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Evaluation of nutrient limitation in aquatic ecosystems with nitrogen fixing bacteria

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Journal of Environmental Sciences 2006年第3期18卷 537-542页

作者： WU Gen-fu WU xue-chang xuan Xiao-dong ZHOU xue-ping College of Life Sciences Zhejiang University Hangzhou 310012 China Science and Technology Committee of Zhejiang Hangzhou 310006 China Institute of Biotechnology Zhejiang University Hangzhou 310029 China

There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems, there are, however, many water sources that are limited by phosphorus or nitrogen. A method named ＂nitrogen fixing bacterial growth potential＂（NFBGP） test, which is based on pre-culturing of autochthonous （target） microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential （AGP） test and the bacterial regrowth potential （BRP） test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.

关键词： environment monitoring nitrogen fixing bacterium limiting nutrient phosphorus growth potential

Addition of Allyltrimethylsilane to tert-Butanesulfinyl Imines Triggered by Tetra-n-butylammonium Fluoride

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Chinese Chemical Letters 2006年第8期17卷 1037-1040页

作者： Wan xuan ZHANG xue Long HOU Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules Faculty of Chemistry and Material Science Hubei University Wuhan 430062 State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032

The addition of allyltrimethylsilane to tert-butanesulfinyl imines triggered by tetra-n-butylammonium fluoride （TBAF） in the presence of 4A molecular sieves has been studied, and homoallylsulfinamides were obtained ... 详细信息

关键词： Stereoselective addition tert-butanesulfinyl imines allyltrimethylsilane tetra-n-butylammonium fluoride.

Association betweenITGA2 C807T polymorphism and gastric cancer risk

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World Journal of Gastroenterology 2011年第23期17卷 2860-2866页

作者： Jie Chen nan-nan Liu Jia-Qi Li Li Yang Ying Zeng Xiao-Mei Zhao Lin-Lin Xu xuan Luo Bin Wang xue-Rong Wang Department of Pharmacology Nanjing Medical University Nanjing210029 Jiangsu Province China Department of General Surgery First Affiliated Hospitalof Nanjing Medical University Nanjing 210029 Jiangsu Prov-ince China

AIM： To evaluate the impact of the ITGA2 gene polymorphism on gastric cancer risk. METHODS： A hospital-based case-control study was conducted, including 307 gastric cancer patients and 307 age- and gender-matched control subjects. The genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism assay. RESULTS： The frequencies of the wild and variant genotypes in cases were significantly different from those of controls （P = 0.019）. Compared with individuals with the wild genotype CC, subjects with the variant genotypes （CT ＋ IT） had a significantly higher risk of gastric cancer （adjusted odds ratio = 1.57, 95% CI = 1.13-2.17, P = 0.007）. In stratified analyses, the elevated gastric cancer risk was especially evident in older individuals aged 〉 58 years, nonsmokers and rural subjects. Further analyses revealed that the variant genotypes were associated with poor tumor differentiation and adjacent organ invasion in the sub-analysis of gastric cancer patients. CONCLUSION： The ITGA2 gene C807T polymorphism may be associated with an increased risk of gastric cancer, differentiation and invasion of gastric cancer.

关键词： Gastric cancer Integrin ITGA2 Polymor-phism Genotype

Segmentation by Elastica Energy with L^(1) and L^(2) Curvatures: a Performance Comparison

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Numerical Mathematics(Theory,Methods and Applications) 2019年第1期12卷 285-311页

作者： xuan He Wei Zhu xue-Cheng Tai Department of Mathematics University of AlabamaBox 870350TuscaloosaAL 35487USA Department of Mathematics Hong Kong Baptist UniversityKowloonTong KowloonHong Kong

In this paper,we propose an algorithm based on augmented Lagrangian method and give a performance comparison for two segmentation models that use the L^(1)-and L^(2)-Euler’s elastica energy respectively as the regularization for image *** capture contour curvature more reliably,we develop novel augmented Lagrangian functionals that ensure the segmentation level set function to be signed dis-tance functions,which avoids the reinitialization of segmentation function during the iterative *** the proposed algorithm and with the same initial contours,we compare the performance of these two high-order segmentation models and numerically verify the different properties of the two models.

关键词： Augmented Lagrangian method Euler’s elastica image segmentation

SFNet:Stellar Feature Network with CWT for Stellar Spectra Recognition

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Research in Astronomy and Astrophysics 2024年第9期24卷 260-270页

作者： Hao Fu Peng Liu xuan Qi xue Mei College of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816China

Stellar spectral classification is crucial in astronomical data ***,existing studies are often limited by the uneven distribution of stellar samples,posing challenges in practical *** when balancing stellar categories and their numbers,there is room for improvement in classification *** study introduces a Continuous Wavelet Transform using the Super Morlet wavelet to convert stellar spectra into wavelet images.A novel neural network,the Stellar Feature Network,is proposed for classifying these *** spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope DR9,encompassing five equal categories(B,A,F,G,K),were *** experiments validate the effectiveness of the proposed methods and network,achieving significant improvements in classification accuracy.

关键词： methods data analysis-techniques image processing-stars imaging-galaxies stellar content

NUMERICAL STUDY OF MULTIDIRECTIONAL FOCUSING WAVE RUN-UP ON A VERTICAL SURFACE-PIERCING CYLINDER

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Journal of Hydrodynamics 2012年第1期24卷 86-96页

作者： SUN Zhong-bin LIU Shu-xue LI Jin-xuan State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

In this article,a numerical model based on improved Boussinesq equations and the Finite Element Method（FEM）with unstructured triangular elements is proposed and verified by experimental results for the focusing wave group interaction with a vertical surface-piercing *** multidirectional focusing waves with different directional spreading parameters and their interaction with a vertical surface-piercing cylinder are numerically *** directional spreading parameter influences the wave form,that is,a wider directional spreading would induce a narrower wave form in *** wave run-up on the cylinder increases with the increase of the wave directional spreading parameter,but when the parameter is greater than 30-40,the wave run-up changes only slightly and the influence of the directional spreading can be neglected.A larger diameter cylinder may have a larger wave run-up at the front *** at the back side,it is other way round.

关键词： focusing waves Finite Element Method(FEM) improved Boussinesq equations run-up

Development of a Bird-like Flapping-wing Aerial Vehicle with Autonomous Take-off and Landing Capabilities

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Journal of Bionic Engineering 2021年第6期18卷 1291-1303页

作者： Dongfu Ma Bifeng Song Zhihe Wang Jianlin xuan Dong xue School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China Yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang215400China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518057China

The lack of autonomous take-off and landing capabilities of bird-like flapping-wing aerial vehicles(BFAVs)seriously restricts their further development and ***,combined with the current research results on the autonomous take-off and landing technology of unmanned aerial vehicles,four types of technologies are studied,including jumping take-off and landing technology,taxiing take-off and landing technology,gliding take-off and landing technology,and vertical take-off and landing(VTOL)*** on the analytic hierarchy process(AHP)-comprehensive evaluation method,a fuzzy comprehensive evaluation model for the autonomous take-off and landing scheme of a BFAV is established,and four schemes are evaluated *** results show that under the existing technical conditions,the hybrid layout VTOL scheme is the ***,the detailed design and development of the prototype of a BFAV with a four-rotor hybrid layout are carried out,and the vehicle performance is *** results prove that through the four-rotor hybrid layout design,the BFAV has good autonomous take-off and landing *** power consumption analysis shows that for a fixed-point reconnaissance mission,when the mission radius is less than 3.38 km,the VTOL type exhibits longer mission duration than the hand-launched type.

关键词： Bird-like flapping-wing aerial vehicle(BFAV) Autonomous take-off and landing Take-off mechanism Hybrid layout

Hydrogen as a carrier of renewable energies toward carbon neutrality:State-of-the-art and challenging issues

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International Journal of Minerals,Metallurgy and Materials 2022年第5期29卷 1073-1089页

作者： xuan Liu Gaoyang Liu Jilai xue Xindong Wang Qingfeng Li Department of Energy Conversion and Storage Technical University of DenmarkFysikvej 3102800 Kgs.LyngbyDenmark School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Energy storage and conversion via a hydrogen chain is a recognized vision of future energy systems based on renewables and,therefore,a key to bridging the technological gap toward a net-zero CO_(2)emission *** paper reviews the hydrogen technological chain in the framework of renewables,including water electrolysis,hydrogen storage,and fuel cell *** electrolysis is an energy conversion technology that can be scalable in megawatts and operational in a dynamic mode to match the intermittent generation of renewable *** concerns include a robust diaphragm for alkaline cells,catalysts and construction materials for proton exchange membrane(PEM)cells,and validation of the long-term durability for solid oxide *** storage via compressed gas up to 70 MPa is optional for automobile *** cells favor hydrogen fuel because of its superfast electrode *** fuel cells and solid oxide fuel cells are dominating technologies for automobile and stationary applications,*** technologies are at the threshold of their commercial markets with verified technical readiness and environmental merits;however,they still face restraints such as unavailable hydrogen fueling infrastructure,long-term durability,and costs to compete with the analog power technologies already on the market.

关键词： carbon neutrality hydrogen energy water electrolysis hydrogen storage fuel cells

A multiscale adaptive framework based on convolutional neural network:Application to fluid catalytic cracking product yield prediction

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Petroleum Science 2024年第4期21卷 2849-2869页

作者： nan Liu Chun-Meng Zhu Meng-xuan Zhang Xing-Ying Lan College of Artificial Intelligence China University of Petroleum(Beijing)Beijing102249China State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)Beijing102249China

Since chemical processes are highly non-linear and multiscale,it is vital to deeply mine the multiscale coupling relationships embedded in the massive process data for the prediction and anomaly tracing of crucial process parameters and production *** the integrated method of adaptive signal decomposition combined with time series models could effectively predict process variables,it does have limitations in capturing the high-frequency detail of the operation state when applied to complex chemical *** light of this,a novel Multiscale Multi-radius Multi-step Convolutional Neural Network(Msrt Net)is proposed for mining spatiotemporal multiscale ***,the industrial data from the Fluid Catalytic Cracking(FCC)process decomposition using Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)extract the multi-energy scale information of the feature ***,convolution kernels with varying stride and padding structures are established to decouple the long-period operation process information encapsulated within the multi-energy scale ***,a reconciliation network is trained to reconstruct the multiscale prediction results and obtain the final *** Net is initially assessed for its capability to untangle the spatiotemporal multiscale relationships among variables in the Tennessee Eastman Process(TEP).Subsequently,the performance of Msrt Net is evaluated in predicting product yield for a 2.80×10^(6) t/a FCC unit,taking diesel and gasoline yield as *** conclusion,Msrt Net can decouple and effectively extract spatiotemporal multiscale information from chemical process data and achieve a approximately reduction of 30%in prediction error compared to other time-series ***,its robustness and transferability underscore its promising potential for broader applications.

关键词： Fluid catalytic cracking Product yield Data-driven modeling Multiscale prediction Data decomposition Convolution neural network