共查询到20条相似文献,搜索用时 125 毫秒
1.
2.
3.
4.
皮肤水分含量较低时会引起皮肤干燥、皮肤炎症、弹性下降及皮肤屏障受损等问题。化妆品用保湿剂市场规模巨大,且随着消费者对功效活性成分和科学护肤的认识提高,皮肤保湿成分的研究受到消费者和企业的关注。文章简单介绍了皮肤结构和保湿机理,保湿剂的市场情况及常见热门化妆品用保湿原料,探讨了化妆品保湿剂开发及相关领域创新研究的新思路。 相似文献
5.
6.
本文从敏感肌的特点及影响因素、形成机制以及敏感肌功效成分等方面对目前敏感肌研究进展进行了概述。敏感肌的成因复杂多样,根据目前研究可总结为皮肤屏障功能受损、表皮存在炎症状态、皮肤感受神经系统异常3个机制,但往往敏感肌的形成是多个机制相互累及的。此外,敏感肌肤人群皮肤或表现为皮肤微生物群异常,可能会加重皮肤敏感程度。同时,从敏感肌形成的角度归纳和总结了对改善敏感肌有效的成分,提出了敏感肌护理以及化妆品开发的相关意见。最后,指出了敏感肌的形成机制与新功效成分,尤其是敏感皮肤的形成与皮肤菌群的关系仍有待深入研究和证实。 相似文献
7.
近年来,越来越多的消费者使用美白化妆品以达到美白皮肤的目的。因此,各种各样的化妆品美白成分成为化妆品行业关注的焦点,并被广泛应用。通过对化妆品美白活性成分及特色植物资源美白成分进行综述,为化妆品美白成分,尤其是为特色植物资源美白成分的研究、开发及应用提供一定的参考。 相似文献
8.
9.
阐述了黑色素的形成原因和生成过程,根据形成原因,分析了祛斑美白的机制;结合美白化妆品中常用美白活性成分的特点和风险分析,对现有美白成分的检测方法进行了阐述,展望了化妆品中美白活性成分检测方法的发展趋势,为化妆品中美白活性成分的检测方法提供思路,为执法部门提供技术支持。 相似文献
10.
11.
针对汽车用塑料灯头的结构特点与工作环境,分析了灯头结构的复杂性、材料性能,注身工艺条件、合理地设计了注射成型模具,采用了组合式下模型芯来完成内孔的复杂成型,同时采用组合式侧抽芯来完成外侧面的卡钩与上面的穿线孔的成型,简化了模具的结构。 相似文献
12.
13.
The choice of chromophores and of their mutual geometrical arrangement for optimized singlet fission (SF) rates are considered. The electronic matrix element that enters the Fermi golden rule for the rate of SF is worked out algebraically for a simple model, but the density of states factor is not analyzed here. The model treats only the highest occupied and lowest unoccupied orbitals of the partners. It provides an approximate formula that requires only the knowledge of the expansion coefficients of these orbitals and of overlap integrals between atomic orbitals on the partners to obtain an estimate of the electronic matrix element. An illustrative application to a pair of ethylene molecules suggests that favored geometries will be those in which one of the AOs on the first ethylene overlaps with both AOs on the second ethylene, while the other AO on the first ethylene overlaps with at least one, and preferably both, AOs of the second ethylene as little as possible. 相似文献
14.
15.
A study of fertilization practices in intensively grown tomatoes, leading to a projection of developments in fertilizer usage is presented. Targets of optimal fertilization strategy were defined as follows: maximize fruit yield; maximize fruit quality; minimize environmental pollution with fertilizers; minimize corrosion of the fertilizer distribution system; minimize expenses on fertilizers. Information was gathered by literature searches and by personal interviews and visits to research institutes and growers.Rechecking of some fertilization practices for greenhouse tomatoes grown in detached media is proposed. The review indicates that the following should be rechecked: ammonium/nitrate ratio in fertilizer formulations; use of urea in fertilizer solutions; levels of phosphates applied; levels of sulphate applied; simple iron salts vs. chelated iron application; osmotic potential (OP), expressed as electrical conductivity (EC), of the nutrient solution at various growth stages.EC, pH and estimated prices of fertilizer solutions were calculated and presented in tables. 相似文献
16.
An equation was obtained for evaluating the thermodynamic affinity of a disperse dye for a fibre. Quantities Δh
D
and K
D
, which are functions of the composition of the dye bath, temperature, and state of the fibre material, can characterize the
change in the affinity of the dye for the fibre when the dyeing conditions are varied. 相似文献
17.
18.
A series of placebo powders for inhalation was characterized regarding bulk density and powder flowability using different techniques. The powders were of the ordered mixture type and were prepared by mixing a pharmaceutical carrier grade of lactose with different fractions of intermediate sized and fine (i.e., micronized) lactose. A modified Hausner Ratio was obtained by measurement of the poured and the compressed bulk densities. Other tests investigated were the angle of repose, the avalanching behaviour using the AeroFlow, and the yield strength using the Uniaxial tester. Furthermore, the relation between ordered mixture composition and flowability was examined.Of the methods investigated, the modified Hausner Ratio discriminates well between the investigated powders and seems to have the widest measuring range. It was also found that the poured and compressed bulk densities provide information about the packing of the particles in the powders. A good correlation was obtained between the modified Hausner Ratio and the angle of repose. The AeroFlow was suitable for powders with a low percentage of fine particles, but could not discriminate between the more cohesive powders. The Uniaxial tester, on the other hand, seems to be better suited for more cohesive powders.Regarding the powder composition, addition of micronized particles has a strong influence on the flowability of ordered mixtures, while intermediate sized particles have little impact on the powder flow. 相似文献
19.
分析了活性石灰回转窑用耐火材料的损坏原因,认为炉衬的附着物质与氧化硅和氧化铁的反应有关,硅酸钙与CaO是结圈的主要成分.改善耐火材料可以提高其使用寿命. 相似文献
20.
房地产业的快速发展也给建筑工程玻璃企业带来了巨大的市场前景。面对如此机遇,企业如何对生产过程进行有效的控制,生产出客户满意的产品,使企业不仅具有良好的市场信誉度,而且也获得了发展空间。 相似文献