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Copper-catalyzed asymmetric dearomatizing amination of 2-naphthols:Csp^(2)–N coupling via 1,3-reductive elimination

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Science China Chemistry 2024年第8期67卷 2694-2700页

作者： Aying Yihuo Maoping Pu Zheng tan Jibang Liao Jiuqi tan Qi-Lin Zhou Xiaohua Liu Xiaoming Feng Key Laboratory of Green Chemistry&Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengdu 610064China Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Frontiers Science Centerfor New Organic MatterNankai UniversityTianjin300071China

An efficient catalytic asymmetric dearomatizing amination of 2-naphthols and phenols catalyzed by N,N′-dioxide-copper(I)complex as a chiral catalyst was presented.A variety of optically activeβ-naphthalenone compounds with a nitrogen-containing quaternary carbon stereocenter were obtained with high yield and enantioselectivity under mild reaction *** studies indicated that this Csp^(2)–N dearomatizing coupling proceeds via 1,3-reductive elimination of phenolate-Cu~Ⅲ-amino intermediate in five-membered ring transition *** origin of enantioselectivity has also been elucidated based on density functional theory calculations.

关键词： asymmetric catalysis amination dearomatization copper catalysis coupling reaction

Light quarkonium and charmonium mass shifts in an unquenched quark model

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Chinese Physics C 2024年第9期48卷 96-106页

作者： Xiaoyun Chen Yue tan College of Science Jinling Institute of TechnologyNanjing 211169China Department of Physics Yancheng Institute of TechnologyYancheng 224000China

The unquenched quark model for the light quarkonium and charmonium states is explored in this *** quark-pair creation operator in the^(3)P_(0) model,which combines the two-quark and four-quark components,is modified by considering the effects of the created quark pair's ***,the separation between the created quark pair and valence quark pair is *** the wave functions,including those for the mesons and the relative motion between two mesons,are obtained by solving the corresponding Schrodinger equation using the Gaussian expansion *** aim of this study is to find a new set of parameters that can accurately describe the mass spectrum of low-lying light quarkonium and charmonium ***,certain exotic states,such as X(3872),can be described well in the unquenched quark model.

关键词： the unquenched quark model Gaussian expansion method light quarkonium and charmonium states

圈卷产色链霉菌san7324和san7324L基因阻断对形态分化和尼可霉素产生的影响

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微生物学报 2019年第2期59卷 235-246页

作者：孙军李敬敬李月王川蔡原谭华荣甘肃农业大学动物科学技术学院甘肃兰州730070 中国科学院微生物研究所微生物资源前期开发国家重点实验室北京100101 甘肃农业大学动物医学院甘肃兰州730070 中国科学院大学生命科学学院北京100049

【目的】圈卷产色链霉菌全局性调控基因wblA阻断突变后,尼可霉素不再产生。RNA-seq和转录分析表明san7324基因在野生型菌株中可以正常转录,而在wblA阻断突变株(ΔwblA)中不能转录,为此本文旨在揭示san7324与尼可霉素产生的关系。【方法... 详细信息

【目的】圈卷产色链霉菌全局性调控基因wblA阻断突变后,尼可霉素不再产生。RNA-seq和转录分析表明san7324基因在野生型菌株中可以正常转录,而在wblA阻断突变株(ΔwblA)中不能转录,为此本文旨在揭示san7324与尼可霉素产生的关系。【方法】利用同源双交换策略对san7324进行基因阻断,而后通过基因遗传回补及对尼可霉素生物合成相关基因的转录分析等方法研究san7324的功能。【结果】在相同培养条件下,阻断突变株Δsan7324与野生型菌株相比失去了合成尼可霉素的能力。我们通过同源比对发现圈卷产色链霉菌中还存在一个与san7324同源的基因san7324L,该基因的阻断导致尼可霉素产量降低。当san7324和san7324L两个基因同时被阻断后,得到的突变株Δsan7324-san7324L生长稀疏而且不能正常发育分化形成灰色表型的孢子或孢子链,只能形成白色表型的气生菌丝,同时也丧失了合成尼可霉素的能力。当这两个基因(san7324-san7324L)回补双突变株后,则恢复了野生型的表型(能形成孢子链并恢复尼可霉素的产生)。进一步的研究初步表明san7324和san7324L的阻断主要影响了尼可霉素生物合成基因簇中途径特异性调控基因sanG的转录水平,从而影响圈卷产色链霉菌的发育分化和尼可霉素的产生。【结论】该结果为链霉菌形态分化与生理代谢关系的研究提供了更多的证据,同时为多效调控基因wblA作用机制的阐明奠定了基础。

关键词：圈卷产色链霉菌基因阻断形态分化尼可霉素

链霉素生产菌——灰色链霉菌和热灰紫链霉菌的原生质体融合的研究

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生物工程学报 1989年第2期5卷 119-123页

作者：谭华荣庄增辉薛禹谷中国科学院微生物研究所

本文采用原生质体融合技术,把链霉素生产菌——灰色链霉菌No. 45 Streptomyces griseus No. 45(Lin^r, Rif^s)同耐高温的不产生抗生素的热灰紫链霉菌T272 Streptomyces thermogriseoviolaceus T272(Lin^s, Rif^r)进行了原生质体融合。以抗性为选择标记,以PEG6000为助融剂;选出了融合体。制备超薄切片后在电镜下观察了原生质体融合的详细过程。在链霉素生物合成受抑制的高温(37℃)下,测定了融合体的抑菌活性;从形态上与两亲株不同的46株融合体中发现6.3%的融合体既有耐高温的特性也有抑菌的活性。

关键词：链霉菌原生质体融合耐高温性

Long-term Evolution of Solar Activity and Prediction of the Following Solar Cycles

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Research in Astronomy and Astrophysics 2024年第3期24卷 194-204页

作者： Pei-Xin Luo Bao-Lin tan National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

Solar activities have a great impact on modern high-tech systems,such as human aerospace activities,satellite communication and navigation,deep space exploration,and related scientific ***,studying the long-term evolution trend of solar activity and accurately predicting the future solar cycles are highly *** on the wavelet transform and empirical function fitting of the longest recorded data of the annual average relative sunspot number(ASN)series of 323 yr to date,this work decisively verifies the existence of the solar century cycles and confirms that its length is about 104.0 yr,and the magnitude has a slightly increasing trend on the timescale of several hundred *** on this long-term evolutionary trend,we predict solar cycles 25 and26 by using phase similar prediction *** for solar cycle 25,its maximum ASN will be about146.7±33.40,obviously stronger than solar cycle *** peak year will occur approximately in 2024,and the period will be about 11±1 *** for solar cycle 26,it will start around 2030,and reach its maximum between2035 and 2036,with maximum ASN of about 133.0±3.200,and period of about 10 yr.

关键词： Sun activity-Sun evolution-(Sun) sunspots-methods data analysis

An ultra-thin bolt tension sensor and online monitoring system:For application in hydropower plant unit

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Frontiers of Structural and Civil Engineering 2024年第9期18卷 1388-1400页

作者： Shaoquan ZHANG Yanke tan Hanbin GE Qilin ZHANG Department of Civil Engineering Meijo UniversityNagoya 4688502Japan College of Civil Engineering Tongji UniversityShanghai 200092China

The condition of bolted connections significantly affects the structural ***,conventional bolt tension sensors fail to provide precise measurements due to their bulky size or inadequate *** study employs the piezoresistive effect of crystalline silicon material to fabricate an ultrathin *** sensor exhibits a linear relationship between pressure and voltage,an exceptional stability at varying temperatures,and a superior resistance to corrosion,making it adaptable and user-friendly for applications of high-strength bolt tension monitoring.A monitoring system,incorporating the proposed sensor,has also been *** system provides real-time display of bolt tension and enables the assessment of sensor and structural conditions,including bolt loosening or component *** efficacy of the proposed sensor and monitoring system was validated through a project carried out at the Xiluodu Hydropower *** to the results,the sensor and online monitoring system effectively gauged and proficiently conveyed and stored bolt tension *** addition,correlations were created between bolt tensions and essential unit parameters,such as water head,active power,and pressures at vital points,facilitating anomaly detection and early warning.

关键词： ultra-thin sensor high-strength bolt tension online monitoring system anomaly alarm hydro-generator units

Eutectic-derived synthesis of hierarchically nanoporous copper for electrochemical actuation and solar steam generation

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Nano Research 2024年第3期17卷 2011-2018页

作者： Qingguo Bai Yan Wang Fuquan tan Zhonghua Zhang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJingshi Road 17923Jinan 250061China School of Applied Physics and Materials Wuyi UniversityDongcheng Village 22Jiangmen 529020China School of Materials Science and Engineering University of JinanWest Road of Nan Xinzhuang 336Jinan 250022China

The utilization of nanoporous copper(np-Cu)as a metallic actuator has gained attention in recent years due to its cost-effectiveness in comparison to other precious *** this,the enhancement of np-Cu’s actuation performance remains a challenge due to limitations in its strain amplitude and actuation ***,np-Cu has been deemed as a promising material for solar absorption due to its localized surface plasmon resonance ***,practical applications such as solar steam generators(SSGs)utilizing np-Cu have yet to be *** this study,we present the development of hierarchically nanoporous copper(HNC)through the dealloying of a eutectic Al-Cu *** hierarchical structure of the HNC features a combination of ordered flat channels and randomly distributed continuous nanopores,which work in synergy to improve actuation *** ordered flat channels,with a sub-micron scale,facilitate rapid mass transport of electrolyte ions,while the nano-sized continuous pores,due to their large specific surface area,enhance the induced *** results indicate that the HNC exhibits improved actuation performance,with a two times increase in both strain amplitude and rate in comparison to other reported ***,the HNC,for the first time,showcases excellent solar steam generation capabilities,with an evaporation rate of 1.47 kg·m^(-2)·h^(-1) and a photothermal conversion efficiency of 92%under a light intensity of 1 kW·m^(-2),which rivals that of nanoporous gold and silver *** enhanced actuation performance and newly discovered solar steam generation properties of the HNC are attributed to its hierarchically porous structure.

关键词： eutectic alloy dealloying hierarchically nanoporous copper(HNC) actuation solar steam generation

Influence of laser parameters on the microstructures and surface properties in laser surface modification of biomedical magnesium alloys

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Journal of Magnesium and Alloys 2024年第1期12卷 72-97页

作者： Chee Ying tan Cuie Wen Hua Qian Ang School of Engineering RMIT UniversityMelbourneVictoria 3001Australia

Biodegradable implants from magnesium(Mg)alloys have emerged in the biomedical field especially in the orthopedic and cardiovascular stent applications owing to their low density,high specific strength,excellent machinability,good biocompatibility,and *** primary shortcoming of Mg-based implants is their low corrosion resistance in the physiological environment,which results in premature mechanical integrity loss before adequate healing and the production of excessive hydrogen gas,which is harmful to the body tissues and negatively affects the biocompatibility of the *** surface modification has recently received attention because it can improve the surface properties such as surface chemistry,roughness,topography,corrosion resistance,wear resistance,hydrophilicity,and thus cell response to the surface of the *** composition and microstructures including textures and phases of laser-treated surfaces depend largely on the laser processing parameters(input laser power,laser scan velocity,frequency,pulse duration,pressure,gas circulation,working time,spot size,beam focal position,and laser track overlap)and the thermophysical properties of the substrate(solubility,melting point,and boiling point).This review investigates the impacts of various laser surface modification techniques including laser surface melting,laser surface alloying,laser cladding,laser surface texturing,and laser shock peening,and highlights their significance in improving the surface properties of biodegradable Mg alloys for implant ***,we explore how different laser process parameters affect its composition,microstructure,and surface properties in each laser surface modification technique.

关键词： Biocompatibility Biodegradability Corrosion Implant applications Laser surface modification Magnesium alloys

One-pot Synthesis of Hierarchical Flower-like WS_(2) Microspheres as Anode Materials for Lithium-ion Batteries

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 1-6页

作者：张向华 tan Hen WANG Ze XUE Maoquan School of Mechanical Engineering Jiangsu University of TechnologyChangzhou 213001China School of Materials Engineering Jiangsu University of TechnologyChangzhou 213001China Changzhou Vocational Institute of Industry Technology Changzhou 213164China

3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal *** as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spectroscopy (EDS),scanning electron microscopy (SEM) and *** images of the samples reveal that the hierarchical flowerlike WS_(2) microspheres with diameters of about 3-5μm are composed of a number of curled *** tests such as charge/discharge,cyclic voltammetry,cycle life and rate performance were carried out on the WS_(2) *** an anode material for lithium-ion batteries,hierarchical flowerlike WS_(2) microspheres show excellent electrochemical *** a current density of100 mA·g^(-1),a high specific capacity of 647.8 mA·h·g^(-1) was achieved after 120 discharge/charge *** excellent electrochemical performance of WS_(2) as an anode material for lithium-ion batteries can be attributed to its special 3D hierarchical structure.

关键词： WS_(2) microspheres lithium-ion batteries electrochemical performance