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asymmetric Schottky Contacts in van der Waals Metal-Semiconductor-Metal Structures Based on Two-Dimensional Janus Materials

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Research 2020年第1期2020卷 1108-1115页

作者： Jia Liu Ji-Chang Ren Tao Shen Xinyi Liu Christopher J.Butch Shuang Li Wei Liu Nano and Heterogeneous Materials Center School of Materials Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China Department of Biomedical Engineering Nanjing UniversityNanjingChina Blue Marble Space Institute of Science SeattleWashingtonUSA

Physical and electronic asymmetry plays a crucial role in rectifiers and other devices with a directionally variant current-voltage(I-V)ratio.Several strategies for practically creating asymmetry in nanoscale components have been demonstrated,but complex fabrication procedures,high cost,and incomplete mechanistic understanding have significantly limited large-scale applications of these components.In this work,we present density functional theory calculations which demonstrate asymmetric electronic properties in a metal-semiconductor-metal(MSM)interface composed of stacked van der Waals(vdW)heterostructures.Janus MoSSe has an intrinsic dipole due to its asymmetric structure and,consequently,can act as either an n-type or p-type diode depending on the face at the interior of the stacked structure(SeMoS-SMoS vs.SMoSe-SMoS).In each configuration,vdW forces dominate the interfacial interactions,and thus,Fermi level pinning is largely suppressed.Our transport calculations show that not only does the intrinsic dipole cause asymmetric I-V characteristics in the MSM structure but also that different transmission mechanisms are involved across the S-S(direct tunneling)and S-Se interface(thermionic excitation).This work illustrates a simple and practical method to introduce asymmetric Schottky barriers into an MSM structure and provides a conceptual framework which can be extended to other 2D Janus semiconductors.

关键词： Schottky asymmetric dipole

asymmetric optical camouflage:tuneable reflective colour accompanied by the optical Janus effect

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Light(Science & Applications) 2020年第1期9卷 325-334页

作者： Taehyun Kim Eui-Sang Yu Young-Gyu Bae Jongsu Lee In Soo Kim Seok Chung Seung-Yeol Lee Yong-Sang Ryu Sensor System Research Center Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Micro/Nano Systems Korea UniversitySeoul 02841Republic of Korea School of Electronic and Electrical Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Nanophotonics Research Center Korea Institute of Science and TechnologySeoul 02792Republic of Korea School of Mechanical Engineering Korea UniversitySeoul 02841Republic of Korea

Going beyond an improved colour gamut,an asymmetric colour contrast,which depends on the viewing direction,and its ability to readily deliver information could create opportunities for a wide range of applications,such as nextgeneration optical switches,colour displays,and security features in anti-counterfeiting devices.Here,we propose a simple Fabry–Perot etalon architecture capable of generating viewing-direction-sensitive colour contrasts and encrypting pre-inscribed information upon immersion in particular solvents(optical camouflage).Based on the experimental verification of the theoretical modelling,we have discovered a completely new and exotic optical phenomenon involving a tuneable colour switch for viewing-direction-dependent information delivery,which we define as asymmetric optical camouflage.

关键词： asymmetric generating readily

asymmetric Dimethylarginine Predicts One-year Recurrent Cardiovascular Events: Potential Biomarker of "Toxin Syndrome" in Coronary Heart Disease

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Chinese Journal of Integrative Medicine 2019年第5期25卷 327-333页

作者： XU Hao CHEN Zhuo SHANG Qing-hua GAO Zhu-ye YU Chang-an SHI Da-zhuo CHEN Ke-ji Cardiovascular Diseases Center Xiyuan HospitalChina Academy of Chinese Medical SciencesBeijing(100091)China Department of Cardiology China-Japan Friendship HospitalBeijing(100029)China

Objective: To examine the prognostic value of serum levels of asymmetric dimethylarginine(ADMA)in patients with stable coronary heart disease(CHD) thus explore a potential biomarker of "toxin syndrome" in CHD.Methods: In this prospective nested case-control study, 36 of 1,503 Chinese patients with stable CHD experienced at least 1 recurrent cardiovascular event(RCE) during 1-year fol ow-up. Serum levels of ADMA at the start of fol ow-up were compared between these 36 cases and 36 controls which matched to cases in terms of gender, age, history of hypertension, and myocardial infarction. Results: Based on the crude model, subjects in the 2 highest ADMA quartiles showed signi?cantly higher risk of developing RCE than those in the lowest ADMA quartile [odds ratio(OR) 4.09, 95%confidence interval(CI) 1.01 to 16.58; OR 6.76, 95% CI 1.57 to 29.07]. This association was also observed in the case-mix model(OR 5.51, 95% CI 1.23 to 24.61; OR 7.83, 95% CI 1.68 to 36.41) and multivariable model(OR 6.64,95% CI 1.40 to 31.49; OR 13.14, 95% CI 2.28 to 75.71) after adjusting for confounders. The multivariable model which combined ADMA and high-sensitivity C-reactive protein(hs CRP) showed better predictive power with areas under the receiver operator characteristic curves(0.779) than the model of either ADMA(0.694) or hs CRP(0.636). Conclusion:Serum ADMA level may be a potential biomarker of "toxin syndrome" in CHD which shows favorable prognostic value in predicting 1-year RCE in patients with stable CHD. [The registration number is Chi CTR-PRNRC-07000012]

关键词： asymmetric dimethylarginine recurrent cardiovascular event nested case-control study coronary heart disease toxin syndrome

Organocatalytic asymmetric synthesis of multifunctionalized α-carboline-spirooxindole hybrids that suppressed proliferation in colorectal cancer cells

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Organic Chemistry Frontiers 2022年第4期9卷 1048-1055页

作者： Xiang-Hong He Xue-Ju Fu Gu Zhan Nan Zhang Xiang Li Hong-Ping Zhu Cheng Peng Gu He Bo Han State Key Laboratory of Southwestern Chinese Medicine Resources Hospital of Chengdu University of Traditional Chinese MedicineSchool of PharmacyChengdu University of Traditional Chinese MedicineChengdu 611137China State Key Laboratory of Biotherapy and Department of Pharmacy West China HospitalSichuan UniversityChengdu610041China Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province Sichuan Industrial Institute of AntibioticsChengdu UniversityChengdu 610052China

Organocatalytic asymmetric[3+3]annulations of isatin-derived MBH carbonates and indolin-2-imines were efficiently achieved.This appears to be the first enantioselective approach for using isatin-derived MBH carbonates as 3C synthons to react with indole-derived C,N-dinucleophiles,yielding a series of multifunctionalized α-carboline-spirooxindole hybrids in good to high yields with high stereoselectivities.

关键词： asymmetric indole catalytic

asymmetric synthesis of pyrrolo[1,2-a]indoles via organocatalytic[3+2]annulation of substituted 2-vinylindoles with azlactones

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Chinese Chemical Letters 2020年第3期31卷 721-724页

作者： Wulin Yang Hao Wang Zirong Pan Zhong Li Weiping Deng Shanghai Key Laboratory of Chemical Biology School of PharmacyEast China University of Science and TechnologyShanghai 200237China Shanghai Key Laboratory of New Drug Design School of PharmacyEast China University of Science and TechnologyShanghai 200237China Shanghai Collaborative Innovation Center for Biomanufacturing Technology Shanghai 200237China

The chiral phosphoric acid catalyzed asymmetric[3+2]annulation of substituted 2-vinylindoles with azlactones has been established.This reaction represented a practical approach for the synthesis of structurally diverse pyrrolo[1,2-a]indoles with two vicinal stereocenters including one tetrasubstituted stereocenter in good yields and good stereoselectivities under mild conditions.

关键词： [3+2]Annulation Azlactones 2-Vinylindoles asymmetric organocatalysis Pyrrolo[1,2-a]indoles Chiral phosphoric acid

Aggregation-Induced Synthesis (AIS): asymmetric Synthesis via Chiral Aggregates

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Research 2022年第4期2022卷 731-739页

作者： Hossein Rouh Yao Tang Ting Xu Qingkai Yuan Sai Zhang Jia-Yin Wang Shengzhou Jin Yu Wang Junyi Pan Hannah LWood James D.McDonald Guigen Li Department of Chemistry and Biochemistry Texas Tech UniversityLubbockTexas 79409-1061USA Institute of Chemistry and BioMedical Sciences School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210093China

A new chiral aggregate-based tool for asymmetric synthesis has been developed by taking advantage of chiral aggregates of GAP(Group-Assisted Purification)reagents,N-phosphonyl imines.This tool was proven to be successful in the asymmetric GAP synthesis of functionalized 2,3-dihydrobenzofurans by reacting salicyl N-phosphonyl imines with dialkyl bromomalonates in various cosolvent systems.The chiral induction can be controlled by differentiating between two asymmetric directions simply by changing the ratios of cosolvents which are commonly adopted in AIE(aggregation-induced emission)systems.The formation of chiral aggregates was witnessed by a new analytical tool-aggregation-induced polarization(AIP).The present synthetic method will be broadly extended for general organic synthesis,particularly,for asymmetric synthesis and asymmetric catalysis in the future.

关键词： asymmetric chiral synthesis

APF-GAN:Exploring asymmetric pre-training and fine-tuning strategy for conditional generative adversarial network

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Computational Visual Media 2024年第1期10卷 187-192页

作者： Yuxuan Li Lingfeng Yang Xiang Li College of Computer Science Nankai UniversityTianjinChina School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjingChina

The use of generative adversarial network(GAN)-based models for the conditional generation of image semantic segmentation has shown promising results in recent years.However,there are still some limitations,including limited diversity of image style,distortion of detailed texture,unbalanced color tone,and lengthy training time.To address these issues,we propose an asymmetric pre-training and fine-tuning(APF)-GAN model.

关键词： tuning network asymmetric

UV light-driven asymmetric vinylogous aldol reaction of isatins with 2-alkylbenzophenones and enantioselective synthesis of 3-hydroxyoxindoles

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Organic Chemistry Frontiers 2022年第3期9卷 643-648页

作者： Shixuan Cao Jiatian Li Taishan Yan Jie Han Zhengjie He State Key Laboratory of Elemento-Organic Chemistry College of ChemistryNankai UniversityTianjin 300071China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin 300071China

Chiral 3-hydroxyoxindoles are biologically important molecular motifs which are frequently present in natural products and artificial compounds.Herein,we report an ultraviolet light-driven asymmetric vinylogous aldol ... 详细信息

关键词： conditions asymmetric alkyl

Simulation and optimization of dopant-free asymmetric heterojunction solar cells

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Optoelectronics Letters 2023年第6期19卷 337-346页

作者： ZHENG Qiaoqiao YUAN Yujie HOU Guofu LI Wei TAO Ke PENG Zhuo Tianjin Key Laboratory of Film Electronic and Communication Devices School of Integrated Circuit Science and EngineeringTianjin University of TechnologyTianjin 300384China Institute of Photoelectronic Thin Film Devices and Technology Nankai UniversityTianjin 300350China

In order to further study doping-free asymmetric heterojunction(DASH) solar cells,we used AFORS-HET software to optimize the structure of Al/SnO_(2)/a-Si:H(i)/c-Si(p)/a-Si:H(i)/NiO_(x)/Ag.In a certain adjustment range,a series of simulations were carried out on the band gap,electron affinity,thickness and work function(WF) of NiO_(x),thickness and WF of SnO_(2),and the thickness of a-Si:H(i).After the above optimization,21.08% efficiency was obtained at 300 K.This study shows that the solar cells with this structure have good light absorption properties in a very wide spectrum.The present simulation provides instructive suggestions for follow-up experiments of DASH solar cells.

关键词： spectrum asymmetric optimization