共查询到20条相似文献,搜索用时 46 毫秒
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采用常规宝石学方法对"天珠"样品的材质进行了研究,通过无机试剂染色实验和加温固色实验,初步探讨了"天珠"的染色工艺过程. 相似文献
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介绍了PA 6生产中三种现代萃取循环工艺(再进料、"超比例"再进料和再聚合).该工艺可以明显降低成本,有利于环境保护. 相似文献
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以"米邦塔"仙人掌为特色原料,合理设计配方,确定加工工艺条件,经调配制成风味独特、具有特定营养保健功能的仙人掌冰淇淋。研究结果表明,其最佳配方为稀奶油8%、牛奶42%、奶粉8%、糖15%、仙人掌原汁15%、明胶0.5%、水11.5%、老化温度1~4℃、老化时间5h。 相似文献
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介绍了"藏魂"系列针织服装的设计灵感来源、色彩选用、面料选择,阐述了服装的尺寸计算、样板设计和缝纫工艺,对成品进行了展示。"藏魂"系列针织服装把民族与时尚融合,展现了女人活泼俏皮又不失典雅端庄的姿态。 相似文献
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关于棉纺"高效工艺"的评议 总被引:1,自引:0,他引:1
当前推行的“高效工艺”实际上是“重定量、大牵伸”工艺。它的定量和牵伸已达国内外推荐值的上限,但未超越最高水平。提高细纱牵伸倍数是高效工艺的核心,改善梳理条件是高效工艺的关键,文章提出了相应的基本要求和改进途径,肯定了高效工艺的作用,但认为不要把精细管理模式和高效工艺模式对立起来。 相似文献
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通过对电镀锌机组生产线上各根钢丝锌层重量与电流分布的测定,证明锌层分布不均匀是因阳极接触面积大小不一而引起的电流分布不均匀造成的。通过对阳极板厚薄、阳极板分布等的优选,钢丝锌层分布均匀性可得到明显的改善,并较大幅度地降低电镀锌机组的生产成本 相似文献
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Beauchemin S Hesterberg D Nadeau J McGeer JC 《Environmental science & technology》2004,38(5):1288-1295
The long-term impacts of chronic metal exposure for aquatic biota are not well understood, partly due to a lack of understanding of metal speciation within tissues. The objective of this study was to determine hepatic Zn speciation of rainbow trout (Oncorhnychus mykiss) exposed to Zn-enriched water in relation to unexposed (control) fish,through direct analysis of freeze-dried liver samples using synchrotron X-ray absorption spectroscopy (XAS). Juvenile rainbow trout (n=30) were exposed to Zn in a two-step process, 200 microg L(-1) for 14 days, followed by 370 microg L(-1) for 23 days. Thirty other trout were grown in a control treatment (10 microg Zn L(-1)). At the end of the experiment, three liver samples per treatment were collected, freeze-dried, ground, and mixed homogeneously. Although Zn concentration was higher in the Zn-exposed livers than in the control livers (22.32 vs 13.73 mg kg(-1), respectively; p < 0.05), Zn speciation was similar for both groups. Extended X-ray absorption fine structure (EXAFS) spectroscopy indicated that Zn was coordinated to 4 sulfur atoms with an average Zn-S bond distance of 2.31 +/- 0.02 A. Sulfur K-XANES analysis confirmed that S was predominantly in reduced organic form analogous to cysteine. Our results are consistent with previous evidence for Zn(II) bonding to S in metallothionein proteins. These results suggest that the mechanisms for dealing with the extra load of bioaccumulated Zn in high exposure conditions were the same as in the control group. 相似文献
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目的 探讨不同补锌制剂对幼儿生长发育的影响 ,对锌酵母与有机锌制剂促进儿童正常生长发育的效果进行对比研究。方法 随机抽取宜昌市城区 4所幼儿园 4 5 0名年龄在 2 5~ 3 5岁的入园新生为研究对象 ,将其随机分成 3组锌酵母制剂组 (16 8人 )、葡萄糖酸锌组 (15 0人 )、对照组(132人 ) ,采用双盲法观察补锌前后身高、体重的变化情况 ,并对其头发中 5种营养元素钙、镁、锌、铁、铜的含量进行检测。对幼儿注意力和食欲状况、患病情况进行问卷调查。结果 3组幼儿补锌前后身高平均增长值各组间差异有非常显著性 (P <0 0 1)。体重增长情况锌酵母制剂组与葡萄糖酸锌组和对照组比较 ,分别为差异有非常显著性 (P <0 0 1)和差异有显著性 (P <0 0 5 ) ,葡萄糖酸锌组与对照组比较 ,仅部分年龄段组间差异有显著性 (P <0 0 5 )。锌酵母制剂组发锌升高达正常者明显高于葡萄糖酸锌组和对照组。锌酵母制剂组常患感冒儿童补锌后大有改观 ,食欲改善情况和集中注意力情况也优于葡萄糖酸锌组和对照组。结论 锌酵母较有机锌能更好地促进儿童正常生长发育。 相似文献
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姬松茸深层发酵富集锌的研究 总被引:11,自引:0,他引:11
对姬松茸菌丝进行了富集锌的研究。首先对姬松茸的耐锌和富锌特性进行了研究,结果表明,姬松茸的耐锌能力和富锌能力都很强,在锌浓度为5 0~2 0 0 0 μg/mL的固体培养基上,菌丝均能生长,当锌浓度超过30 0 μg/mL时,菌丝生长受到一定影响;采用液体深层培养,当锌浓度为2 0 0 μg/mL时,富锌率最高。实验中还对培养条件进行了优化,在培养温度2 5℃,pH 5 1,振荡速度15 0r/min ,2 5 0mL三角瓶装液5 0mL ,接种量15 %(v/v) ,培养基中锌添加量为2 0 0 μg/mL时,姬松茸菌丝的生物转化量及菌丝体富锌率最高,达到12 6 4 %。最后对锌的有机化进行了研究,结果表明,姬松茸对锌有生物转化能力,加入的锌并非机械地物理吸附在菌体表面,而是发生了有机的生物转化,形成了牢固结合的复杂的有机锌,其有机化程度在5 7%左右。 相似文献
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分析影响电镀电流的4个因素D,d,n,η,指出参数的变化对电镀质量的影响。通过公式计算出最小镀锌量时的电流值。用公式B=m/I有效预测出钢丝的最大镀锌量和最小镀锌量,并以此来调整工艺,指导生产。 相似文献
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Hyperaccumulation of Zn by Thlaspi caerulescens can ameliorate Zn toxicity in the rhizosphere of cocropped Thlaspi arvense 总被引:3,自引:0,他引:3
The metal hyperaccumulating plant Thlaspi caerulescens is effective in depleting plant-available metals from the soil. We hypothesized that this reduction of toxic metals in the rhizosphere of T. caerulescens would increase the growth of less metal-tolerant plants with their roots permitted to intermingle and develop coincident rhizospheres. The extent of rhizosphere interaction between T. caerulescens and a coplanted nonaccumulator species, Thlaspi arvense, was controlled using barriers. Two media with elevated concentrations of water-extractable Zn were prepared by enriching one soil with zinc oxide (ZnO) or zinc sulfide (ZnS). The shoot mass of T. arvense was increased by 30% when its roots were permitted to intermingle with those of T. caerulescens in the ZnO treatment. The concomitant 2-3-fold reduction in shoot Zn concentration in T. arvense confirmed that its improved growth was associated with reduced uptake and phytotoxicity of Zn. Thlaspi arvense also showed increased growth and reduced metal uptake when cocropped with T. caerulescens in the ZnS treatment. We conclude that the strong Zn accumulation by T. caerulescens might enhance the establishment and development of surrounding less-tolerant species on soils that are naturally- or anthropogenically-enriched with metals. 相似文献