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101.
利用真空高电压放电场可节能、高效干燥木材,为研究不同高压脉冲形式下的干燥特性,分别对直流电压、交流电压、脉冲电压作用下的真空放电木材干燥及常规自然干燥和对流干燥进行比较试验。结果表明,通过调整电脉冲参数,使用真空放电法,能加速木材干燥过程。 相似文献
102.
Iron-ruthenium catalysts prepared by impregnation of calcination products of -, , -and -iron oxide-hydroxides with either ruthenium chloride or ruthenium red were tested for the activity for the water-gas shift reaction. The effect of support, ruthenium containing impregnation agent and thermal treatment on catalyst performance was discussed. 相似文献
103.
The location of transition ions in copper- and copper-zinc-loaded Y type zeolites prepared by different procedures has been studied by temperature-programmed reduction, infrared spectroscopy of CO adsorbed on pretreated samples and X-ray photoelectron spectroscopy. Samples outgassed at 673 K showed Cu+ species due likely to reduction of Cu2+ ions under vacuum. Over exchanged CuY zeolites copper species in exchange sites were detected, while an impregnated sample exhibited bands of CO adsorbed on both Cu2+ and Cu+ ions developed at the surface of CuO crystals, and small proportions of Cu+ ions located in accessible exchange sites SII and SnII. Similar findings were observed in Zn- and Cu-exchanged zeolites although the relative proportion of Cu in SI positions was decreased due to competition between Cu2+ and Zn2+ ions. Samples reduced in hydrogen at 523 K showed the appearance of Cu0 species in impregnated samples, whereas Cu+ dominated in the exchanged counterparts. Reduction at 598 K led to substantial changes in Cu-exchanged samples in water. The proportion of Cu+ species decreased by reduction to Cu0 and simultaneously migration to Cu+ to SII sites occurred. While Cu2+ or Cu+ were found on outgassed samples, only Cu0 and intrazeolite Cu+ were observed after H2-reduction at 623 K. Changes in copper exposure as a function of sample pretreatments were also revealed by X-ray photoelectron spectroscopy. 相似文献
104.
Wood celluloseis a mainraw material for prepar-ing NC[1],there are different reactivities of the threehydroxyl groups in an anhydrogluose unit,in differ-ent positions along molecular chain and within differ-ent points of cellulose samples[2].Allowance shouldbe madefor the existenceincellulose of tworegions ofunequal accessibility to reactants.The“amorphous”regionis more or less freely accessible to all the con-stituents of the nitrating bath,and hydroxyl groupshere are esterified without any… 相似文献
105.
胶合板缺陷模糊神经网络检测算法 总被引:3,自引:2,他引:3
讨论了模糊逻辑和神经网络的工作原理,笔者在神经网络中引入模糊逻辑算法,将模糊逻辑处理不精确不完备信息的能力和神经网络的自适应自学习能力相结合,提出一种模糊神经网络算法,构建出模糊神经网络分类器,并且以胶合板缺陷检测为应用背景,对其分类的实时性、准确率等指标进行了验证,得到了分类精度93 33%,和训练次数5856次的良好性能.实验结果表明:在引入模糊逻辑算法后,基于模糊逻辑的神经网络分类器在模式分类精度和实时性等方面性能指标都得到了提高. 相似文献
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108.
Tuomas Alapieti Emmanuelle Castagnoli Laura Salo Raimo Mikkola Pertti Pasanen Heidi Salonen 《Indoor air》2021,31(5):1563-1576
The emissions of volatile organic compounds (VOCs) from building materials may significantly contribute to indoor air pollution, and VOCs have been associated with odor annoyance and adverse health effects. Wood materials together with coatings are commonly used indoors for furniture and large surfaces such as walls, floors, and ceilings. This leads to high surface-to-volume ratios, and therefore, these materials may participate remarkably to the VOC levels of indoor environment. We studied emissions of VOCs and carbonyl compounds from pinewood (Pinus sylvestris) boards of 10% and 16% moisture contents (MC) with three paints using small-scale test chambers (27 L). The emissions from uncoated pinewood and paints (on a glass substrate) were tested as references. The 28-day experiment showed that the VOC emissions from uncoated pinewood were lower from sample with 16% MC. Painted pinewood samples showed lower emissions compared to paints on glass substrate. Additionally, paints on 16% MC pinewood exhibited lower emissions than on drier 10% MC wood. The emissions from painted pinewood samples were dominated by paint-based compounds, but the share of wood-based compounds increased over time. However, we noticed differences between the paints, and wood-based emissions were clearly higher with the most permeable paint. 相似文献
109.
Dairy cattle managed in some pasture-based systems such as in New Zealand are predominantly kept outdoors all year around, but are often taken off pasture for periods of time in wet weather to avoid soil damage. It is common to keep cattle on concrete surfaces during such “stand-off” practices and we investigated whether the addition of rubber matting onto concrete areas improves the welfare of dairy cattle. Sixteen groups of 5 cows (4 groups/treatment, 5 cows/group) were allocated to 1 of 4 treatments (concrete, 12-mm-thick rubber mat, 24-mm-thick rubber mat, or deep-bedded wood chips) and kept on these surfaces for 18 h/24 h for 4 consecutive days (6 h on pasture/24 h). Each 4-d stand-off period was repeated 4 times (with 7 d of recovery between periods) to study the accumulated effects of repeated stand-off. Lying behavior was recorded continuously during the experiment. Gait score, stride length, hygiene score, live weight, and blood samples for cortisol analysis were recorded immediately before and after each stand-off period. Cows on wood chips spent the most time lying, and cows on concrete spent the least time lying compared with those on other surfaces [wood chips: 10.8 h, 24-mm rubber mat: 7.3 h, 12-mm rubber mat: 6.0 h, and concrete: 2.8 h/18 h, standard error of the difference (SED): 0.71 h]. Cows on concrete spent more time lying during the 6 h on pasture, likely compensating for the reduced lying during the stand-off period. Similarly, cows on concrete spent more time lying on pasture between stand-off periods (concrete: 12.1 h, 12-mm rubber mat: 11.1 h, 24-mm rubber mat: 11.2 h, and wood chips: 10.7 h/24 h, SED: 0.28 h). Cows on concrete had higher gait score and shorter stride length after the 4-d stand-off period compared with cows on the other surface types, suggesting a change in gait pattern caused by discomfort. Cows on rubber mats were almost 3 times dirtier than cows on concrete or wood chips. Cortisol and live weight decreased for all treatment groups during the stand-off period. We observed no major effect of the repeated stand-off exposure. In summary, adding rubber matting onto concrete surfaces for stand-off purposes is beneficial for animal welfare. A well-managed wood chip surface offered the best welfare for dairy cows removed from pasture, and the findings of this study confirm that a concrete surface decreases the welfare of cows removed from pasture. 相似文献
110.
ABSTRACTNostoc sphaeroides Kützing (N. sphaeroides) is a kind of edible algae widely growing in China. The paper is aimed at developing a novel snack food of N. sphaeroides using vacuum impregnation. The samples from freeze drying (FD) have large volume and loose structure, which were found suitable for processing. With nuclear magnetic resonance and imaging, the water signal of N. sphaeroides was measured in FD, and different drying-stage raw N. sphaeroides were selected to impregnate by different solutions, when the products’ impregnated mass, water activity, and flavor difference were analyzed. Results indicate that the water distribution in FD was uniform. Sucrose impregnated product was stable with large impregnated mass and low water activity, whereas trehalose impregnated product was easy to separate from the solution with low sweetness. For the products with the raw N. sphaeroides dried for 9 and 12?h, no obvious difference was found in water activity and flavor. Result shows that N. sphaeroides dehydrated for 9?h in FD is suitable for vacuum impregnation, and different impregnated products are acceptable from the point of view of flavor and storage stability. 相似文献