chemical

摘要： Coal is of utmost importance for the energy and chemical engi-neering fields of China,as it contributes to 56.8%of primary energy supply in 2020 in the country.On the one hand,coal is the major source of energy and resources for its rich endowment in China;However,on the other hand,it is the major source of environmen-tal pollution due to the implementation of outdated technologies.Therefore,according to Professor Kechang Xie in 2004,“The only way out is to develop and promote the clean and efficient coal uti-lization technologies”.In the past 40 years,China has made a sig-nificant progress in research and development related to modern coal chemical engineering,including lab-scale fundamental research and industrial-scale construction of many giant chemical plants.

摘要： Dear editor,In recent decades, researchers have started seeking for substitutes for silicon based circuits to perform computation in other fields, including synthetic biology and molecular computing [1, 2].Previous researches indicate that many circuit behaviors can be mapped to chemical reactions [3, 4].

摘要： With the discovery of the“central dogma”of life science,the molecular mechanism of genetics and evolution of biological species has basically been established.However,the completion of the Human Genome Project at the turn of the 21st century has begun to uncover the complexity of individual lives.Although the evolution of living individuals depends mainly on the sequence of genes,its complexity and diversity cannot be explained by the“central dogma”alone.Biomolecules,including proteins,nucleic acids and polysaccharides,are the basic“building blocks”of life,providing the material basis for living processes,and are subject to dynamic chemical modifications and regulation.The dynamic chemical modifications of these biomolecules play a key role in the development of individual organisms and in the regulation of cell fate,and also play a decisive role in the onset and development of diseases.

摘要： Farmers perception about availability and utilization of Spirulina (Arthrospira fusiformis) were assessed and its nutritive value compared against reference proteins (soybean and nuge cake). Samples of Spirulina were collected from Arenguade and Chitu lakes of rift valley of Ethiopia. A survey was conducted on purposively selected 100 households (HH) living around the Lakes which are located in Gerbicha and Labu subuqa districts of Debre Zeit town and west Arsi zone, respectively. Chemical composition and in vitro dry matter digestibility (IVDMD) and total gas volume (TGV) of feed samples were determined. Respondents of both districts are not aware of Spirulina as animal feed. Spirulina was available during dry season in Arenguade and whole year in Chitu. The highest (p 0.05) in crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) and metabolizable energy (ME) contents between Spirulina from both lakes. Spirulina from Chitu produced the highest TGV (31.2 ml) and fermented faster than Spirulina from Arenguade. Lowest (p < 0.05) ash, EE, CP and IVDMD and higher (p < 0.05) CF, NDF, ADF, ADL and TGV were recorded for reference proteins than Spirulina. ME content of Spirulina (3200 kcal/kg) was higher (p < 0.05) than that of nuge cake (3011 kcal/kg) but lower (p < 0.05) than that of soybean (3474 kcal/kg). Therefore, the chemical composition and IVDMD showed the potential of Spirulina to be used as a substitute of the reference feeds.

摘要： Tea is grown in Bangladesh under marginal climatic and soil conditions. Its production is greatly influenced by many physical, chemical, biological and natural factors. The increasing land use intensity without adequate and balanced use of chemical fertilizers and with little or no use of organic manure has caused severe fertility deterioration of our soils resulting in stagnating or even declining of crop productivity. The need of the hour is to achieve substantially higher crop yield than the present yield levels from our limited land resources on a sustainable basis. A feasibility study was carried out of one and only organic tea garden namely Kazi & Kazi Tea Estate at Panchaghar and compared to ordinary tea gardens located at Sylhet namely Zareen Tea Estate, Nurjahan Tea Estate and Malnichara Tea Estate as secondary data to investigate the fertility status of soil. Results of the present study showed that soil solutions were acidic in nature in all seasons. Medium to high soil organic matter, medium to high available iron and phosphorous, and low availability of potash showed that soils were not sufficiently fertile for crop production. Student t-test values of all the parameters with control sample showed statistically significant results for SOM and available P. The critical values have been fixed at 0.1% for N and 1% for OM, 10 μg/g for P, 80 μg/g for K, 25 μg/g for Mg, 90 μg/g for Ca, 2 μg/g for Zn and 20 μg/g for S. The nutrient status is much higher in Kazi & Kazi organic tea estate in compared to other ordinary tea estates in Bangladesh.

摘要： Background: Over the last few years sunscreen products have been suspected to be harmful to corals, especially because of their putative negative impact on symbiotic microalgae housed by these cnidarians. Previous publications reported that minerals or chemical UV filters could induce the release of microalgae from corals inducing their bleaching. The study of the ecotoxicity of finished cosmetic products containing these filters is important. Objectives: We sought to assess ex vivo the toxicity of five emulsions containing UV-filters on coral cuttings of Seriatopora hystrix. Materials and Methods: Coral cuttings were put in contact with 5 different emulsions containing UV-filters. The toxicity readout was the ability to induce polyp retraction and/or fragment bleaching of the coral cuttings of Seriatopora hystrix. Results: In our experimental conditions, none of the five tested formulas neither induced any significant polyp retraction nor triggered fragment bleaching of the coral. Conclusions: The five tested emulsions containing UV-filters did not modify coral cuttings. In vivo, larger tests are necessary to verify the results of this ex vivo pilot study.

摘要： The tuneable band gap property of Cadmium-sulphur-selenide (CdS1–xSex) thin film makes it an appropriate material for a wide range of optoelec-tronic applications and this has aroused a lot of interest. In this paper, we report the study of Cadmium-sulphur-selenide (CdS1–xSex) thin films, successfully grown on commercial glass slide substrate by the chemical bath deposition technique. The effect of selenium content (x value) on the structural, and some optical properties have been studied. The bath solution contained cadmium acetate dehydrate [Cd(CH3COO)2·2H2O], so-dium selenosulphate [Na2SeSO3] and thiourea [CS(NH2)2] were used as the sources of Cd2+, Se2﹣ and S2+, respectively. Tartaric acid (C4H6O6) was used as a complexing agent. The pH of the solution was adjusted to 12 by drop-wise addition of ammonia. The bath temperature was kept at 90°C for a deposition time of 1 hour. Post deposition annealing processes of the thin films were performed in a furnace at a temperature of 400°C for two hours. Both as-deposited and annealed films were characterised by Powder X-Ray Diffraction, Scanning Electron Microscopy, UV-Visible Optical Absorption Spectroscopy and Energy Dispersive X-Ray Analysis. Optical absorption data analysis indicates that direct allowed transitions occur in the films. The band gap of the as-deposited CdS1–xSex decreased linearly from 2.34 eV to 1.48 eV, with increasing selenium content, and in the annealed samples, decreased from 1.84 eV to 1.36 eV. X-ray diffrac-tion measurements revealed, that pure CdS, and CdSe had mixed hexago-nal and cubic phases. All the remaining ternary compounds were com-posed of cubic CdS and hexagonal CdSe phases. The annealed samples showed well defined and more intense peaks, suggesting an improvement in crystallinity. The average grain size increased slightly with increasing selenium content. SEM micrographs showed that the films were compact with a smooth texture and good coverage across the entire area of the substrate.

摘要： A numerical simulation is conducted to investigate arc-anode attachment behavior, especially the formation mechanism of the constricted arc attachment mode for the water-cooled anode of wall-stabilized transferred argon arcs. Argon molecular ions and the corresponding kinetic processes are included to the finite-rate chemistry model in order to capture the chemical nonequilibrium characteristics of the arc near the anode region. Modeling results show that constricted and diffusive arc–anode attachments can be self-consistently obtained at different arc currents while keeping other parameters unchanged. The dominant kinetic processes contributing to ionization and recombination in the arc center and fringes are presented. The results show that in arc fringes and the arc attachment region, molecular ion recombination plays an important role which leads to the rapid loss of electrons. The radial evolution of the production, loss and transport processes of electrons is further analyzed. It is found that for the constricted arc attachment mode, both the recombination and convection transport caused by the anode jet result in the loss of electrons at the arc fringes, which leads to the shrinkage of the arc column at the anode. The formation of the anode jet is due to the combined action of radial and axial Lorentz forces in the anode region.

摘要： Objective: To assess glycosaminoglycan (GAG) content of lumbar intervertebral discs (IVDs) in patients with radiculopathy compared with healthy volunteers with glycosaminoglycan chemical exchange saturation transfer (gagCEST). Methods: The lumbar spines of 15 patients with radiculopathy (9 women, 6 men;mean age 45 years;range: 19 - 80 years) and 13 healthy controls (10 women, 3 men;mean age 29 years;range: 19 - 38 years) without lumbar back pain or previous spine surgery were examined at a 3 Tesla (T) magnetic resonance imaging (MRI) scanner in this prospective study. The MRI protocol included standard morphological, sagittal, and transverse T2-weighted (T2w) images of the five lumbar IVDs (L1-S1) to assess Pfirrmann score and to detect disc disorders according to the Combined Task Force classification. To analyze biochemically the lumbar IVDs, a gagCEST sequence was applied to measure the GAG content of the nucleus pulposus (NP) and annulus fibrosus (AF). Results: Patients with radiculopathy indicated significantly lower gagCEST values in NP than healthy volunteers (2.82% ±3.12% vs. 4.09% ±2.25%, P = 0.017). The GAG content of AF showed no significant difference between volunteers and patients (2.66% ±2.01% vs. 1.92% ±2.56%;P = 0.175). Conclusions. Patients with radiculopathy presented with lower GAG values than healthy volunteers in NP, indicating an association between pain and IVD degeneration. gagCEST of lumbar IVDs is a powerful, non-invasive tool to investigate early disc degeneration, which we could demonstrate in the NP in our study collective.

摘要： A new pulsed chemical vapor deposition (PCVD) process has been developed to fabricate iron (Fe) and iron carbide (Fe1-xCx) thin films at low temperature range from 150°C to 230°C. The process employs bis(1,4-di-tert-butyl-1,3-diazabutadienyl)iron(II) as iron source and hydrogen gas or hydrogen plasma as the coreactant. The films deposited with hydrogen gas are demonstrated polycrystalline with body-centered cubic Fe. However, for the films deposited with hydrogen plasma, the amorphous phase of iron carbide is obtained. The influence of the deposition temperature on iron and iron carbide characteristics have been investigated.