scholarly journals Transformation products of the high-volume production chemicals 1-vinyl-2-pyrrolidinone and 2-piperazin-1-ylethanamine formed by UV photolysis

Chemosphere ◽  
2021 ◽  
pp. 132394
Author(s):  
Benigno José Sieira ◽  
Rosario Rodil ◽  
Rafael Cela ◽  
José Benito Quintana ◽  
Rosa Montes
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jort Hammer ◽  
Hidenori Matsukami ◽  
Satoshi Endo

AbstractChlorinated Paraffins (CPs) are high volume production chemicals and have been found in various organisms including humans and in environmental samples from remote regions. It is thus of great importance to understand the physical–chemical properties of CPs. In this study, gas chromatographic (GC) retention indexes (RIs) of 25 CP congeners were measured on various polar and nonpolar columns to investigate the relationships between the molecular structure and the partition properties. Retention measurements show that analytical standards of individual CPs often contain several stereoisomers. RI values show that chlorination pattern have a large influence on the polarity of CPs. Single Cl substitutions (–CHCl–, –CH2Cl) generally increase polarity of CPs. However, many consecutive –CHCl– units (e.g., 1,2,3,4,5,6-C11Cl6) increase polarity less than expected from the total number of –CHCl– units. Polyparameter linear free energy relationship descriptors show that polarity difference between CP congeners can be explained by the H-bond donating properties of CPs. RI values of CP congeners were predicted using the quantum chemically based prediction tool COSMOthermX. Predicted RI values correlate well with the experimental data (R2, 0.975–0.995), indicating that COSMOthermX can be used to accurately predict the retention of CP congeners on GC columns.


1986 ◽  
Vol 67 ◽  
Author(s):  
Chris R. Ito ◽  
M. Feng ◽  
V. K. Eu ◽  
H. B. Kim

ABSTRACTA high-volume epitaxial reactor has been used to investigate the feasibility for the production growth of GaAs on silicon substrates. The reactor is a customized system which has a maximum capacity of 39 three-inch diameter wafers and can accommodate substrates as large as eight inches in diameter. The MOCVD material growth technique was used to grow GaAs directly on p-type, (100) silicon substrates, three and five inches in diameter. The GaAs surfaces were textured with antiphase boundaries. Double-cyrstal rocking curve measurements showed single-cyrstal GaAs with an average FWHMof 520 arc seconds measured at four points over the wafer surface. Within-wafer thickness uniformity was ± 4% with a wafer-to-wafer uniformity of ± 2%. Photoluminescence spectra showed Tour peaks at 1.500, 1.483, 1.464, and 1.440 ev. Schottky diodes were fabricated on the GaAs on silicon material.


2017 ◽  
Vol 52 (3) ◽  
pp. 395-404
Author(s):  
Xiuqi Lyu ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Isamu Ohsawa

Chopped carbon fiber tape-reinforced thermoplastic material is specifically developed for the high-volume production of lightweight automobiles. With excellent design processability and flexibility, the carbon fiber tape-reinforced thermoplastic material is manufactured by compressing large amounts of randomly oriented, pre-impregnated unidirectional tapes in a plane. Therefore, the carbon fiber tape-reinforced thermoplastic material presents transversely isotropic properties. Transverse shear effect along the thickness direction of carbon fiber tape-reinforced thermoplastic beam has a distinct influence on its flexural deformation. Accordingly, the Timoshenko beam theory combined with vibration frequencies was proposed to determine the set of transverse flexural and shear moduli. Meanwhile, the transverse flexural and shear moduli of carbon fiber tape-reinforced thermoplastic beam were finally determined by fitting all the first seven measured and calculated eigenfrequencies with the least squares criterion. In addition, the suggested thickness to length ratio for the 3-point bending test and Euler–Bernoulli model was given.


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