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Chinese Journal of Chemistry 2024年第8期42卷 835-840页

作者： xiaohua Chang Qunli Yu Dan Ji Yutian Zhu College of Material Chemistry and Chemical EngineeringKey Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of EducationHangzhou Normal UniversityHangzhouZhejiang311121 China

Comprehensive Summary Metal nanoparticles(NPs)decorated block copolymer(BCP)hybrid nanoparticles have attracted enormous attention for their actual value in catalysis,medical therapy,and *** confined assembly of BCPs within evaporative emulsion droplet is verified as an effective method to provide polymeric scaffolds to load metal ***,to date,it remains challenging to generate different types of metal NPs decorated BCP hybrid ***,we employed the emulsion confined self-assembly of poly(styrene-b-2-vinylpyridine)(PS-b-P2VP)and the followed seed-mediated growth of Au and palladium(Pd)NPs onto well-defined BCP particles to design a series of Au/Pd decorated BCP hybrid nanoparticles,which exhibited excellent catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol with the reductant of *** work may inspire more researchers to investigate the selective decoration of different metal NPs onto the polymeric scaffolds,broadening the potential applications of the inorganic/organic hybrid nanoparticles.

关键词： Block copolymers Emulsion confined self-assembly Hybrid nanoparticles Catalytic activity Recyclability

Characteristics of Bi-2223 HTS Tapes Under Short-Circuit Current Impacts in Hybrid Energy Transmission Pipelines

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 736-745页

作者： Yuguang Sun Chao Yin Weizhen Li Xinyang Li xiaohua Jiang Department of Electric Engineering Tsinghua UniversityBeijing 100084China

A hybrid energy transmission pipeline is proposed with the aim of long-distance cooperative transmission of electricity and chemical fuels, which is composed of an inner high-temperature superconducting (HTS) power cable and outer liquefied natural gas (LNG) pipeline. The flowing LNG could maintain the operating temperature of the inner HTS power cable within the range of 85 K-90 K, thus the Bi-2223 superconductors in the HTS power cable produce little Joule loss with the transmission current below the critical current. Owing to the advantages of high power density, low transmission losses and economical manufacturing costs, the hybrid energy transmission pipeline is expected to be widely utilized in the near future. In order to ensure the safety of the HTS power cable and explosive LNG in case of short-circuit faults, this paper tests and analyzes the characteristics of Bi-2223 HTS tapes of the Type HT-CA, Type HT-SS and Type H models under short-circuit current impacts at the LNG cooling temperature (85 K-90 K). An experimental platform is designed and established for the ampacity tests of HTS tapes above LN2 cooling temperature (77 K). The AC over-current impact tests at 85 K-90 K are carried out on each sample of Bi-2223 tapes respectively, and the experimental results are analyzed and compared to evaluate their performances under different operating conditions. The results indicate that the Type HT-CA tape can withstand 50 Hz short-circuit current impact with the amplitude of 1108 A (10 times of critical current Ic ) for 100 ms at 90 K, and its resistance is the smallest of the three tested samples under similar current impacts. Therefore, the Type HT-CA Bi-2223 tape is the optimal superconductor of the HTS power cable in the hybrid energy transmission pipeline.

关键词： Bi-2223 high-temperature superconducting(HTS)tape critical current hybrid energy transmission pipeline liquefied natural gas(LNG)cooling temperature short-circuit current impact characteristics

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机械平面手性轮烷研究进展

中国科学：化学 2023年第12期53卷 2460-2475页

作者：周肖华王威华东师范大学化学与分子工程学院上海200062

作为一类经典的机械互锁分子,轮烷可在其骨架中不含有经典手性元素的情况下仍能表现出手性特征,也就是轮烷的机械平面手性.与传统的手性轮烷相比,机械平面手性为轮烷的手性增加了新的维度.相较于经典的手性,轮烷独特的空间结构和运动特... 详细信息

作为一类经典的机械互锁分子,轮烷可在其骨架中不含有经典手性元素的情况下仍能表现出手性特征,也就是轮烷的机械平面手性.与传统的手性轮烷相比,机械平面手性为轮烷的手性增加了新的维度.相较于经典的手性,轮烷独特的空间结构和运动特性将会进一步丰富其手性内涵,使得其在手性传感和不对称催化等领域具有广阔的应用潜力,因此近年来机械平面手性轮烷引起了越来越多的关注.本文从机械平面手性轮烷的手性特性、制备策略和应用这三个角度出发综述了近年来机械平面手性轮烷的研究进展,并分析了当前所面临的挑战,并展望了该领域未来的发展机遇.

关键词：机械互锁分子机械键平面手性不对称催化手性识别

Numerical and experimental investigation on hydraulic-electric rock fragmentation of heterogeneous granite

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International Journal of Mining Science and Technology 2024年第1期34卷 15-29页

作者： xiaohua Zhu Ling He Weiji Liu Yunxu Luo Youjian Zhang Wuji Tang School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China School of Mechanical Engineering Sichuan University of Science and EngineeringYibin 643002China

Hydraulic-electric rock fragmentation(HERF)plays a significant role in improving the efficiency of high voltage pulse rock ***,the underlying mechanism of HERF remains *** this study,considering the heterogeneity of the rock,microscopic thermodynamic properties,and shockwave time domain waveforms,based on the shockwave model,digital imaging technology and the discrete element method,the cyclic loading numerical simulations of HERF is achieved by coupling electrical,thermal,and solid mechanics under different formation temperatures,confining pressure,initial peak voltage,electrode bit diameter,and loading ***,the HERF discharge system is conducive to the laboratory experiments with various electrical parameters and the resulting broken pits are numerically reconstructed to obtain the geometric *** results show that,the completely broken area consists of powdery rock *** the pre-broken zone,the mineral cementation of the rock determines the transition of type CⅠcracks to type CⅡand type CⅢ***,the peak pressure of the shockwave increased with initial peak voltage but decreased with electrode bit diameter,while the wave front time ***,increasing well depth,formation temperature and confining pressure augment and inhibit HERF,but once confining pressure surpassed the threshold of 60 MPa for 152.40,215.90,and 228.60 mm electrode bits,and 40 MPa for 309.88 mm electrode bits,HERF is ***,for the same kind of rock,the volume and width of the broken pit increase with higher initial peak voltage and rock fissures will promote ***,the electrode drill bit with a 215.90 mm diameter is more suitable for drilling pink *** research contributes to a better microscopic understanding of HERF and provides valuable insights for electrode bit selection,as well as the optimization of circuit parameters for HERF technology.

关键词： Hydraulic-electric rock fragmentation Shockwave Thermodynamics Microcracks Weak Linear Parallel Bond Model

政府补助在IPO新股定价中的角色:折价还是溢价效应?

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财贸研究 2022年第10期33卷 75-88页

作者：徐辉周兵周孝华重庆工商大学会计学院重庆400067 重庆大学经济与工商管理学院重庆400044

以IPO定价为切入点,从一、二级市场两个维度综合考察政府补助对IPO定价的影响,结果发现:政府补助加剧了IPO新股发行溢价,也刺激了二级市场交易溢价,且这一现象在国有企业中更明显。进一步地,基于双边随机边界模型的IPO抑价分解结果表明... 详细信息

以IPO定价为切入点,从一、二级市场两个维度综合考察政府补助对IPO定价的影响,结果发现:政府补助加剧了IPO新股发行溢价,也刺激了二级市场交易溢价,且这一现象在国有企业中更明显。进一步地,基于双边随机边界模型的IPO抑价分解结果表明:政府补助会促使IPO抑价提升,且折价效应和溢价效应是IPO高抑价的主要诱因,但溢价效应占主导地位。此外,项目补助、税收返还以及创新支持类政府补助会导致IPO新股定价被高估,但在信誉奖类补助中未发现这一现象。

关键词：政府补助产权性质 IPO定价溢价抑价分解

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Hydraulic Fracturing-induced Seismicity at the Hot Dry Rock Site of the Gonghe Basin in China

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Acta Geologica Sinica(English Edition) 2021年第6期95卷 1835-1843页

作者： CHEN Zubin ZHAO Fa SUN Feng LU Hao WANG Chunlu WU Haidong zhou xiaohua College of Instrumentation&Electrical Engineering Jilin UniversityChangchun 130026China Key Lab of Geo-Exploration Instrumentation of the Ministry of Education Jilin UniversityChangchun 130026China Center for Hydrogeology and Environmental Geology China Geological SurveyBaodingHebei 071000China

Hot dry rock is becoming an important clean energy source. Enhanced geothermal systems(EGS) hold great promise for the potential to make a contribution to the energy inventory. However, one controversial issue associated with EGS is the impact of induced seismicity. In August 2019, a hydraulic stimulation experiment took place at the hot dry rock site of the Gonghe Basin in Qinghai, China. Earthquakes of different magnitudes of 2 or less occurred during the hydraulic stimulation. Correlations between hydraulic stimulation and seismic risk are still under discussion. Here, we analyze the hydraulic stimulation test and microseismic activity. We quantify the evolution of several parameters to explore the correlations between hydraulic stimulation and induced seismicity, including hydraulic parameters, microseismic events, bvalue and statistical forecasting of event magnitudes. The results show that large-magnitude microseismic events have an upward trend with an increase of the total fluid volume. The variation of the b-value with time indicates that the stimulation experiment induces small amounts of seismicity. Forecasted magnitudes of events can guide operational decisions with respect to induced seismicity during hydraulic fracturing operations, thus providing the basis for risk assessment of hot dry rock exploitation.

关键词： EGS hot dry rock hydraulic stimulation induced seismicity

Sedimentary Facies, Provenance and Geochronology of the Heshangzhen Group: Implications for the Tectonic Evolution of the Eastern Jiangnan Orogen, South China

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Acta Geologica Sinica(English Edition) 2020年第4期94卷 1138-1158页

作者： zhou xiaohua HU Xiumian JIANG Ren GAO Tianshan MA Xue XING Guangfu SUN Gaoyuan SHU Xujie ZHAO Xilin Nanjing Center China Geological SurveyNanjing 210016China State Key Laboratory for Mineral Deposits Research Department of Earth Sciences and EngineeringNanjing UniversityNanjing 210024China Wuhan Center China Geological SurveyWuhan 430205China College of Oceanography Hohai UniversityNanjing 210098China

The Neoproterozoic Jiangnan orogen plays an important role in the study of the Precambrian tectonic evolution of South China. The tectonic nature of the Neoproterozoic sedimentary basins is still controversial, due to poor understanding of the sedimentary sequences and the lack of geochronological data. Here, we present sedimentological, provenance and geochronological data from the Heshangzhen Group in the eastern Jiangnan orogen. Sedimentological analysis shows that the Luojiamen Formation was deposited in a submarine fan, and the overlying Hongchicun Formation was deposited in front of a fan delta. The youngest detrital zircons constrain the lower Luojiamen and Hongchicun formations with ages of 827.3 ± 8.4 Ma and 825 ± 12 Ma, respectively. The sandstones of the Luojiamen Formation are characterized by a large number of intermediate to felsic volcanic grains, suggesting a volcanic arc source. In contrast, quartz and sedimentary lithic grains increase in the Hongchicun Formation, showing a new input from a collisional orogenic source. Detrital zircon from six sandstone samples in the Luojiamen and Hongchicun formations yield similar age spectra of 930–820 Ma with a peak at ca. 845–860 Ma, with one main cluster at 930–820 Ma. Detrital zircons of 930–845 Ma show a positive value of εHf(t)(+2.4 to +11, mean +7.6), which is similar to the volcanic arc of the nearby Shuangxiwu Group. There are a minor group of zircons with U-Pb ages ranging from 820 Ma to 845 Ma from the middle part of the Luojiamen Formation and Hongchicun Formation, with εHf(t) values between-20 to +2.4, which are consistent with the characteristics of the Shuangqiaoshan Group. within light of the bidirectional paleocurrents in the Luojiamen Formation, it is speculated that the zircons of 820–845 Ma were recycled from the Shuangqiaoshan Group, which is derived from a continental arc to the northwest. Our data suggests that the Luojiamen Formation was formed in an inter-arc basin, while the Hongchicun

关键词： provenance detrital zircon chronology Heshangzhen Group Neoproterozoic Jiangnan orogen South China

Regioselective and asymmetric allylic alkylation of vinyl epoxides for the construction of allylic alcohols via synergistic catalysis

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Science China Chemistry 2024年第2期67卷 542-550页

作者： Min Chen Longqing Yang Yuzhen Li Yinhe Qu Guihua Pan Xiaoming Feng xiaohua Liu Key Laboratory of Green Chemistry&Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengdu610064China

A highly efficient asymmetric allylic alkylation of cyclic and acyclic carbon nucleophiles with vinyl epoxides has been developed,which exhibits good functional group compatibility,high atomic and step *** protocol utilizes a strategy of synergistic catalysis with a chiral N,N'-dioxide/Ni~Ⅱ complex and an achiral Pd~0 catalyst,generating a series of multisubstituted allylic alcohols with a quaternary carbon stereocenter in high yield and excellent regio-,Z/E-and enantioselectivity under mild *** transformations of the product demonstrate the potential utility of this protocol in the synthesis of allyl alcohol derivatives and natural product *** studies revealed that the N,N′-dioxide/metal complexes play an important role in controlling the Z/E-and *** density functional theory(DFT) calculations further demonstrated that multiple C–H···π interactions between the aromatic rings of the two substrates and the amide moiety in the ligand stabilized the dominant transition state.

关键词： asymmetric allylic alkylation synergistic catalysis vinyl epoxides allyl alcohol multiple weak interactions

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

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Science China Chemistry 2024年

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 Education College of Chemistry Sichuan University Key Laboratory and Institute of Elemento-Organic Chemistry College of Chemistry Frontiers Science Center for New Organic Matter Nankai University

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 active β-naphthalenone compounds with a nitrogen-containing quaternary carbon stereocenter were obtained with high yield and enantioselectivity under mild reaction conditions. Mechanistic studies indicated that this Csp2–N dearomatizing coupling proceeds via 1,3-reductive elimination of phenolate-CuIII-amino intermediate in five-membered ring transition states. The origin of enantioselectivity has also been elucidated based on density functional theory calculations.

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Realization of Low in-Band Harmonic for Compact 6–18-GHz T/R Module Under TX-Mode Operation

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Chinese Journal of Electronics 2024年第2期33卷 380-384页

作者： Jinming LAI Zhiyou LI Chaojie WANG Hailong WANG xiaohua MA School of Microelectronics Xidian University CETC 29th Research Institute

Wideband high power amplifier(PA) with poor harmonic suppression will degrade the performance of the active electronically scanned array(AESA) due to its harmonic products falling into the operating bandwidth of a wideband T/R module. In view of this, a compact reconfigurable harmonic suppress circuit(HSC) is proposed to achieve low in-band harmonic for compact T/R module with multiple octaves under TX-mode operation. The HSC consists of eight microstrip resonant stubs with high impedance and multiple p-i-n switches. By controlling the p-i-n switches, the HSC can work in three states. When six of the used p-i-n switches are “ON” state, the corresponding microstrip resonant stubs are loaded onto the 50 Ω transmission line, which performs a bandstop filter(BSF). For verification, the HSC with bandwidth of 12–15 GHz/15–18 GHz is designed to apply to a 6–18 GHz T/R module. As a result, the second harmonic of 6–9 GHz transmitting signal can be suppressed below 32 d Bc when compared to the PA's fundamental output. While the p-i-n switches are “OFF” state, the HSC is almost the same as a 50 Ω transmission line, which will have a little effect on the 9–18 GHz transmitting signal. The measurement results approximately agree with the calculated results and simulated results, which demonstrate the validity of the proposed HSC.

关键词： Microstrip filters Harmonics suppression Power transmission lines PIN photodiodes Switches Harmonic analysis Transmission line measurements