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Exploring seasonal acidification in the Yellow Sea

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Science China Earth Sciences 2018年第6期61卷 647-658页

作者： Weidong zhai Institute of Marine Science and Technology Shandong University

The Yellow Sea on the western continental margin of the North Pacific Ocean is of major ecological and economic importance. Four field surveys were conducted during May and November 2012, August 2015, and January 2016, investigating seasonal variations in dissolved oxygen and carbonate system parameters of this marginal sea. Results showed that the Yellow Sea cold water mass accumulated respiration-induced CO_2 in subsurface and bottom waters in summer and autumn, leading to acidified seawaters with critical carbonate saturation states of aragonite(Ω_(arag)) of less than 1.5. These seriously acidified seawaters occupied one third of surveyed areas in summer and autumn, likely affecting local calcified organisms and benthic communities. In a future scenario for the 2050 s, in which the atmospheric CO_2 mole fraction increases by 100 μmol mol-1, half of the Yellow Sea benthos would be seasonally covered by acidified seawater having a critical Ω_(arag) of less than 1.5. The corresponding bottom-water p H_T would be around 7.85 in summer, and 7.80 in autumn. Of the China seas, the Yellow Sea cold water mass represents one of the ecosystems most vulnerable to ocean acidification.

关键词： CaCO_3saturation state Ocean acidification Yellow Sea pH Dissolved oxygen Benthic communities

ALTERNATING OPTIMIZATION METHOD FOR ISOGEOMETRIC TOPOLOGY OPTIMIZATION WITH STRESS CONSTRAINTS

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Journal of Computational Mathematics 2024年第1期42卷 134-155页

作者： xiaoya zhai School of Mathematical Sciences University of Science and Technology of ChinaHefei 230071China

Topology optimization (TO) has developed rapidly recently. However, topology optimization with stress constraints still faces many challenges due to its highly non-linear properties which will cause inefficient computation, iterative oscillation, and convergence guarantee problems. At the same time, isogeometric analysis (IGA) is accepted by more and more researchers, and it has become one important tool in the field of topology optimization because of its high fidelity. In this paper, we focus on topology optimization with stress constraints based on isogeometric analysis to improve computation efficiency and stability. A new hybrid solver combining the alternating direction method of multipliers and the method of moving asymptotes (ADMM-MMA) is proposed to solve this problem. We first generate an initial feasible point by alternating direction method of multipliers (ADMM) in virtue of the rapid initial descent property. After that, we adopt the method of moving asymptotes (MMA) to get the final results. Several benchmark examples are used to verify the proposed method, and the results show its feasibility and effectiveness.

关键词： Isogeometric topology optimization Stress constraints The ADMM-MMA solver

Mapping non-laminar proton acceleration in laser-driven target normal sheath field

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High Power Laser Science and Engineering 2022年第1期10卷 10-16页

作者： C.Y.Qin H.Zhang S.Li S.H.zhai A.x.Li J.Y.Qian J.Y.Gui F.x.Wu Z.x.Zhang Y.xu x.Y.Liang Y.x.Leng B.F.Shen L.L.Ji R.x.Li State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Ultra-intense Laser Science Shanghai 201800China Department of Physics Shanghai Normal UniversityShanghai 200234China ShanghaiTech University Shanghai 201210China

We report on experimental observation of non-laminar proton acceleration modulated by a strong magnetic field in laser irradiating micrometer aluminum *** results illustrate the coexistence of ring-like and filamentation *** implement the knife edge method into the radiochromic film detector to map the accelerated beams,measuring a source size of 30-110μm for protons of more than 5 *** diagnosis reveals that the ring-like profile originates from low-energy protons far off the axis whereas the filamentation is from the near-axis high-energy protons,exhibiting non-laminar ***-in-cell simulations reproduced the experimental results,showing that the short-term magnetic turbulence via Weibel instability and the long-term quasi-static annular magnetic field by the streaming electric current account for the measured beam *** work provides direct mapping of laser-driven proton sources in the space-energy domain and reveals the non-laminar beam evolution at featured time scales.

关键词： knife-edge technique laser-plasma interaction non-laminar proton source target normal sheath acceleration Weibel instability

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Striking stripes

Science China(Physics,Mechanics & Astronomy) 2017年第8期60卷 80-81页

作者： Hui zhai Institute for Advanced Study Tsinghua University

Spin-orbit coupling is a relativistic effect for the charge par- ticles such as electrons. It has been found that the spin-orbit coupling plays an important role in many branches of physics, for instance, in condensed matter physics, the spin-orbit cou- pling is the key ingredient responsible for the spintronics [ 1 ] and the topological insulator [2]. Nevertheless, in the past, the effect of spin-orbit coupling has only been investigated in many-body systems of fermions. What happens if the spin-orbit coupling is introduced to an interacting boson sys- tem？ Previously, such a system barely exists, while the recent progress of cold atom physics makes it possible. In fact, this is one of a few examples that the recent developments of cold atom physics introduce new physics to us.

关键词：自旋-轨道耦合自旋轨道耦合原子物理学自旋电子学条纹多体系统相对论效应凝聚态物理

Manin’s conjecture for a class of singular cubic hypersurfaces

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Frontiers of Mathematics in China 2022年第6期17卷 1089-1132页

作者： Wenguang zhai Department of Mathematics China University of Mining and TechnologyBeijing100083China

Letℓ≥2 be a fixed positive integer and Q(y)be a positive definite quadratic form inℓvariables with integral *** aim of this paper is to count rational points of bounded height on the cubic hypersurface defined by u^(... 详细信息

关键词： Manin’s conjecture quadratic form asymptotic formula divisor problem exponential sum

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微合金化铸铁同质焊条焊接工艺

焊接学报 2007年第10期28卷 53-56页

作者：翟秋亚翟波唐桢徐锦锋西安理工大学材料科学与工程学院西安710048

应用微合金化铸铁同质焊条,采用小电流打底、大电流连续焊工艺,研究了预热温度与焊缝组织及性能之间的相关性。结果表明,微合金化铸铁焊条石墨化能力强,焊缝白口倾向小;小电流打底、大电流连续焊工艺可有效地减小熔深,在很大程度上抑制... 详细信息

应用微合金化铸铁同质焊条,采用小电流打底、大电流连续焊工艺,研究了预热温度与焊缝组织及性能之间的相关性。结果表明,微合金化铸铁焊条石墨化能力强,焊缝白口倾向小;小电流打底、大电流连续焊工艺可有效地减小熔深,在很大程度上抑制了熔合区白口的产生。微合金化铸铁焊条可实现常温焊接。预热温度小于200℃即可获得组织和性能与母材一致的同质焊缝。随着焊件预热温度的升高,焊缝中的石墨形态由细小的点状逐渐向菊花状、片状过渡,铁素体含量增多,焊缝硬度减小。焊件预热至200℃所获得的焊缝组织由珠光体、铁素体和细片状石墨及菊花状石墨组成,熔合区则由珠光体、少量碎块状铁素体及过冷石墨片组成,接头力学性能良好。

关键词：微合金化铸铁焊条铸铁件常温焊接头组织与性能

A Generalized Version of Branner-Hubbard Conjecture for Rational Functions

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Acta Mathematica Sinica,English Series 2010年第11期26卷 2199-2208页

作者： Yu zhai Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 P. R. China

In 1992, Branner and Hubbard raised a conjecture that the Julia set of a polynomial is a Cantor set if and only if each critical component of its filled-in Julia set is not periodic. This conjecture was solved recentl... 详细信息

关键词： Julia set filled-in Julia set Branner-Hubbard puzzle KSS nest

Cratonization and the Ancient North China Continent:A summary and review

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Science China Earth Sciences 2011年第8期54卷 1110-1120页

作者： zhai MingGuo Key Laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Cratonization is a key geological process to form stable continental masses with a considerable *** Precambrian global cratonization and formation of supercratons in the world is an unrepeated event in the history of the Earth's formation and *** based on study of early Precambrian geology in Eastern Hebei Region and combining other Archean regions in the North China Craton (NCC),the author proposes a two-stage cratonization model of the *** first stage took place at the end of Neoarchean of ～2.5 Ga (boundary time between Archean and Proterozoic),when several micro-blocks were amalgamated together with amphibolite-granulite facies metamorphism and intrusion of crustal-melting granites to form the present-scale *** second cratonization event is cratonic reworking,corresponding to rifting-subduction-collision at 2.3-1.97 Ga and subsequent extension-uplifting related to upwelling mantle at 1.97-1.82 Ga,which could be linked to,respectively,assembly and breaking up of the Columbia *** main Paleoproterozoic mobile belts in the NCC record that small remnant Neoarchean ocean basins and continental rift basins within the craton were opened and finally closed,and metamorphosed to greenschist-amphibolite facies at ～2.0-1.97 *** that,high-grade granulite facies (HT-HP and HT-UHT) metamorphism with abnormally high heat occurred at 1.97-1.82 Ga.A metamorphism-migmatization event that includes lower crust of the NCC uplifting as a whole,intrusion of mafic dyke swarms,continental rifting and anorogenic magmatic action took place in 1.82-1.65 Ga,marking that the second cratonization of the NCC was finally accomplished and started to evolve to a period of stable continent (platform).

关键词： cratonization North China ancient continent

Osteogenesis and angiogenesis of a bulk metallic glass for biomedical implants

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Bioactive Materials 2022年第2期7卷 253-266页

作者： K.Sun R.Fu x.W.Liu L.M.xu G.Wang S.Y.Chen Q.J.zhai S.Pauly Institute of Materials Shanghai UniversityShanghai200444China Department of Neurology Tongren HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200336China Sports Medicine Department of Huashan Hospital Fudan UniversityShanghai200040China University of Applied Sciences Aschaffenburg Würzburger Straße 45D-63743AschaffenburgGermany

Implantation is an essential issue in orthopedic *** metallic glasses(BMGs),as a kind of novel materials,attract lots of attentions in biological field owing to their comprehensive excellent ***,we show that a Zr_(61)Ti_(2)Cu_(25)Al_(12)(at.%)BMG(Zr-based BMG)displays the best cytocompatibility,pronounced positive effects on cellular migration,and tube formation from in-vitro tests as compared to those of commercial-pure titanium and *** in-vivo micro-CT and histological evaluation demonstrate the Zr-based BMG can significantly promote a bone *** tests and digital reconstructed radiographs manifest a stimulated effect on early blood vessel formation from the Zr-based ***,the intimate connection and coupling effect between angiogenesis and osteogenesis must be effective during bone regeneration after implanting Zr-based *** gait analysis in rats after implanting Zr-based BMG demonstrates a tendency to decrease the pain level during recovery,simultaneously,without abnormal ionic accumulation and inflammatory *** suitable mechanical properties,we provide a realistic candidate of the Zr61Ti2Cu25Al12 BMG for biomedical applications.

关键词： Metallic glasses Bio-corrosion Biocompatibility Osteogenesis Angiogenesis