雪茄种植户的农机使用情况对其雇工的影响研究——基于四川什邡烟农调研数据

  目的  探究雪茄种植户的农机使用情况与雇工行为的关系, 以指导雪茄烟农业生产。  方法  首先对烟叶种植中的机械和劳动力使用的变迁进行回顾分析,再以四川什邡的雪茄烟农调查数据为基础,运用二元Logit模型和因变量受限Tobit模型分析雪茄种植户农机使用对其雇工行为的影响。  结果  ① 近15年来烟田亩均投入的租赁作业费、机械作业费、人工成本持续上升,印证了烟草种植劳动与资本“双密集”的特征。②在以小规模家庭经营为基础的雪茄烟叶种植模式下,农机的使用并未明显替代人工投入,反而对雪茄种植户雇工有正向显著的影响。③是否加入合作社、种植规模、家庭外出打工成员情况对小规模农户农业雇工也有正向显著的影响,而种植经验、是否为生产组长、购买农业保险则对农业雇工呈现负向显著影响。  结论  雪茄种植过程中使用农业机械能够显著提高雇工概率,这是种植过程中机械与人工环节的不完全替代性以及种植规模扩大的结果,同时雪茄种植户不能仅靠使用农机来提高生产效益,需要进一步优化生产组织模式来提质增效。      

石羊河流域甜菜机械穴播膜下滴灌栽培技术

提高水资源利用率已成为关系甘肃河西灌区可持续发展的战略任务,作为甘肃甜菜产区的石羊河流域水资源紧缺,推行甜菜滴灌可起到节水、稳产、增产效果,生产上有较强的实用性和较好的推广价值.甜菜机械穴播膜下滴灌栽培技术实现机械覆膜、打孔、播种、铺设滴灌带一次性作业,全生育期滴水7～9次,每次300～ 500m3/hm2左右,总用水量3800 ～ 4200 m3／hm2,节水20％以上.     

宽窄行种植对桃树光照分布与果实产量和品质的影响--测试文章

以桃品种‘改良白凤’为试验材料,以常规种植(株行距为5 m×2 m,999株·公顷^-1)为对照,分析宽窄行种植模式(WN,株距2 m,宽行4 m,窄行1 m,1 998 株·公顷^-1)对光照分布、单位面积产量、果实品质的影响。结果表明：常规种植开心形光照主要集中在上层,下层相对光照强度多低于20%;宽窄行种植V型,上层相对光照强度基本保持在80%以上,中下层相对光照强度基本保持在40%左右; 2011、2012年和2013年宽窄行处理单位面积产量分别比常规处理高31.3%、41.0%和33.1%;宽窄行种植显著提高桃果实中蔗糖含量、降低苹果酸含量、提高果实糖酸比。因此,宽窄行种植不仅可以改善树体冠层内光照强度,还能改善果实产量与品质,是一种理想的栽培方式。     

Combinatorial effects of mechanical activation and chemical stimulation on the microwave assisted acetylation of corn (Zea mays) starch

The changes in the physical characteristics of ball milled corn starch (BMS) after chemical modification were investigated. The SEM and XRD analysis of BMS granules showed a fragmented aspect with a total loss of their initial crystallinity and an increase of their potential hydroxyl substitution sites. This morphology facilitated the access of the esterifying solvents into the starch molecule as corroborated by the spectacular increase of the water solubility index (WSI) and water absorption index (WAI). Following the acetylation, the degree of substitution (DS) increased up to 2.83 with the augmentation of the iodine catalyst content (p = 0.011). However, under the same condition of esterification, the DS of the BMS was slightly lower in comparison to the control, due to an increase in the number of free hydroxyl groups. Consequently to the modification, a reduction in the T_g, strong hydrophobicity and important exo‐corrosion affecting the granules were noticed.     

世界木工机械主要生产国家和地区出口情况分析

分析了中国、德国、意大利、日本、美国和中国台湾省(简称"6个国家和地区")木工机械出口情况及变化趋势,并据此为我国木工机械的出口战略提出建议.     

Materials based on maize biopolymers: Effect of flour components on mechanical and thermal behavior

The present study describes the effects of glycerol, relative humidity (RH) and the minor components of corn flour on mechanical and thermal properties of native flour, defatted flour, and starch‐based materials. The kinetic of retrogradation for these different materials were dissimilar. For all samples, strain at break shows a maximum value as a function of RH followed by a decrease, explained by the appearance of water and glycerol clusters. Starch controls the mechanical properties of corn flour‐based material and their variations with temperature and humidity. Lipid and protein have negative effect on mechanical properties of thermoplastic flour toward starch but they did not have a plasticizing effect on the physicochemical behavior of the matrix. T_gs decreased as a result of water content increase.     

基于HACCP的农产品基地种植与流通环节质量安全监控——以杨桃基地为例

本文采用分析危害和控制关键点(hazard analysis critical control point,HACCP)体系,以杨桃基地为例,对农产品基地生产与销售环节质量安全重点危害因子展开分析,确定了关键控制点,新建了农产品基地质量安全管控体系,并在实际应用中提出了管控建议,以提高农产品基地产销过程质量安全。     

“十二五”塑料机械产品结构调整与绿色技术应用的分析研究(Ⅳ)

绿色技术应用和开拓是十二五塑料机械产品结构调整的核心。绿色技术主要体现在提高能源和其他资源的利用效率、降低成型加工成本、减少对环境的污染、提高清洁度等方面。国内塑料机械中、低端化的现状不容乐观,一旦塑料机械市场萎缩,首先是中、低端市场萎缩,国内制造商受到的打击最大;高端塑料机械迎合了相关产业科技进步的需要,拥有广阔的发展空间。高端塑料机械实质是充分体现出绿色技术的设备。重点分析研究了注塑设备、拉吹成型设备、挤出设备、中空设备等4类主要塑料机械的产品结构调整和绿色技术应用需要解决的几个问题。转变陈旧发展理念,着力创新技术研发思路,用科学的发展理念加快自主创新塑料机械设备,开发高端塑料机械,掌握绿色核心技术,是改变中、低端化的现状、力做中国创造的绿色技术的唯一出路。     

Effects of ingredient composition on optical and mechanical properties of pullulan film for food-packaging applications

In the present research, the effects of pullulan (Pul), glycerin (Gly), xanthan gum (Xa) and locust bean (Lb) concentrations on pullulan film properties were investigated using a Central Composite Rotatable Design. Optimal ingredient combination was determined and antimicrobial activity of films combined with sakacin A was confirmed against Listeria monocytogenes. Using predictive models, contour plots and the characteristics of commercial LDPE films as constraints, the following combination within the optimal region was selected: Pul 100 g/l, Gly 10 g/l, Xa 1 g/l and Lb 1 g/l. Statistical analysis demonstrated that Pul and Gly significantly influenced the properties of pullulan films. Strong interactions were observed between Pul-Gly and Xa-Gly. When sakacin A was added to the film mixture, no significant influence on films optical properties was reported, while an increase in flexibility was observed. Results obtained indicate the potential application of pullulan film developed in this study as an effective antimicrobial biopolymer in food-packaging systems.     

An approach for the enhancement of the mechanical properties and film coating efficiency of shellac by the formation of composite films based on shellac and gelatin

The purpose of this study was to enhance the mechanical properties and film coating efficiency of shellac by the formation of composite films with different concentrations of gelatin. The composite films were prepared by the casting method and their mechanical and physicochemical properties were investigated. The results demonstrated that the puncture strength and percentage elongation of the composite film increased from 3.61 to 15.58 MPa and from 3.80% to 32.47% as the gelatin concentration increased to 50% w/w, respectively, indicating the enhancement of the strength and flexibility of the shellac film. The efficiency of the composite film over two model substrates, i.e., hydrophilic and hydrophobic substrates, respectively, was also studied. The work of adhesion and spreading coefficient of the composite film increased from 66.42 to 83.53 mN/m and from −8.14 to −3.07 mN/m for the hydrophilic substrate, indicating the improvement of the coating efficiency whereas the hydrophobic substrate showed the opposite trend with the increase in gelatin concentration. Therefore, the formation of the composite film not only improved the mechanical properties of shellac but also enhanced the efficiency of film coating by the modification of different concentrations of hydrocolloid polymer to suit with the type of coating substrate. Hence the knowledge of composite film could make beneficial contributions to the various applications in film coating for the food and pharmaceutical industries.