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Phosphatase activity and culture conditions of the yeast Candida mycoderma sp. and analysis of organic phosphorus hydrolysis ability

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Journal of Environmental Sciences 2014年第11期26卷 2315-2321页

作者： Mang Yan Liufang Yu Liang Zhang Yuexia Guo Kewei dai Yuru Chen Jiangsu Engineering and Technology Research Centre for Microbiology Resource Jiangsu Key Laboratory for Biodiversity and BiotechnologyJiangsu Key Laboratory for Microbes and Functional Genomic College of Life Science Nanjing Normal University School of Biotechnology and Chemical Engineering Taizhou College Nanjing Normal University College of Geographical Sciences Nanjing Normal University

Orthophosphate is an essential but limiting macronutrient for plant growth. About 67% cropland in China lacks sufficient phosphorus, especially that with red soil. Extensive soil phosphorus reserves exist in the form of organic phosphorus, which is unavailable for root uptake unless hydrolyzed by secretory acid phosphatases. Thus, many microorganisms with the ability to produce phosphatase have been exploited. In this work, the activity of an extracellular acid phosphatase and yeast biomass from Candida mycoderma was measured under different culture conditions, such as pH, temperature, and carbon source. A maximal phosphatase activity of 8.47 × 10^5±0.11× 10^5 U/g was achieved by C. Mycoderma in 36 hr under the optimal conditions. The extracellular acid phosphatase has high activity over a wide pH tolerance range from 2.5 to S.0 （optimum pH 3.5）. The effects of different phosphorus compounds on the acid phosphatase production were also studied. The presence of phytin, lecithin or calcium phosphate reduced the phosphatase activity and biomass yield significantly. In addition, the pH of the culture medium was reduced significantly by lecithin. The efficiency of the strain in releasing orthophosphate from organic phosphorus was studied in red soil （used in planting trees） and rice soil （originating as red soil）. The available phosphorus content was increased by 230% after inoculating 20 days in rice soil and decreased by 50% after inoculating 10 days in red soil. This work indicates that the yeast strain C. mycoderma has potential application for enhancing phosphorus utilization in plants that grow in rice soil.

关键词： Acid phosphatase Organic phosphorus compounds Candida mycoderma Lecithin Available phosphorus

Study on Unstable Characteristics of Centrifugal Pump under Different Cavitation Stages

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Journal of Thermal Science 2019年第4期28卷 608-620页

作者： DONG Liang SHANG Huanhuan ZHAO Yuqi LIU Houlin dai Cui WANG Ying Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China

In order to reveal the regularity of unsteady flow of centrifugal pump under different cavitation stages,a visual closed test-bed is built to collect signals such as the distribution of cavitation bubbles at the impeller inlet and external characteristics,*** the process of cavitation of centrifugal *** with the shape and distribution of bubbles captured by high-speed photography,the cavitation stage of the centrifugal pump is *** addition,the variation of vorticity distribution,pressure pulsation and radial force of centrifugal pump under different cavitation stages are studied using the standard κ-ε turbulence model and the Kunz cavitation *** contributions are as follows:The cavitation bubbles can absorb the energy of vortex core to a certain extent and increase the volume of vortex *** bubbles can also block the flow-path and induce the distortion of the internal flow field,resulting in unstable pressure waves that cause a significant increase in pressure pulsation ***,with the development of cavitation,the radial force on the impeller tends to remain invariable first and then decrease,and trajectory of the radial force changes from closed to open.

关键词： centrifugal pump cavitation development stage cavitation bubble distribution pressure pulsation radial force

Mouse Karyotype Obtained by Combining DAPI Staining with Image Analysis

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Wuhan University Journal of Natural Sciences 2006年第2期11卷 441-446页

作者： dai Xiaohua YANG Guangxu LIU Jingyu SONG Yunchun College of Life Science Henan University Kaifeng 475001 Henan China Department of Life Science Western Chongqing University Chongqing 402168 Siehuan China The Key l.aboratory of the Ministry of Education of Plant Developmental Biology Wuhan University Wuhan 430072 Hubei China

In this study, mitotic metaphase chromosomes in mouse were identified by a new chromosome fluorescence banding technique combining DAPI staining with image analysis. Clear 4＇, 6-diamidino-2-phenylindole （DAPI） multiple bands like （J-hands could be produced in mouse. The Meta- Morph software was then used to generate linescans of pixel intensity for the banded chromosomes from short arm to long arm. These linescans were sufficient not only to identify each individual chromosome but also analyze the physical sites of bands in chromosome. Based on the results, the clear and accurate karyotype of mouse metaphase chromosomes was established. The technique is therefore considered to he a new method for cytological studies of mouse.

关键词： mouse 4 ', 6 ditlmidino-2-phenylindole (DA-Pl) fluorescence staining image analysis karyotype

Concurrent catalytic removal of typical volatile organic compound mixtures over Au-Pd/α-MnO2 nanotubes

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Journal of Environmental Sciences 2018年第2期30卷 276-288页

作者： Yunsheng Xia Lu Xia Yuxi Liu Tao Yang Jiguang Deng Hongxing dai College of Chemistry and Chemical Engineering Bohai University Jinzhou 121013 China Key Laboratory of Beijing on Regional Air Pollution Control Beijing Key Laboratory for Green Catalysis and Separation MOE Laboratory of Enhanced Heat Transfer and Energy Conservation and College of Environmental and Energy Engineering Beijing University of Technology Beijing 100124 China Mechanical Engineering Department University of Aveiro 3810-193 Aueiro Portugal

α-MnO2 nanotubes and their supported Au-Pd alloy nanocatalysts were prepared using hydrothermal and polyvinyl alcohol-protected reduction methods, respectively. Their catalytic activity for the oxidation of toluene/m-xylene, acetone/ethyl acetate, acetone/m-xylene and ethyl acetate/m-xylene mixtures was evaluated. It was found that the interaction between Au-Pd alloy nanoparticles and α-MnO2 nanotubes significantly improved the reactivity of lattice oxygen, and the 0.91 wt.% Au0.48 Pd/α-MnO2 nanotube catalyst outperformed the α-MnO2 nanotube catalyst in the oxidation of toluene, m-xylene, ethyl acetate and acetone. Over the0.91 wt.% Au0.48 Pd/α-MnO2 nanotube catalyst,（i） toluene oxidation was greatly inhibited in the toluene/m-xylene mixture, while m-xylene oxidation was not influenced;（ii） acetone and ethyl acetate oxidation suffered a minor impact in the acetone/ethyl acetate mixture; and（iii） m-xylene oxidation was enhanced whereas the oxidation of the oxygenated VOCs（volatile organic compounds） was suppressed in the acetone/m-xylene or ethyl acetate/m-xylene mixtures. The competitive adsorption of these typical VOCs on the catalyst surface induced an inhibitive effect on their oxidation, and increasing the temperature favored the oxidation of the VOCs. The mixed VOCs could be completely oxidized into CO2 and H2 O below 320°C at a space velocity of 40,000 m L/（g·hr）. The 0.91 wt.% Au0.48 Pd/α-MnO2 nanotube catalyst exhibited high catalytic stability as well as good tolerance to water vapor and CO2 in the oxidation of the VOC mixtures. Thus, the α-MnO2 nanotube-supported noble metal alloy catalysts hold promise for the efficient elimination of VOC mixtures.

关键词： Volatile organic compound mixture Manganese dioxide nanotubes Supported gold–palladium alloy catalyst Catalytic oxidation Competitive adsorption

Characteristics of Eddy Current Attenuation and Thickness Measurement of Metallic Plate

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Chinese Journal of Mechanical Engineering 2019年第6期32卷 92-100页

作者： Zhiwei Zeng Pengcheng Ding Jiayi Li Shaoni Jiao Junming Lin Yonghong dai School of Aerospace Engineering Xiamen UniversityXiamen 361005China Work Station of Academicians Fujian Province(Eddysun)Xiamen 361008China

In eddy current testing, the law of attenuation of eddy current(EC) is of great concern. In conductive half space under the excitation of uniform magnetic field, the EC density decreases exponentially in the depth direction. However, in conductor with finite thickness tested by coil, the distribution of EC in the depth direction is more complicated. This paper studies the characteristics of EC attenuation in metallic plate of finite thickness. Simulation results show that there is an EC reflection at the bottom of plate, which changes the law of EC attenuation. A new concept, namely the equivalent attenuation coefficient, is proposed to quantify the speed of EC attenuation. The characteristics of EC attenuation are utilized to explain the nonmonotonic relation between coil voltage and plate thickness. Procedure of selecting frequency is discussed. Thereafter, measurement of plate thickness is carried out and accurate result is obtained.

关键词： Eddy current testing Attenuation of eddy current Thickness measurement Metallic plate

Amorphous transformation of ternary Cu_(45)Zr_(45)Ag_(10) alloy under microgravity condition

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Chinese Physics B 2022年第9期31卷 587-591页

作者： Ming-Hua Su Fu-Ping dai Ying Ruan School of Physical Science and Technology Northwestern Polytechnical UniversityXi'an 710072China

The influences of undercooling rate and cooling rate on the microstructural evolution of ternary Cu_(45)Zr_(45)Ag_(10) alloy using single-roller melt spinning and drop tube are *** rapidly quenched alloy ribbons achieve a homogeneous glass *** microstructure of the droplets transforms from the Cu_(10)Zr_(7) dendrites plus(Cu_(10)Zr_(7)+AgZr)eutectic into Cu_(10)Zr_(7) dendrite with the decrease of droplet *** the diameter decreases to 180μm,the Cu_(45)Zr_(45)Ag_(10) alloy changes from crystal to amorphous structure,showing that the cooling rate is not the only influence factor and the undercooling play a certain role in the forming of the amorphous alloy at the same time under microgravity condition.

关键词： Cu-Zr-Ag rapid solidification microgravity glass transformation

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准噶尔盆地乌夏断裂带构造演化及油气聚集

中国石油大学学报（自然科学版） 2008年第3期32卷 23-29页

作者：冯建伟戴俊生葛盛权中国石油大学地球资源与信息学院山东东营257061 中石油塔里木油田分公司新疆库尔勒841000

针对乌夏断裂带构造变形十分复杂,油气地质条件多变,油气成藏条件极不均衡,勘探程度尚低的状况,应用断层生长指数分析法和深层地震相分析法,对该地区进行了构造层和构造单元划分及变形特征、火山岩和油气生储盖组合分析。结果表明:乌夏... 详细信息

针对乌夏断裂带构造变形十分复杂,油气地质条件多变,油气成藏条件极不均衡,勘探程度尚低的状况,应用断层生长指数分析法和深层地震相分析法,对该地区进行了构造层和构造单元划分及变形特征、火山岩和油气生储盖组合分析。结果表明:乌夏断裂带具有多期叠瓦冲断和分段性构造特征,从石炭纪末洋壳俯冲结束、弧陆强烈碰撞造山活动后,经历了前陆盆地短期伸展火山活动、前陆盆地前展逆冲-断展褶皱、陆内坳陷后展逆冲-断展褶皱、陆内坳陷压张转换和整体抬升剥蚀4个演化阶段,各阶段有着不同的沉积特征,发育不同的沉积旋回。构造演化不仅控制着烃源岩的分布和油气生成,形成了多套断裂体系和地层不整合面,同时也控制着油气成藏期次和运聚过程。受构造演化的多旋回性及储盖组合的联合控制,乌夏断裂带共有4期油气充注过程,油气沿玛湖凹陷呈环带状分布。

关键词：乌夏断裂带构造演化断裂系统沉积特征油气聚集

High-resolution Absorption Spectra of Acetylene in 142.8-152.3 nm

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Chinese Journal of Chemical Physics 2008年第5期21卷 415-420页

作者： Ya-hua Hu Chen Zhen Jing-hua dai Xiao-guo Zhou Shi-lin Liu Hefei National Laboratory for Physical Sciences at Microscale Department of Chemical Physics University of Science and Technology of China Hefei 230026 China

The absorption spectra of acetylene molecules was measured under jet-cooled conditions in the wavelength range of 142.8-152.3 nm, with a tunable and highly resolved vacuum ultraviolet （VUV） laser generated by two-photon resonant four wave difference frequency mixing processes. Due to the sufficient vibrational and rotational cooling effect of the molecular beam and the higher resolution VUV laser, the observed absorption spectra exhibit more distinct spectral features than the previous works measured at room temperature. The major three vibrational bands are assigned as a C-C symmetry stretching vibrational progress （v2=0.2） of the C^1Πu state of acetylene. The observed shoulder peak at 148,2 nm is assigned to the first overtone band of the trans-bending mode V4 of the C^1Πu state of acetylene. Additionally, the two components, 4^20（μ^1Π） and 4^20（k^1Πu）, are suggested to exhibit in the present absorption spectra, due to their Renner-Teller effect and transition selection rule. All band origins and bandwidths are obtained subsequently, and it is found that bandwidths are broadened and lifetimes decrease gradually with the excitation of vibration.

关键词： Acetylene Vacuum ultraviolet Absorption spectrum

Harmonic Balance Methods:A Review and Recent Developments

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Computer Modeling in Engineering & Sciences 2023年第11期137卷 1419-1459页

作者： Zipu Yan Honghua dai Qisi Wang Satya N.Atluri School of Astronautics Northwestern Polytechnical UniversityXi’an710072China National Key Laboratory of Aerospace Flight Dynamics Northwestern Polytechnical UniversityXi’an710072China Department of Mechanical Engineering Texas Tech UniversityLubbock79401USA

The harmonic balance(HB)method is one of the most commonly used methods for solving periodic solutions of both weakly and strongly nonlinear dynamical ***,it is confined to low-order approximations due to complex symbolic *** variants have been developed to improve the HB method,among which the time domain HB-like methods are regarded as crucial improvements because of their fast computation and simple *** far,there are two problems remaining to be addressed.i)A dozen of different versions of HB-like methods,in frequency domain or time domain or in hybrid,have been developed;unfortunately,misclassification pervades among them due to the unclear borderlines of different ***)The time domain HB-like methods suffer from non-physical solutions,which have been shown to be caused by aliasing(mixture of the high-order into the low-order harmonics).Although a series of dealiasing techniques have been developed over the past two decades,the mechanism of aliasing and the final solution to dealiasing are still not well known to the academic *** paper aims to provide a comprehensive review of the development of HB-like methods and enunciate their principal *** particular,the time domain methods are emphasized with the famous aliasing phenomenon clearly addressed.

关键词： Harmonic balance frequency domain HB-like method time domain HB-like method dealiasing technique HB algebraic equation