The production of ligninolytic enzymes and protease by Phanerochaete chrysosporium was investigated under different culture conditions. Different amounts of medium were employed in free and immobilized culture, togeth...
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The production of ligninolytic enzymes and protease by Phanerochaete chrysosporium was investigated under different culture conditions. Different amounts of medium were employed in free and immobilized culture, together with two kinds of medium with different C/N ratios. Little lignin peroxidase （LIP） （〈 2 U/L） was detected in free culture with nitrogen-limited medium （C/N ratio： 56/2.2, in mmol/L）, while manganese peroxidase （MnP） maximum activity was 231 and 240 U/L in 50 and 100 ml medium culture, respectively. Immobilized culture with 50 ml nitrogen-limited medium gave the highest MnP and LiP production with the maximum values of 410 and 721 U/L separately on the day 5; however, flasks containing 100 ml nitrogen-limited medium only produced less MnP with a peak value of 290 U/L. Comparatively, carbon-limited medium （C/N ratio： 28/44, in mmol/L） was adopted in culture but produced little MnP and LiE Medium type had the greatest impact on protease production. Large amount of protease was produced due to glucose limitation. Culture type and medium volume influence protease activity corporately by affecting oxygen supply. The results implied shallow immobilized culture was a possible way to gain high production of ligninolytic enzymes.
Traction control methods of special off-road vehicle with the power take-off were analyzed. The traction control strategy on the low attachment coefficient road relying on adjusting the clutch, axle differential and b...
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Traction control methods of special off-road vehicle with the power take-off were analyzed. The traction control strategy on the low attachment coefficient road relying on adjusting the clutch, axle differential and brake was presented. A full-time four-wheel-drive special off-road vehicle model with clutch was established. A software in-the-loop simulation platform with MATLAB was built and the simulation was analyzed. The results show that the traction control methods of special off-road vehicle with the power take-off can control the slip rate of over-spin wheels at the best value range without adjusting engine throttle, therefore the vehicle can pass the low adhesion road region.
The busbars in high power neutral point clamped three-level inverters are modeled using the Maxwell Q3D Extractor software, which is based on the partial element equivalent circuits method. The equivalent circuits of ...
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The busbars in high power neutral point clamped three-level inverters are modeled using the Maxwell Q3D Extractor software, which is based on the partial element equivalent circuits method. The equivalent circuits of the busbars and devices model are simulated in the electric simulator PSlM to analyze the effects of the parasitic inductance on the switching characteristics of the integrated gate commutated thyristor （IGCT） in different topology positions. The simulation results agree well with the measured impedance analyzer results and the IGCT test results, which proves the effectiveness of the modeling method for the large, complex busbars.
Integrated Assessment of Environmental Carrying Capacity(ECC) is one of important tool to detect status of sustainable development for a region. Most of traditional assessments of ECC couldn't discriminate pressur...
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Integrated Assessment of Environmental Carrying Capacity(ECC) is one of important tool to detect status of sustainable development for a region. Most of traditional assessments of ECC couldn't discriminate pressure index and state index, and misused pressure index with carrying capacity index. They might not present a real carrying status using linear plus model. Most important is that they couldn't bring out accurate and quantitative assessment results, and couldn't tell the specific degree of over-carrying or carrying. A new model, vector-capacity surplus model, based on computing all parts of ECC, is proposed. Except the carrying capacity index system, a state index system rapidly indicating carrying status and a pressure-mitigated index system showing the level of reducing environmental pressures are suggested.
X-ray photoelectron spectroscopy, IR and chemical analysis were employe to study the adsorption mechanisms of crosslinked chitosan (CCTSCd) on cadmium. According to IR, it showed that -NH2 groups of chitosan were prot...
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X-ray photoelectron spectroscopy, IR and chemical analysis were employe to study the adsorption mechanisms of crosslinked chitosan (CCTSCd) on cadmium. According to IR, it showed that -NH2 groups of chitosan were protected by template method and others -NH2 groups which didn't complex with cadmium ions took part in crosslinking reaction. Investigating the changes of element binding energy of O1s, C1s, N1s and Cd3d of XPS, there were chemical shifts of both N1s and Cd3d5/2 and Cd3d3/2 of the sample of adsorption comparing with unadsorption, but O1s and C1s hadn't. At the same time, N1s peak had a shoulder peak. The results indicate that -NH2 groups on CCTSCd complexes with cadmium ions by N1s fit spectra. The adsorption is a chemical adsorption and the experimental data fits Freundlich adsorption isotherm. The sorbent has selectivity and memory to metal ions.
Ambient volatile organic compounds （VOCs） were sampled at six sites in Beijing in the summer of 2004 and analyzed by GCMS. The chemical reactivities of 73 quantified VOCs species were evaluated by OH loss rates （LO...
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Ambient volatile organic compounds （VOCs） were sampled at six sites in Beijing in the summer of 2004 and analyzed by GCMS. The chemical reactivities of 73 quantified VOCs species were evaluated by OH loss rates （LOH） and ozone formation potentials （OFPs）. Top 15 reactive species, mainly alkenes and aromatics, were identified by these two methods, and accounted for more than 70% of total reactivity of VOCs. In urban areas, isoprene was the most reactive species in term of OH loss rate, contributing 11.4% to the LOH of VOCs. While toluene, accounting for 9.4% of OFPs, appeared to have a long-time role in the photochemical processes. Tongzhou site is obviously influenced by local chemical industry, but the other five sites showed typical urban features influenced mainly by vehicular emissions.
Acetone plays an important role in photooxidation processes in the atmosphere. Up to date, little is known regarding the heterogeneous fate of acetone. In this study, the adsorption and desorption processes of acetone...
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Acetone plays an important role in photooxidation processes in the atmosphere. Up to date, little is known regarding the heterogeneous fate of acetone. In this study, the adsorption and desorption processes of acetone on SiO2 particles, which are the major constituent of mineral dust in the atmos-phere, have been investigated for the first time under the simulated atmospheric conditions, using in situ transmission Fourier transform infrared spectroscopy. It is found that acetone molecules are ad-sorbed on the surfaces of SiO2 particles by van der Waals forces and hydrogen bonding forces in a nonreactive and reversible state. The rates of initial adsorption and initial desorption, initial uptake coefficients and adsorption concentrations at equilibrium have been determined at different relative humidity. The presence of water vapor cannot result in the formation of new substances, but can de-crease the adsorption ability by consuming or overlapping the isolated OH groups on the surfaces of SiO2 particles. In the desorption process, a considerable amount of acetone molecules will remain on SiO2 particles in dry air, whereas acetone molecules are almost completely desorbed at a high relative humidity. In order to evaluate the role of heterogeneous reactions of acetone and other carbonyl compounds in the atmosphere, a new model fitting the atmospheric conditions is needed.
In this paper, based on a battery pure electric city bus, principle researches have been offered on the parameters matching of the power-train and main components. The vehicle system was designed integrated, and then ...
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The assessment of the ecosystem health of urban rivers and lakes is the scientific basis for their management and ecological *** study developed a three-level indicator system for its *** results indicated that:Zhongh...
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The assessment of the ecosystem health of urban rivers and lakes is the scientific basis for their management and ecological *** study developed a three-level indicator system for its *** results indicated that:Zhonghai and Nanhai are in the state of transition from unhealthy to critical state and all the other lakes are in unhealthy *** environmental quality,structure and function of the aquatic ecosystem,and the structure of waterfront areas were the *** was ranked as poor and the others were all ranked as very ***,the ecological environment of Zhonghai and Nanhai were better than the others,the sums of the degree of membership to the healthy state and critical state were all close to *** the restorations of these lakes were *** sums of the degree of membership to the healthy state and critical state of the other lakes were under 0.3,as it was difficult to restore these *** suggestions on scientific management and ecological restoration of the six lakes were proposed:①To control non-point pollution and to improve the water quality of six lakes and the water entering into these lakes;②To improve the hydrological conditions of six lakes;③To rehabilitate the aquatic ecosystem and waterfront areas.
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