龙骨间距对三层实木复合体育木地板运动功能性能的影响

以三层实木复合体育馆用木地板为研究对象,研究测试位置和地板铺装时的龙骨间距对其运动功能性能测试结果的影响。结果表明:测试位置对测试结果有着显著影响,减震垫处的标准垂直变形量和冲击吸收率最小,两列龙骨中间位置的性能测试值最大;随着龙骨间距的增加,标准垂直变形、相对垂直变形率和冲击吸收率呈增加趋势,本试验中最优龙骨间距为440 mm。     

稻壳酶解制备还原糖的研究

用木聚糖酶酶解稻壳,首先对稻壳的酶解影响因素做单因素试验,然后做响应面试验,最终得到最佳参数条件是:温度为50.00℃,加酶量为10.20%,pH值为4.00,时间为20.00h,所得的酶解率为8.02%.对酶解率影响较为显著的单因素为pH值和时间.温度和加酶量的交互作用、温度和时间的交互作用对酶解率的预测结果有显著影响.     

微波对苦瓜叶绿素的影响

采用响应面分析法研究不同微波处理条件下苦瓜叶绿素含量的变化并建立相应的回归模型.结果表明,微波功率、微波处理时间对苦瓜叶绿素的影响达到极显著水平,而切片厚度和载样量影响则不明显.各因素的影响大小排列如下:微波功率、微波处理时间、切片厚度、载样量.各因素间交互作用分析表明,微波功率与微波处理时间、微波处理时间与载样量之间存在着一定的交互作用;微波功率与苦瓜切片厚度、微波功率与载样量、微波处理时间与切片厚度、切片厚度与载样量之间交互作用不明显.     

预打孔卷烟接装纸施胶效果及胶辊设计参数对通风率的影响

为考察预打孔卷烟接装纸施胶效果对通风率的影响,建立了一种接装纸施胶效果评价及无胶区偏移时的优化调整方法,在无胶区处于理想状态下利用正交试验研究了无胶区长度、宽度以及施胶厚度对通风率的影响。结果表明:(1)对预打孔卷烟通风率的影响依次为无胶区长度、宽度和施胶厚度,无胶区长度对通风率的影响达到显著水平。(2)随着无胶区长度的增加,预打孔卷烟通风率均值呈上升趋势,通风率变异系数呈下降趋势。(3)根据试验结果可确定"黄山(B)"牌号卷烟最佳胶辊参数组合为无胶区长度22mm,宽度8mm,施胶厚度0.03mm。该方法为提高预打孔卷烟通风率的稳定性提供了技术支持。     

微波膨胀烟梗二次切丝工艺参数研究

为研究微波膨胀烟梗二次切丝工艺参数对微波膨胀梗丝品质的影响,采用均匀实验设计法分析了不同切片厚度、切丝宽度组合对微波膨胀梗丝填充值、梗丝耐加工性、感官质量的影响,在此基础上建立了切丝参数组合对梗丝品质影响的回归方程,并进行了外部验证。结果表明:1整丝率、填充值与切片厚度、切丝宽度极显著正相关;碎丝率与切片厚度、切丝宽度极显著负相关;2切片厚度相同时,感官质量随切丝宽度的增加而降低;切丝宽度相同时,随切片厚度的增加,感官质量得分先增加后降低;3切片厚度范围0.75~0.85 mm、切丝宽度范围0.30~0.35 mm时,微波膨胀梗丝的综合品质最优。      

胚芽米微波灭酶工艺

以胚芽米为原料,采用单因素试验及响应面分析研究微波处理对胚芽米脂肪酶灭活率的影响。结果表明:微波辐射具有较好的灭活脂肪酶的作用,其灭活效果受胚芽米初始水分质量分数、微波剂量、微波时间以及物料厚度等因素的影响,各因素间均有显著的交互作用。微波灭酶的最佳条件是:初始水分质量分数为16%;微波剂量为2.0 kW/kg;微波时间为2.6 min;物料厚度为3.3 cm;在此条件下胚芽米脂肪酶灭活率为68.12%。微波处理后对胚芽米主要指标没有明显影响。     

载亚硒酸钠壳聚糖微球的制备、表征及缓释性能研究

采用壳聚糖为壁材、乳化交联法制备载亚硒酸钠微球。以微球形貌、包封率、载药量和缓释性能为指标,通过单因素及正交试验优化制备工艺条件,并用SEM扫描电镜、红外、原子荧光、TG热重等分析手段对微球粒径外观和结构性能进行表征。以自配的SBF模拟体液为体外环境,研究微球缓释硒的性能。结果显示,制备微球的最佳工艺条件为温度65℃,壳聚糖浓度3%,亚硒酸钠浓度0. 8%,交联剂用量15%,该条件下的微球形貌优良,包封率和载药量分别为65. 89%,5. 05%,微球平均粒径为10μm;体外缓释试验表明,通过改变相关变量因素水平,可调控球壁厚度和交联度是影响释放速率的关键因素,实现载硒微球硒的可控缓释;最佳工艺制备的微球具有较好的长效缓释能力,缓释速率在482 h后达平稳,有效缓释时间达35 d。壳聚糖载硒微球能有效避免硒的突释效应,可为缺硒群体的科学补硒提供新途径。     

人机界面特征对按摩椅腰部揉捏按摩效应的影响研究

探究人机界面因素影响按摩效应规律,为按摩椅腰部揉捏按摩效应的优化设计提供参考依据。运用酸胀度评价、正交试验和温度试验,分析按摩头形状、按摩头大小和按摩器包覆层厚度等人机界面特征因素对腰部揉捏按摩效应的作用原理,阐释各影响因素的主次顺序及交互作用规律,探寻人机界面各因素的优化参数。人机界面各因素不同水平对按摩效应的影响差异性均显著,按摩头形状是影响揉捏按摩效应的最主要因素,按摩器包覆层厚度影响按摩效应相对最小。     

多因子交互作用对鞋子止滑性能影响的研究

选择4种鞋底材料、4种地面、4种污染物和5种花纹沟槽设计,进行了4因素3重复试验,测定鞋底的摩擦系数COF值.结果表明:各因素之间的交互作用(P<0.0001)都会显著地影响COF值.在受水、水和清洁剂混合污染的大理石地面,较大花纹宽度的PU鞋底具有较好的防滑性能(COF>0.7).受油污染的大理石地面,1.2 cm沟槽宽度的EVA和PU鞋底具有较好的止滑性;在水和清洁剂混合污染的地面,1.2 cm花纹宽度的PU鞋底的COF值最高;在油污染的水泥地面,1.2 cm花纹宽度的EVA鞋底的COF值最高.     

超临界CO_2萃取生姜油的模型方程和条件优化

优化超临界CO2萃取生姜油的工艺条件,提高生姜油的萃取率.以生姜油萃取率为响应值,利用单因素试验、正交试验、回归分析和响应面分析法对超临界CO2萃取生姜油的工艺条件进行系统研究.建立对萃取率可以进行较好预测的数学模型方程,证明影响萃取率的各主要因素间存在不同大小的交互作用,得到了生姜油超临界CO2萃取的最佳工艺条件:萃取压力29MPa;萃取温度50℃;萃取时间180min;解析压力5.6MPa;解析温度36℃.最佳工艺条件下生姜油萃取率为:7.461%.     

Experimental assessment of participating width of wood floor sheathing subjected to concentrated load: case study of OSB

An equation for the participating width (elastic) of one-way orthotropic wood joist floor sheathing subjected to concentrated loading has been recently developed. The participating width is the length of sheathing normal to the span or parallel to the joists that is structurally involved in supporting the concentrated load. In this paper, the participating widths of 18-mm thick one-way simply supported oriented strand board sheathings with spans of 300 mm and 600 mm (span–thickness ratios of 16.7 and 33.3, respectively), determined by laboratory tests are reported. The experimentally determined participating widths appear consistent with the analytically predicted participating widths of the sheathings. In addition, it has been shown that the participating width in the linear elastic stage of behaviour is roughly equal to the participating width near maximum load. Subject to experimental validation by other types, thicknesses and spans of sheathing, the analytically derived participating-width equation is recommended in modelling wood joist floor sheathing for concentrated load performance assessment.     

覆膜间隔时间和墨层厚度对预涂膜覆膜质量的影响

为研究印刷后到覆膜的间隔时间及墨层厚度对预涂膜覆膜质量的影响,得到最佳的覆膜间隔时间和合适的墨层厚度参数,采用IGT印刷适性仪在一定印刷条件下打样,在相同的覆膜工艺条件下,对不同间隔时间的印刷样张进行覆膜;改变印刷墨层厚度进行打样,在相同的覆膜工艺条件下,对不同墨层厚度的样张进行覆膜,分别测试上述两种条件下,各样张的剥离强度,探讨了覆膜间隔时间和墨层厚度对预涂膜复合质量的影响。结果表明,覆膜印品的剥离强度与覆膜间隔时间和墨层厚度有关。在现有实验条件下,最佳覆膜间隔时间为48h左右,合适的墨层厚度为1～2μm。     

Praktische Erfahrungen bei der Prüfung des Biegeverhaltens dünner Spanplatten

The influence of several parameters on bending properties of thin particle boards was investigated basing on proposals in literature and standards. Varied parameters were thickness (3.2 mm; 4.5 mm; 6.5 mm), relation between the distance of supports and thickness (20, 24, 30), diameter of the bearing rolls and load rolls (8 mm; 12.5 mm) and width of test pieces (50 mm; 75 mm; 100 mm). As testprogram was selected a multifactoral two-step-test plan with an additional central-composite-plan. The results were submitted to a multiple regression analysis with target bending strength and modulus of elasticity in bending. For most of the investigated parameters a significant influence could be proved on the set values and the determined bending properties within the individual thickness as well as the total range of thickness.     

羽绒制品热传递的有限元仿真

针对现有羽绒制品保暖性测试方法的测试时间较长、成本较高等不足,提出一种数值模拟测试方法。采用ANSYS有限元软件建立“羽绒-织物-皮肤”的三维几何模型,模拟分析不同织物、不同填充密度、不同绗缝数量条件下模型内部与外表面的温度分布特征,探究不同条件对热量沿厚度方向和宽度方向传递的影响,计算其保暖性,并进行实验验证。结果表明:羽绒填充密度增加,热量沿模型厚度方向的传递距离增大,外表面温度及热流密度减小;绗缝数量增加,热量沿模型厚度方向的传递增大,沿模型宽度方向的传递距离减小,外表面温度及热流密度逐渐增大;织物对羽绒制品保暖性的影响较小;模拟结果与实验结果的最大相对误差为4.79%,二者吻合度较好。     

基于水果包装的可发性聚乙烯结构缓冲性能研究

目的研究可发性聚乙烯水果缓冲包装结构性能。方法以中小尺寸水果包装的圆型结构和方型结构为基础,进行静载实验和跌落冲击实验,分析可发性聚乙烯结构在相关尺寸变化时的缓冲性能。结果随着厚度和宽度的增加,单元结构的载荷逐渐增大,加速度峰值逐渐降低,当宽高比在0.15～0.2变化时,结构的载荷净增值趋于平稳,载荷增长稳定,且圆型结构的承载能力和抗冲击能力均优于方型结构。结论在水果的缓冲包装中,合理设计结构的几何尺寸,更好的发挥材料的缓冲性能,提高结构的缓冲能力和材料利用率,实现缓冲结构的保护功能。     

Effect of muscle location, fiber direction, and slice thickness on the processing characteristics and tenderness of beef stir-fry strips from the round and chuck

The objective was to assess different beef muscles for use as stir-fry. Inside round, outside round, eye of round, knuckle, chuck clod, and chuck tender were obtained from six beef carcasses. Different slice thickness (2, 4, or 8 mm) and muscle fiber direction were evaluated. Slices were cooked from frozen on a flat grill and then cut into strips for shear and sensory testing. While meat cut had little effect on shear values of these thin slices, increasing slice thickness greatly affected tenderness and cook yield. The sensory panel found that strips from the knuckle were more tender and juicy, with less connective tissue and with a better flavor than that of slices from the eye of round and outside round. Increasing slice thickness resulted in detection of greater amounts of connective tissue but did not result in a significant difference in the perception of tenderness. Fiber direction was also of importance. Slices removed perpendicular to the fiber direction had shear values up to 50% lower than slices removed parallel.     

干燥条件对挂面干燥脱水过程的影响

为了解烘房内干燥介质条件(温度、相对湿度和气体流速)对挂面干燥脱水速率的影响,以及脱水速率在厚度相同,宽度不同(1 mm、2 mm和3 mm)挂面间的差异,本研究以某挂面生产企业5排60 m隧道式烘房生产线为研究对象,利用多功能便携式气候仪(Kestrel-4500),在线监测挂面干燥过程中干燥介质的温度、相对湿度和风速,每种条形挂面采集12班次(重复),在动态监测挂面干燥介质条件参数的同时,测定挂面在隧道式烘房1 m、15 m、30 m、45 m、59 m干燥距离处的含水率,分析各因素对挂面干燥脱水速率的影响。结果表明,采用基本相同的干燥工艺干燥厚度相同、宽度为1、2、3 mm的挂面,脱水速率之间无显著差异;影响挂面干燥脱水量的主要因素是相对湿度,其次是温度和风速;干燥介质各因素对挂面干燥脱水量的影响大于相同厚度、不同宽窄条形对挂面干燥脱水速率的影响。     

滚筒复烤方式下不同尺寸烟片的干燥与收缩特性对比分析

以贵州C3F、河南C3F、河南B3F 3种烟叶为原料,利用实验室批式滚筒复合传热干燥装置进行试验。结果表明:滚筒复烤方式下,同种烟叶烟片尺寸规格的变化对其干燥速率和复烤后温度无明显影响。网孔12.70 mm以上的筛分烟片,烤后225~625 mm 2的叶片比例增加明显;网孔6.35~12.70 mm的筛分烟片,烤后36~225 mm 2的叶片比例增加明显。复烤后烟片总体尺寸分布在225~625 mm 2和36~225 mm 2面积区间呈集中趋势。烟片尺寸规格对滚筒复烤皱缩率影响显著,3种烟叶原料烤后烟片的皱缩率均随尺寸规格的增大呈明显上升趋势。     

Effect of engine load on diesel soot particles

This study concentrates on characterization of nonvolatile fraction of diesel particles. These particles have an impact on earth's radiation balance as well as on health effects of vehicle emissions. In addition to composition and size distribution of particles, an important factor affecting their health effects and properties and lifetimes in the atmosphere is their morphology. The effect of engine parameters on soot particle size distributions and also on particle morphology has been studied. It was found that the shape of the size distribution and also the structure of diesel particles depend on engine load. The number distributions were found to obey log-normal assumption. The width of the distribution increased with increasing engine load. The geometric standard deviations of measured distributions varied from 1.7 to 2.1. Simultaneously, the fractal dimension of particles decreased with increasing engine load. The values for mass fractal dimensions based on sealing of particle mass and mobility size were between 2.6 and 2.8. Both electron microscopy and measurements of aerodynamic size versus mobility size suggest that the morphology of particles in different size regimes vary, with the large particles being less compact than the small ones.