Modification of natural bamboo fibers for textile applications

Natural bamboo fibers have excellent properties suggesting that there is a good potential for them to be used in textiles; however, they have not received the attention that they deserve owing to their coarse and stiff quality. Therefore, a chemical method for extraction and modification of natural bamboo fibers for textile end uses were developed and optimized in this paper. The quality of natural bamboo fibers were characterized by their chemical composition, linear density, and tenacity. Experimental results show that the modified bamboo fibers are finer, with significant lower content of noncellulosic substances. The processing parameters are optimized as: 20 g/l NaOH, 3 g/l Na₅P₃O₁₀, 5 g/l Na₂SO₃, 3 g/l penetrating agent, with a fiber to liquid ratio of 1:10, at 100 °C for 2 h, and the bamboo fiber thus produced has cellulose amount of 73.25 %, fineness of 3.26 tex, average length of 44.5 mm, breaking elongation of 2.8 % and tenacity of 2.41 cN/dtex. The result of this study may offer a possibility of developing natural bamboo fibers into practical applications in textiles.     

Drape simulation of three-dimensional virtual garment enabling fabric properties

This study analyzes how the silhouette of virtual garments applied to virtual avatars is altered according to various virtual fabric properties. This study measures the properties of real fabrics that include a charmeuse (#F1) and gabardine (#F2) using the Fabric Analysis by Simple Testing system; in addition, the material properties of different real fabrics were applied to that of the virtual fabric. It then evaluates the drape stiffness and silhouette of the virtual garments according to the different fabrics. This study also compared the virtual garment silhouette of sample fabric #F1-S that changed only the stretch property of the sample fabric #F1 with the virtual garment silhouette of sample fabric #F1. The results show that the fabric properties including bend, thickness, weight, stretch, shear values affect the drape stiffness, silhouette, and fit of the virtual garment simulated on virtual avatars and may be used for the realistic virtual garment technology.     

Investigation of jute-lignin-poly (3-hydroxybutyrate) hybrid biodegradable composites with low water absorption

This study developed a novel PHB-lignin-jute biodegradable composite with preferable mechanical properties and low water absorption. The appearances of fracture surface of composites were analyzed by scanning electron microscope. The result suggested a Gaussian-like distribution of the size particles supporting the presence of lignin with a radius smaller than 0.5 μm. According to X-ray diffraction, the presence of lignin and jute fibers was decreased the crystallization of PHB. Moreover, the glass transition temperature of PHB increased, and the endotherm during glass transition was decreased. The maximum tensile strength and modulus of composites were obtained with 30 wt% jute fiber contents and 4 wt% lignin contents. The presence of jute fibers was largely increased the water absorption of composites. However, the presence of lignin was effectively decreased the water absorption of composites at saturation levels.     

定量机械通风对华南地区哺乳猪舍环境和母猪繁殖性能的影响

为探究定量机械通风对华南地区哺乳猪舍环境和母猪繁殖性能的影响,该研究实测并比较了该地区冬季自然通风和定量机械通风2种模式对两广小花猪哺乳猪舍的环境温度、湿度、二氧化碳、氨气浓度和母猪繁殖性能、呼吸频率、直肠温度等指标的影响。结果表明,在夜晚期间,自然通风哺乳舍的二氧化碳和氨气浓度分别为（817.16±25.28）和（7.88±0.34）mg/m3,均显著高于定量机械通风哺乳舍的（645.71±9.49）和（5.59±0.14）mg/m3（P＜0.01）;自然通风哺乳舍的全天二氧化碳和氨气浓度分别为（707.34±20.42）和（6.63±0.27）mg/m3,均显著高于定量机械通风哺乳舍的（583.25±10.06）和（4.81±0.13）mg/m3（P＜0.01）。定量机械通风模式下的出生活仔猪数为（12.50±0.55）头,与自然通风模式的（11.13±0.66）头相比具有升高的趋势（P=0.08）;定量机械通风模式的仔猪平均日增质量为（146±40）g,与自然通风模式的（133±70）g相比也具有增加的趋势（P=0.09）。然而,与定量机械通风相比,自然通风模式下的母猪平均日体质量损失（P=0.06）和平均日背膘损失（P=0.08）均有降低的趋势。此外,在哺乳第21天,自然通风模式的母猪呼吸频率为（69.50±3.85）次/min,显著高于定量机械通风模式的（57.29±1.54）次/min（P＜0.05）。综上,定量机械通风模式可对冬季华南地区两广小花猪哺乳母猪舍内空气质量有明显改善,提高母猪繁殖性能。     

大蒜播种时鳞芽朝向对大蒜生长发育影响的试验研究(简报)

为了研究大蒜播种时鳞芽朝向对大蒜生长发育的影响,为研究大蒜播种机械提供参考依据,该文以徐州白蒜为供试品种,将鳞芽分为朝上、朝下和随机3种情况种植,观察大蒜生长发育情况.试验结果表明:播种时鳞芽朝下、朝上和随机时,大蒜均能顺利生长.但是,鳞芽朝下和随机时,发芽叶出土缓慢而且细弱,出苗期加长,出苗不整齐.在幼苗期,幼叶长大缓慢,露出土面较晚.大蒜植株较矮,叶面积小.蒜头重量轻,横径小.大蒜地下部分生长姿态与播种时鳞芽的姿态一致.鳞芽朝向随机和朝下时,蒜头在地下生长姿态呈倒立或平躺状.     

Effect of soil sealing on the microbial biomass,N transformation and related enzyme activities at various depths of soils in urban area of Beijing,China

Purpose  

Sealing of soils prevents the exchange of gas, water and nutrient between soil and other environmental compartments, and affects urban N flux, thereby resulting in certain negative impacts on soil functioning and urban environment. However, little information is available on the biogeochemical cycling and biological activities after sealing of soils in urban areas. The aim of this study was to assess the effects of soil sealing on N transformation and associated microbial properties.     

川西名山县阶地漂洗土壤分类及参比研究

经历了强烈漂洗作用的土壤是一类形态独特的土壤,在分类系统中具有重要地位。本文在四川西部漂洗土壤集中分布的名山县第二至五级阶地上对这类土壤进行了野外调查采样和室内测试分析,按中国土壤系统分类的原理和方法,通过水耕表层、水耕氧化还原层、漂白层、人为滞水土壤水分状况、氧化还原特征等诊断层和诊断特性的确定及按顺序检索的方法,将其归入人为土纲,水耕人为土亚纲,简育水耕人为土和铁聚水耕人为土土类,漂白简育水耕人为土、漂白铁聚水耕人为土和普通铁聚水耕人为土亚类;同时按发生分类系统进行了类型划分,它们均归入漂洗水稻土亚类。比较而言,系统分类能更精确地区别土壤分异,有利于土壤精准化管理,但仍需进一步修订完善。     

调亏灌溉对滴灌成龄香梨果树生长及果实产量的影响

调亏灌溉对果树节水、提高果实产量和品质具有一定效果。2009-2010年,在新疆库尔勒巴州农业科学研究所进行试验,研究滴灌调亏时间及土壤水分亏缺程度对树龄24a的成龄库尔勒香梨果树生长及产量的影响。果实细胞分裂期、果实缓慢膨大期、果实细胞分裂期至缓慢膨大期,分别进行中度土壤水分亏缺与重度土壤水分亏缺灌溉。中度土壤水分亏缺的灌水量为美国A级蒸发皿蒸发量(Ep)的60%,重度土壤水分亏缺的灌水量为Ep的40%。其它时段灌水量与对照相同,为Ep的80%;对照处理整个生育期灌水量均为Ep的80%。灌溉周期为7d。结果表明,前2个生长阶段的调亏灌溉均抑制了香梨树的营养生长,提高了香梨果实产量和灌溉水利用效率。各调亏处理的夏季修剪量比对照减小了8.4%～43.2%。2a内,细胞分裂期重度调亏处理,产量分别比对照增加了15.5%和19.2%,较对照节水9.7%和8.1%;果实缓慢膨大期中度调亏处理,产量分别比对照增加了14.0%和18.0%,较对照节水13.2%和11.3%;果实细胞分裂期及果实缓慢膨大期的重度调亏处理,产量分别比对照减少了15.4%和13.2%,较对照节水34.7%和28.4%。调亏灌溉对香梨果实品质无显著影响。结果对成龄库尔勒香梨灌溉管理具有指导意义。     

流固耦合作用对离心泵内外特性的影响

应用双向流固耦合方法对导叶式离心泵的外特性和内流场进行分析,研究流固耦合作用对外特性影响的内流机理。流场的定常数值模拟采用雷诺时均方法和标准k-ε湍流模型,非定常数值模拟采用大涡模拟方法,结构响应采用线性瞬态动力学方程。通过对流固耦合前后内部流场的对比,包括叶轮出口处的总压分布和相对速度分布,分析了流固耦合作用对外特性预测值影响的内流机理。同时,对叶轮出口处的压力脉动进行了分析。结果表明,流固耦合作用产生的叶轮变形,尤其是叶轮出口处的较大变形是导致离心泵外特性预测值变化的主要原因。考虑流固耦合作用后,叶轮出口处压力脉动周期性变化的总体趋势与非流固耦合结果基本一致,但振幅更大。考虑流固耦合作用后的最大压力脉动幅值提高了3.1%。研究结果为离心泵性能预测及流动诱导振动的研究提供参考。     

气候和土地利用变化对潮白河流域径流变化的定量影响

为量化气候和土地利用变化对流域径流的影响,该文以华北土石山区潮白河流域为研究对象,利用AWY(annual water yield)模型及分离评判法定量分析了1956-2010年气候和土地利用变化对流域年径流的影响。结果表明:研究时段内,潮白河流域年降水量和年径流量呈显著下降趋势;流域年径流量在1979年发生减少突变;气候变化是潮河、白河流域年径流减少的主要原因,贡献率分别为59.3%和93.5%;土地利用变化贡献率相对较小,分别为40.7%和6.5%;不同土地利用类型对流域年径流变化的影响差异较大:林地对径流变化贡献率平均达到67%,耕地和草地分别为18%和15%,水域、未利用地因所占面积比例小,与流域年径流变化相关性并不显著。研究结果可为流域内水土资源规划及管理提供参考。