黄河三角洲退化刺槐林不同改造方式对土壤酶活性及理化性质的影响

采用野外典型抽样调查和室内分析测定相结合的方法,选取黄河三角洲重度退化刺槐林的4种改造方式,即棉田、白蜡林、白蜡+刺槐(混交林)、白蜡+棉花(农林间作),以未改造的重度退化刺槐林地作为对照,对改造5a后的土壤酶活性、土壤容重、孔隙度、盐碱状况及养分含量进行了测定分析。结果表明:(1)4种改造方式都不同程度地增加了土壤磷酸酶、脲酶活性,降低了多酚氧化酶活性。过氧化物酶虽有增加趋势,但差异不显著。多酚氧化酶和脲酶活性排序均为:混交林>白蜡林>农林间作>棉田;混交林、农林间作、白蜡林、棉田改造方式下的磷酸酶活性分别是对照的3.5,3.2,1.7,1.6倍。(2)改造林地的土壤容重、含盐量均表现降低趋势,其均值大小均表现为:混交林<农林间作<白蜡林<棉田,分别比对照下降14.5%,12.3%,9.0%,7.7%和35.3%,27.9%,13.2%,7.4%;总孔隙度表现为增大趋势,棉田、白蜡林改造方式表现出一定的增碱负效应。(3)改造后土壤养分增加显著,土壤有机质及有效N,P,K总体表现为混交林改造方式下最高,农林间作高于白蜡林,棉田波动较大。混交林和农林间作改造方式对土壤酶活性及理化性质的总体改善效果较好,建议作为重度退化刺槐林的主要改造方式进行推广。     

电子束辐照对大米营养和蒸煮品质的影响

为进一步发展、完善辐照杀虫灭菌技术应用于储粮方面的理论研究,该研究采用0、0.83、1.56、2.30、4.93kGy不同剂量的电子束辐照大米样品,考察其对大米品质的影响。结果表明:不同剂量的电子束辐照对大米的蛋白质含量、氨基酸的含量与组成无明显影响(p>0.05);随着辐照剂量的增加,大米的脂肪酸值、胶稠度升高(p<0.05),吸水率、膨胀率下降(p<0.05);电子束辐照对大米糊化温度的影响不明显(p>0.05),但显著降低大米的峰值黏度、衰减值、回生值(p<0.05),明显影响米饭的蒸煮品质(p<0.05),剂量为4.93kGy时蒸煮米饭出现明显的褐变。电子束辐照大米的剂量不宜超过2.30kGy,以0.83kGy的辐照剂量较佳,该研究结果将为储藏和进出口检疫中对大米进行辐照杀虫、灭菌时的剂量选择提供参考。     

糙米机械破碎力学特性试验与分析

为了研究糙米机械破碎力学特性及其与籽粒结构特性的关系。采用物性测试仪对糙米的锥刺、三点弯曲、剪切、挤压4种机械破碎力学特性进行测试与分析,并对糙米和精米的破碎力学特性(三点弯曲)进行了比较。结果表明:糙米的断裂是由于内部胚乳组织不均匀,在外力作用下首先形成内部裂纹,裂纹尖端处的应力集中又进一步促进裂纹扩展,最终导致籽粒断裂;厚度为(1.0±0.5)mm的不同样品锥刺破碎力在10N左右,各样品籽粒内部的结合力相差较小,籽粒的断裂主要与厚度及胚乳特性有关,其中三点弯曲力更能反映籽粒的破碎特性,糙米的糠层对籽粒有一定的保护作用,糙米力学特性比精米好。该文为糙米储藏加工技术参数的确定提供依据。     

不同有机物料对黑土及其复合胶体比表面积和电荷性质的影响

通过盆栽试验研究了施用动物粪便、动物残体、草本残体、木本残体4种不同有机物料对黑土胶体及黑土阳离子交换量(CEC)的影响。结果表明:不同来源有机物料对黑土胶体及黑土CEC的影响存在差异。与CK相比,动物粪便处理下黑土胶体比表面降低7.33%,而动物残体处理下提高了59.58%,木本残体提高了57.46%,草本残体提高了100.18%。pH<6时,各处理土壤胶体表面可变电荷量(Q表面)的曲线大致相似;在pH>6时,各有机处理土壤胶体样的表面电荷(Q样)均高于CK,并且动物粪便与木本残体的Q表面曲线相似且数值较高,CK与动物残体Q表面的曲线大致相同且数值较低。在pH为8～10时,各处理Q样由大到小依次为:动物粪便>木本残体>动物残体>草本残体>CK,动物粪便土壤胶体参比的表面电荷(Q参)与动物残体Q参的曲线大致相同并且数值较高,CK与草本残体Q参曲线相似且数值较低。不同来源有机物料对黑土CEC的影响也有所不同,动物粪便、动物残体、木本残体显著提高黑土CEC,而草本残体作用不明显。     

根渗灌管水力性能试验研究

基于室内试验,对2种管径的新型根渗灌管的水力性能进行了初步研究.结果表明,在微压(2.5～20 kPa)水头工作下,2种管径根渗灌管的流量与压力之间都存在很好的幂函数关系;Φ50管各种组合和Ф32管的孔距为1 m、孔径为2 mm组合的流量均匀系数(大于0.89)均较高;同一压力下,孔径是决定流量大小的主要控制因素,而相同管径同一组合条件下,压力是决定流量大小的主要控制因素.     

甜玉米粒物理性质及其皮渣超细粉碎的研究

分析了甜玉米粒的相关物理属性如球度、千粒重、体积密度、真密度、孔隙率、自由沉降速度等,对甜玉米粒的表皮特性进行了研究,为深入研究玉米工业皮渣超细粉碎提供了可靠的实验数据。     

Superfine pigment dyeing of silk fabric by exhaust process

The surface of silk is modified by a cationic reagent, N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride(CHTAC) in order to enable the fibre to be dyed with superfine pigments by an exhaust process. The effects of cationization pretreatment conditions such as the amount of cationic reagent, pH, treatment temperature and time on color yield are discussed in detail. The result shows that the condition suitable for modification treatment is that the concentrationc of cationic reagent is 10 g/l, pH 8, liquor to goods ratio of 100:1 and 60°C for 30 min. The white index decreases with the increase of alkali of cationic treatment. The crock fastness and wash fastness of silk dyed by pigment exhaust dyeing achieve 3–4 and 4 scale, respectively. The treated silk fabrics still retain a soft handle because the bending rigidity B and hysteresis 2HB increase slightly after cationization pretreatment and dyeing procedure. It has been demonstrated that properties of surface modified silk dyed with superfine pigment by exhaust process are acceptable.     

Effect of pineapple protease on the characteristics of protein fibers

A pineapple protease, bromelain, was used to improve the dyeing properties of protein fibers such as wool and silk. The optimal condition for the activity of the pineapple protease was about 60 °C at pH 7. The wool and silk were treated with the protease extracted from a pineapple and the K/S values of the dyed wool and silk were measured using a spectrophotometer in order to compare the dye uptake. The protease treatment enhanced the dyeing properties of protein fibers without severe changes in mechanical properties. The surface appearances of protease-treated fibers were observed by microscopy.     

The mechanical properties and abrasion behavior of warp knitted fabrics for footwear

The abrasion behavior of three kinds of warp knitted fabrics, which are normally used for upper sole of footwear, was evaluated. We measured the changes of mechanical and structural properties of each sample as abrasion cycle increased. Each sample showed similar trends in compression and surface properties but there were significant differences in abrasion rate among the samples. The mechanical properties showed remarkable differences with directions. The frictional coefficient (MIU) of fabric surface increased at the beginning of abrasion and decreased as abrasion cycles increased. The weight and thickness of the fabric linearly decreased with abrasion cycles. The surface roughness (SMD) and the compressional resilience (RC) decreased as abrasion cycles increased while compressional energy (WC) increased.     

湿热处理对糯小麦淀粉理化性质的影响

【目的】研究不同湿热处理条件,包括时间、温度和水分含量,对糯小麦淀粉性质的影响.【方法】以糯小麦淀粉糊的透明度、溶解度和膨胀度、冻融稳定性、颗粒形貌及颗粒结晶性质的变化考察湿热处理对糯小麦淀粉的影响.【结果和结论】与原淀粉相比,经湿热处理后,糯小麦淀粉糊的透光率,溶解度,冻融稳定性指标均有一定程度的降低,而膨胀度有一个先降低后增加的过程.湿热处理后糯小麦淀粉的颗粒形状和大小基本没有发生改变,但颗粒表面变得不均匀,中央部位变得模糊,出现了裂纹和压痕,偏光十字强度减弱.X射线衍射分析数据也证实了偏光显微镜得到的结果,淀粉的相对结晶度降低,但湿热处理未改变糯小麦淀粉的结晶结构类型,仍为A型.