The relationship between the improvement of sludge dewaterability and variation of organic matters has been studied in the process of sludge pre-conditioning with modified cinder, especially for extracellular polymeric substances （EPS） in the sludge. During the conditioning process, the decreases of total organic carbon （TOC） and soluble chemical oxygen demand （SCOD） were obviously in the supernatant especially for the acid modified cinder （ACMC）, which could be attributed to the processes of adsorption and sweeping. The reduction of polysaccharide and protein in supernatant indicated that ACMC might adsorb EPS so that the tightly bound EPS （TB-EPS） decreased in sludge. In the case of ACMC addition with 24 g·L^-1, SRF of the sludge decreased from 7.85 × 10^12 m·kg^-1 to 2.06× 10^12 m·kg^-1, and the filter cake moisture decreased from 85% to 60%. The reconstruction of ＂floc mass＂ was confirmed as the main sludge conditioning mechanism. ACMC promoted the dewatering performance through the charge neutralization and adsorption bridging with the negative EPS, and provided firm and dense structure for sludge floc as skeleton builder. The passages for water quick transmitting were built to avoid collapsing during the high-pressure process.
An environmentally friendly approach is presented to synthesize sulfonated reduced graphene oxide （S-rGO） by using L-ascorbic acid （L-AA） and aryl diazonium salt of sulfanilic acid. The preparation conditions have been optimized in order to obtain isolated and conductive S-rGO, and the products have been characterized by Ultraviolet-Visible spectroscopy, Fourier transformed infrared spectroscopy, Raman, X-ray photoelectron spectroscopy and X-ray powder diffraction and electrochemical methods. The results show that the S-rGO sheets possess excellent water-solubility and high electrical conductivity, which implies that the oxygen-containing functional groups have been removed and conjugated sp2 network has been restored. What＇s more, the electrochemical measurements reveal that the capacitive performance of the S-rGO has been improved compared with the graphene oxide （GO） and the reduced graphene oxide （rGO, reduced by L-AA）. The optimum S-rGO exhibits a specific capacitance of 205 F·g^-1 and good cycling stability （3.9% decreasing after 10000 cycles）, which are better than those for graphene oxide （109 F·g^-1 and decreasing 6.6% after 10000 cycles） and rGO （139 F·g^-1 and decreasing ll.3% after 10000 cycling）. This approach proves a new route to improve the capacitive properties of rGO.
Six new ZnIIcoordination polymers,namely,[Zn(CH3-ip)(btb)]n·2H2O(1),[Zn2(CH3-ip)2(btb)1.5]n(2),[Zn(CH3-ip)(btp...
Min-Le Han,Lu-Fang Ma *,Xin-Hong Chang,Li-Ya Wang,* Zhen-Zhen Shi College of Chemistry and Chemical Engineering,Luoyang Normal University,Luoyang,471022
The preparation of highly active electrocatalysts with good durability and low cost for fuel cells is highly desir- able but still remains a significant challenge. Here we synthesized two dimensional （2D） C3N4 nanosheets supported palladium composites （C3N4/Pd） via a simple and convenient sonochemical approach. We have systematically stud- ied the electrocatalytic performance of as-prepared catalysts. We found that the prepared C3N4/Pd composites pos- sessed excellent catalytic activity and stability for oxygen reduction reaction （ORR） in alkaline media. Encourag- ingly, the C3N4/Pd catalysts exhibit the excellent electrocatalytic activity for methanol oxidation reaction （MOR） in alkaline media, even better than that of the commercial Pt/C catalyst, The excellent electrocatalytic performance of the 2D C3N4 nanosheets supported palladium composites catalysts results from their synergy effect between the ul- trathin substrate material with large surface area and excellent dispersion of palladium nanoparticles. This study demonstrates that sonochemical method opens up a new avenue for the preparation of electrocatalysts for fuel cells. We expect these materials are likely to find uses in a broad range of applications, for example, fuel cells, solar cells, batteries and other electrochemical analysis.
In modern computer systems, system event logs have always been the primary source for checking system status. As computer systems become more and more complex, the interaction between software and hardware increases frequently. The components will generate enormous log information, including running reports and fault information. The sheer quantity of data is a great challenge for analysis relying on the manual method. In this paper, we implement a management and analysis system of log information, which can assist system administrators to understand the real-time status of the entire system, classify logs into different fault types, and determine the root cause of the faults. In addition, we improve the existing fault correlation analysis method based on the results of system log classification. We apply the system in a cloud computing environment for evaluation. The results show that our system can classify fault logs automatically and effectively. With the proposed system, administrators can easily detect the root cause of faults.
Effects of copper （Cu） accumulation by the flesh fly Boettcherisca peregrina （R.- D.） （Diptera： Sarcophagidae） on the ectoparasitic wasp Nasonia vitripennis （Walker） （Hymenoptera： Pteromalidae） were investigated experimentally by exposing host larvae to contaminated diets with final Cu concentrations of 400μg/g and 800μg/g diet fresh weight （DFW）, respectively. Results showed that Cu can be transferred along food chains to secondary consumers （parasitoids） in small amounts, resulting in negative effects on parasitoid growth and development （body weight and developmental duration） as well as fecundity （number of offspring per female）. Copper exposure also inhibited vitellogenesis ofparasitoids from Cu-contaminated host pupae. It is suggested that the decreased fecundity and inhibition of vitellogenesis ofN. vitripennis resulted from poor host nutritional state rather than from direct effects of Cu stress.
Gong-Yin Ye Sheng-Zhang Dong Hui Dong Cui Hu Zhi-Cheng Shen Jia-An Cheng
Ion beam figuring （IBF） technology is an effective technique for fabricating continuous phase plates （CPPs） with small feature structures. This study proposes a multi-pass IBF approach with different beam diameters based on the frequency filtering method to improve the machining accuracy and efficiency of CPPs during IBF. We present the selection principle of the frequency filtering method, which incorporates different removal functions that maximize material removal over the topographical frequencies being imprinted. Large removal functions are used early in the fabrication to figure the surface profile with low frequency. Small removal functions are used to perform final topographical correction with higher fre- quency and larger surface gradient. A high-precision surface can be obtained as long as the filtering frequency is suitably selected. This method maximizes the high removal efficiency of the large removal function and the high corrective capability of the small removal function. Consequently, the fast convergence of the machining accuracy and efficiency can be achieved.
