密度法测试落叶松浓胶干物含量的研究

探讨了落叶松浓胶的密度与其干物含量之间的关系，并求出了相应的回归方程式，用密度法测试落叶松浓胶的干物含量，操作简单，准确度达到较高要求。     

落叶松鲜针叶精油的化学成分及杀虫活性研究北大核心

采用同时蒸馏萃取(SDE)法以正己烷为溶剂提取落叶松鲜针叶精油,并对其进行了气相色谱-质谱(GC-MS)分析,研究了落叶松鲜针叶精油与松木屑木醋液复配物对舞毒蛾2龄幼虫的杀虫活性。结果表明:落叶松鲜针叶精油得率为0.93%,共鉴定出63种成分,总GC含量为98.11%,GC含量最高的化合物为3-蒈烯(12.13%),其次是2,4-二(1-甲基-1-苯基乙基)苯酚(10.71%)。雌舞毒蛾引诱剂(+)-(7R,8S)-7,8-环氧-2-甲基十八烷的GC含量为0.10%。落叶松鲜针叶精油-木醋液(体积比1∶9,稀释至原体积5倍)对舞毒蛾2龄幼虫喷雾法杀虫活性实验的校正死亡率24 h达到83.33%,优于木醋液5倍稀释液,且72 h内无变化。落叶松鲜针叶精油与松木屑木醋液复配能起到增效作用。     

落叶松鲜针叶精油的化学成分及杀虫活性研究

采用同时蒸馏萃取(SDE)法以正己烷为溶剂提取落叶松鲜针叶精油,并对其进行了气相色谱-质谱(GC-MS)分析,研究了落叶松鲜针叶精油与松木屑木醋液复配物对舞毒蛾2龄幼虫的杀虫活性。结果表明:落叶松鲜针叶精油得率为0.93%,共鉴定出63种成分,总GC含量为98.11%,GC含量最高的化合物为3-蒈烯(12.13%),其次是2,4-二(1-甲基-1-苯基乙基)苯酚(10.71%)。雌舞毒蛾引诱剂(+)-(7R,8S)-7,8-环氧-2-甲基十八烷的GC含量为0.10%。落叶松鲜针叶精油-木醋液(体积比1:9,稀释至原体积5倍)对舞毒蛾2龄幼虫喷雾法杀虫活性实验的校正死亡率24 h达到83.33%,优于木醋液5倍稀释液,且72h内无变化。落叶松鲜针叶精油与松木屑木醋液复配能起到增效作用。     

兴安落叶松树木中酚类化合物组成研究

研究了混合态的兴安落叶松树木中酚类化合物的组成。实验中采用冷水 (室温 )、热水 (1 0 0℃ )、亚硫酸盐水溶液 (1 0 0℃ )、苯 /乙醇混合液(1∶1 ,V/V ,78℃ )、1 %氢氧化钠水溶液 (1 0 0℃ )等溶剂分别对兴安落叶松木粉和树皮粉进行分步浸提 ,根据每种溶剂浸提物占原料中的质量分数及其甲氧基含量 ,初次完整地确定了原料中单宁、木质素、红粉和酚酸的质量分数及它们的甲氧基含量。实验得出愈创木基型木质素、原花青定型缩合单宁、红粉、酚酸在兴安落叶松树皮中的质量分数 (% )分别为1 6 .1 7、1 1 .90、1 2 .64和 2 6 .54 ,在边材中的质量分数 (% )分别为 31 .45、0 .95、0 .95和 3 .39,以原料的 72 %H2 SO4 不溶物为基准 ,兴安落叶松树皮和边材中甲氧基含量 (% )分别为 5 .2 4和 1 5.39;树皮中红粉、木质素、酚酸的甲氧基含量 (% )分别为 0 .56、3 .53和 1 .1 5 ;边材中红粉、木质素、酚酸的甲氧基含量 (% )分别为 0 .33、1 4 .2 5和 0 .81。     

华北落叶松鞘蛾性信息素及其应用研究成功

华北落叶松鞘蛾是我国华北地区落叶松栽植区的食叶害虫之一，仅山西省内林区年发生面积就在40万亩以上，经济损失非常在大。在系统研究了华北落叶松鞘蛾成虫的繁殖行为后，首次发现华北落叶松鞘蛾性引诱剂和性抑制剂的成分，成功实现性信息素的人工合成，经数年应用，表明其人工产品的效果及可操作性均优于传统监测手段，特别是在中、低虫口密度的林中，     

落叶松浓胶及甲醛含量对落叶松单宁胶粘剂粘度的影响

通过对不同配比的液体落叶松单宁胶粘剂粘度及干燥后的粉状落叶松单宁胶粘剂粘度进行测定，探明了液体落叶松单宁胶粘剂与粉状落叶松单宁胶粘剂粘度之间的关系，为制定合理的生产工艺参数提供了可靠的理论依据。     

落叶松浓胶及甲醛含量对落叶松单宁胶粘剂粘度的影响

通过对不同配比的液体落叶松单宁胶粘剂粘度及干燥后的粉状落叶松单宁胶粘剂粘度进行测定,探明了液体落叶松单宁胶粘剂与粉状落叶松单宁胶粘剂粘度之间的关系,为制定合理的生产工艺参数提供了可靠的理论依据。     

纯化胶清橡胶的热氧降解研究

采用离心分离的方法制备了胶清橡胶,并测定了该胶清橡胶的蛋白质含量、水溶物含量、丙酮溶物含量、P0和PRI。为探讨水溶物和丙酮溶物对胶清橡胶的热稳定性的影响,采用热重分析法研究了胶清橡胶在空气气氛中的热氧降解行为。研究结果表明,胶清橡胶的蛋白质含量、水溶物含量和丙酮溶物含量较高,Po和PRI数值较低;胶清橡胶在空气中有3个降解过程,经过水和丙酮提纯后的胶清橡胶的热稳定性显著提高。     

超声波法提取木材中阿拉伯半乳聚糖的工艺参数优化

以兴安落叶松(LarixgmeiniiRupr.)木材的加工剩余物为原料,采用超声波法提取阿拉伯半乳聚糖。根据前期单因素试验确定的主要影响因素,采用正交试验研究了不同参数对超声波法提取阿拉伯半乳聚糖提取率的影响,另外组合对试验结果有最大影响的各因素为追加试验的工艺参数。较佳工艺参数为:原料粒度60～80目的兴安落叶松木粉5.0g,超声波功率160W,料液比1∶30,提取时间50min,阿拉伯半乳聚糖粗糖收率19.47%。通过红外光谱和紫外光谱分析鉴定其结构。     

落叶松单宁改性酚醛胶推广应用取得重大进展

南京林业大学竹材工程研究中心与内蒙古森工拷胶制品有限公司经过5年多的联合攻关,推广应用落叶松单宁改性酚醛胶,近期取得重大进展。由于使用落叶松单宁(拷胶)取代酚醛胶中60%的苯酚,因而改性胶中游离酚≤0.3%,游离醛≤0.2%,大大低于普通酚醛胶的游离酚和游离醛的含量。它是一种低毒性酚醛胶,由于是粉状,因而运输、贮存、使用方便、降低成本、安全卫生,贮存期可达一年以上。大量试验证明,其性能与普通水溶性酚醛树脂胶相当,可在普通水泥模板、集装箱底板和特殊要求的包装胶合板中代替酚醛胶使用。目前已有许多厂家使用落叶松单宁改性酚醛胶…     

Response of wheat to nitrogen fertilization,a data set to validate simulation models for nitrogen dynamics in crop and soil

A data set originating from winter wheat experiments at three locations during two years is described. The purpose is to provide sufficient data for testing simulation models for soil nitrogen dynamics, crop growth and nitrogen uptake. Each experiment comprised three different nitrogen treatments, and observations were made at intervals of two or three weeks. The observations included measurements of soil mineral nitrogen content, soil water content, groundwater table, dry matter production and dry matter distribution, nitrogen uptake, nitrogen distribution and root length density.     

ENERGY REQUIREMENTS FOR DRYING LARGE ROUND BALES

Uniform density and softcore large round forage bales were dried under a variety of airflow and temperature regimes. The energy required to operate the fans and heaters was measured as the bales dried to an average final moisture content of 18 percent, wet basis. The energy requirement for drying both types of bales was found to be 33 kWh/tonne dry matter/moisture point reduction.

The soft-core bales tended to dry at a faster rate than the uniform density bales. Also, the final moisture content variation within the softcore bales was less than that within uniform density bales.     

ENERGY REQUIREMENTS FOR DRYING LARGE ROUND BALES

Uniform density and softcore large round forage bales were dried under a variety of airflow and temperature regimes. The energy required to operate the fans and heaters was measured as the bales dried to an average final moisture content of 18 percent, wet basis. The energy requirement for drying both types of bales was found to be 33 kWh/tonne dry matter/moisture point reduction.

The soft-core bales tended to dry at a faster rate than the uniform density bales. Also, the final moisture content variation within the softcore bales was less than that within uniform density bales.     

兴安落叶松阿拉伯糖基半乳聚糖化学结构的研究

木粉在室温下用冷水所得到的提取液，经离心除去沉淀后首先用聚酰胺柱纯化，然后再用乙醇沉淀而制得高纯度阿拉伯糖基-半乳聚精（AG），HPLC分析表明AG聚糖D-半乳糖和L-阿拉伯糖组成，其摩尔比为7．41：1。高碘酸盐消耗为1．12摩尔，甲酸生成量为0．53摩尔，数值与文献值基本一致。13C－NMR研究表明：AG聚糖主链由1～3连接的β-D-吡喃型半乳糖基构成，每个主链半乳精基C—6上有两个或一个1-6连接的β-D-吡喃型半乳糖基和3（2）-O-α－L-呋喃型拉伯糖基-L-呋喃型阿拉伯糖。     

脲醛树脂耐水性的研究

为了提高短切玻纤毡用脲醛树脂粘合剂的耐水性,尤其是耐热水性,研究了尿/醛比、三聚氰胺、醇类的醚化、聚乙烯醇以及聚丙烯酸乳液对脲醛树脂耐水性的影响。其主要影响因素是交联密度和亲水性物质的含量,良好的交联密度和尽可能少的亲水性物质是脲醛树脂耐水性的保障。     

紫外法和皮粉法测定塔拉单宁含量的对比研究

分别采用紫外法和皮粉法对5种不同含量的塔拉单宁进行对比研究,并利用SPSS软件对单宁含量测定结果进行显著性检验,结果表明：高纯度塔拉单宁（93%）分别用紫外法和皮粉法测定单宁含量时实验结果并未显著差异（P>0.05）,而4种纯度为60%左右塔拉单宁的实验结果均具有显著性差异（P < 0.05）,皮粉法测得的单宁含量均比用紫外法测得的结果高,差值约为1.5%~2.0%,并由此计算出紫外法测定塔拉单宁含量计算公式中的矫正常数p为1.03。紫外-可见吸收光谱与HPLC分析结果表明：塔拉单宁与五倍子单宁的最大吸收峰均为276 nm,同质量浓度下塔拉单宁的吸收峰强度高于五倍子单宁,塔拉单宁成分出峰时间主要在20~40 min,五倍子单宁主要在30~45 min。     

Prediction of Physicochemical Properties of Raspberry Dried by Microwave-Assisted Fluidized Bed Dryer Using Artificial Neural Network

The main target of this research is to dry raspberries in a microwave-assisted fluidized bed dryer. Artificial neural network (ANN) modeling was used in order to evaluate and predict the physicochemical properties of this fruit. In this research, the effects of five variables—microwave power (0, 300, and 600 W), temperature (55, 70, and 85°C), air flow rate (15, 20, and 25 m/s), starting time of microwave input (from the moment when the moisture content decreased until 334, 400, and 466 g water/g dry matter), and amount of loaded material (50, 100, and 150 g)—on nine outputs—drying time, rehydration capacity, density, porosity, hardness, water activity, phenolic compounds content, anthocyanins content, and the antioxidant activity of dried raspberries—were studied. A feed-forward multilayered perceptron trained by back-propagation algorithms for five independent variables was developed to predict these nine outputs. The optimal configuration of the neural network model had a hidden layer with nine neurons. The predictive ability of the ANN was compared using a separate data set of 52 unseen experiments based on root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R ²) for each output parameter. The optimum model was able to predict the nine output parameters with a coefficient of determination higher than 0.92. The results indicated that the experimental and ANN-predicted data sets were in good agreement, so it is feasible to use an ANN to predict the physicochemical properties of dried black raspberry.     

阴极电泳漆几项性能评价及测试方法探讨

对阴极电泳漆的干膜密度、溶剂含量、烘干减量的测试方法、影响因素进行了探讨。介绍了阴极电泳漆的几种性能测试方法。     

马占相思树皮单宁含量的影响因素研究

研究了产地、树龄、部位以及贮存时间对马占相思树皮单宁含量的影响。结果表明:不同产地的该种树皮的单宁含量差异较大;树龄对树皮的单宁含量影响较明显,随着树龄的增加,单宁含量逐渐减少;从主干的根部往顶部,树皮的单宁含量逐渐降低,非单宁含量逐渐增加;贮存时间的延长,单宁含量减少,因此,贮存时间不能过长。研究结果表明马占相思树皮是适合工业生产的一种优良栲胶原料。     

Influence of Dry Matter Content and Drying Conditions on Effective Diffusion Coefficient of Onion (Allium cepa,L.)

ABSTRACT

Demand for fresh and dehydrated onions has increased considerably over the last two decades. To meet this challenge new varieties possesing superior field characteristics have been developed whose dehydration characteristics differ markedly. In this work the influence of dry matter content in the raw onion and drying conditions on the effective diffusion coefficient is studied. In the falling rate period, the diffusion activation energy was found to be 33.9 kJ/mol, and the D_σ parameter (the effective diffusivity at high moisture contents) was found to be 5.0736×10^-5 m²/s. On the basis of measurements with seven different onion varieties (with raw dry matter content between 19.5 and 23.5 kg dry matter/kg fresh product) an exponential relationship was found between the effective diffusivity and dry matter content of the raw onion.