基于DSP的在线薄膜厚度检测系统

对生产过程中快速、高精度的厚度在线检测问题进行了研究,用TI公司的TMS320F2812DSP芯片作为硬件电路的微处理器完成系统中的输入信号检测和系统的控制。并且依据界面美观、功能实用、操作方便的思想对系统的监控终端的操作和显示界面以及管理软件进行了程序设计。     

Effect of press cycle time and resin content on physical and mechanical properties of particleboard panels made from the underutilized low-quality raw materials

In this study, the influence of press cycle time and resin content (RC) on some of the physical and mechanical properties of single-layer particleboard manufactured from the low-quality raw materials were determined. Eucalyptus (Eucalyptus camaldulensis), mesquite (Prosopis juliflora), saltcedar (Tamarix stricta) and date palm (Phoenix dactylifera) wood, which is underutilized invasive species in southern parts of Iran, were used as alternative raw materials for particleboard manufacturing. Variable factors were as resin content (9, 10 and 11%) and press time (PT) (4, 5 and 6 min). Other parameters such as type of resin (UF), hardener content (2%), type of hardener (NH₄Cl), press-closing time (4.5 mm/s), board density (0.75 g/cm³), press pressure (30 kg/m²) and press temperature (160 °C) were held constant. The experimental panels were tested for their mechanical strength including modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) and physical stability properties (thickness swelling) according to the procedures defined by European Union (EN) Standard. Overall results showed that most panels made from above-mentioned materials exceed the EN Standards for IB, MOE and MOR. The mechanical properties of particleboard were improved as the resin content increased from 9 to 11%. The results indicated that the polymerization of resin and wood is better at 11% resin content and 5 min of press time. However, thickness-swelling (TS) values were higher (poor) than requirements. Panels made of mesquite, saltcedar and date palm with a resin content of 11% and pressed for 5 min is adequate for general uses while eucalyptus with a resin content of 11% and pressed for 6 min is suitable for interior decoration.     

竹束去青程度对竹束单板层积材物理力学性能的影响1）

采用通过帚化技术去青后的慈竹竹束单板，制备了28 mm厚的竹束单板层积材，探讨了竹束去青程度对竹束单板层积材的尺寸稳定性、静曲强度、弹性模量和水平剪切强度的影响。研究结果表明：随竹束去青程度的提高，竹束表面的明度L倡呈上升趋势，红绿轴色度指数a倡和黄蓝轴色度指数b 倡增加，色差ΔE倡增大；竹束去青程度越高，竹束表面的静态接触角越小，对应制得的竹束单板层积材的尺寸稳定性越好，干态静曲强度、弹性模量和水平剪切强度变化不大或稍有减小，但经过28 h处理后的强度均表现出更小的削减；不去青对竹束单板层积材强度降低的影响是最大的；针对水平剪切强度， A、B、C、D组板材均符合GBT／20241—2006《单板层积材》标准要求，A、B、C组达到《重组竹》（报批稿）规定的9V－12H级别。     

利用电容法测量滑板与土壤间充气层的厚度

介绍了一种滑板土壤问充气层厚度的测量方法——电容法的系统组成和工作原理,并对系统标定结果和测量结果进行了初步分析。     

越冬期埋土防寒层厚度对贺兰山东麓葡萄园土壤温度的影响

2019/2020年和2020/2021年冬季于贺兰山东麓葡萄园开展不同埋土防寒层厚度试验,结合不同深度土壤温度监测结果,研究越冬期葡萄园埋土防寒层覆盖下根区土壤温度变化规律,明确不同埋土防寒层厚度对根区土壤温度和葡萄越冬冻害的影响,为葡萄越冬冻害监测、评估及葡萄园冬季埋土管理提供参考。结果表明：（1）酿酒葡萄越冬期（12月−翌年2月）土壤温度呈先下降后上升的趋势;土壤温度随土层深度的增加而增加,波动随深度增加而缩小,埋土防寒层的覆盖,进一步减少了土壤温度的波动。（2）土壤温度随着埋土防寒层厚度的增加而增加,与不埋土处理（H0）相比,埋土防寒层厚度60cm（H60）处理, 20cm日最低土壤温度冬季可提高0.2～2.7℃,冬季平均可提高1.1℃;40cm土壤温度冬季可提高0.1～1.3℃,冬季平均可提高0.6℃。（3）0cm、20cm、40cm土壤温度日较差随着埋土防寒层厚度增加而减小,且极值出现时间依次滞后,60cm土壤温度几乎恒定。（4）20cm土壤温度,根干（C0）处显著高于距根干50cm（C50）、距根干100cm（ C100）和距根干150cm（C150）(P<0.05),距离根干越远土壤温度越低。土壤温度最低日,埋土防寒层厚度30cm、40cm、50cm三个处理根干（C0）处20cm土层温度较C50、C100和C150分别提高1.7～2.2℃、1.7～3.3℃、2.4～3.4℃。可见,根系受冻风险随土壤深度增加而降低,增加埋土防寒层厚度可提高土壤温度,减少土壤温度的波动,最低温度出现的时间随着埋土防寒层厚度增加而出现滞后。越冬冻害发生程度随埋土厚度增加而减少,其中副根受冻率高于主根。     

生物降解地膜对黄土旱塬玉米产量及水分利用效率的影响

研究黄土旱塬不同厚度生物降解地膜对作物产量和水分利用效率的影响,为黄土旱塬区生物降解地膜应用提供参考依据。采用0.006、0.008、0.010 mm 3种厚度的生物降解地膜,以裸地为对照,测定不同处理土壤水分、植株性状、产量和水分利用效率等指标。结果表明,生物降解地膜厚度减薄会显著降低地膜对水分的保蓄能力,覆膜后150 d,0.006 mm生物降解地膜单株叶面积小于裸地,0.008、0.010 mm生物降解地膜单株叶面积较裸地分别增加20.2%、22.2%。覆膜后120 d,0.006、0.008 mm生物降解地膜叶片SPAD值与裸地没有明显差异,0.010 mm生物降解地膜叶片SPAD值较裸地增加4.2%。生物降解地膜厚度对春玉米产量和水分利用效率有显著影响,生物降解地膜越厚,春玉米产量和水分利用效率越高,但0.008、0.010 mm生物降解地膜在产量和水分利用效率上没有显著差异。     

Effects of hardness and thickness of polyurethane foam midsoles on bending properties of the footwear

In sports shoe design to achieve better athletics performance, the bending stiffness of a footwear is an important parameter. Its bending stiffness is mostly dependent on its midsole material. Specifically, hardness and thickness of the midsole material are the major factors on its bending stiffness. Hence, this study focuses on studying the effect of hardness and thickness on bending stiffness of sports shoes by using polyurethane(PU) foam midsole. The results from the experiments show that the bending moment increases as the bending angle increases. Increased hardness and increased thickness of midsole also cause a greater bending moment of the sports shoe, respectively. Moreover, the effect of hardness and thickness of midsole on bending moment measured with assembled shoes is much greater than the one measured with midsoles alone. Therefore, low bending stiffness of the midsole material can not be ignored in shoe design because it could result in high bending stiffness of an assembled shoe.     

玉米果皮研究概述

玉米果皮是子粒的重要组成成分,具有保护子粒免受物理和生物损伤的作用,特别是对保护种子活性、活力有非常重要的意义。玉米果皮与玉米的商品品质、营养品质、食用品质相关联,尤其是与甜玉米及糯玉米的适口性、爆裂玉米爆花品质有着非常密切的关系。玉米果皮厚薄受数量基因控制,所涉及的基因数有3～8个,因品种的不同而存在差异。     

Models for Predicting Wood Properties in Stems of Picea abies and Pinus sylvestris in Sweden

To study and model the variation of wood properties, sample trees were selected from 42 Norway spruce and 20 Scots pine stands covering a wide variation in climatic and site conditions, stand maturation and tree sizes. Plot and tree measurements were followed by sampling wood from different heights in each sample tree and laboratory measurements of wood properties. Mixed linear and non-linear prediction models were developed using diameters, number of annual rings and climatic indices as explanatory variables. The variation in spruce properties explained by these variables was: basic density 50%, latewood content 52%, juvenile wood diameter 85%, heartwood diameter 94% and bark thickness 76%. The corresponding values for pine were 59, 54, 79, 92 and 85%. Random among-tree variance was an important contributor to the remaining variation for density and latewood. In general, only a minor part of the random variation was related to variance between stands. Predictions derived from the models for density and juvenile wood in both species, and heartwood in pine showed good agreement when validated with data sets from two other studies. The resulting models may be used for predicting wood properties in forest planning and in bucking computers in harvesters, provided that the essential information is available.     

土地复垦的覆土厚度及覆土基质确定

1研究方法 1．1研究区概况研究区位于河南省巩义市大峪沟煤矿,属黄土丘陵地区,为较典型的半干旱气候类型。土地复垦的主要内容为塌陷区土地复垦和矸石山复垦。 1．2调查方法该研究的重点放在不同生活型植物物种与地境层片的对应关系,以及各层片的水肥条件与植物长势的关联这两个问题上。地面以上开展植被调查,地面以下开展地境结构及地境内生态因子调查：