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Isobaric enzymatic assays reveal depth-dependent variation in microbial ectoenzyme activities in the deepest ocean on Earth

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Science China Earth Sciences 2025年第1期68卷 185-194页

作者： Junwei CAO Jiahua WANG Hongge ZHANG Junhao DENG Binbin PAN jiawang CHEN Li ZHANG Jiasong FANG College of Oceanography and Ecological Science Shanghai Ocean University Ocean College Zhejiang University Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology

Microbial ectoenzymes play essential roles in the transformation and mineralization of organic matter in the ***, conventional methods for measuring microbial ectoenzyme activities(MEAs) in the deep ocean under atmospheric conditions can misrepresent the metabolic activities of indigenous microbial communities. To overcome this limitation, we measured the activities of three microbial ectoenzymes(aminopeptidase, α-glucosidase, and β-glucosidase) under both atmospheric and in situ pressure conditions in seawater collected using pressure-retaining and non-pressure-retaining samplers in the Challenger Deep, Mariana Trench. In the case of aminopeptidase and α-glucosidase, the highest isobaric MEAs were observed in the surface layer(50 m), followed by those at abyssopelagic depths(4,000–6,000 m) for aminopeptidase, hadal realm(10,903 m)for α-glucosidase, while β-glucosidase activity exhibited the highest value at 10,903 m. Furthermore, the isobaric MEAs in hadal waters were commonly found to be higher than the decompressed counterparts, highlighting the importance of pressure-retaining sampling and isobaric enzymatic assays. The half-saturation constant(Km) showed a general decreasing trend with depth,suggesting that the deep ocean microbes might have adapted to the high-pressure and oligotrophic environment by increasing their ectoenzyme's affinity to substrate. Furthermore, particle-free MEAs contribute more to the total MEAs in the deep ocean than particle-associated MEAs, suggesting the significance of cell-associated and dissolved ectoenzymes in ocean *** study provides a foundation for future investigations of MEAs in the ocean and has important implications for understanding the dynamics of microbially mediated biogeochemical cycling in marine ecosystems.

关键词： Pressure-retaining sampling Microbial ectoenzyme activity Deep-sea microbes High pressure Mariana Trench

Sum of squares methods for minimizing polynomial forms over spheres and hypersurfaces

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Frontiers of Mathematics in China 2012年第2期7卷 321-346页

作者： jiawang NIE Department of Mathematics University of California San DiegoLa Jolla CA 92093 USA

Abstract This paper studies the problem of minimizing a homogeneous polynomial （form） f（x） over the unit sphere Sn-1 = {x ∈ R^n：｜｜X｜｜2 = 1}. The problem is NP-hard when f（x） has degree 3 or higher. Denote by fmin （resp. fmax） the minimum （resp. maximum） value of f（x） on S^n-1. First, when f（x） is an even form of degree 2d, we study the standard sum of squares （SOS） relaxation for finding a lower bound of the minimum .fmin ：max γ s.t.f（x）-γ.｜｜x｜｜2^2d is *** fos be be the above optimal value. Then we show that for all n ≥ 2d,Here, the constant C（d） is independent of n. Second, when f（x） is a multi-form and ^-1 becomes a muilti-unit sphere, we generalize the above SOS relaxation and prove a similar bound. Third, when f（x） is sparse, we prove an improved bound depending on its sparsity pattern; when f（x） is odd, we formulate the problem equivalently as minimizing a certain even form, and prove a similar bound. Last, for minimizing f（x） over a hypersurface H（g） = {x E lRn： g（x） = 1} defined by a positive definite form g（x）, we generalize the above SOS relaxation and prove a similar bound.

关键词： Approximation bound form hypersurface L2-norm G-norm,multi-form polynomial semidefinite programming sum of squ^res

An Approximation Bound Analysis for Lasserre’s Relaxation in Multivariate Polynomial Optimization

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Journal of the Operations Research Society of China 2013年第3期1卷 313-332页

作者： jiawang Nie Department of Mathematics University of California San Diego9500 Gilman DriveLa JollaCA 92093USA

Suppose f,g1,…,gm are multivariate polynomials in x∈R^(n)and their degrees are at most *** the problem:Minimize f(x)subject to g1(x)≥0,…,gm(x)≥*** f_(min)(resp.,f_(max))be the minimum(resp.,maximum)of f on the feasible set S,and f_(sos)be the lower bound of_(fmin)given by Lasserre’s relaxation of order *** paper studies its approximation *** a suitable condition on g1,…,gm,we prove that(f_(max)−f_(sos))≤Q(f_(max)−f_(min))with Q a constant depending only on g1,…,gm but not on *** particular,if S is the unit ball,Q=O(n^(d));if S is the hypercube,Q=O(n^(2d));if S is the boolean set,Q=O(n^(d)).

关键词： Approximation bound Lasserre’s relaxation Polynomials Semidefinite programming Sum of squares

A MULTI-OBJECTIVE ROBUST OPERATION MODEL FOR ELECTRONIC MARKET ENABLED SUPPLY CHAIN WITH UNCERTAIN DEMANDS

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Journal of Systems Science and Systems Engineering 2007年第1期16卷 74-87页

作者： jiawang XU Xiaoyuan HUANG Nina YAN Management Department Shenyang Institute of Aeronautical Engineering Shenyang 110136 China School of Business Administration Northeastern University Shenyang 110004 China

A multi-objective robust operation model is proposed in this paper for an electronic market enablexi supply chain consisting of multi-supplier and multi-customer with uncertain demands. Suppliers in this supply chain provide many kinds of products to different customers directly or through electronic market. Uncertain demands are described as a scenario set with certain probability;, the supply chain operation model is constructed by using the robust optimization method based on scenario analyses. The operation model we proposed is a multi-objective programming problem satisfying several conflict objectives, such as meeting the demands of all customers, minimizing the system cost, the availabilities of suppliers＇ capacities not below a certain level, and robustness of decision to uncertain demands. The results of numerical examples proved that the solution of the model is most conservative; however, it can ensure the robustness of the operation of the supply chain effectively.

关键词： Operation management robust optimization objective programming electronic market

Phonon anharmonicity:a pertinent review of recent progress and perspective

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Science China(Physics,Mechanics & Astronomy) 2021年第11期64卷 10-43页

作者： Bin Wei Qiyang Sun Chen Li jiawang Hong Henan Key Laboratory of Materials on Deep-Earth Engineering School of Materials Science and EngineeringHenan Polytechnic UniversityJiaozuo 454000China School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Department of Mechanical Engineering University of CaliforniaRiversideRiverside CA 92521USA Materials Science and Engineering University of CaliforniaRiversideRiverside CA 92521USA

Anharmonic lattice vibrations play pivotal roles in the thermal dynamics in condense matters and affect how the atoms interact and conduct *** in-depth understanding of the microscopic mechanism of phonon anharmonicity in condensed systems is critical for developing better functional and energy *** recent years,various novel behaviors in condense matters driven by phonon anharmonic effects were discovered,such as soft mode phase transition,negative thermal expansion(NTE),multiferroicity,ultralow thermal conductivity(κ),high thermal resistance,and high-temperature *** properties have endowed anharmonicity with many promising applications and provided remarkable opportunities for developing“Anharmonicity Engineering”-regulating heat transport towards excellent performance in *** this work,we review the recent development of studies on phonon anharmonic effect and summarize its origin,mechanism,research methods,and ***,the remaining challenges,future trends,and prospects of phonon anharmonicity are also discussed.

关键词： phonon phonon anharmonicity thermodynamics inelastic neutron/X-ray scattering

Development of underwater electric manipulator based on interventional autonomous underwater vehicle (AUV)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第3期25卷 238-250页

作者： Xiaohui HU jiawang CHEN Hang ZHOU Ziqiang REN Ocean cllege Zhejiang UniversityZhoushan 316021China Hainan Institute Zhejiang UniversitySanya 572025China The Engineering Research Center of Oceanic Sensing Technology and Equipment Ministry of EducationZhoushan 316021China

In applications such as marine rescue,marine science,archaeology,and offshore industries,autonomous underwater vehicles(AUVs)are frequently used for survey missions and monitoring tasks,with most operations being performed by manned submersibles or remotely operated vehicles(ROVs)equipped with robotic arms,as they can be operated remotely for days without ***,they require expensive marine vessels and specialist pilots to operate *** exploring oceans are no longer satisfied with the use of manned submersibles and *** is a growing desire for seabed exploration to be performed using smarter,more flexible,and automated *** improving the field operation and intervention capability of AUVs,large-scale and long-range seafloor exploration and sampling can be performed without the support of a mother ship,making it a more effective,economical,convenient,and rapid means of seafloor exploration and sampling operations,and playing a critical role in marine resource *** this study,we explored the integration technology of underwater electric robotic arms and AUVs and designed a new set of electric manipulators suitable for water depths greater than 500 *** reliability of the key components was analyzed by finite element analysis and,based on the theory of robot kinematics and dynamics,simulations were performed to verify the reliability of the key *** were conducted on land and underwater,trajectory tracking experiments were completed,and the experimental data in air and water were compared and ***,the objectives for further research on the autonomous control of the manipulator underwater were proposed.

关键词： Underwater electric manipulator Inverse kinematics Trajectory planning Trajectory tracking accuracy

Atomic-scale simulations for lithium dendrite growth driven by strain gradient

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Applied Mathematics and Mechanics(English Edition) 2020年第4期41卷 533-542页

作者： Gao XU Feng HAO jiawang HONG Daining FANG State Key Laboratory for Turbulence and Complex Systems&Center for Applied Physics and Technology College of EngineeringPeking UniversityBeijing 100871China Department of Engineering Mechanics Shandong UniversityJinan 250100China School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China

Dendrite formation is a major obstacle, e.g., capacity loss and short circuit,to the next-generation high-energy-density lithium(Li)-metal batteries. The development of successful Li dendrite mitigation strategies is impeded by an insu?cient understanding in Li dendrite growth mechanisms. The Li-plating-induced internal stress in Li-metal and its e?ects on dendrite growth have been widely studied, but the underlying microcosmic mechanism is elusive. In the present study, the role of the plating-induced stress in dendrite formation is analyzed through ?rst-principles calculations and ab initio molecular dynamic(AIMD) simulations. It is shown that the deposited Li forms a stable atomic nano?lm structure on the copper(Cu) substrate, and the adsorption energy of Li atoms increases from the Li-Cu interface to the deposited Li surface, leading to more aggregated Li atoms at the interface. Compared with the pristine Li-metal, the deposited Li in the early stage becomes compacted and su?ers the in-plane compressive stress. Interestingly,there is a giant strain gradient distribution from the Li-Cu interface to the deposited Li surface, making the deposited atoms adjacent to the Cu surface tend to press upwards with perturbation and causing the dendrite growth. This provides an insight into the atomicscale origin of Li dendrite growth, and may be useful for suppressing the Li dendrite in Li-metal-based rechargeable batteries.

关键词： lithium(Li)-metal-based battery Li dendrite strain gradient depositing

Static mechanics analysis of no bumping no vibration welding structure with double-inclined surface for high-speed & heavy-load CWR

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Science China(Technological Sciences) 2011年第3期54卷 603-609页

作者： SONG YuQuan WANG MingHui SONG jiawang Superplasticity and Plasticity Research Institute Jilin University Changchun 130022 China

It is known from our former theoretical analysis that the single-inclined welding surface which is inclined towards the transverse direction of the rail can only eliminate vertical bumping, and the single-inclined welding surface which is inclined towards the vertical direction of the rail can only eliminate lateral vibration. In this paper, we put forward a welding structure of double-inclined welding surface to eliminate the vertical bumping and lateral vibration at the same time, and analyze the stress state of continuous welded rail (CWR) by combining geometrical azimuth. Furthermore, the increase of bearing capacity of CWR with the double-inclined welding surface is theoretically analyzed.

关键词： continuous welded rail double-inclined welding surface bearing capacity regularity

Preparation of Spherical Tungsten Particles Assisted by Hydrothermal Method

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Journal of Wuhan University of Technology(Materials Science) 2023年第6期38卷 1457-1462页

作者： GUO jiawang WEN Xiaoqiang WU Ying XU Jianbing ZHOU Jieying Ganzhou Nonferrous Metallurgy Research Institute Co. LtdGanzhou 341000China

We presented a strategy to prepare spherical tungsten powder by the combination of hydrothermal method and H2reduction *** hydrothermal process,the micelle of tetraethylammonium bromide(TEAB)act as spherical templates for the deposition of tungsten oxide,whereas the excessive TEAB inhibit the formation of spherical tungsten oxide due to the dense molecular layer of TEAB on the tungsten oxide *** acid(CA)can control the formation rate and structure of the tungsten oxide when its concentration is more than 0.2 mol/L,because of its ability to coordinate with tungsten *** synergistic effect of TEAB and CA facilitates the formation of spherical tungsten oxide with nanorod *** being treated by H_(2)at 600 and 650℃,the tungsten oxide particles are reduced to tungsten particles,which maintain the spherical structure of tungsten oxide and have porous structure.

关键词： spherical tungsten particles spherical tungsten oxide hydrothermal method citric acid tetraethylammonium bromide