体饮料。     

木质纤维生物量一步法(SSF)转化成乙醇的研究(Ι)——木质纤维原料蒸汽爆破预处理的研究

该研究采用蒸汽爆破法 ,以速生毛白杨为原料 ,在爆破时间都为 4min ,爆破压力分别为 1.5 ,2 .0 ,2 .5 ,2 .7MPa的压力条件下 ,研究比较了不同爆破压力对原料得率、产酶活力和纤维素酶解糖化的影响 .研究结果表明 :①在相同条件下 ,随着爆破压力由 1.5MPa升至 2 .7MPa ,原料得率由 84%逐渐降低至 5 1% ;②以不同爆破压力获取的毛白杨原料配合麦麸作为纤维素酶产酶培养基 ,随着爆破压力的增加 ,酶活性也随之增加 ,但也与爆破后原料的纤维素含量有关 .只有爆破后毛白杨原料的纤维素含量高时 ,酶活性才大 .每克干曲酶活力高达 139.3U/ g ;③将经过不同爆破条件预处理的毛白杨木粉进行酶解实验 ,随着爆破压力的增加 ,酶解糖化率也随之增加 ,最高爆破压力 (2 .7MPa)处理过的木粉可使酶解糖化率高达 6 5 .0 % ,比对照提高了 4.0倍 .     

土壤蒸汽消毒机的脉动燃烧器喷管结构及工作特性

为解决因连作障碍等引起的设施园艺中土壤病虫害防治问题,拟开发一种以脉动燃烧器为热动力源的土壤蒸汽消毒机。根据土壤蒸汽消毒机的最小蒸汽量为100 kg/h,确定脉动燃烧器的最小功率为28.2 kW。脉动燃烧器主要由燃烧室与喷管组成,采用长度为200、400、800、1 000 mm的直喷管和800 mm的弯喷管,通过法兰拼接组合成不同长度的直喷管(600、800、1 000、1 400、1 600、1 800、2 200、2 600、2 800、3 000 mm)和弯喷管(800、1 600 mm),研究不同喷管结构对脉动燃烧器启动性能、工作稳定性能等的影响。结果表明：喷管长度在800~2 600 mm启动;工作频率与压力振幅呈线性关系,频率高,压力幅值大;同一长度直喷管的燃油消耗率、频率与压力振幅均大于弯喷管的,且油门开度2、3、4时弯喷管燃烧器压力振幅标准差小,具有更好的稳定性;喷管长度为1 800 mm左右的直喷管脉动燃烧器性能最佳。故选择喷管长度为1 800 mm的弯喷管脉动燃烧器作为土壤蒸汽消毒机蒸汽发生装置热源,既能保证脉动燃烧器的工作特性,又能促使蒸汽发生装置小型化。