排序方式： 共有34条查询结果，搜索用时 15 毫秒
1.
《Journal of Cultural Heritage》2014,15(2):128-135
Many whale (baleen whale or toothed whale) skeletons still contain residual lipids even after an initial osteological preparation. This paper examines the different possibilities of re-treatment. Before a conservation intervention, it was necessary to determine the materials of which bones are made up. The samples were analyzed by Raman spectroscopy. Different compounds were identified: a mineral part (apatite), an organic part (collagen) and lipids. Chromatography analysis yielded a detailed composition of the lipids. It was in fact degraded fat with saturated and unsaturated fatty acids. To remove these lipids, several techniques were identified and tested: enzymatic treatments, supercritical CO2, and green or organic solvents. Esterification catalyzed by lipases could be suitable for a degreasing treatment since the solubility of esters is higher than that of the corresponding fatty acids. The enzymatic treatment acted only on the surface and did not appear to be very efficient. The use of supercritical CO2 was even less effective. Some green solvents can partially extract lipids but prove difficult to eliminate after treatment. The best results for degreasing were achieved using organic solvents. Different solutions were evaluated at hot or ambient temperature and in simple immersion or with agitation (Soxhlet or pulsed pressure): hexane, heptane, a mixture of hexane/isopropanol, or an azeotropic mixture of methanol/chloroform. Only the mixture of methanol/chloroform succeeded in extracting the overall fat content, but this treatment degraded the organic part of the bones. The other organic solvents extracted mainly colored fat, which generally corresponded to a weight loss of 20 to 50%. The majority of fat was extracted during the first bath. Thus the treatment selected is that of immersion in heptane at ambient temperature. The degreasing of whole bones is less effective because of the film of sticky degraded fat on the bone's surface. A pre-cleaning is necessary to eliminate this film. 相似文献
2.
3.
4.
城市生活垃圾堆肥产品的应用和发展 总被引：1，自引：0，他引：1
丁爱芳 《南京晓庄学院学报》2002,18(4):84-87
城市生活垃圾的三种处理方式填埋、焚烧和堆肥各有利与弊 ,其中堆肥只有与其它处理方法相配合 ,才是一种有前途的垃圾处理技术 ;文章论述了施用堆肥对农林生产的作用和对环境的影响 ,并指出了堆肥今后的发展方向 相似文献
5.
李利 《洛阳师范学院学报》2009,28(5):127-128
针对目前国有施工企业改制过程中资产评估发生的增值和减值及企业所得税的纳税调整等问题,从会计实务的角度出发,探讨了施工企业进行资产评估结果的会计处理方法,以及在企业所得税纳税调整等方面应注意的具体事项. 相似文献
6.
施肥处理对黄瓜营养品质的影响 总被引：8，自引：0，他引：8
本试验以露地栽培的黄瓜为试材，探讨了施肥对黄瓜营养品质的影响．结果表明五种施肥处理中最佳施肥处理为半量虫粪(3750Kg／hm2)与50％NPK配施，可显著提高黄瓜中Vc、可溶性糖、可溶性Pr、果胶质含量，降低硝酸盐含量及纤维素含量，从而提高蔬菜营养品质和产量．与单施尿素处理比较，黄瓜中糖酸比增加41．09％，硝酸盐含量降低9％． 相似文献
7.
根据自己的教学经验及体会,结合对当前应用语言学理论及教学法的学习与研究,从分析外语学习中错误形成的原因入手,探讨了对待学习者语言错误应有的态度及应对策略。 相似文献
8.
罗选初 《湖南城市学院学报》2006,27(3):106-107
对急性踝关节扭伤的治疗,已有较多的研究和实践。对急性踝关节扭伤治疗需与现行的常规治疗方法进行对照,并选择可客观测量的特征性效应指标。只有这样,才能对各种治疗方法的意义和价值作出客观准确的评价,提高临床科研和治疗水平。 相似文献
9.
Ling ZHANG Tian TANG Zhen-liang ZHANG Bing LIANG Xiao-miao WANG Bai-ping FU 《Journal of Zhejiang University. Science. B》2013,14(11):1013-1024
Objective:This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths(μTBSs)of conventional and resin-modified glass ionomer cements(GICs/RMGICs).Methods:Forty-eight bovine incisors were prepared into rectangular blocks.Highly-polished labial enamel surfaces were either acid-etched,conditioned with liquids of cements,or not further treated(control).Subsequently,two matching pre-treated enamel surfaces were cemented together with one of four cements[two GICs:Fuji I(GC),Ketac Cem Easymix(3M ESPE);two RMGICs:Fuji Plus(GC),RelyX Luting(3M ESPE)]in preparation forμTBS tests.Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy(SEM).Results:Phosphoric acid etching significantly increased the enamelμTBS of GICs/RMGICs.Conditioning with the liquids of the cements produced significantly weaker or equivalent enamelμTBS compared to the control.Regardless of etching,RMGICs yielded stronger enamelμTBS than GICs.A visible hybrid layer was found at certain enamelcement interfaces of the etched enamels.Conclusions:Phosphoric acid etching significantly increased the enamelμTBSs of GICs/RMGICs.Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays,using GICs/RMGICs to improve the bond strengths.RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength. 相似文献
10.
《Journal of College Student Psychotherapy》2013,27(1):35-46
University and college counseling centers struggle with rising service demands without a corresponding increase in resources. Consequently, counseling centers must seek creative ways to not only maintain the status quo, but expand capacity while preserving effectiveness. In other countries, therapist-assisted, Internet-delivered treatment has been effective in treating several common disorders while conserving one third to one half the per client therapist time, suggesting that Therapist-Assisted Internet Based Cognitive Behavioral Treatment (TAI-CBT) could be an alternative treatment option offered through counseling centers in the United States and one possible solution to increase the number of students effectively treated per therapist hour for certain students seeking services. In this study, 334 students were surveyed to assess the acceptability of this mode of treatment; 217 of these students were currently in counseling or had received counseling in the past. TAI-CBT was endorsed by 34% of the students with past counseling and 16% of the students with no history of receiving counseling. These proportions were comparable to the rates for those who expressed interest in group therapy, which is commonly offered in counseling centers. 相似文献