不同储存形态玉米水分的变化规律

本文阐述了不同储存形态玉米水分的变化幅度。既包装玉米大于囤积玉米;囤积大于散装玉米;穗藏大干粒藏玉米;露天储存玉米大于仓内储藏玉米。无论哪种储存形态的玉米,其水分的变化幅度都遵循一个规律：上层玉米（接触空气多）水分的变化,一般大于下层,了解这一规律对安全储存玉米具有实际指导意义。     

玉米根系几何造型研究

通过对玉米根系形态建成过程根系的结构、生长及分布特点和规律观测研究,构建了描述玉米根系形态变化的数学模型。结合粒子系统和计算机图形学技术,在计算机上实现了玉米根系生长的三维显示。其结果和实际的玉米根系的生长发育过程基本一致,为农学研究者提供了一个可视化的根系模型。本模型结构简单、可交互、真实感强,可以较好地虚拟玉米根系的生长过程。     

大揽堆棒储玉米脂肪酸值变化趋势分析

作者通过对农民大揽堆棒储玉米的脂肪酸值进行跟踪测定，找出了大揽堆棒储的玉米随着储存时间的延长、水分的降低，其脂肪酸值不断升高的变化趋势，从而达到指导农民如何科学储粮的目的，做到服务于农业、服务于农村、服务于农民。     

冻结速度对黄土物理性质影响的试验研究

冻结速度堆黄土物性参数具有总要影响。使土样在封闭系统开展天然状态不同冻结速度的冻融循环试验。试验表明：土在冻结过程中，环境水分向冻结锋面迁移，致使土体的含水量增大：随着冻结速度的增大，即冻结时间的缩短，环境水分迁移的量减小。对于冻结速度较慢的情况，水分冻胀作用对黄土的体积影响不明显：对于冻结速度较快的情况，冻结速度越大，体积变化越小，液塑限越大。试验表明昼夜温差的变化对黄土土性的影响大于数月温度缓慢变化的影响。     

冻结速度对黄土物理性质影响的试验研究

冻结速度堆黄土物性参数具有总要影响。使土样在封闭系统开展天然状态不同冻结速度的冻融循环试验。试验表明：土在冻结过程中,环境水分向冻结锋面迁移,致使土体的含水量增大;随着冻结速度的增大,即冻结时间的缩短,环境水分迁移的量减小。对于冻结速度较慢的情况,水分冻胀作用对黄土的体积影响不明显;对于冻结速度较快的情况,冻结速度越大,体积变化越小,液塑限越大。试验表明昼夜温差的变化对黄土土性的影响大于数月温度缓慢变化的影响。     

储存环节玉米脂肪酸值变化趋势探析

经过对储存环节玉米脂肪酸值检测结果进行统计分析,得出了储存环节玉米脂肪酸值的变化趋势,达到为粮食企业科学保粮、确保粮食储存安全提供技术指导、为国家粮食局修订现行《玉米储存品质判定规则》提供了科学准确数据支撑的目的。同时,对修订《玉米储存品质判定规则》提出了建议。     

果皮蜡质与果实贮藏关系的研究进展

目的概述果皮蜡质的成分、性质、形态结构,以及调控与转运途径等,以探讨果皮蜡质与果实耐藏性的关系及其作用机理,展望如何延长果实的贮藏期。方法通过分析文献,理清果皮蜡质与果实耐藏性关系的研究范畴和热点,从果皮天然蜡质的成分、性质、形态结构,果皮蜡质与果实耐藏性的关系及其作用机理,果皮蜡质的合成、调控与转运途径等方面入手,对相关研究成果进行整理与综述,并对蜡质研究在果实采后贮藏中的应用前景进行展望。结论果实表面的蜡质层是保护果实的天然屏障,具有防止果实水分散失、维持表面清洁、避免病菌侵害等作用,对果实耐藏性具有重要的影响。     

主运移通道控烃成藏论在自来屯地区的应用

针对黄骅坳陷自来屯地区地层剥蚀严重,油气成藏规律复杂等特点,笔者引入“主运移通道控烃成藏理论”,对油气运移通道、空间分布形态进行了详细的阐述,进而在重构自来屯地区构造模型的基础上,对该区的构造特征、已探明油藏与主运移通道之间的空间关系、以及油气成藏规律开展了深入的研究,建立了自来屯地区油气成藏模式剖面图,井结合地震构造图部署滚动勘探井位,达到了增储与建产的双重目的。该技术方法对我国复杂断块油气藏的勘探开发具有借鉴意义。     

不同气流量下气泡帷幕对水下冲击波衰减特性研究

为了研究不同气流量下气泡帷幕对水下冲击波的衰减特性,采用高速摄像探究气泡帷幕在受到冲击波冲击后形态变化,结合冲击波压力时程曲线进行分析。结果表明,气泡帷幕中的气泡受到冲击波作用后会发生数次膨胀收缩行为,随着气流量增加,气泡膨胀的最大直径增大,第一次膨胀收缩周期变长;且气泡帷幕对水下冲击波压力有很强的衰减作用,气流量上升幅度越大,冲击波压力峰值衰减越明显,在气流量40 L/min下,冲击波峰值衰减高达88.98%;气流量大于20 L/min后,冲击波冲量衰减幅度均大于50.00%。针对气流量大小与压力峰值下降幅度的关系进行曲线拟合,提出适用于该工况下的经验方程,以期指导实际工程。     

芽孢杆菌修复剂修复再生混凝土裂缝试验研究

以芽孢杆菌浓度和再生粗骨料取代率为变化参数,深入分析了再生骨料混凝土试件开裂后表观变化、破坏形态和芽孢杆菌修复等规律。结果表明:再生骨料取代率较低时,混凝土试件的开裂变化、破坏形态与普通混凝土试件相似,且不随芽孢杆菌浓度的变化而出现较大的修复效能波动;随着再生骨料取代率的升高,再生骨料混凝土试件裂缝修复的增长速度大于普通混凝土试件,取代率低于30%时,再生混凝土试件开裂后的修复效果并不明显,而普通混凝土试件强度、抗离子侵蚀能力的退化大于再生混凝土试件,取代率超过30%后,普通混凝土试件抗离子侵蚀能力的退化较再生混凝土试件显著;随着芽孢杆菌浓度的提高,再生混凝土试件修复的增幅明显大于普通混凝土试件,而浓度超过30%时,试件内芽孢杆菌修复的能力出现退化且修复效果仍明显优于普通混凝土试件。     

相变储湿纤维/石膏复合材料的制备及综合性能

以抹灰石膏作为基体材料,将相变储湿纤维掺入抹灰石膏中,制备相变储湿纤维/石膏复合材料,对其基本性能、储湿调湿性能、相变调温性能和耐久性能进行测试与分析。利用FTIR和SEM研究相变储湿纤维/石膏复合材料的结构组成和微观形貌。结果表明：当相变储湿纤维掺量为40.0wt%时,相变储湿纤维/石膏复合材料具有最佳性能和良好耐久性能,其标准扩散度用水量为0.70、初凝时间为40 min、终凝时间为55 min、体积密度为1 005.56 kg·m^-3、拉伸连接强度为0.10 MPa、抗压强度为2.55 MPa;在相对湿度40%~65%时的平衡含湿量为0.0395~0.0935 g·g^-1;从35℃至20℃的降温时间为100 s,相变平台明显;经过循环试验,相变储湿纤维/石膏复合材料的吸放湿性能下降小于10%,相变调温性能下降小于5%。     

癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料的制备及性能

以抹灰石膏作为基体材料,将癸酸-棕榈酸-SiO_2相变储湿材料掺入抹灰石膏中,制备癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料,对其基本性能、储湿调湿性能、相变调温性能和耐久性能进行测试与分析。利用FTIR和SEM研究癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料的结构组成和微观形貌。结果表明:当癸酸-棕榈酸-SiO_2相变储湿复合材料掺量为40wt%的癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料具有最佳性能和良好耐久性能。其标准扩散度用水量为0.69、初凝时间为37min、终凝时间为51min、体积密度为916.67kg·m~(-3)、拉伸连接强度为0.08 MPa、抗压强度为1.76 MPa;在相对湿度40%~65%的平衡含湿量为0.0620~0.0849g·g~(-1);从30℃至15℃的降温时间为610s,相变平台明显;经过循环试验,吸放湿性能下降了6.44%~9.45%,相变调温性能仅下降了7.2%。     

Aging of Tablets Prepared by Direct Compression of Bases with Different Moisture Content

Abstract

Properties of aged tablets prepared by the wet granulation method were found to be affected by the moisture content of the granules. In this study, the storage-induced changes in hardness, disintegration and drug release were evaluated for tablets made by direct compression of three different bases with different initial moisture content. Tablets with high initial moisture content were found to increase in hardness upon storage. The magnititude of such increase is dependant upon the physical properties of the base and the absolute moisture content. The increase in hardness may increase the disintegration time and decrease drug release. Tablets with low initial moisture content were minimally affected by storage. The gain of moisture by some of these tablets led to enhancement in disintegration and drug release. Among the tablets studied lactose based tablets with different initial moisture content were found to be the most resistant to changes upon storage.     

淀粉基生物质发泡材料发泡倍率的影响因素

利用植物纤维增强玉米淀粉复合材料的熔融共混挤出发泡试验,通过对样条径向膨胀率的测试,研究了挤出压力、挤出速率、加热温度、含水率对复合发泡材料发泡倍率的影响。结果表明：复合材料的发泡倍率随挤出压力的增大而先增大后减小,当挤出压力为80 MPa时,发泡倍率达最大值,为14.8;随着挤出速率的升高,材料的发泡倍率呈非线性变化,当挤出速率为20 cm/s时,发泡倍率达最大值,为14.8;材料的发泡倍率随加热温度的升高而先增大后减小,当加热温度为135℃时,发泡倍率达最大值,为13.8;材料的发泡倍率随含水率的增加而先增大后减小,当含水率为13%时,发泡倍率达最大值,为13.8。分析材料相关参数与发泡倍率的相关变化曲线,总结其作用机理,对优化材料的加工工艺有着重要意义。     

New calibration technique for microwave moisture sensors

A new calibration technique was developed for implementation with microwave moisture sensors. The calibration permittivity function used for this purpose allows computation of moisture content in granular materials with significant differences in shape, dimensions, and composition, independent of bulk density and with temperature compensation. A 3D representation is used to plot the calibration permittivity function as it depends on temperature and moisture content in wheat and corn. For each material, data points form a plane surface. These planes have nearly the same coefficients, which can be utilized for the development of a “universal” calibration method for moisture sensing in natural and manufactured granular materials. Foundations of the method are discussed based on results obtained for wheat and corn over a wide temperature range and at moisture contents of practical interest     

包装箱用竹木复合层合板断裂特性的研究

采用二次回归正交组合设计法分析了含水率、裂纹长度和加载速率三个因素对竹木复合层合板断裂韧性(K1c)的影响.结果表明含水率对竹木复合层合板断裂韧性的影响最大;建立了含水率、裂纹长度和加载速率三个因素和断裂韧性(K1c)之间的回归方程."Z"字型裂纹为纤维本身破坏形式,"T"字型和"V"字型为纤维间破坏形式.     

Moisture absorption by epoxy/montmorillonite nanocomposite

The peculiarities of moisture absorption of epoxy–nanoclay composite are estimated in the paper. Second Fick’s law of diffusion was used to predict moisture diffusivity and equilibrium moisture content using accelerated analytical procedure. It was experimentally confirmed that sorption process in NC passes more slowly than in pure epoxy resin, for the highest filler content diffusivity reduces about half of diffusivity as for epoxy resin. The deviation from mixture rule was obtained for the equilibrium moisture content and the estimation of interphase content in composite was undertaken. It was determined that the higher content of interphase consistently leads to greater moisture absorption.     

Nanophase change for data storage applications

Phase change materials are widely used for date storage. The most widespread and important applications are rewritable optical disc and Phase Change Random Access Memory (PCRAM), which utilizes the light and electric induced phase change respectively. For decades, miniaturization has been the major driving force to increase the density. Now the working unit area of the current data storage media is in the order of nano-scale. On the nano-scale, extreme dimensional and nano-structural constraints and the large proportion of interfaces will cause the deviation of the phase change behavior from that of bulk. Hence an in-depth understanding of nanophase change and the related issues has become more and more important. Nanophase change can be defined as: phase change at the scale within nano range of 100 nm, which is size-dependent, interface-dominated and surrounding materials related. Nanophase change can be classified into two groups, thin film related and structure related. Film thickness and clapping materials are key factors for thin film type, while structure shape, size and surrounding materials are critical parameters for structure type. In this paper, the recent development of nanophase change is reviewed, including crystallization of small element at nano size, thickness dependence of crystallization, effect of clapping layer on the phase change of phase change thin film and so on. The applications of nanophase change technology on data storage is introduced, including optical recording such as super lattice like optical disc, initialization free disc, near field, super-RENS, dual layer, multi level, probe storage, and PCRAM including, superlattice-like structure, side edge structure, and line type structure. Future key research issues of nanophase change are also discussed.