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1.
Huang J.  Ni D.  Ni X.  Chen W.  Fu Y. 《丝绸》2022,(12):187-196
Silk is a kind of natural fiber with good luster strength elasticity dyeability hygroscopicity and other advantages. Silk products are quite popular to the customers because of their excellent performance such as heat preservation air permeability and so on which make them comfortable to use. Silk floss which is made from pupa lining secondary cocoon etc. can be used as floc and filler materials and is an important part of silk products. According to its production mode silk floss can be divided into manual silk floss and machine-made silk floss and the latter has become the main processing mode of silk floss production due to its high production efficiency. In terms of composition silk flossing generally contains 20% - 30% sericin pupa oil and impurities so in the degumming process in addition to adding sodium carbonate and other degumming agents to remove sericin a large amount of hydrogen peroxide with strong oxidation property is also used to increase the cleanliness and smoothness. Unfortunately hydrogen peroxide is highly flammable and explosive and poses a risk in transportation and storage causing potential safety hazards to the silk processing industry. In order to solve this problem we innovatively propose two hydrogen peroxide-free processing methods of machine-made silk floss by using sodium percarbonate degumming or sodium carbonate-ozone. As an environmentally friendly solid oxidant sodium percarbonate can produce hydrogen peroxide and sodium carbonate after decomposition and is often used to degrade organic harmful substances. Similarly ozone is a common strong oxidant with broad-spectrum antibacterial properties and because ozone can be produced instantly by ozone generators there is no risk of transport and storage. Silk is composed of silk fibroin and sericin. Among them silk fibroin is fibrous protein which will swell in hot water while sericin is globular protein which is easy to dissolve in hot water. As a result in this paper heated sodium percarbonate solution and sodium carbonate-ozone system were used to deglue silk floss. The methods were as follows silk floss was degummed three times in boiling 0. 78 g / L sodium percarbonate solution for 30 minutes each time or was degummed three times in boiled 0. 5 g / L Na2 CO3 solution with ozone continuously flow at a rate of 100 mg / L - h for 30 minutes each time. After cleaning and drying the degummed silk floss can be obtained. After the experiment the apparent morphology sericin residual efficiency impurity rate compression resilience whiteness and other silk floss quality indexes of the two methods were analyzed and compared with superior machine-made silk floss processed by commercial way with hydrogen peroxide. The results show that both two processing methods got uniform degumming effect of silk floss and the surface of the single fiber was smooth and the degumming effect was basically the same as that of commercial products prepared with hydrogen peroxide. The sericin residual rate of silk floss was between 3% - 4% which was in line with the requirements of less than 5% of superior silk floss. There was no significant difference between silk floss obtained and commercial superior products in smoothness and whiteness. In conclusion the performance of silk floss in all aspects has reached the standard of superior products that is the sericin content is not more than 5% the impurity content is not more than 0. 1% the compression rate is not less than 45% and the response rate is not less than 92% . Based on the experimental results and analysis it can be concluded that the machine-made silk floss with good performance can be prepared without hydrogen peroxide showing the feasibility of processing machine-made silk floss without hydrogen peroxide which is of great significance to the research and development of a safe and reliable oxidant system for the removal of impurities in silk floss and to further improve the safety of machine-made silk floss production process. © 2022 China Silk Association. All rights reserved.  相似文献   
2.
试验以实验室保藏的6株乳酸菌为研究对象,筛选出最佳试验条件下富硒率和产胞外多糖含量最优的菌株,以期为生产富硒调味品提供一定的理论依据。通过测定其生长曲线确定各菌的加硒时间,对比6株乳酸菌在不同亚硒酸钠质量浓度下的颜色变化、富硒率变化和胞外多糖含量变化,选定鼠李糖乳杆菌作为最佳试验菌株;通过测定鼠李糖乳杆菌在不同培养时间、培养温度、接种量、亚硒酸钠含量条件下富硒率和产胞外多糖含量的变化,通过此单因素试验确定了正交试验的因素及水平,由正交试验结果得到最佳试验条件。结果表明,培养时间24 h、接菌量5%、亚硒酸钠质量浓度12.5μg/mL、培养温度37℃的条件下,鼠李糖乳杆菌的富硒率为79.21%,胞外多糖含量为51.47μg/mL。  相似文献   
3.
针对新疆阜康冶炼厂造锍捕集所得贵金属合金,通过硫酸化焙烧和水淬所得渣,采用亚硫酸钠溶液浸出法对其中的银开展湿法提取试验考察。本文系统考察了固液比(20g/l~400g/l)、亚硫酸钠浓度(50g/l~200g/l)、pH(6.5-10.5)、浸出时间(30min~720min)、粒径(0.425mm、0.25mm和0.18mm)以及浸出温度(25℃、50℃和75℃)对银的浸出率的影响。银的最优浸出条件为,固液比200g/l,亚硫酸钠150g/l,pH为7.5,浸出时间120min,浸出温度20℃,在此条件下,可以高效提取渣中的银,浸出率为93.66%。  相似文献   
4.
5.
Konjac glucomannan/sodium alginate composite edible boba (KGM/SA-boba) with good taste is very popular in China, and it is an outstanding carrier for health potential ingredients. In this work, KGM/SA-boba were fortified with 0.25, 0.50, 0.75 and 1.00% purple sweet potato anthocyanin (PSPA), then characterised by the water distribution, texture, microstructure, in vitro release property of PSPA and antioxidant capacity. LF-NMR analysis demonstrated that the free water of KGM/SA-boba could transfer to tightly bound water with the addition of PSPA that made it with better water-binding ability, higher springiness and lower hardness. And the results of SEM and rheology showed that PSPA could stabilise the microstructure of KGM/SA-boba by forming more amorphous regions and hydrogen bonds proved by the results of DSC and FT-IR. Furthermore, 50% of PSPA in PSPA-fortified KGM/SA-boba can be released at the first hour in a simulated gastrointestinal environment. And the scavenging capacity of DPPH and ABTS of the PSPA-fortified KGM/SA-boba after digestion was higher than that of PSPA alone. Generally, PSPA could improve the texture while KGM/SA-boba in turn would make PSPA more stable in the gastrointestinal digestive system.  相似文献   
6.
通过自组装方法制备了十聚甘油单油酸酯(DGMO)与酪蛋白酸钠(NaCas)的复合物,以粒径、PDI和Zeta-电位为评价指标,探究了两者质量比对NaCas-DGMO复合物的影响,并通过荧光光谱、紫外-可见分光光度计、傅里叶红外光谱对复合物进行表征,同时考察了NaCas-DGMO复合物的pH值、盐离子耐受性及米糠油水包油乳液乳化性质。结果表明:NaCas与DGMO质量比1:2、80 ℃反应1 h能获得稳定复合物,粒径为238.10 nm,PDI为0.27;浊度实验表明NaCas-DGMO复合物能稳定存在,荧光光谱和FT-IR表明NaCas与DGMO通过疏水相互作用结合,同时两者相互作用导致NaCas的表面疏水性增强(319.46增至596.45);NaCas-DGMO复合物更耐酸和盐离子变化;NaCas-DGMO复合物具有优异的稳定水包油(O/W)乳液性质,能在油滴表面形成稳定的界面层,防止油滴凝聚。构建的O/W乳液包封柠檬醛后具有很好稳定性,粒径为208~225 nm,PDI为0.18~0.27,储存28 d柠檬醛保留率达78.83%,能实现对柠檬醛的有效保护。因此,NaCas-DGMO复合物不仅能有效稳定O/W乳液,更能将O/W乳液应用于脂溶性活性物质的良好递送载体。  相似文献   
7.
吴章海 《冶金分析》2022,42(4):57-63
准确、快速地测定含铁尘泥中有害元素,对含铁尘泥节能降废项目研究及综合利用有着重要的指导意义。实验针对含铁尘泥试样因含碳量高,导致常规酸溶解方法如果不增加除碳步骤则很难完全分解试样的问题,采用高温熔融法将试样制成熔融液后倾倒于稀酸中溶解的方法,解决了碳含量高难溶解的问题。采用四硼酸锂-碳酸锂混合熔剂在高温下将试样熔融,熔融液高温倾倒于稀酸中制成澄清溶液,由于骤冷,试样炸裂成微小玻璃珠,无迸溅,操作简单,使得后续溶解过程快速完成,从而建立了电感耦合等离子体原子发射光谱(ICP-AES)测定P、Pb、K、Na、Zn共5种有害元素的方法。按照实验方法测定含铁尘泥中P、Pb、K、Na、Zn,测定值的相对标准偏差(RSD,n=9)在1.4%~5.7%之间,加标回收率在96%~110%之间。研究结果表明方法能够满足含铁尘泥样品中5种元素的定量分析要求。  相似文献   
8.
梁钪  郑松波  高颂  张涛  张艳 《冶金分析》2022,42(10):16-23
准确测定粉末高温合金中微量及痕量元素,对粉末高温合金的生产、应用具有重要意义。将样品在放电电流40~45 mA,放电电压1 100~1 200 V,氩气流速400~450 mL/min下进行辉光放电激发,选择合适的同位素和分辨率以消除质谱干扰,使用基体匹配的内控标准样品和标准物质校准各待测元素的相对灵敏度因子(RSF),实现了高流速高分辨辉光放电质谱法(GDMS)对粉末高温合金中硼、钠、镁等26种微量及痕量元素的测定。采用实验方法对粉末高温合金内控样品中26种微量及痕量元素进行测定,各待测元素的测定值与参考值基本一致,测定结果的RSD(n=6)在0.9%~15.4%之间。采用实验方法对粉末高温合金样品进行测定,测定结果分别与电感耦合等离子体原子发射光谱法(ICP-AES)测定硼、铁和锆,高频感应燃烧红外吸收法测定硫,原子荧光光谱法测定硒,高分辨电感耦合等离子体质谱法(HR-ICP-MS)测定其余元素(钠、镁、硅、磷、钙、钒、锰、铜、镓、砷、银、锡、锑、碲、镧、铈、铪、钽、铊、铅和铋)的结果保持一致,测定结果的RSD(n=6)在0.2%~26.6%之间。  相似文献   
9.
江西某石英型萤石矿,其中大部分萤石与石英紧密连生,造成单体解离困难,从而影响矿物选别指标。化学多元素分析结果表明,矿石中CaF2品位为67.86%,SiO2、CaO、Al2O3含量较高,分别为19.04%、5.91%和3.32%。这表明矿石中脉石以石英和硅酸盐矿物为主,其他成分含量较少。本文探究了油酸钠(NaOl)和叔十二烷基硫醇(TDM)组合捕收剂对该石英型萤石矿的浮选效果,并对捕收剂进行了表面张力测定。浮选结果表明,组合捕收剂在矿浆pH为9.5,油酸钠和叔十二烷基硫醇摩尔比为8:2时,对萤石的浮选指标最好,通过1粗4精3扫全闭路浮选流程可获得CaF2品位为94.06%,回收率为99.55%的高品级萤石精矿。捕收剂的表面张力测试表明,组合捕收剂的CMC值略小于油酸钠,且在气—液界面的分子排列紧密度高于油酸钠。因此,相比于油酸钠来说,组合捕收剂可以更好的改变矿物表面的疏水能力。上述研究成果可为嵌布粒度细的石英型萤石矿的有效回收利用提供技术支持。  相似文献   
10.
The mechanics of glass-ceramics subjected to sharp contact or other loading conditions remain elusive, even after being commercialized in many industrial applications. We present work herein to reveal atomic details of such deformations that are otherwise extremely difficult to probe experimentally for a lithium disilicate (LS2) and β-quartz containing glass-ceramics via molecular dynamics simulations. Specifically, the materials are comprised of LS2 and β-quartz nanocrystals in a residual glass matrix. Regardless of the deformation mechanism, whether it be nanoindentation or crack propagation for samples with pre-existing flaws, we observe that the LS2 nanocrystal itself undergoes substantial deformation, either by activating dislocations, forming an amorphization zone, or by initiating microcracks at glass-crystal interfaces or weak crystallographic planes. In contrast, the β-quartz nanocrystal is not easily deformed and remains almost intact with minimal plastic deformation, thereby forcing shear flow and crack propagation pathways to predominately occur in the residual glass and/or at interfaces. The dramatic difference between the crystalline phases also manifests itself in the deformation mode of interfaces under pure shear loading, in which shear bands preferably occur at the LS2-glass interfaces, while cavities form at the β-quartz-glass interfaces. These observations significantly advance our understanding of glass-ceramics and pave ways to exploit the understanding for more applications.  相似文献   
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