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Abstract  

In order to study the thermal properties of new type environment-friendly binary hydrate for cold storage in air-conditioning system, tests have been carried out by DSC comprehensively on the phase-change temperature and fusion heat of TBAB hydrate, THF hydrate, and TBAB–THF hydrate mixture. The results show a good trend that TBAB–THF hydrate has the superiority for more proper phase-change temperature and increased fusion heat. A broader and more developed view is that adding appropriate amount of hydrate with lower phase-change temperature to hydrate with higher one can make the hydrate mixture more suitable for cold storage (especially for 278–281 K); some hydrates with lower phase-change temperature can even make the fusion heat of mixture hydrate increased greatly. Several new environmental working pairs for binary gas hydrates have been listed to help to promote the application.

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Abstract  

The bentonite/iron oxide magnetic composites were prepared by co-precipitation method, and characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction and scanning electron microscope. The prepared bentonite/iron oxide magnetic composites were used as a sorbent for the removal of Co(II) ions from radioactive wastewater. The results demonstrated that the sorption of Co(II) was strongly dependent on pH and ionic strength at low pH values. The sorption of Co(II) was dominated by outer-sphere surface complexation or ion exchange at low pH whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The presence of iron oxide in the composites also contributes to the sorption of Co(II) ions on the magnetic composites. The experimental data were well described by Langmuir model. The thermodynamic parameters (∆G °, ∆S °, ∆H °) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on bentonite/iron oxide magnetic composites was an endothermic and spontaneous processes.

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Abstract  

The degradation characteristics of clopyralid irradiated by electron beam (EB) was studied in aqueous solutions. The effects of factors, such as initial clopyralid concentrations, addition of radicals scavenger, initial solution pH and addition of H2O2, were investigated on clopyralid degradation efficiency and mechanism. It was found that the EB-radiolysis was an effective way to degrade clopyralid and its degradation rate decreased with the increasing of substrate concentration. In the investigated initial concentrations range of 100–400 mg L−1, the radiolytic degradation of clopyralid followed a pseudo-first kinetic order. The results from addition of radicals scavenger indicated that both OH and e aq played significant roles in the degradation of clopyralid. Furthermore, the alkaline condition and addition of H2O2 (<10 mM) in the solution also slightly enhanced the efficiency of clopyralid degradation. The ion chromatography analysis showed that some organic acids (formic acid, acetic acid and oxalic acid) were formed, while the completely dechlorination of the substrate was achieved and organic nitrogen was recovered in the form of ammonium and nitrate ions during the irradiation process.

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The oxidation of cyclohexane to cyclohexanone, cyclohexanol, and adipic acid, which are important raw materials in nylon industry, is still being challenged in conventional processes. Microreactors and gold catalysts are both widely researched areas at present, so an effort was made to make use of collaborative properties of both. In this study, stainless steel microcapillary coated with a supported nano-gold catalyst was prepared, characterized, and employed for the oxidation of cyclohexane. Under the temperature of 180 °C, residence time of 4 min, reaction pressure of 3 MPa and molar ratio of oxygen to cyclohexane of 0.3:1, the conversion of cyclohexane was 2.09%, with the selectivity of cyclohexanol, 29.37%; cyclohexanone, 39.89%; cyclohexyl hydroperoxide, 2.46%; and adipic acid, 18.87%. Experiments showed that stainless steel microcapillary coated with a supported nano-gold catalyst in cyclohexane oxidation is a feasible process; the reaction time is very short, and the process operation runs safely.

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Scientometrics
Authors:
Chuanfu Chen
,
Kai Sun
,
Gang Wu
,
Qiong Tang
,
Jian Qin
,
Kuei Chiu
,
Yushuang Fu
,
Xiaofang Wang
, and
Jing Liu

Abstract  

The quality and credibility of Internet resources has been a concern in scholarly communication. This paper reports a quantitative analysis of the use of Internet resources in journal articles and addresses the concerns for the use of Internet resources scholarly journals articles. We collected the references listed in 35,698 articles from 14 journals published during 1996 to 2005, which resulted in 1,000,724 citations. The citation data was divided into two groups: traditional citations and Web citations, and examined based on frequencies of occurrences by domain and type of Web citation sources. The findings included: (1) The number of Web citations in the journals investigated had been increasing steadily, though the quantity was too small to draw an inclusive conclusion on the data about their impact on scientific research; (2) A great disparity existed among different disciplines in terms of using information on the Web. Applied disciplines and interdisciplinary sciences tended to cite more information on the Web, while classical and experimental disciplines cited little of Web information; (3) The frequency of citations was related to the reputation of the author or the institution issuing the information, and not to the domain or webpage types; and (4) The researchers seemed to lack confidence in Internet resources, and Web information was not as frequently cited as reported in some publications before. The paper also discusses the need for developing a guideline system to evaluate Web resources regarding their authority and quality that lies in the core of credibility of Web information.

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Abstract

Background

The advancement of communication technology and the impact of the COVID-19 pandemic have led to an increased reliance on online education. However, the effects of the long-term use of smart devices for online learning on students' social anxiety and problematic smartphone use (PSU) and the role of fear of missing out (FoMO) in this process have yet to be fully explored.

Methods

This study analysed longitudinal data from 2,356 high school students (female = 1,137 (48.26%), mean age = 13.84, SD age = 1.37) in China, divided into high- and low-FoMO groups based on their scores on the FoMO scale, to examine the impact of four months of online learning on social anxiety and PSU. The Social Anxiety Scale (SAS) and Mobile Phone Addiction Index (MPAI) were used to assess social anxiety and PSU symptoms.

Results

The undirected symptom networks revealed more bridge symptoms among the students in the high-FoMO group, although their overall symptom scores decreased. The results of the directed cross-lagged panel networks showed that “productivity loss” predicted other symptoms in the low-FoMO group but that “afraid of negative evaluation” was the predictor in the high-FoMO group. Meanwhile, “withdrawal/escape” and “productivity loss” were the symptoms that were most affected by other symptoms in the high-FoMO and low-FoMO groups, respectively.

Conclusions

The current study therefore sheds light on the changes in social anxiety and PSU symptoms among secondary school students during long-term online learning, as well as the moderating role of FoMO.

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