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71.
华治国 《混凝土与水泥制品》2020,(6):70-72
选择了几份典型的外墙外保温系统标准,通过对这几份标准中胶粘剂和抹面胶浆的成型和检测方法的比较,分析了现有检测技术的优劣,并结合工作实践提出了建议。 相似文献
72.
Muhammad Tuseef Asghar Yus Aniza Yusof Mohd Noriznan Mohammad Effendy Yaacob Hasanah Mohd Ghazali Lee Sin Chang Yanty Noorzianna Manaf 《International Journal of Food Science & Technology》2020,55(7):2762-2770
Coconut (Cocos nucifera L.) sugar is a more nutritious alternative sugar source as compared to sugar palm (Borassus flabellifer) and sugarcane (Saccharum officinarum L.). This work was aimed to investigate the browning index (BI), vitamin profile and antioxidant properties of coconut sap sugar syrups, which were produced by different processing methods: rotary evaporation (RE), microwave evaporation (ME) and open-heat evaporation (OHE). The results obtained showed that coconut sugar syrup produced by RE-60 contained high antioxidant activities [DPPH (36.71%) and ABTS (34.84%), TPC (299.87 mg per 100 g sample) and FRAP (3.74 mm )]. These values were slightly lower than those of ME and OHE. Coconut sugar syrup (RE-60) also contained higher amounts of vitamin C (1587.27 mg L−1), vitamin B1 (97.44 mg L−1) and vitamin B3 (19.84 mg L−1) compared with those of ME and OHE coconut sugar syrups. RE-60 was the best method to produce coconut sugar syrup in a shorter time with lower browning index and higher vitamin contents. 相似文献
73.
74.
《Ceramics International》2020,46(1):768-774
The construction of three dimensional macroporous architectures holds exciting implications for applications such as catalysis, sensing, tissue engineering and thermal insulation. Here, we report a general self-assembly process for inorganic sponges with hierarchical porosity of intrafibre micro-/meso-/macropores and interfibre macropores. The as-fabricated SiO2-TiO2 sponge possesses a high porosity of >99.86%, ultralow bulk density of 2.9 mg cm−3 and enhanced compressibility (recovery from 50% compression). The self-assembly mechanism of the SiO2-TiO2 sponge has been investigated in detail. The results confirmed that the hydrolysis and polycondensation of mixed inorganic alkoxides could affect the solidification process and the charge transpote during electrospinning, and plays an essential role on the hierarchical porosity and the self-assembly of the sponge macro-structure. The concerted effects of the solidification and electrostatic repulsion between fibres are responsible for the self-assembly process of the electrospun PVP-SiO2-TiO2 sponge. When used as a thermal insulation material, the SiO2-TiO2 sponge shows good fireproof performances. The current contribution may guide more construction of functional inorganic macroporous architectures for advance applications in future. 相似文献
75.
Tadeusz Zając Agnieszka Klimek-Kopyra Ryszard Mazurek Andrzej Oleksy Jacek Strojny 《Journal of Natural Fibers》2020,17(8):1199-1211
ABSTRACT Nine sowing densities of linseed were compared in a two-year experiment. Self-regulation of the density of a linseed stand resulted in a differentiated branching of the plants. The number of capsules on a linseed shoot, as well as seeds in the capsule, and the number of seeds from the shoot were highly varied from year to year, and there is even a stronger differentiation in the weight of 1000 seeds. Linear relationships were noted between the mass of seeds from the linseed plant and the number of capsules. The yield of linseed was affected by both factors. An increasing sowing rate reduced the seed yield from the shoot and the plant. At lower seeding rates, the lateral shoots contributed in the seeds yield of the plant to a higher degree compared to the main ones. 相似文献
76.
Shahriar Ghaffari Mosanenzadeh Mohammed Alshrah Zia Saadatnia Chul B. Park Hani E. Naguib 《大分子材料与工程》2020,305(4)
Aerogels owe their high thermal insulation and other unique properties to their nanostructure configuration. However, controlling the aerogels' morphology is always a scientific challenge. In this study, double dianhydride backbone (double backbone) polyimide aerogels with tailored nanostructure assembly are created for the first time. This is achieved by controlled polymerization reaction of oligomers with distinct dianhydride monomers. Combining the two oligomers through a controlled polymerization reaction is a successful strategy for tailoring the aerogels nanostructure assembly as well as other properties. The fabricated double backbone aerogel presents 40% reduced thermal conductivity of 19.7 mW mK?1 over previously studied polyimide aerogels along with the compression modulus of 1.64 MPa at a relatively low density of 0.068 g cm?3. Such low thermal conductivity is comparable with the inorganic counterparts. Light in weight and high thermally insulated polyimide aerogels with suitable mechanical properties and high service temperature are an appropriate replacement for current fireproof insulation materials. 相似文献
77.
高折射率和非线性光学玻璃可以用于高速光开关、光学存储器、新型光纤和光学运算元件等,其研究受到各国科技工作者的高度重视,本文采用熔融淬冷法制备了组成为(85-x)B2O3-15K2O-xSb2O3(x=70, 75, 80, 85)的4组玻璃,测试了玻璃样品的密度、折射率、热学性能、拉曼光谱和吸收光谱,利用玻璃样品的吸收光谱计算了其直接允许光学带隙、间接允许光学带隙及Urbach能量。结果表明:随着Sb2O3含量的增加,玻璃样品的密度从4.445g/cm3逐渐增加到4.767g/cm3,折射率从1.9438增加到2.0058,玻璃转变温度从291℃降低到260℃,玻璃析晶温度从463℃降低到370℃,直接光学带隙从3.2775eV降低到3.1379eV,间接光学带隙从3.1444eV降低到3.0256eV,Urbach能量从0.137eV逐渐减小到0.107eV。说明Sb2O3-K2O-B2O3系统玻璃可以作为新型的非线性光学玻璃候选材料之一。 相似文献
78.
由于对置受限式撞击流反应器较高的传热及混合效率,能够制备出粒径小、均匀且分布范围窄的超细颗粒。本文采用碘化物-碘酸盐平行竞争反应体系研究入射速度、结构尺寸对对置受限式撞击流反应器微观混合效果的影响规律,并将混合腔尺寸同等比例放大一倍进行对比研究。结果表明,随着入射速度的增大,离集指数减小,微观混合效果提高。喷嘴间距与喷嘴直径比的增大使得离集指数增大,微观混合效果降低。离集指数随着混合腔高度、混合腔出口尺寸的增大呈现先增大后减小的趋势,且混合腔高度对混合效果的影响较混合腔出口尺寸显著。将对置受限式撞击流反应器混合腔尺寸扩大一倍,离集指数增加到原来的2.4倍,微观混合效果显著下降,但是在较大入射速度下,两种结构的混合效果差距减小。研究结果可为纳米复合含能材料的制备提供高效、安全的技术支持。 相似文献
79.
80.
Serena Finco Daria Battini Xavier Delorme Alessandro Persona Fabio Sgarbossa 《国际生产研究杂志》2020,58(4):1255-1270
Ergonomic aspects have a crucial role in manual assembly systems. They impact on the workers’ health, final product quality and productivity. For these reasons, there is the necessity to integrate them into the assembly line balancing phase as, whereas, only time and cost variables are considered. In this study, human energy expenditures are considered as ergonomic aspects and we integrate them, for the first time, into the assembly line balancing problem type 2 through the rest allowance evaluation. We consider as an objective function the minimization of the smoothness index. Firstly, a new optimal method based on mixed integer linear programming and a new linearization methodology are proposed. Then, a heuristic approach is introduced. To complete the study, a computational experimentation is presented to validate the mathematical model and to compare the methodologies proposed in terms of computational time, complexity and solution. Additionally, we provide a detailed analysis of the impact that rest allowance evaluation can have on productivity comparing the results obtained, taking into account the rest allowance integration before, during and after the assembly balancing process. 相似文献