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471.
Jang Cheongjae Noh Yung-Kyun Park Frank Chongwoo 《Advances in Data Analysis and Classification》2021,15(3):673-699
Advances in Data Analysis and Classification - A growing number of problems in data analysis and classification involve data that are non-Euclidean. For such problems, a naive application of vector... 相似文献
472.
473.
Yongho Shin Chang Jo Kim Sujin Baek Leesun Kim Kyeong-Ae Son Hee-Dong Lee Danbi Kim Jeong-Han Kim Hyun Ho Noh 《Molecules (Basel, Switzerland)》2020,25(24)
Tenebrio molitor larvae (mealworm) is an edible insect and is considered a future food. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a novel method for simultaneous analysis of 353 target analytes was developed and validated. Various sample preparation steps including “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) extraction conditions, number of acetonitrile-hexane partitions, and dispersive-solid phase extraction (dSPE) sorbents were compared, and the optimal conditions were determined. In the established method, 5 g of homogenized mealworms was extracted with acetonitrile and treated with QuEChERS EN 15662 salts. The crude extract was subjected to three rounds of acetonitrile-hexane partitioning, and the acetonitrile layer was cleaned with C18 dSPE. The final solution was matrix-matched and injected into LC-MS/MS (2 μL). For target analytes, the limits of quantitation (LOQs) were ≤10 μg/kg, and the correlation coefficient (r2) of calibration was >0.990. In recovery tests, more than 90% of the pesticides showed an excellent recovery range (70–120%) with relative standard deviation (RSD) ≤20%. For more than 94% of pesticides, a negligible matrix effect (within ±20%) was observed. The analytical method was successfully applied and used for the detection of three urea pesticides in 4 of 11 mealworm samples. 相似文献
474.
Dong-ho Lee Keun-byung Yoon Eok-hyung Lee Seok-kyun Noh Chul-soo Lee Wan-soo Huh 《Macromolecular rapid communications》1996,17(5):325-331
The disiloxane-bridged zirconocene complexes, tetramethyldisiloxanediylbis (cyclopentadienyl)zirconium dichloride and tetramethyldisiloxanediylbis(cyclopentadienyl) dimethylzirconium initiate the homopolymerization of ethene as well as the copolymerization of ethene and α-olefin with a modified methylaluminoxane as cocatalyst. The catalyst systems give resonable activity but the molecular weight of polyethene decreases drastically with increasing polymerization temperature. 相似文献
475.
Dong-ho Lee Keun-byoung Yoon Seok-kyun Noh Su-chan Kim Wan-soo Huh 《Macromolecular rapid communications》1996,17(9):639-644
In the polymerization of ethene cocatalyzed with modified methylaluminoxane, the catalyst activities of the siloxane-bridged dinuclear zirconocenes, tetramethyldisiloxanediylbis(cyclopentadienylindenylzirconium dichloride) ( 3 ) and hexamethyltrisiloxanediylbis(cyclopentadienylindenylzirconium dichloride) ( 4 ) were lower than that obtained with the siloxane-bridged mononuclear zirconocene, tetramethyldisiloxanediyldicyclopentadienyldimethylzirconium ( 1 ). On the other hand, weight-average molecular weight M̄w and ratio of weight- to number-average molecular weights M̄w/M̄n of polyethene (PE) obtained with 3 or 4 were higher than those of PE obtained with 1. For a binary mixture of 1/3 or 1/4 , it was found that the obtained PE exhibits a bimodal molecular weight distribution for an appropriate composition of the mixed zirconocenes. M̄w/M̄n of PE could be adjusted by changing the relative concentrations of the two zirconocenes. 相似文献