无公害添加剂预混料对育肥牛胴体性状和肉品质影响的研究

将45头供试牛按体重大小排序,平均分成对照组、营养调控组和中草药组3个组,后两组作为试验组,分别饲喂课题组自主研制的营养调控预混料和中草药添加剂预混料。结果表明：对照组胴体重210.6kg、营养调控组为245.0kg;中草药组为249.6kg;其屠宰率分别为51.18%、55.75%、58.05%;两组试验牛在净肉率、胴体产肉率、眼肌面积、优质肉块数量等性状方面都明显好于对照组。     

The application of biochar on soil acidity and other physico‐chemical properties of soils in southern Ethiopia

The aim of this research was to investigate the effect of biochar amendment on soil acidity and other physico‐chemical properties of soil in Southern Ethiopia using a field experiment of three treatments: (1) biochar made of corn cobs, (2) biochar made of chopped Lantana camara stem, and (3) biochar made of Eucalyptus globulus feedstock and a control, in which neither of the biochar was used. Each treatment had three levels of 6, 12 and 18 t ha⁻¹. The experiment was setup with RCBD in a factorial arrangement with three replications. In this regard, a total of 36 plots (each 2 × 2 m size) were applied with three replications to the depth of 0–15cm. From these 36 plots, composite soil samples were collected to the depth of 0–30 cm and analyzed for bulk density, total porosity, pH, soil organic carbon, total nitrogen, available phosphorus, potassium, and exchangeable acidity using standard procedures before and after biochar application. Two‐way ANOVA was also used to analyze the impact of the biochars on soil acidity and other properties. For the treatments that had significant effects, a mean separation was made using Least Significance Difference (LSD) test. The results showed the application of biochar significantly reduced, soil bulk density and exchangeable acidity when compared with a control (p < 0.05). Moreover, the total soil porosity, soil pH, total nitrogen, soil organic carbon, available phosphorus, and potassium were significantly increased in the soil. From among applied biochar treatments, Lantana camara applied at the level of 18 t ha⁻¹ had a higher impact in changing soil physico‐chemical properties. In general, the study suggests that the soil acidity can be reduced by applying biochar as it can amend other soil physico‐chemical properties.     

杨树低产林成因及对策——以宿州市踊桥区祁县镇为例

通过设立固定标准地对杨树的中幼林龄期和近熟林龄期生长情况进行调查分析，了解踊桥区祁县镇不同立地条件下杨树长势，判断林分立地条件对生长量影响的关键因子，并进行了标准地土壤剖面结构、理化性质和土壤养分含量对比，结论如下：影响杨树生长的关键因素是林地土层厚度，分析了杨树低产林形成原因是：土壤层浅、瘠薄、空隙度小、质地粘重。并提出相应对策：杨树低产林改造；加强中幼林抚育、进行土壤改良；发展林下经济改善土壤结构理化性质；营造复层林、间接改良土壤，提高林地综合利用率。     

CerealBeta-Amylases

Cerealbeta-amylases are perhaps best known in terms of the vital role they play in releasing easily fermentable sugars from cereal grain starch to fuel the production of alcohol by yeast in brewing. The extent to which they have been investigated is indeed largely due to their significance in this economically important industry. However, cerealbeta-amylases are also, or could be, employed in many other aspects of the food industry and the analysis of starch, and they constitute valuable markers in cereal assessment and breeding studies. Quite apart from their practical significance, they are rewarding objects of biochemical and physiological research. They are interesting models for the study of enzyme polymorphism, post-translational modification and the differential expression of isoenzymes. In spite of their often high activitiesin situand all that is known about their generation, they are an enigma in that their physiological function, or even necessity, remains unclear. It has been recently recognised that there are two different categories of cerealbeta-amylases which exhibit different tissue and taxonomic specificities and physiological developmental patterns. The «classical»beta-amylases present at high activities in cereal seeds appear to be limited to the endosperm of the species of the Triticeae tribe of the Festucoideae subfamily of the Gramineae (wheat, barley and rye), whereas all cereals exhibit a different, tissue-«ubiquitous» form of the enzyme which is present at much lower activity levels. The physiological phenomenology and the usage of cerealbeta-amylases are discussed in relation to these two categories of enzyme.     

密度对寿竹竹基纤维复合材料性能的影响

为开发竹材人造板新产品,利用4～5年生寿竹为原料,采用热压生产工艺制备竹基纤维复合材料,并分析复合材料密度对其物理和力学性能的影响。结果表明:随着密度增加,复合材料厚度方向上的吸水膨胀率增加,宽度方向的吸水膨胀率下降,力学性能逐渐增加。     

烤烟和作物轮间作提高烟叶品质的研究现状

烤烟是我国重要的经济作物，但栽培过程中存在连作障碍。烟田连作导致病害增加，影响烟叶和轮间作作物的品质，进一步影响农田产出，另一方面，连作障碍导致烤烟种植土地匮乏。生产实践发现通过与其他作物轮间作可以改善烤烟连作障碍。本文从作物-土壤-微生物组成的根际微生态系统的视角，综述了烤烟与不同作物轮间作的现状以及轮间作后的土壤生物学性状变化，分析了不同轮间作模式下土壤理化性质和根际微生物群落的变化，特别是烤烟产量和烟叶内在品质的变化，对于烤烟与作物的轮间作机制进行了总结和展望，为烤烟轮间作种植模式提供了科学依据。     

多年生香豌豆的形态特征及经济性状研究

多年生香豌豆是黄河水利委员会天水水土保持试验站引进的国外优良牧草品种。试验针对多年生香豌豆的形态特征、经济性状及其生长状况进行了试验研究，发现多年生香豌豆无论是作为牧草还是水土保持物种都具有极高的经济价值和生态价值，适于黄土高原及其与青藏高原结合部的气候条件下生长，对于解决上述地区牧草品种单一，植被退化及农村饲料短缺等实际问题，改善西北地区生态环境，促进农业产业结构调整，实现区域生态经济可持续发展等都具有重要的意义。     

木塑复合材料的耐老化性能研究

木塑复合材料的老化性能直接关系其使用寿命和适用范围。该研究使用稻壳、橡胶木锯末和橡胶籽壳分别与回收聚乙烯混合制备木塑复合材料,通过色差分析、红外光谱分析研究了3种木塑复合材料经荧光紫外老化后表面颜色、化学成分的变化。结果表明,经2 000 h老化后,3种木塑复合材料表面均出现褪色、羰基浓度增大,并随着老化时间增加而增加。其中橡胶籽壳基WPCs的变化最大,稻壳次之,橡胶锯末最小。     

榆树叶绿色素的提取与性质研究

研究了从榆树叶中提取天然绿色素的工艺方法以及其榆树叶绿色素的理化性质。结果表明：从榆树叶里提取绿色素时用75%的乙醇（pH值7.80）为提取液效果较好;该色素溶解性和热稳定性良好,在pH值为5～9时较稳定。该色素具有一定的开发利用价值。     

后期热固化处理对竹基纤维复合材料性能的影响

对竹基纤维复合材料进行两种条件(80℃处理8h和50℃处理24 h)的热固化处理后,观测其表观形貌,并进行拉伸、压缩、水平剪切性能以及疲劳性能检测.结果表明:经过热固化处理后,竹基纤维复合材料表面有不连续的微小裂纹产生,其拉伸、压缩、水平剪切性能略有提高,疲劳性能则无显著变化.