Terahertz spectral identification and low-frequency vibrational analysis of dinitrotoluene isomers.

Identifying dinitrotoluene (DNT) isomers has always been a challenging problem. In this study, five DNT isomers were investigated using terahertz time-domain spectroscopy (THz-TDS), which demonstrated significant spectral differences including variations in absorption positions and intensities. This suggests that THz-TDS is ideal for rapid identification of DNT isomers. We also employed density functional theory to further discuss the origin of these spectral differences. The results indicate that steric effects between substitute groups, rather than inter-molecular hydrogen bonding, lead to differences in low-frequency vibrations.

Terahertz spectral investigation of temperature induced polymorphic transformation of 2,2dinitroethylene-1,1-diamine.

The dynamic process of polymorphic transformations provides deep insights into the understanding of both the performance of explosives and its packing sensitivity. While terahertz spectroscopy is a sensitive tool that can be used to characterize its intermolecular forces. In this paper, terahertz time-domain spectroscopy (THz-TDS) is employed to investigate the polymorphic transformations of the explosive 2,2dinitroethylene-1,1-diamine (FOX-7) under a heating process. Solid-state density functional theory (DFT) uncovers the physical mechanisms that contribute to the polymorphic transformation. This is achieved by assessing the calculated spectra relative to the actual spectra from experiment. The results suggest that the THz spectral features that arise represent a redistribution of the intermolecular forces during the polymorphic transformations. This research will assist the understanding of the evolving properties of FOX-7, under external stimuli, which is vital knowledge for an explosive substance that can combust or detonate.

Quality of life among primary and middle school students and its association with negative emotions and social support in Henan Province / 中国学校卫生

Objective@#To understand the current status of health related quality of life among primary and middle school students aged 9 to 15 years old in Henan Province, and to explore its relationship with negative emotions and social support.@*Methods@#Between January and June 2016, 24 primary and middle schools were selected from 6 cities of Henan Province, and 5 867 primary and middle school students were included and completed the Pediatric Quality of Life Inventory Measurement, Stress Anxiety Depression Scale, Perceived Social Support Scale. Hierarchical linear regression analysis was used to examine the moderating effect of social support.@*Results@#The total score of health related quality of life of primary and middle school students in Henan was (81.21±12.49). There were statistically significant differences in the quality of life among primary and middle school students with different gender, study period, family monthly income, subjective parental relationship and parental education ( P <0.05). Negative emotions were negatively correlated with quality of life ( r =-0.51, P <0.01) and social support ( r =-0.30, P <0.01), while social support was positively correlated with quality of life ( r =0.29, P <0.01). Regression analysis showed that negative emotional was negatively associated with quality of life ( β =-0.23, P <0.01), while social support was positively associated with quality of life ( β =0.16, P <0.01). The interaction of negative emotions and social support was negatively associated with quality of life ( β =-0.18, P <0.01).@*Conclusion@#Health related quality of life among 9-15 year old primary and middle school students in Henan province is satisfactory. Social support might buffer the negative impact of negative emotions including depression, anxiety and stress on quality of life of primary and secondary school students.

Clinical Effective Research of the Implantation of Phakic Iris-fixated Intraocular Lens for High Myopia / 医学研究杂志

Objective To evaluate the effeciency and safety of the implantation of phakic iris-fixated intraocular lens for high myopia.Methods 12 cases(18 eyes)with the mean spherieal equivalent refraction was(-15.12?5.23)diopters of myopia,following up 3~6 months after surgery(averaging 5.1 months)were enrolled.Visual acuity,intraocular pressure,contrast sensitivity,glare sensitivity,corneal endothelium and the stable of intraocular lens and the turbid level of lens were observed.Results A postoperation uncorrected visual acuity of(0.73?0.21)was observed in 18 eyes at 6 months.There was significant difference as compared with preoperation corrected visual acuity of(0.52?0.17)(P