MEDV-13 for QSRR of 62 Polychlorinated Naphthalenes

A molecular electronegativity distance vector based on 13 atomic types (MEDV-13) is used to describe the structures of 62 polychlorinated naphthalene (PCN) congeners and related to the gas chromatographic relative retention indices (RIs) of PCNs. Using multiple linear regression, a 4-variable quantitative structure-retention relationship (QSRR) with the correlation coefficient of estimations (r) being 0.9912 and the root mean square error of estimations (RMSEE) being 31.4 and the correlation coefficient of predictions (q) and the root mean square error of predictions (RMSEP) in the leave-one-out procedure are 0.9898 and 33.76, respectively.

Experimental Study on Measurement of Carbonation Depth of Concrete

Based on the test results, the differences of the carbonized depth of concrete measured by phenolphthalein indicator and rainbow indicator were discussed, the effects of the water to cement ratio of concrete, the carbonized age and the relative humidity of environment on the carbonized depth of concrete and the depth of half-carbonized zone corresponding to green zone measured by rainbow indicator were also analyzed. It is proved that the depth measured by phenolphthalein indicator is always smaller than that measured by rainbow indicator, and the half-carbonized zone can only be measured by rainbow indicator. The carbonized and half-carbonized depths of concrete are influenced by the carbonation age, the water to cement ratio of concrete and the relative humidity of environment. It is suggested that the phenolphthalein indicator can be used to measure the carbonized depth of concrete when the strength grade of concrete is below C45, otherwise, the rainbow indicator should be utilized.

The stance and factors of international organizations towards countries from a Chinese perspective

The degree and scope of constraints imposed by International Organizations(IOs)on States are increasing,and identifying the factors affecting the IOs’stances on States is helpful to enhance the state's discourse power and influence in the international community.First,by coding the records of Regular Press Conferences of the Speaking Office of the Chinese Ministry of Foreign Affairs during the period of 20182022,we obtained a dataset of IOs’stances on China-related events.Second,we constructed political relation,economic relation,and humanistic relation indicators to complement the influence factors,adopted the Bayesian logit model,and applied the Monte Carlo Markov chain algorithm and Gibbs sampling to analyze the probability of IOs’positive stances towards China.The result shows that IOs’category,length of establishment,functional position,and relationship with China are all related to their tendency of making a statement about China.In terms of the heterogeneity of event types,forum-type IOs are significantly inclined to give positive assessment compared to service-type IOs on events focusing on China's own development.Further analysis reveals that the model for analyzing and predicting the attitudes of IOs is more effective when the international situation is in a stable period.

Polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls in surface soil from the Tibetan Plateau

Concentrations of Polychlorinated dibenzo-p-dioxins and dibenzofurans（PCDD/Fs） and polychlorinated biphenyls（PCBs） in soil samples from Tibetan Plateau were determined. The average concentration of total 2,3,7,8-PCDD/Fs was（2.30 ± 1.02） pg/g, and World Health Organization Toxicity Equivalency（WHO-TEQ） average concentration was（0.013 ± 0.010）pg WHO-TEQ/g. The average concentration of ∑PCBs（7 indicator PCB and 12 dioxin like-PCB congeners） was（16.2 ± 9.25） pg/g, and WHO-TEQ average concentration was 0.043 ±0.049 pg WHO-TEQ/g. Comparing to previous studies in similar environmental conditions,PCDD/Fs and PCBs in this study showed a relatively lower concentration. The altitude dependences of PCDD/Fs and PCBs were also studied. Total organic carbon（TOC） normalized concentrations presented a quadratic relation with the altitudes, and an inflection could be found on the parabola of the total concentrations and some congeners of high concentration.The concentrations decreased with altitudes below about 4500 m above sea level（a.s.l.）, while they increased with altitudes above it. These phenomena indicate that cold condensation of PCDD/Fs and PCBs would happen above 4500 m a.s.l, on the Tibetan Plateau.