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Nano Research 2022年第9期15卷 7917-7924页

作者： Rui jiang Qian Li Xue Zheng weizhe wang Shuangbao wang Zhimou Xu Jiabin Wu School of Optical and Electronic Information Huazhong University of Science and Technology(HUST)Wuhan 430074China Department of Chemistry Tsinghua UniversityBeijing 100084China

Hydrogen release through water splitting is essential for reducing carbon emissions and promoting the hydrogen economy.One of the crucial challenges for industrial applications of water electrolysis is the manufacture of electrocatalysts which can reduce the kinetic energy barrier of the hydrogen evolution reaction(HER).Loading transition metal(TM)nanoparticles(NPs)or single atoms(SAs)into heteroatom-doped carbon materials(HCMs)is an effective method to improve electrochemical activity and stability.To this end,we synthesized N-doped porous carbon(NC)encapsulated Co NPs and isolated Co SA nanocatalysts(denoted as Co NPs@SAs-NC)using metal-organic frameworks(MOFs)as sacrificial precursors.The Co NPs@SAs-NC nanocatalysts displayed outstanding HER activity with a 110 mV overpotential in 1 M KOH,47 mV overpotential in 0.5 M H2SO4 and 171 mV in 0.5 M phosphate-buffered saline(PBS)to reach a current density of 10 mA·cm^(−2).In addition,the mechanism of the synergistic effect of Co NPs,Co SAs and N species was investigated in-depth using in situ shielding experiments and density functional theory(DFT)calculations.

关键词： metal-organic frameworks hydrogen evolution reaction nanocatalysts single atoms pH universal

Simple,stable and efficient nonlinear pulse compression through cascaded filamentation in air

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High Power Laser Science and Engineering 2023年第6期11卷 193-198页

作者： Tao Pu Kan Tian Bo Hu Zhongjun Wan Linzhen He Xuemei Yang Han Wu Yang Li weizhe wang Houkun Liang College of Electronics and Information Engineering Sichuan UniversityChengduChina

Nonlinear compression has become an obligatory technique along with the development of ultrafast lasers in generating ultrashort pulses with narrow pulse widths and high peak power.In particular,techniques of nonlinear compression have experienced a rapid progress as ytterbium(Yb)-doped lasers with pulse widths in the range from hundreds of femtoseconds to a few picoseconds have become mainstream laser tools for both scientific and industrial applications.Here,we report a simple and stable nonlinear pulse compression technique with high efficiency through cascaded filamentation in air followed by dispersion compensation.Pulses at a center wavelength of 1040 nm with millijoule pulse energy and 160 fs pulse width from a high-power Yb:CaAlGdO_(4) regenerative amplifier are compressed to 32 fs,with only 2.4% loss from the filamentation process.The compressed pulse has a stable output power with a root-meansquare variation of 0.2% over 1 hour.

关键词： femtosecond pulse filamentation nonlinear compression

Multigigawatt 50 fs Yb:CALGO regenerative amplifier system with 11 W average power and mid-infrared generation

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Photonics Research 2021年第8期9卷 1439-1445页

作者： weizhe wang HAN WU CHENG LIU BIAO SUN HOUKUN LIANG College of Electronics and Information Engineering Sichuan UniversityChengdu 610064China Beijing Wave Quanta Technology Co. Ltd.Beijing 102208China Hangzhou Yacto Technology Ltd. Hangzhou 311305China

Lasers with high average and high peak power as well as ultrashort pulse width have been all along demanded by nonlinear optics studies,strong-field experiments,electron dynamics investigations,and ultrafast spectroscopy.While the routinely used titanium-doped sapphire(Ti:sapphire)laser faces a bottleneck in the average power upscaling,ytterbium(Yb)-doped lasers have remarkable advantages in achieving high average power.However,there is still a substantial gap of pulse width and peak power between the Ti:sapphire and Yb-doped lasers.Here we demonstrate a high-power Yb:CaAlGdO4(Yb:CALGO)regenerative amplifier system,delivering 1040 nm pulses with11 W average power,50 fs pulse width,and 3.7 GW peak power at a repetition rate of 43 k Hz,which to some extent bridges the gap between the Ti:sapphire and Yb lasers.An ultrabroadband Yb-doped fiber oscillator,specially designed spectral shapers,and Yb:CALGO gain medium with broad emission bandwidth,together with a double-end pumping scheme enable an amplified bandwidth of 19 nm and 95 fs output pulse width.To the best of our knowledge,this is the first demonstration of sub-100 fs regenerative amplifier based on Yb-doped bulk medium without nonlinear spectral broadening.The amplified pulse is further compressed to 50 fs via cascaded-quadratic compression with a simple setup,producing 3.7 GW peak power,which boosts the record of peak power from Yb:CALGO regenerative amplifiers by 1 order.As a proof of concept,pumped by the high-power,50 fs pulses,7.5–11.5μm midinfrared(MIR)generation via intrapulse difference-frequency generation is performed,without the necessity of nonlinear fiber compressors.It leads to a simple and robust apparatus,and it would find good usefulness in MIR spectroscopic applications.

关键词： amplifier power pumped

Numerical Study on Effect of Non-uniform CMAS Penetration on TGO Growth and Interface Stress Behavior of APS TBCs

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 98-113页

作者： Zhenwei Cai Zifan Zhang Yingzheng Liu Xiaofeng Zhao weizhe wang Key Laboratory of Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China Gas Turbine Research Institute Shanghai Jiao Tong UniversityShanghai200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200240China

The penetration of CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)is one of the most significant factors that induce the failure of air-plasma-sprayed thermal barrier coatings(APS TBCs).The direct penetration of CMAS changes the thermal/mechanical properties of the top coat(TC)layer,which affects the thermal mismatch stress behavior and the growth of thermally grown oxide(TGO)at the TC/bond coat(BC)interface,thereby resulting in a more complicated interface stress state.In the present study,a two-dimensional global model of APS TBCs with half of the TC layer penetrated by CMAS is established to investigate the effect of non-uniform CMAS penetration on the interface stress behavior.Subsequently,a local model extracted from the global model is established to investigate the effects of interface morphologies and CMAS penetration depth.The results show that non-uniform CMAS penetration causes non-uniform TGO growth in APS TBCs,which consequently causes the stress behavior to vary along the interface.Furthermore,the CMAS pen-etration depth imposes a significant effect on the TC/TGO interface stress behavior,whereas the interface roughness exerts a prominent effect on the stress level at the BC/TGO interface under CMAS penetration.This study reveals the mechanism associated with the effect of non-uniform CMAS penetration on the interface stress behavior in APS TBCSs.

关键词： CMAS non-uniform penetration TGO growth Interface stress CMAS penetration depth Interface roughness

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贤得所用:体制引力、人才配置与高质量发展

经济学（季刊） 2024年第2期24卷 605-623页

作者：王炜哲赵忠胡凯中国人民大学劳动人事学院中南民族大学经济学院

本文基于奖励结构理论,提出了体制引力理论并建立了一个两部门模型,以此解释中国的人才配置格局及其对企业全要素生产率的影响和作用机制。实证研究表明:反映体制部门比较优势的显性体制引力显著抑制了企业全要素生产率的提升,诱导人才... 详细信息

本文基于奖励结构理论,提出了体制引力理论并建立了一个两部门模型,以此解释中国的人才配置格局及其对企业全要素生产率的影响和作用机制。实证研究表明:反映体制部门比较优势的显性体制引力显著抑制了企业全要素生产率的提升,诱导人才向体制部门过量配置和对创新外溢效应的抑制是主要机制。此外,显性体制引力的作用还会通过体制部门隐性比较优势,即社会网络、超额报酬和福利与薪酬保障等得到进一步放大。本研究对理解人才错配的制度根源和精准改进人才配置效率具有一定的理论价值和现实意义。

关键词：体制引力人才配置全要素生产率

Widely tunable continuous-wave visible and mid-infrared light generation based on a dual-wavelength switchable and tunable random Raman fiber laser

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Photonics Research 2023年第5期11卷 808-816页

作者： HAN WU weizhe wang BO HU YANG LI KAN TIAN RUI MA CHUNXIAO LI JUN LIU JIYONG YAO HOUKUN LIANG College of Electronics and Information Engineering Sichuan UniversityChengdu 610064China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China Beijing Center for Crystal Research and Development Key Laboratory of Functional Crystals and Laser TechnologyTechnical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China

Nonlinear frequency conversion of wavelength agile and high-power random fiber lasers can provide a promising way to generate continuous-wave(CW)visible and mid-infrared(MIR)light with unique properties such as the continuous modeless spectrum,low temporal/spatial coherence,and high temporal stability.Here,we report a dual-wavelength switchable and tunable random Raman fiber laser(RRFL)based on a phosphosilicate fiber that has two Raman gain peaks for the first time and demonstrate its superior capability to generate widely tunable CW visible and mid-infrared light via nonlinear frequency conversions.By using the combination of a tunable pump and two tunable gratings in Littrow configuration that can provide separated point feedback for the two Stokes wavelengths corresponding to silica-and phosphorus-related Raman peaks,the spectrum of an RRFL can be flexibly manipulated for the aim of nonlinear frequency conversions,including single-wavelength tunable emission at the 1.1μm or 1.2μm band for second-harmonic generation(SHG),dual-wavelength simultaneously tunable emission at the 1.1μm and 1.2μm bands for the sum-frequency generation(SFG),and dual-wavelength separation tunable emission for difference-frequency generation(DFG).As a result,with the combination of SHG and SFG in a periodically poled lithium niobate crystal array,we experimentally demonstrate the broadest tuning range(560-630 nm)of visible light generated from an RRFL,to the best of our knowledge.The tunable MIR light in the range of 10.7-12.3μm is also demonstrated through DFG of an RRFL operating in separation tunable dual-wavelength emission mode in a Ba Ga4Se7(BGSe)crystal,which is the first realization of>10μm CW DFG in the BGSe crystal.We believe the developed dual-wavelength switchable and tunable RRFL can provide a new compact,robust,and cost-effective platform to realize broadly tunable light in both the visible and MIR regions,which can also find potential applications in imaging,sensing,and temporal ghost imaging in various spectral bands.

关键词： tunable fiber tuning

Dual-Wavelength Spectrum-Shaped Mid-Infrared Pulses and Steering High-Harmonic Generation in Solids

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Ultrafast Science 2023年第3期3卷 19-28页

作者： Linzhen He weizhe wang Kan Tian Maoxing Xiang Zhongjun Wan Bo Hu Yang Li Han Wu Zi-Yu Chen Fan Yang Houkun Liang College of Electronics and Information Engineering Sichuan UniversityChengduSichuan 610064China Key Laboratory of High Energy Density Physics and Technology(MoE) College of PhysicsSichuan UniversityChengdu 610064China. College of Physics Key Laboratory of High Energy Density Physics and Technology of the Ministry of EducationSichuan UniversityChengduSichuan 610064China

Mid-infrared(MIR)ultra-short pulses with multiple spectral-band coverage and good freedom in spectral and temporal shaping are desired by broad applications such as steering strong-field ionization,investigating bound-electron dynamics,and minimally invasive tissue ablation.However,the existing methods of light transient generation lack freedom in spectral tuning and require sophisticated apparatus for complicated phase and noise control.Here,with both numerical analysis and experimental demonstration,we report the first attempt,to the best our knowledge,at generating MIR pulses with dual-wavelength spectral shaping and exceptional freedom of tunability in both the lasing wavelength and relative spectral amplitudes,based on a relatively simple and compact apparatus compared to traditional pulse synthesizers.The proof-of-concept demonstration in steering the high-harmonic generation in a polycrystalline ZnSe plate is facilitated by dual-wavelength MIR pulses shaped in both spectral and temporal domains,spanning from 5.6 to 11.4μm,with multi-microjoule pulse energy and hundred-milliwatt average power.Multisets of harmonics corresponding to different fundamental wavelengths are simultaneously generated in the deep ultraviolet region,and both the relative strength of individual harmonics sets and the spectral shapes of harmonics are harnessed with remarkable freedom and flexibility.This work would open new possibilities in exploring femtosecond control of electron dynamics and light–matter interaction in composite molecular systems.

关键词： synthesizer harmonics apparatus

FMSA:a meta-learning framework-based fast model stealing attack technique against intelligent network intrusion detection systems

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Cybersecurity 2024年第1期7卷 110-121页

作者： Kaisheng Fan weizhe Zhang Guangrui Liu Hui He School of Cyberspace Science Harbin Institute of TechnologyHarbin 150001China Department of New Networks Peng Cheng LaboratoryShenzhen 518055GuangdongChina

Intrusion detection systems are increasingly using machine learning.While machine learning has shown excellent performance in identifying malicious traffic,it may increase the risk of privacy leakage.This paper focuses on imple-menting a model stealing attack on intrusion detection systems.Existing model stealing attacks are hard to imple-ment in practical network environments,as they either need private data of the victim dataset or frequent access to the victim model.In this paper,we propose a novel solution called Fast Model Stealing Attack(FMSA)to address the problem in the field of model stealing attacks.We also highlight the risks of using ML-NIDS in network security.First,meta-learning frameworks are introduced into the model stealing algorithm to clone the victim model in a black-box state.Then,the number of accesses to the target model is used as an optimization term,resulting in minimal queries to achieve model stealing.Finally,adversarial training is used to simulate the data distribution of the target model and achieve the recovery of privacy data.Through experiments on multiple public datasets,compared to existing state-of-the-art algorithms,FMSA reduces the number of accesses to the target model and improves the accuracy of the clone model on the test dataset to 88.9%and the similarity with the target model to 90.1%.We can demonstrate the successful execution of model stealing attacks on the ML-NIDS system even with protective measures in place to limit the number of anomalous queries.

关键词： AI security Model stealing attack Network intrusion detection Meta learning

Strategies of selective electroreduction of aqueous nitrate to N_(2) in chloride-free system:A critical review

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Green Energy & Environment 2024年第2期9卷 198-216页

作者： Fukuan Li weizhe Zhang Peng Zhang Ao Gong Kexun Li College of Environmental Science and Engineering Nankai UniversityTianjin300350China MOE Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlTianjin Key Laboratory of Environmental Technology for Complex Trans-Media PollutionNankai UniversityTianjin300350China

Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for converting nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or into value-added ammonia from the perspective of electrocatalytic NH_(3) synthesis.By reason of the undesired formation of ammonia is dominant during electroreduction of nitrate-containing wastewater,chloride has been widely used to improve N_(2) selectivity.Nevertheless,selective electroreduction of nitrate to N2 gas in chloride-containing system poses several drawbacks.In this review,we focus on the key strategies for efficiently enhancing N_(2) selectivity of electroreduction of nitrate in chloride-free system,including optimal selection of elements,combining an active metal catalyst with another metal,manipulating the crystalline morphology and facet orientation,constructing core–shell structure catalysts,etc.Before summarizing the strategies,four possible reaction pathways of electro-reduction of nitrate to N_(2) are discussed.Overall,this review attempts to provide practical strategies for enhancing N2 selectivity without the aid of electrochlorination and highlight directions for future research for designing appropriate electrocatalyst for final electrocatalytic denitrifi-cation.

关键词： Nitrate Chloride Electroreduction Selectivity Nitrogen

Simple and versatile in situ thermo-sensitive hydrogel for rectal administration of SZ-A to alleviate inflammation and repair mucosal barrier in ulcerative colitis

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Chinese Chemical Letters 2024年第6期35卷 462-468页

作者： Yu Yan Jiawei Song Dongdong Liu Zihan Liu Jialing Cheng Zhiyang Chen Yanfang Yang weizhe Jiang Hongliang wang Jun Ye Yuling Liu State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China College of Pharmacy Guangxi Medical UniversityNanning 530021China Beijing Key Laboratory of Drug Delivery Technology and Novel Formulation Institute of Materia MedicaChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Ulcerative colitis(UC)is a chronic inflammatory bowel disease characterized by persistent inflammation of the colon and disrupted intestinal function.Ramulus mori(Sangzhi)alkaloids(SZ-A),derived from twigs of mulberry,were approved by the National Medical Products Administration in 2020 for treating type 2 diabetes mellitus.Accumulated evidence has confirmed that SZ-A also alleviates non-alcoholic fatty liver disease and ameliorates inflammation,indicating its potential to address inflammation in UC.However,the treatment of UC faces challenges due to low drug delivery efficiency and short retention time.To overcome these challenges,an injectable and adherent in-situ thermo-sensitive hydrogel containing SZ-A was developed for rectal drug delivery,utilizing the thermo-sensitive polymers Poloxamer 407and 188.The thermo-sensitive hydrogel system was designed with a moderate gelation temperature of 32±0.5℃,a short gelation time of 64 s,a p H range of 7-10,high moisturizing capability exceeding 90%,and moderate mechanical strength of 4-5 s.In a rat model with UC,the in situ thermo-sensitive hydrogel significantly extended the retention time at the colonic site and enabled sustained release after rectal administration.Symptoms of UC were markedly reduced following rectal administration of SZ-A thermosensitive hydrogel.Furthermore,the release of inflammatory factors,such as interleukin-1β(IL-1β),IL-6,IL-18,tumor necrosis factor-α(TNF-α),and transforming growth factor-β1(TGF-β1),significantly decreased in the SZ-A thermo-sensitive hydrogel group.The integrity of the colonic mucosal barrier was significantly enhanced following the application of SZ-A thermo-sensitive hydrogel.In conclusion,rectal administration of SZ-A in situ thermo-sensitive hydrogel effectively alleviated UC symptoms,inhibited the secretion of inflammatory factors,and promoted the repair of the colonic mucosal barrier.This approach holds promise as a potential treatment for UC.

关键词： Ulcerative colitis SZ-A Thermo-sensitive hydrogel Rectal administration Alleviation of inflammation Mucosal barrier repair