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采用经典的凯氏定氮法[1]对包膜型控释尿素总氮含量的测定,试样需经过消解、蒸馏、滴定三个操作步骤。该方法分析人员在操作过程中稍有不慎易导致误差,分析速度慢。改用KDY-9830型凯氏定氮仪法可减少或避免分析人员操作误差,分析速度较快。用该方法测定包模型控释尿素样品中总含氮量与用国标法(GB/T23348—2009)测定的相比,结果相差小于0.5%。KDY-9830型凯氏定氮仪法较经典的凯氏定氮法操作简便、快速、导致误差的几率少,测定数据稳定可靠,且可进行大批量样品的测定。 相似文献
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利用相平衡原理得出的焦油蒸馏时一次汽化温度的计算方法,其结果与按经验公式的计算结果进行了比较,同时讨论了一次汽化温度与焦油馏分产率及二段蒸发器过热蒸汽用量的关系。 相似文献
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《Journal of Adhesion Science and Technology》2013,27(1):261-275
—Due to its chemistry, no structural adhesive system (epoxies, acrylics, etc.) is likely to offer an ideal combination of toughness, strength, moisture resistance, and ambient-temperature curing. Therefore, for effective use of adhesives in primary structures, an engineer must be able to identify adhesives that represent an optimum compromise among the different properties. In this paper, we present techniques for screening high-strength, ambient-temperature-curing adhesives for (1) moisture resistance under sustained loading and (2) fracture resistance in a way that is directly related to joint performance. 相似文献
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Su Yeon Kwon Jung Hee Shim Yu Ha Kim Chang Su Lim Seong Bae An Inbo Han 《International journal of molecular sciences》2021,22(23)
Whitlockite (WH) is the second most abundant inorganic component of human bone, accounting for approximately 25% of bone tissue. This study investigated the role of WH in bone remodeling and formation in a mouse spinal fusion model. Specifically, morphology and composition analysis, tests of porosity and surface area, thermogravimetric analysis, an ion-release test, and a cell viability test were conducted to analyze the properties of bone substitutes. The MagOss group received WH, Group A received 100% beta-tricalcium phosphate (β-TCP), Group B received 100% hydroxyapatite (HAp), Group C received 30% HAp/70% β-TCP, and Group D received 60% HAp/40% β-TCP (n = 10 each). All mice were sacrificed 6 weeks after implantation, and micro-CT, hematoxylin and eosin (HE) staining, and Masson trichome (MT) staining and immunohistochemistry were performed. The MagOss group showed more homogeneous and smaller grains, and nanopores (<500 nm) were found in only the MagOss group. On micro-CT, the MagOss group showed larger fusion mass and better graft incorporation into the decorticate mouse spine than other groups. In the in vivo experiment with HE staining, the MagOss group showed the highest new bone area (mean: decortication group, 9.50%; A, 15.08%; B, 15.70%; C, 14.76%; D, 14.70%; MagOss, 22.69%; p < 0.0001). In MT staining, the MagOss group demonstrated the highest new bone area (mean: decortication group, 15.62%; A, 21.41%; B, 22.86%; C, 23.07%; D, 22.47%; MagOss, 26.29%; p < 0.0001). In an immunohistochemical analysis for osteocalcin, osteopontin, and CD31, the MagOss group showed a higher positive area than other groups. WH showed comparable bone conductivity to HAp and β-TCP and increased new bone formation. WH is likely to be used as an improved bone substitute with better bone conductivity than HAp and β-TCP. 相似文献
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《China Chemical Reporter》2010,(19)
<正> After June this year China's regions growingmiddle and late rice had widespread blastand sheath/culm blight.Such diseasesplagued 19.2 million hectares.Starting fromJuly the market for new fungicides that cancontrol blast and sheath/culm blight for ricewas more and more active.Makers of traditional pesticides for thecontrol of blast have to contend with fiercecompetition from new pesticides in marketthis year.Kitazine,iprobenfos,isoprothiolane and tricyclazole,oftenused by farmers in the past,are graduallybeing replaced by new varieties with high 相似文献
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