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91.
木材干燥过程中,介质循环速度是一个影响木材干燥的重要工艺参数.在木材各含水率阶段,通过试验分析研究不同介质循环速度对木材干燥速度的影响.结果表明,介质循环速度对干燥速度的影响显著,但其影响随木材含水率(MC)的降低而减弱.在低介质循环速度条件下,试件MC大于45%时,表现为木材干燥速度和木材含水率偏差(△MC)随循环风速的增加而增加,呈显著正相关关系;试件MC介于35% ~ 45%之间时,正相关关系存在但不显著;试件MC小于35%时,干燥室内循环风速的大小不影响木材的干燥速度和木材含水率偏差(△MC).对试件表层含水率分析,试件表层含水率大于25%时,试件表面循环风速对试件表层含水率的影响显著;试件表层含水率小于25%时,试件表面循环风速对试件表层含水率的影响很小,不同循环风速下试件表层含水率基本一样. 相似文献
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[Objective] In order to guarantee the quality and safety of cotton products and to explore the feasibility of alternative planting, the contamination condition of the heavy metals in cotton seeds in Hunan province was investigated and evaluated. [Method] Fifty-six cotton seed samples, collected in 6 counties of Hunan province, were collected to determine 6 indicators including cadmium, lead, copper, chromium, mercury and inorganic arsenic contents. This was followed by pollution index calculation, correlation analysis, and cluster analysis. [Results] The range of comprehensive pollution indexes of Junshan district, Anxiang county, Nanxian county, Wangcheng and Dingcheng districts varied between 0.366 5–0.577 0, which belonged to a secure level. However, the single pollution indexes of Hengyang county are relatively high. The comprehensive pollution index of Hengyang county was 0.801 6, meaning a mild pollution level. [Conclusion] The pollution status of cadmium, lead, copper, chromium, mercury and arsenic in Hunan cottonseed samples are generally acceptable. Cotton could be a substitute for rice on contaminated soil. 相似文献
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增强病虫害防治能力提高森林资源的质量 总被引:3,自引:0,他引:3
针对江西森林病虫害发生现状、成因及防治存在的主要问题,阐述提高森林质量、增强病虫害防治能力的有效途径。 相似文献
97.
Liping Liang Mengyao Su Cong Zheng Jiaqi Li Haihua Zhan Xuming Li Xu Meng 《Fibers and Polymers》2017,18(12):2307-2314
A straightforward approach was proposed to modify cotton fabric for oil/water separation based on musselinspired reaction. The poly(DMA-Octadecyl acrylate) was designed to contain key chemical constituents present in mussel adhesive proteins by free radical polymerization of dopamine hydrochloride and octadecyl acrylate, which strongly adsorbed to fabric substrates, providing a special surface for fabric. The chemical structure, surface topography, and surface wettability of the fabric were characterized. The results showed that as-prepared cotton fabric displayed a high CA of >150° when dripped water droplets were on the modified fabric surface, and the oil contact angle (OCA) was close to 0°, it had excellent potential to be used in practical applications and has created a new method of fabric modification for oil/water separation. 相似文献
98.
选取重庆某住宅卧室进行实测分析,在供水温度为20、18、16℃,室外天气为晴天、多云、阴天(雨)工况下,研究毛细管地板供冷房间温度、地板供冷量、地板结露特征。供水温度为20、18、16℃时,室内最高温度27.6℃,最大供冷量分别为23、33、32 W/m2。开始结露时间为10:30-14:50之间,其中80%区域开始结露的时段为11:00-13:00之间,室内气流涡旋区最早出现结露。供水温度为18℃时,除湿能明显改变地板结露现象;供水温度为16℃时,除湿能改变大部分地板结露现象,室内气流涡旋区仍为结露区,但结露时间延后1 h以上。地板结露区域与室内气流组织有关,毛细管铺设位置应避开房间气流漩涡区。 相似文献
99.
Yan Lei Jiang Xuexin Ji Xiaonan Zhou Liting Li Siying Chen Chen Li Peiye Zhu Yuanchen Dong Tianhao Meng Qingfeng 《Journal of Soils and Sediments》2020,20(1):24-31
Journal of Soils and Sediments - Soil aggregates are the basic units of soil structure. Water-stable aggregates (WSAs) are greatly influenced by tillage practices. The main objective of our study... 相似文献
100.
Yi Zhao Shuxia Wu Roland Bol Mansoor Ahmed Bughio Wenliang Wu Yecui Hu Fanqiao Meng 《植物养料与土壤学杂志》2020,183(2):155-168
Intensive vegetable production in greenhouses has rapidly expanded in China since the 1990s and increased to 1.3 million ha of farmland by 2016, which is the highest in the world. We conducted an 11‐year greenhouse vegetable production experiment from 2002 to 2013 to observe soil organic carbon (SOC) dynamics under three management systems, i.e., conventional (CON), integrated (ING), and intensive organic (ORG) farming. Soil samples (0–20 and 20–40 cm depth) were collected in 2002 and 2013 and separated into four particle‐size fractions, i.e., coarse sand (> 250 µm), fine sand (250–53 µm), silt (53–2 µm), and clay (< 2 µm). The SOC contents and δ13C values of the whole soil and the four particle‐size fractions were analyzed. After 11 years of vegetable farming, ORG and ING significantly increased SOC stocks (0–20 cm) by 4008 ± 36.6 and 2880 ± 365 kg C ha?1 y?1, respectively, 8.1‐ and 5.8‐times that of CON (494 ± 42.6 kg C ha?1 y?1). The SOC stock increase in ORG at 20–40 cm depth was 245 ± 66.4 kg C ha?1 y?1, significantly higher than in ING (66 ± 13.4 kg C ha?1 y?1) and CON (109 ± 44.8 kg C ha?1 y?1). Analyses of 13C revealed a significant increase in newly produced SOC in both soil layers in ORG. However, the carbon conversion efficiency (CE: increased organic carbon in soil divided by organic carbon input) was lower in ORG (14.4%–21.7%) than in ING (18.2%–27.4%). Among the four particle‐sizes in the 0–20 cm layer, the silt fraction exhibited the largest proportion of increase in SOC content (57.8% and 55.4% of the SOC increase in ORG and ING, respectively). A similar trend was detected in the 20–40 cm soil layer. Over all, intensive organic (ORG) vegetable production increases soil organic carbon but with a lower carbon conversion efficiency than integrated (ING) management. 相似文献