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Merging bound states in the continuum in an open acoustic resonator

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 124-131页

作者： Lujun Huang Bin Jia Artem S.Pilipchuk Sibo Huang Chen Shen Almas F.Sadreev Yong Li Andrey E.Miroshnichenko School of Physics and Electronic Sciences East China Normal University institute of Acoustics Tongji University L.V.Kirensky institute of Physics Department of Mechanical Engineering Rowan University School of Engineering and Technology University of New South Wales at Canberra

Bound states in the continuum （BICs） are perfectly localized resonances despite embedding in the continuum ***,an isolated BIC is very sensitive to the structure ***,we report merging acoustic BICs in a single open resonator,robust against the structure *** find that both symmetry-protected BIC and Friedrich-Wintgen BIC are sustained in a single coupled waveguide-resonator *** varying the height and length of the resonator,these two BICs move toward each other and merge into a single one at a critical *** to an individual BIC,the merged BIC is robust against fabrication error because its Q-factor is proportional to ΔL-4,whereΔL embodies the structure *** essence of this extraordinary phenomenon is perfectly explained by the two-and three-level approximations of the effective nonHermitian ***,we present direct experimental demonstrations of the moving and merging of BICs in a coupled 3D waveguide-resonator,which are evidenced by the vanishing of the linewidth of Fano resonance in the transmission *** results may find exciting applications in designing high-quality acoustic sources,sensors and filters.

关键词： acoustic resonances bound state in the continuum high-Q resonances

Reactivity Ratios of Diethyldiallylammonium Chloride with Acrylamide or Acrylic Acid

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Chinese Chemical Letters 2006年第11期17卷 1523-1526页

作者： Li Hua LIU Zhi Qiang LIU Zhu Qing GONG College of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan 411201 metallurgical Physical Chemistry institute Central South University Changsha 410083

The compositions of copolymers of diethyldiallylammonium chloride （DEDAAC） with acrylamide （AM）, acrylic acid （AA） or sodium acrylic acid （NaAA） at low conversion were determined by elemental analysis, and the reactivity ratios of monomers in copolymerization were obtained by Kelen-Tudos method. The results showed that the reactivity ratios rDE and rAM are 0.31 and 5.27 for DEDAAC with AM, rDE and rAA are 0.28 and 5.15 for DEDAAC with AA, and roe and rNsAA are 0.40 and 3.97 for DEDAAC with NaAA, respectively. The copolymerizations for DEDAAC with AM, AA or NaAA are non-ideal copolymerization and the products are random copolymers.

关键词： Diethyldiallylammonium chloride (DEDAAC) acrylamide (AM) acrylic acid (AA),copolymerization reactivity ratios.

Arsenic dynamics in the rhizosphere and its sequestration on rice roots as affected by root oxidation

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Journal of Environmental Sciences 2014年第4期26卷 892-899页

作者： Weisong Pan Chuan Wu Shengguo Xue William Hartley institute of Environmental Engineering School of Metallurgical Science and Engineering Central South University College of Bioscience and Biotechnology Hunan Agricultural University Crop and Environment Sciences Department Harper Adams University

A pot experiment was conducted to investigate the effects of root oxidation on arsenic （As） dynamics in the rhizosphere and As sequestration on rice roots. There were significant differences （P 〈 0.05） in pH values between rhizosphere and non-rhizosphere soils, with pH 5.68-6.16 in the rhizosphere and 6.30-6.37 in non-rhizosphere soils as well as differences in redox potentials （P 〈 0.05）. Percentage arsenite was lower （4%-16%） in rhizosphere soil solutions from rice genotypes with higher radial oxygen loss （ROL） compared with genotypes with lower ROL （P 〈 0.05）. Arsenic concentrations in iron plaque and rice straw were significantly negatively correlated （R = -0.60, P 〈 0.05）. Genotypes with higher ROL （TD71 and Yinjingmanzhau） had significantly （P 〈 0.001） lower total As in rice grains （1.35 and 0.96 mg/kg, respectively） compared with genotypes with lower ROL （IAPAR9, 1.68 mg/kg; Nanyangzhan 2.24 mg/kg） in the As treatment, as well as lower inorganic As （P 〈 0.05）. The present study showed that genotypes with higher ROL could oxidize more arsenite in rhizosphere soils, and induce more Fe plaque formation, which subsequently sequestered more As. This reduced As uptake in aboveground plant tissues and also reduced inorganic As accumulation in rice grains. The study has contributed to further understanding the mechanisms whereby ROL influences As uptake and accumulation in rice.

关键词： arsenic iron plaque rhizosphere radial oxygen loss rice

Constraints of REE and trace elements of high-pressure-veins and host rocks in western Tianshan on origin of deep fluids in paleosubduction zones

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Journal of central south University of Technology 2005年第2期12卷 192-198页

作者：黄德志高俊戴塔根 School of Geoscience and Environmental Engineering Central South University Changsha 410083 China institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The western Tianshan high-pressure(HP) metamorphic belt represents the paleosubduction mélange of paleozoic south Tianshan ocean between the Yili-central Tianshan and Tarim plates. High-pressure veins are extensively developed in this HP belt. Compared with normal mid-ocean ridge basalt(N-MORB), the high-pressure veins and host rocks are enriched in light rare earth elements(LREE) and incompatible elements. But high-pressure veins show a larger variation than host rocks in total REE abundance. On the trace element spidergram, all the samples are enriched in incompatible elements and show strong positive Pb anomaly relative to N-MORB. The array tendency lines of plots of the HP rocks have apparent slopes on diagram of m(Sr) vs m(Sr)/m(Zr), m(Li) vs m(Li)/m(Y) and (m(Ce)) vs m(Ce)/m(Pb), which indicates that the enrichment in LREE and incompatible elements relative to N-MORB of the HP-metamorphic rocks from western Tianshan is not attributed to magma evolution process of the protolith. High field strength elements, such as Nb, Ta, Ti, Zr and Hf, do not show negative anomaly relative to N-MORB, which is dissimilar to that of island arc basalts. Therefore, the enrichment in LREE and incompatible elements of the HP rocks is not attributed to the enrichment of the source of the protolith. The mass ratios of Rb to Ba, Ce to Pb, Nb to U and Ta to U of high-pressure veins and host rocks are intermediate of mid-ocean ridge basalt or oceanic island basalt and continental crust. The fluids in western Tianshan paleosubduction zones are mixtures of two sources, dehydration or devolatilization of host rocks and of subducted sediments.

关键词： rare earth elements trace element fluid in paleosubduction zone high-pressure vein host rock western Tianshan

A new method to improve surface morphology of Ni-Fe-Mo-Co alloy electrode and its catalytic activity for HER

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Rare Metals 2007年第3期26卷 205-212页

作者： LUO Beiping REN Buye XU You ZHENG Yajie Department of Chemistry and Chemical Engineering Hunan Institute of Science and Technology Yueyang 414000 China College of metallurgical Science and Engineering Central South University Changsha 410083 China Research institute of Materials Science South China University of Technology Guangzhou 510640 China

A new pretreatment method has been developed to improve the catalytic activity of the Ni-Fe-Mo-Co alloy electrode for hydrogen evolution reaction （HER）. The procedure involves pre-electrolyzing the Ni-Fe-Mo-Co alloy electrode in 30% KOH solution containing 10% potassium sodium tartrate at 70℃ for 2 h, until some of the Mo and Fe elements are leached out. The surface morphology of the Ni-Fe-Mo-Co alloy demonstrates a unique hive-like structure after the pre- treatment, which has the pore size in a nanometer range （about 50 nm）, a very large real surface area, and good stability. The results of the electrochemical studies show that compared to other similar electrode materials and the treated Ni-Fe-Mo-Co electrode by leaching method, the pre-treated Ni-Fe-Mo-Co electrode has a much lower overpotential and much higher exchange current density for HER. In addition, a long-term continuous electrolysis test with a current interruption shows that the Ni-Fe-Mo-Co alloy has excellent catalytic stability.

关键词： catalytic activity surface treatment Ni-Fe-Mo-Co alloy hydrogen evolution electrodeposition

Effects of low-intensity pulsed ultrasound stimulation on porous hydroxyapatite blocks for posterolateral fusion of lumbar spine in rabbits

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Transactions of Nonferrous Metals Society of China 2010年第10期20卷 1921-1927页

作者：卓祥龙吕红斌徐大启刘彬王锡阳张莹胡建中 Department of Spinal Surgery Xiangya HospitalCentral South University Orthopedic institute of central south University Department of Sports Medicine Xiangya HospitalCentral South University Research Center of Sports Medicine Central South University State Key Laboratory of Powder Metallurgy Central South University

he effects of porous hydroxyapatite blocks（PHABs） and an adjunct low-intensity pulsed ultrasound stimulation（LIPUS） on the fusion rate in a rabbit spinal posterolateral fusion（PLF） model were *** rabbits underwent PLF with autograft and PHABs were randomly assigned to two groups：treated group with 20 min LIPUS daily and untreated control group for 4 weeks until *** fused motion segments were subjected to manual palpation,gross observation,and radiographic investigation before histomorphologic and scanning electron microscopic *** differences between the LIPUS group and the control group are found in the fusion rate,bone density gray scale,trabecular bone formation,osteoblast-like cells,chondrocytes and positive expression of BMP-2 and TGF-β1 in the junction zone（significance level p〈0.05）.The results suggest that LIPUS can increase fusion rates and accelerate bone in-growth into ***,PHAB and LIPUS may be used together to increase fusion rates in a rabbit spinal fusion model with a promising extension to human application.

关键词： low-intensity pulsed ultrasound stimulation lumbar posterolateral fusion porous hydroxyapatite blocks

Forward modeling for “earth-ionosphere” mode electromagnetic field

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Journal of central south University 2016年第9期23卷 2305-2313页

作者： LI Di-quan Key Laboratory of Metallogenic Prediction of Nonferrous Metals of Ministry of Education (central south University) Changsha 410083 China School of Geosciences and Info-Physics Central South University Changsha 410083 China institute of geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

A fixed artificial source(greater than 200 kW) was used and the source location was selected at a high resistivity region to ensure high emission efficiency. Some publications used the "earth-ionosphere" mode in modeling the electromagnetic(EM) fields with the offset up to a thousand kilometer, and such EM fields still have a signal/noise ratio of 10-20 dB. This means that a new EM method with fixed source is feasible, but in their calculation, the displacement in air was neglected. In this work, some three-layer modeling results were presented to illustrate the basic EM fields' characteristics in the near, far and waveguide areas under "earth-ionosphere" mode, and a standard is given to distinguish the boundary of near, far and waveguide areas. Due to the influence of the ionosphere and displacement current in the air, the "earth-ionosphere" mode EM fields have an extra waveguide zone, where the fields' behavior is very different from that of the far field zone.

关键词： earth-ionosphere mode large power large offset electromagnetic field forward modeling

Characterization of a newly Isolated Bacterium Pandoraea sp.B-6 capable of degrading kraft Lignin

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Journal of central south University 2013年第3期20卷 757-763页

作者：郑玉柴立元杨志辉张欢陈跃辉 institute of Environmental Science & Engineering School of Metallurgical Science and EngineeringCentral South University Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution

A newly isolated bacterium was screened out for its survival on medium with 6 000 mg/L kraft lignin as the sole carbon source and energy, and identified as Pandoraea sp. by 16S rRNA gene sequence analysis. The biodegradation experiment was carried out in mineral salt medium, containing 5 000 mg/L kraft lignin as only carbon and energy at pH 8.0 and 30℃. Under these conditions, significant reduction in color and lignin content by the strain was observed after incubation for 5 d. The strain attains maximum reduction capability in color （44.6%） and lignin content （39.9%） within 5 d of incubation, and reduced chemical oxygen demand（COD） from initial concentration 7 399 to 3 980 mg/L at maximum reduction level of 46.2% on the 4th day. The total ion chromatograph （TIC） of compounds presented in the chloroform extract of control and bacterial treated samples shows the formation of several lignin-related aromatic compounds including some small molecular lignin fragments, indicating a strong destruction in the lignin structure.

关键词： kraft lignin Pandoraea sp. biodegradation gas chromatography-mass spectrophotometry relative molecular massdistribution

A Survey on Emerging Computing Paradigms for Big Data

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Chinese Journal of Electronics 2017年第1期26卷 1-12页

作者： ZHANG Yaoxue REN Ju LIU Jiagang XU Chugui GUO Hui LIU Yaping School of Information Science and Engineering Central South University Research institute of Information Security and Big Data Central South University

The explosive growth of data volume and the ever-increasing demands of data value extraction have driven us into the era of big data. The "5V"(Variety,Velocity, Volume, Value, and Veracity) characteristics of big data pose great challenges to traditional computing paradigms and motivate the emergence of new *** computing is one of the representative technologies that can perform massive-scale and complex data computing by taking advantages of virtualized resources, parallel processing and data service integration with scalable data storage. However, as we are also experiencing the revolution of Internet-of-things(IoT), the limitations of cloud computing on supporting lightweight end devices significantly impede the flourish of cloud computing at the intersection of big data and IoT era. It also promotes the urgency of proposing new computing paradigms. We provide an overview on the topic of big data, and a comprehensive survey on how cloud computing as well as its related technologies can address the challenges arisen by big ***, we analyze the disadvantages of cloud computing when big data encounters IoT, and introduce two promising computing paradigms, including fog computing and transparent computing, to support the big data services of IoT. Finally, some open challenges and future directions are summarized to foster continued research efforts into this evolving field of study.

关键词： Computing paradigm Big data Cloud computing Transparent computing Fog computing Internet-of-things(IoT)