Investigation into the surface active groups of coal

The oxidation heat of coal is the direct reason leading to coal spontaneous combustion. When coal is exposed in oxygen atmosphere, the physical adsorption and chemisorption happened, and then which resulting chemical reaction followed heat between coal and oxygen. Owing to the complexity and uncertain of molecular structure of coal,it was only reduced that bridge bonds, side chains and O 2 containing functional groups in coal may be prone to oxidation in last year, but not to deeply investigate into the structures and the type of the active radicals. In this paper, according to the last achievements in coal structure research, the hypomethylether bond, hypoalkyl bond of α carbon atom with hydroxyl and α carbon atom with hypomethy side chain and hypomethyl bonds linking up two aromatic hydrocarbon in bridge bonds, and methoxy,aldehyde and alkyls of α carbon atom with hydroxy in side bonds are inferred to be free radical easily to lead to oxidize coal under the ambient temperature and pressure. The order from strong to weak of oxide activation of the seven surface active groups is aldehyde side chains, hypomethylether bonds, hypoalkyl bonds of α carbon atom with hydroxyl, hypoalkyl bonds of α carbon atom with hypomethyl, hypomethyl bonds linking up two aromatic hydrocarbon,methoxy, alkyls side chains of α carbon atom with hydroxyl. Because of the two unsaturated molecular tracks of O 2, unpaired electron clouds of the part of surface active groups of coal enter molecular tracks of O 2 to lead to chemisorb on the conjugate effect and induced effect of surface active groups, and then chemical reaction followed heat happens in them. On the basis of change of bond energy, weighted average method is adopted to count the reaction heat value of each mol CO,CO 2 and H 2O. The property of coal spontaneous combustion is different for the different number and oxidability of the active structure in the coal resulting in the different oxidation heat.

FUNCTIONALIZED CYCLODEXSTRINS BEARING AM INOALKYLIMINO GROUPS AS ACTIVE CENTERS TO CATALYZE ALDOL CONDENSATIONS

Efficient catalysis of functinnatized β-cyctodextrins bearing aninoatkytimino groups for atdot condensations of nitrobenzatdehydes and acetone has been effected and substantiated by preparative experiments

Analysis of Influential Factors of Konjac Glucomannan(KGM) Molecular Structure on Its Activity

Biological activity of konjac glucomannan is closely related to its structure,in particular to its high-level structure.Researches on the activity mechanism of konjac glucomannan are significant for revealing the mysteries of participation in life activity.In this paper,analysis of the effects of konjac glucomannan configuration and various factors on its structure and activity was conducted,mechanism of biological activity of konjac glucomannan was explored,and the hot research topic of konjac glucomannan was given.

Unlocking high-performance organic cathodes:tailoring active group densities in covalent frameworks for aqueous zinc ion batteries

Aqueous zinc ion batteries(AZIBs)are a promising energy storage technology due to their cost-effectiveness and safety.Organic materials with sustainable and designable structures are of great interest as AZIBs cath-odes.However,small molecules in organic cathode materials face dissolution problems and suboptimal cycle life,whereas large molecules suffer from a low theoretical capacity due to their inert carbon skeletons.Here,we designed two covalent organic framework(COF)materials(benzoquinoxaline benzoquinone-based COF(BB-COF)and triquinoxalinylene benzoquinone-based COF(TB-COF))with the same structure and number of energy storage groups to investigate the correlation between the densities of active sites and electrochemi-cal performance.We conclude that the electrochemical behavior of organic conjugate-based energy storage materials lacks a linear correlation with active site quantity.Adjusting active site densities is crucial for mate-rial advancement.BB-COF and TB-COF with dual active sites(C=O and C=N)exhibit distinct characteristics.TB-COF,which has dense active groups,shows a high initial capacity(222 mAh g^(-1)).Conversely,BB-COF,which features a large conjugated ring diameter,presents superior rate performance and enduring cycle stability.It even maintains stable cycling for 2000 cycles at-40℃.In-situ electrochemical quartz crystal mic-robalance tests reveal the energy storage mechanism of BB-COF,in which H+storage is followed by Zn2+storage.

Electrochemically reduced graphene oxide with enhanced electrocatalytic activity toward tetracycline detection

An electrochemically reduced graphene oxide sample, ERGO_0.8v, was prepared by electrochemical reduction of graphene oxide （GO） at -0.8 V, which shows unique electrocatalytic activity toward tetracycline （TTC） detection compared to the ERGO-12v （GO applied to a negative potential of-1.2 V）, GO, chemically reduced GO （CRGO）-modified glassy carbon electrode （GC） and bare GC electrodes. The redox peaks of TTC on an ERGO-0.8v-modifled glass carbon electrode （GC/ERGO-0.8v） were within 0-0.5 V in a pH 3.0 buffer solution with the oxidation peak current correlating well with TTC concentration over a wide range from 0.1 to 160 mg/L Physical characterizations with Fourier transform infrared （FT-IR）, Raman, and X-ray photoelectron spectroscopies （XPS） demonstrated that the oxygen-containing functional groups on GO diminished after the electrochemical reduction at -0.8 V, yet still existed in large amounts, and the defect density changed as new sp2 domains were formed. These changes demonstrated that this adjustment in the number of oxygen-containing groups might be the main factor affecting the electrocatalytic behavior of ERGO. Additionally, the defect density and sp2 domains also exert a profound influence on this behavior. A possible mechanism for the TTC redox reaction at the GC/ERGO-0.8v electrode is also presented. This work suggests that the electrochemical reduction is an effective method to establish new catalytic activities of GO by setting appropriate parameters.

Liquid-Liquid Equilibria of Water + Butyric Acid + Nonanol Ternary System

Liquid-liquid equilibrium (LLE) data for the water + butyric acid + nonanol system have been determined experimentally at the temperatures of 298.15 K, 308.15 K and 318.15 K. Tie-line compositions were correlated by Othmer-Tobias method. The universal quasichemical functional group activity coefficient (UNIFAC) and modified UNIFAC methods were used to predict the phase equilibrium in the system using the interaction parameters between CH3, CH2, COOH, OH and H2O functional groups. Distribution coefficients and separation factors were evaluated for the immiscibility region.

Team management in college English classroom teaching

With the rapid development and furthering of higher education, most Chinese colleges have carried out large-scale enrollment program, which is a necessary improvement toward higher education reform. Meanwhile, the increasing number of students has posed new problems and requirements for the old teaching method： the English teachers are facing more students and larger classes. In Zhejiang University, City College （ZUCC） the credit system and course selection has challenged the English teachers on a higher level. Every English teacher is facing classes of more than 40 students from various departments with sharp contrast among individual students in their English proficiency level and local background. How can every student actively participate in teaching activity so as to achieve better performance in English class？ Many teachers, therefore, have adopted team activity and cooperative teaching method to stimulate student participation in class. Inspired by the management theory to optimize student groups into independent teams, the concept of team construction and team management has been introduced into College English Teaching in ZUCC, which has given new meaning to team activity--it will become an interdisciplinary teaching method with its own feature.

Catalytic aquathermolysis of Shengli heavy crude oil with an amphiphilic cobalt catalyst

An interfacially active cobalt complex,cobalt dodecylbenzenesulfonate,was synthesized.Elemental analysis,atomic absorption spectroscopy,Fourier transform infrared spectroscopy（FT-IR）,thermogravimetric analysis,and surface/interfacial tension determination were performed to investigate the properties of the catalyst.Results showed that the synthesized catalyst showed active interfacial behavior,decreasing the surface tension and interfacial tension between heavy oil and liquid phase to below 30 and 1.5 mN/m,respectively.The catalyst was not thermally degraded at a temperature of 400 ℃,indicating its high thermal stability.Catalytic performance of the catalyst was evaluated by carrying out aquathermolysis.The viscosity determination showed that the viscosity of the heavy oil decreased by 38%.The average molecular weight,group compositions,and average molecular structure of various samples were analyzed using elemental analysis,FT-IR,electrospray ionization Fourier transform ion cyclotron resonance（ESI FT-ICR MS）,and ～1H nuclear magnetic resonance.Results indicated that the catalyst could attack the sulfur- and O_2-type heteroatomic compounds in asphaltene and resin,especially the compounds with aromatic structure,leading to a decrease in the molecular weight and then the reduction in the viscosity of heavy oil.Therefore,the synthesized catalyst might find an application in catalytic aquathermolysis of heavy oil,especially for the high-aromaticity heavy oil with high oxygen content.

Acid/Base Treatment of Monolithic Activated Carbon for Coating Silver with Tunable Morphology

Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs＇ Brunauer-EmmettTeller（BET） surface area, surface groups, and silver coating morphology were characterized by N2 adsorption, elemental analysis（EA）, X-ray photoelectron spectroscopy（XPS）, and scanning electron microscopy（SEM）, respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO3 treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, Na OH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while Na OH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag（NH3）2]NO3 concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on Na OH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.

SYNTHESIS AND CHARACTERIZATION OF PHTHALAZINONE POLY(ARYL ETHER SULFONE KETONE)WITH CARBONYL GROUP

A kind of novel heat-resistant, high performance engineering thermoplastic phthalazinone poly(aryl ether sulfone ketone) (PPESK) containing a carboxyl group in its side chain was prepared by the nucleophilic displacement reaction of 4-(4-hydroxylphenyl)- 1 (2H)-phthalazinone with di(4-chlorophenyl) sulfone, 4,4'-difluoro-benzophenone and phenolphthalin in sulfolane in the presence of K2CO3 to produce high molecular weight polymers which can be dissolved in some polar solvents such as chloroform and nitrobenzene at room temperature and can be easily cast into flexible, yellowish and transparent films. PPESK is an amorphous polymer having a decomposition temperature above 400degreesC, which indicates that it has high thermal stability. At the same time, the thermal properties of PPESKs with dicyandiamide (DICY) as curing agent indicated that the heat-resistance properties of the PPESKs are improved after curing. The apparent activation energy (A-E) of the cross-linking reaction and the reaction order (n) of PPESK/DICY were found to be 52.2 kJ/mol and ca. 1.0, respectively. Therefore, the cross-linking reaction is approximately a first order reaction.

Recognition of Group Activities Using Complex Wavelet Domain Based Cayley-Klein Metric Learning

A group activity recognition algorithm is proposed to improve the recognition accuracy in video surveillance by using complex wavelet domain based Cayley-Klein metric learning.Non-sampled dual-tree complex wavelet packet transform(NS-DTCWPT)is used to decompose the human images in videos into multi-scale and multi-resolution.An improved local binary pattern(ILBP)and an inner-distance shape context(IDSC)combined with bag-of-words model is adopted to extract the decomposed high and low frequency coefficient features.The extracted coefficient features of the training samples are used to optimize Cayley-Klein metric matrix by solving a nonlinear optimization problem.The group activities in videos are recognized by using the method of feature extraction and Cayley-Klein metric learning.Experimental results on behave video set,group activity video set,and self-built video set show that the proposed algorithm has higher recognition accuracy than the existing algorithms.

Rescuing the intracluster medium of NGC 5813

We use recent X-ray observations of the intracluster medium （ICM） of the galaxy group NGC 5813 to confront theoretical studies of ICM thermal evolution with the newly derived ICM prop- erties. We argue that the ICM of the cooling flow in the galaxy group NGC 5813 is more likely to be heated by mixing of post-shock gas from jets residing in hot bubbles with the ICM, than by shocks or turbulent- heating. Shocks thermalize only a small fraction of their energy in the inner regions of the cooling flow; in order to adequately heat the inner part of the ICM, they would overheat the outer regions by a large factor, leading to its ejection from the group. Heating by mixing, which was found to be much more efficient than turbulent-heating and shocks-heating, hence, rescues the outer ICM of NGC 5813 from its predestined fate according to cooling flow feedback scenarios that are based on heating by shocks.

Learning group interaction for sports video understanding from a perspective of athlete

Learning activities interactions between small groups is a key step in understanding team sports videos.Recent research focusing on team sports videos can be strictly regarded from the perspective of the audience rather than the athlete.For team sports videos such as volleyball and basketball videos,there are plenty of intra-team and inter-team relations.In this paper,a new task named Group Scene Graph Generation is introduced to better understand intra-team relations and inter-team relations in sports videos.To tackle this problem,a novel Hierarchical Relation Network is proposed.After all players in a video are finely divided into two teams,the feature of the two teams’activities and interactions will be enhanced by Graph Convolutional Networks,which are finally recognized to generate Group Scene Graph.For evaluation,built on Volleyball dataset with additional 9660 team activity labels,a Volleyball+dataset is proposed.A baseline is set for better comparison and our experimental results demonstrate the effectiveness of our method.Moreover,the idea of our method can be directly utilized in another video-based task,Group Activity Recognition.Experiments show the priority of our method and display the link between the two tasks.Finally,from the athlete’s view,we elaborately present an interpretation that shows how to utilize Group Scene Graph to analyze teams’activities and provide professional gaming suggestions.

Synthesis and Self-Assembly of Two 1,3-Alternate Thiacalix[4]arenes Derivatives Bearing Amide Groups

Two 1,3-alternate thiacalix[4]arene derivatives bearing amide groups, 1,3-alternate p-tert-butylthiacalix[4]arene tetraamide （4）, and 1,3-alternate p-H-thiacalix[4]arene tetraamide （6） were prepared, and their crystal structures were determined by single-crystal X-ray diffraction method. The steric hindrances posed by tert-butyl groups play an important part in the synthesis and the self-assembly of the two compounds. Compound 6 was synthesized from the corresponding ester, which was obtained by the reaction of acid chloride with ammonia. In the crystal structure, compound 4 presents a highly symmetric molecular structure, while for compound 6, because of absence of tert-butyl groups, it presents a more flexible molecular structure.

A Comprehensive Review of Group Activity Recognition in Videos

Human group activity recognition(GAR)has attracted significant attention from computer vision researchers due to its wide practical applications in security surveillance,social role understanding and sports video analysis.In this paper,we give a comprehensive overview of the advances in group activity recognition in videos during the past 20 years.First,we provide a summary and comparison of 11 GAR video datasets in this field.Second,we survey the group activity recognition methods,including those based on handcrafted features and those based on deep learning networks.For better understanding of the pros and cons of these methods,we compare various models from the past to the present.Finally,we outline several challenging issues and possible directions for future research.From this comprehensive literature review,readers can obtain an overview of progress in group activity recognition for future studies.

Adsorption and desorption of SO_2, NO and chlorobenzene on activated carbon

Activated carbon（AC） is very effective for multi-pollutant removal; however, the complicated components in flue gas can influence each other＇s adsorption. A series of adsorption experiments for multicomponents, including SO_2, NO, chlorobenzene and H2 O,on AC were performed in a fixed-bed reactor. For single-component adsorption, the adsorption amount for chlorobenzene was larger than for SO_2 and NO on the AC. In the multi-component atmosphere, the adsorption amount decreased by 27.6% for chlorobenzene and decreased by 95.6% for NO, whereas it increased by a factor of two for SO_2,demonstrating that a complex atmosphere is unfavorable for chlorobenzene adsorption and inhibits NO adsorption. In contrast, it is very beneficial for SO_2 adsorption. The temperature-programmed desorption（TPD） results indicated that the binding strength between the gas adsorbates and the AC follows the order of SO_2〉 chlorobenzene 〉 NO. The adsorption amount is independent of the binding strength. The presence of H2 O enhanced the component effects, while it weakened the binding force between the gas adsorbates and the AC. AC oxygen functional groups were analyzed using TPD and X-ray photoelectron spectroscopy（XPS） measurements. The results reveal the reason why the chlorobenzene adsorption is less affected by the presence of other components. Lactone groups partly transform into carbonyl and quinone groups after chlorobenzene desorption. The chlorobenzene adsorption increases the number of C = O groups, which explains the positive effect of chlorobenzene on SO_2 adsorption and the strong NO adsorption.