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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 646-657页

作者： Juanjuan Wang Wei Chen Yuekun Liu Chuang fu Yunming ye Junjie Feng School of Electric Power South China University of TechnologyGuangzhouChina Guangdong Power Grid Co. Ltd.GuangzhouChina Electric Power Research Institute China Southern Power GridGuangzhouChina

In recent years, high-frequency resonance (HFR) events occurred in several modular multilevel converter based high-voltage direct current (MMC-HVDC) projects. The time delay of an MMC-HVDC system is the critical factor that induces HFR. The frequency coupling affects the impedance characteristics of an MMC and further deteriorates system stability. Therefore, in this paper, a multi-input multi-output admittance model of an MMC-HVDC system is developed to analyze its frequency characteristics. The effects of current loop, power loop, phase-locked loop, and operating point on the MMC frequency coupling degree are analyzed in detail. Meanwhile, to further suppress HFR in the MMC-HVDC system, an enhanced impedance reshaping control strategy based on the equivalent single-input single-output impedance model is proposed. Finally, the accuracy of the enhanced impedance model and the effectiveness of the impedance reshaping control are verified by electromagnetic transient simulations in PSCAD.

关键词： Modular multilevel converter based high-voltage direct current(MMC-HVDC) high-frequency resonance frequency coupling impedance model impedance reshaping control

Low-temperature NH_(3) abatement via selective oxidation over a supported copper catalyst with high Cu^(+) abundance

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Journal of Environmental Sciences 2024年第9期143卷 12-22页

作者： Zhiming Yang Lin Peng Leneng Yang Mingli fu Daiqi ye Peirong Chen Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control National Engineering Laboratory for VOCs Pollution Control Technology and EquipmentSchool of Environment and EnergySouth China University of TechnologyGuangzhou 510006China Guangdong Chengyi Environmental Technology Corp. Shaoguan 512158China

Selective catalytic NH_(3)-to-N_(2) oxidation(NH_(3)-SCO)is highly promising for abating NH_(3) emissions slipped from stationary flue gas after-treatment *** practical application,however,is limited by the non-availability of low-cost catalysts with high activity and N_(2) ***,using defect-rich nitrogen-doped carbon nanotubes(NCNT-AW)as the support,we developed a highly active and durable copper-based NH_(3)-SCO catalyst with a high abundance of cuprous(Cu^(+))*** obtained Cu/NCNT-AW catalyst demonstrated outstanding activity with a T_(50)(*** temperature to reach 50% NH_(3) conversion)of 174℃ in the NH_(3)-SCO reaction,which outperformed not only the Cu catalyst supported on N-free O-functionalized CNTs(OCNTs)or NCNT with less surface defects,but also those most active Cu catalysts in open *** kinetics measurements and temperature-programmed surface reactions using NH_(3)as a probe molecule revealed that the NH_(3)-SCO reaction on Cu/NCNT-AW follows an internal selective catalytic reaction(i-SCR)route involving nitric oxide(NO)as a key *** to mechanistic investigations by X-ray photoelectron spectroscopy,Raman spectroscopy,and X-ray absorption spectroscopy,the superior NH_(3)-SCO performance of Cu/NCNT-AW originated from a synergy of surface defects and ***,surface defects promoted the anchoring of Cu O nanoparticles on N-containing sites and,thereby,enabled efficient electron transfer from N to Cu O,increasing significantly the fraction of SCR-active Cu^(+)sites in the *** study puts forward a new idea for manipulating and utilizing the interplay of defects and N-dopants on carbon surfaces to fabricate Cu^(+)-rich Cu catalysts for efficient abatement of slip NH_(3)emissions via selective oxidation.

关键词： NH_(3)-SCO XANES Localized etching N-doping N_(2) selectivity i-SCR

Unraveling the enigma:A comprehensive review of solid pseudopapillary tumor of the pancreas

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 614-629页

作者： ye-Cheng Xu De-Liang fu Feng Yang Department of Pancreatic Surgery Pancreatic Disease InstituteHuashan HospitalFudan UniversityShanghai 200040China

Solid pseudopapillary tumor of the pancreas(SPTP)is a rare neoplasm predom-inantly observed in young ***,CTNNB1 mutations,β-catenin nuclear accumulation,and subsequent Wnt-signaling pathway activation are the leading molecular *** preoperative diagnosis often relies on imaging techniques and endoscopic *** resection remains the mainstay *** models,such as the fudan Prognostic Index,show promise as predictive tools for assessing the prognosis of *** three types of metachronous liver metastasis can be beneficial in tailoring individu-alized treatment and follow-up *** advancements,challenges persist in understanding its etiology,establishing standardized treatments for unresectable or metastatic diseases,and developing a widely recognized grading *** comprehensive review aims to elucidate the enigma by consolidating current knowledge on the epidemiology,clinical presentation,pathology,molecular characteristics,diagnostic methods,treatment options,and prognostic factors.

关键词： Pancreas Solid pseudopapillary tumor β-catenin Endoscopic ultrasound Surgery Recurrence Liver metastasis Prognostic prediction

A Video Captioning Method by Semantic Topic-Guided Generation

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Computers, Materials & Continua 2024年第1期78卷 1071-1093页

作者： Ou ye Xinli Wei Zhenhua Yu Yan fu Ying Yang College of Computer Science and Technology Xi’an University of Science and TechnologyXi’an710054China

In the video captioning methods based on an encoder-decoder,limited visual features are extracted by an encoder,and a natural sentence of the video content is generated using a ***,this kind ofmethod is dependent on a single video input source and few visual labels,and there is a problem with semantic alignment between video contents and generated natural sentences,which are not suitable for accurately comprehending and describing the video *** address this issue,this paper proposes a video captioning method by semantic topic-guided ***,a 3D convolutional neural network is utilized to extract the spatiotemporal features of videos during the ***,the semantic topics of video data are extracted using the visual labels retrieved from similar video *** the decoding,a decoder is constructed by combining a novel Enhance-TopK sampling algorithm with a Generative Pre-trained Transformer-2 deep neural network,which decreases the influence of“deviation”in the semantic mapping process between videos and texts by jointly decoding a baseline and semantic topics of video *** this process,the designed Enhance-TopK sampling algorithm can alleviate a long-tail problem by dynamically adjusting the probability distribution of the predicted ***,the experiments are conducted on two publicly used Microsoft Research Video Description andMicrosoft Research-Video to Text *** experimental results demonstrate that the proposed method outperforms several state-of-art ***,the performance indicators Bilingual Evaluation Understudy,Metric for Evaluation of Translation with Explicit Ordering,Recall Oriented Understudy for Gisting Evaluation-longest common subsequence,and Consensus-based Image Description Evaluation of the proposed method are improved by 1.2%,0.1%,0.3%,and 2.4% on the Microsoft Research Video Description dataset,and 0.1%,1.0%,0.1%,and 2.8% on the Microsoft Research-Video to Text dataset

关键词： Video captioning encoder-decoder semantic topic jointly decoding Enhance-TopK sampling

Dynamic Effect of Landslides Triggered by Earthquake:A Case Study in Moxi Town of Luding County,China

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Journal of Earth Science 2024年第1期35卷 221-234页

作者： Hongfu Zhou Fei ye Wenxi fu Bin Liu Tian Fang Rui Li Chengdu Center China Geological SurveyChengdu 610081China State Key Laboratory of Hydraulics and Mountain Rivers Protection Sichuan UniversityChengdu 610065China Sichuan Geological Survey Chengdu610081China Shandong University of Science and Technology Qingdao 266590China

The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered ***,the dynamic effect mechanism and phenomena of earthquake-triggered landslides were summarized in this ***,the primary types of dynamic effects were further used to interpret the Mogangling landslide in Moxi Town of Luding County,China.A field investigation,remote sensing,numerical calculation and theoretical analysis were carried out to illustrate the failure mechanism of slope rock masses affected by *** interaction between seismic waves and slope rock masses and the induced dynamic effect of slope rock masses were primarily accounted for in the *** slope topography,rock mass weathering and unloading characteristics,river erosion,regional seismogenic structure,and rock mass structure characteristics were also *** results showed that the formation of the Mogangling landslide was mainly related to the high amplification effect of seismic acceleration and back slope effects,interface dynamic stress effects,and double-sided slope effects of seismic waves caused by the catastrophic Ms 7.75 Moxi Earthquake in *** principles for the site and route selection of large-scale infrastructure in the planning stage and the scientific prevention of seismic geological disasters were proposed on the basis of the dynamic effect of earthquake-induced landslides.

关键词： dynamic effect coupling of endogenic and exogenic processes landslides earthquakes disaster prevention

Large-scale toppling slope under water level fluctuation of reservoir:A case of Yunnan Province,China

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3034-3046页

作者： Leilei Jin Yufeng Wei Fei ye Wenxi fu Jianfeng Liu Shuwu Li State Key Laboratory of Hydraulic and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China Northwest Engineering Corporation Limited Xi’an710065China

Landslides induced by reservoir inundation are common in Southwest China,negatively influencing hydropower *** hydropower station dam was constructed in the upper reaches of the Lancang River,accordingly causing the water level at the Lajinshengu slope to increase by 30 m.A tension crack with a visible depth of 8 m was observed in the upper sector of the Lajinshengu slope after reservoir impoundment for 170 *** the following days,numerous cracks appeared on the surface of the slope,and the maximum displacement of the slope reached 3.22 ***,a large-scale active deformation body within the Lajinshengu slope formed with an area of 2.62×10^(5)m^(2)and a volume of 1.65×10^(7)m^(3).Detailed field investigations,on-site monitoring,and centrifugal model tests were carried out to analyze the surface features,deformation characteristics,and failure mechanism of the Lajinshengu *** results show that the slope is an ancient landslide,divided into two parts(*** A and zone B)by the *** B is a traction landslide caused by the displacement of zone *** longterm inundation weakens the soft rock at the slope foot,intensifying the toppling of bedrock and consequently triggering the sliding of the overburden in zone *** failure mode of the Lajinshengu slope is a typical case of toppling-sliding failure,and the underlying rock toppling drives the overlying *** addition,early identification methods for toppling deformation covered by overburdened soil were proposed based on monitoring data and deformation signs.

关键词： Lajinshengu slope Reservoir impoundment Early identification Failure mechanism Toppling-sliding slope failure mode

PEDOT-based thermoelectric composites:Preparation,mechanism and applications

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Chinese Chemical Letters 2024年第9期35卷 54-64页

作者： Jia fu Shilong Zhang Lirong Liang Chunyu Du Zhenqiang ye Guangming Chen College of Materials Science and Engineering Shenzhen UniversityShenzhen 518055China

Thermoelectric(TE)materials enable effective and direct energy conversions between heat and electricity,displaying wide applications including waste/low-grade heat harvesting,local cooling,sensing and wearable *** the recently-developed organic and composite TE materials,poly(3,4-ethylenedioxythiophene)(PEDOT)is perhaps the most successful and frequently reported ***,we aim to review the recent advances of the synthesis,mechanism and applications of PEDOT-based TE ***,the research background and the history of TE materials are briefly ***,the synthesis and TE performance of PEDOT-based composites are summarized according to the sequence of films,hydrogels/aerogels and fibers/***,the mechanism,structure and property are *** that,the recent development and its applications of power generation and sensing are ***,we provide an outlook on the prospects and the challenges of PEDOT-based TE composites.

关键词： Thermoelectric PEDOT Composites Preparation Mechanism Application

Generic attacks on small-state stream cipher constructions in the multi-user setting

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Cybersecurity 2024年第3期7卷 69-79页

作者： Jianfu Huang ye Luo Qinggan fu Yincen Chen Chao Wang Ling Song College of Cyber Security Jinan UniversityGuangzhou 510632China National Joint Engineering Research Center of Network Security Detection and Protection Technology Jinan UniversityGuangzhou 510632China

Small-state stream ciphers(SSCs),which violate the principle that the state size should exceed the key size by a factor of two,still demonstrate robust security properties while maintaining a lightweight *** ciphers can be clas-sifed into several constructions and their basic security requirement is to resist generic attacks,ie.,the time-mem-ory-data tradeoff(TMDTO)*** this paper,we investigate the security of small-state constructions in the multi-user *** on it,the TMDTO distinguishing attack and the TMDTO key recovery attack are developed for such a *** is shown that SSCs which continuously use the key can not resist the TMDTO distinguishing ***,SSCs based on the continuous-IV-key-use construction cannot withstand the TMDTO key recovery attack when the key length is shorter than the IV length,no matter whether the keystream length is limited or ***,We apply these two generic attacks to TinyJAMBU and DRACO in the multi-user *** TMDTO distinguish-ing attack on TinyJAMBU with a 128-bit key can be mounted with time,memory,and data complexities of 264,248,and 232,*** attack is comparable with a recent work on ToSC 2022,where partial key bits of TinyJAMBU are recovered with more than 250 users(or keys).As DRACO's IV length is smaller than its key length,itis vulnerable to the TMDTO key recovery *** resulting attack has a time and memory complexity of both 2112,which means DRACO does not provide 128-bit security in the multi-user setting.

关键词： Small-state stream ciphers TMDTO attacks Multi-user setting

Preparation and Rheological Characterization of Long Chain Branching Polyglycolide

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Chinese Journal of Polymer Science 2024年第8期42卷 1177-1184页

作者： Wei-Lin Liu Ming-fu Lyu Heng-Yuan Zhang Jian-ye Liu Shi-Jun Zhang Beijing University of Chemical Technology Beijing 100029China SINOPEC(Beijing)Research Institute of Chemical Industry Co. Ltd.Beijing 100013China

The long chain branching(LCB)polyglycolide(PGA)was successfully prepared by the successive reactions of the terminal hydroxyl groups of PGA with triglycidyl isocyanurate(TGIC)and pyromellitic dianhydride(PMDA).The influence of LCB produced by functional group reaction on rheological and crystallization behavior was studied and discussed through linear rheology,uniaxial elongation and DSC(differential scanning calorimetry).The much higher viscosity and the more notable strain hardening behavior of modified PGA indicates the LCB with high degree of entanglements are *** melt strength of PGA is finally improved greatly and can make su re that the supercritical CO_(2)foaming can be carried out successfully.

关键词： Polyglycolide(PGA) Long chain branching(LCB) Rheology

Acute effect of foot strike patterns on in vivo tibiotalar and subtalar joint kinematics during barefoot running

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Journal of Sport and Health Science 2024年第1期13卷 108-117页

作者： Dongqiang ye Lu Li Shen Zhang Songlin Xiao Xiaole Sun Shaobai Wang Weijie fu Key Laboratory of Exercise and Health Sciences of Ministry of Education Shanghai University of SportShanghai 200438China Shanghai Frontiers Science Research Base of Exercise and Metabolic Health Shanghai University of SportShanghai 200438China

Background:Foot kinematics,such as excessive eversion and malalignment of the hindfoot,are believed to be associated with running-related *** maj ority of studies to date show that different foot strike patterns influence these specific foot and ankle ***,technical deficiencies in traditional motion capture approaches limit knowledge of in vivo joint kinematics with respect to rearfoot and forefoot strike patterns(RFS and FFS,respectively).This study uses a high-speed dual fluoroscopic imaging system(DFIS)to determine the effects of different foot strike patterns on 3D in vivo tibiotalar and subtalar joints ***:Fifteen healthy male recreational runners underwent foot computed tomography scanning for the construction of 3-dimensional models.A high-speed DFIS(100 Hz)was used to collect 6 degrees of freedom kinematics for participants’tibiotalar and subtalar joints when they adopted RFS and FFS in barefoot ***:Compared with RFS,FFS exhibited greater internal rotation at 0%-20%of the stance phase in the tibiotalar *** peak internal rotation angle of the tibiotalar joint under FFS was greater than under RFS(p2).RFS showed more dorsiflexion at 0%-20%of the stance phase in the tibiotalar joint than *** also presented a larger anterior translation(p28)in the subtalar joint at i nitial contact than ***:Running with acute barefoot FFS increases the internal rotation of the tibiotalar joint in the early *** use of high-speed DFIS to quantify the movement of the tibiotalar and subtalar joint was critical to revealing the effects of RF S and FFS during running.

关键词： Foot strike patterns High-speed dual fluoroscopic imaging system In vivo kinematics Running