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Exploration of chromene-based BioAIEgens

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National Science Review 2024年第3期11卷 47-48页

作者： Fritz E.k.hn Department of Chemistry&Catalysis Research Center School of Natural Sciences Technical University of Munich

photoemission efficiency is usually higher in solution than in solid *** compounds however, display a reverse behavior. Such a behavior is called aggregation-induced emission(AIE).

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Utilization of Logistical Regression to the Modified Sine-Gordon Model in the MST Experiment

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Open Journal of Modelling and Simulation 2024年第2期12卷 43-58页

作者： Nizar J. Alk.ateeb Hameed k. Ebraheem Eman M. Al-Otaibi Department of Electronic Engineering Technology College of Technological Studies (CTS) The Public Authority of Applied Education and Training (PAAET) Kuwait City Kuwait

In this paper, a logistical regression statistical analysis (LR) is presented for a set of variables used in experimental measurements in reversed field pinch (RFp) machines, commonly k.own as “slink. mode” (SM), observed to travel around the torus in Madison Symmetric Torus (MST). The LR analysis is used to utilize the modified Sine-Gordon dynamic equation model to predict with high confidence whether the slink. mode will lock.or not lock.when compared to the experimentally measured motion of the slink. mode. It is observed that under certain conditions, the slink. mode “lock.” at or near the intersection of poloidal and/or toroidal gaps in MST. However, lock.d mode cease to travel around the torus;while unlock.d mode k.eps traveling without a change in the energy, mak.ng it hard to determine an exact set of conditions to predict lock.ng/unlock.ng behaviour. The significant k.y model parameters determined by LR analysis are shown to improve the Sine-Gordon model’s ability to determine the lock.ng/unlock.ng of magnetohydrodyamic (MHD) modes. The LR analysis of measured variables provides high confidence in anticipating lock.ng versus unlock.ng of slink. mode proven by relational comparisons between simulations and the experimentally measured motion of the slink. mode in MST.

关键词： Madison Symmetric Torus (MST) Magnetohydrodyamic (MHD) Sine-Gordon Toroidal Dynamic Modelling Reversed Field pinch (RFp) Logistical Regression

Direct-to-indirect mapping for optimal low-thrust trajectories

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Astrodynamics 2024年第1期8卷 27-46页

作者： David Ottesen Ryan p.Russell Department of Aerospace Engineering and Engineering Mechanics The University of Texas at AustinAustinTexas78712USA

Optimal,many-revolution spacecraft trajectories are challenging to solve.A connection is made for a class of models between optimal direct and indirect *** transfers that minimize thrust-acceleration-squared,primer vector theory maps direct,many-impulsive-maneuver trajectories to the indirect,continuous-thrust-acceleration *** mapping algorithm is independent of how the direct solution is obtained and requires only a solver for a boundary value problem and its partial derivatives.A Lambert solver is used for the two-body problem in this *** mapping is simple because the impulsive maneuvers and co-states share the same linear space around an optimal *** numerical results,the direct coast-impulse solutions are demonstrated to converge to the indirect continuous solutions as the number of impulses and segments *** two-body design space is explored with a set of three many-revolution,many-segment examples changing semimajor axis,eccentricity,and *** first two examples involve a small change to either semimajor axis or eccentricity,and the third example is a transfer to geosynchronous *** a single processor,the optimization runtime is seconds to minutes for revolution counts of 10 to 100,and on the order of one hour for examples with up to 500 *** of these thrust-acceleration-squared solutions are good candidates to start a homotopy to a higher-fidelity minimization problem with practical constraints.

关键词： direct optimization indirect optimization impulsive maneuvers Lambert's problem two-body dynamics primer vectortheory

palladium-catalyzed S_(N)2 glycosylation of phenols

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Science China Chemistry 2024年第4期67卷 1037-1038页

作者： Yu Zhu p.Andrew Evans Department of Chemistry Queen’s University90 Bader LaneKingstonK7L 3N6Canada Xiangya School of pharmaceutical Sciences Central South UniversityChangsha 410013China

Glycosides are essential structural motifs present in an array of important medicines,materials,and natural products[1].Nevertheless,the chemo-and stereoselective construction of the glycosidic link.ge is a long-standing challenge because relatively minor variations in the glycosyl donor or acceptor’s structure can impact stereoselectivity,thus influencing the product's functional properties.

关键词： properties palladium catalyzed

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Classification of Conversational Sentences Using an Ensemble pre-Trained Language Model with the Fine-Tuned parameter

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Computers, Materials & Continua 2024年第2期78卷 1669-1686页

作者： R.Sujatha k.Nimala Department of Network.ng and Communications SRM Institute of Science and TechnologyKattankulathurChengalpattuTamilnadu603203India

Sentence classification is the process of categorizing a sentence based on the context of the *** categorization requires more semantic highlights than other task.,such as dependence parsing,which requires more syntactic *** existing strategies focus on the general semantics of a conversation without involving the context of the sentence,recognizing the progress and comparing *** ensemble pre-trained language model was tak.n up here to classify the conversation sentences from the conversation *** conversational sentences are classified into four categories:information,question,directive,and *** classification label sequences are for analyzing the conversation progress and predicting the peck.ng order of the *** of Bidirectional Encoder for Representation of Transformer(BERT),Robustly Optimized BERT pretraining Approach(RoBERTa),Generative pre-Trained Transformer(GpT),DistilBERT and Generalized Autoregressive pretraining for Language Understanding(XLNet)models are trained on conversation corpus with *** tuning approach is carried out for better performance on sentence *** Ensemble of pre-trained Language Models with a Hyperparameter Tuning(EpLM-HT)system is trained on an annotated conversation *** proposed approach outperformed compared to the base BERT,GpT,DistilBERT and XLNet transformer *** proposed ensemble model with the fine-tuned parameters achieved an F1_score of 0.88.

关键词： Bidirectional encoder for representation of transformer conversation ensemble model fine-tuning generalized autoregressive pretraining for language understanding generative pre-trained transformer hyperparameter tuning natural language processing robustly optimized BERT pretraining approach sentence classification transformer models

Controlled deployment of a long tether to operate as a partial space elevator

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Astrodynamics 2024年第2期8卷 311-321页

作者： Jinbang Huang Arun k.Misra Department of Mechanical Engineering McGill UniversityMontrealQCH3A 0C3Canada

The deployment of a long tether to operate as a partial space elevator,starting from a nucleus in geostationary orbit,is *** deployment is an inherently unstable process because the center of orbit gradually decreases from the geostationary altitude when deployment *** is also observed that the elasticity of the tether has an important effect on deployment *** is shown that the application of a transverse force on the main spacecraft,determined by using linear state feedback.and appropriate gains,can stabilize the *** LQR controller is *** of the dynamics of the system are carried out using this controller for various parametric values of tether elasticity,deployment rates,etc.,to evaluate the efficacy of the controller.

关键词： tether space elevator deployment stability control

Trusted Certified Auditor Using Cryptography for Secure Data Outsourcing and privacy preservation in Fog-Enabled VANETs

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Computers, Materials & Continua 2024年第5期79卷 3089-3110页

作者： Nagaraju pacharla k.Srinivasa Reddy School of Computer Science and Engineering VIT-AP UniversityAmaravatiAndhra Pradesh522237India

With the recent technological developments,massive vehicular ad hoc network.(VANETs)have been established,enabling numerous vehicles and their respective Road Side Unit(RSU)components to communicate with *** best way to enhance traffic flow for vehicles and traffic management departments is to share thedata they *** needs to be more protection for the VANET *** effective and safe methodof outsourcing is suggested,which reduces computation costs by achieving data security using a homomorphicmapping based on the conjugate operation of *** research proposes a VANET-based data outsourcingsystem to fix the *** k.ep data outsourcing secure,the suggested model tak.s cryptography models *** will k.ep the generated k.ys for the purpose of vehicle *** controlling and overseeingthe outsourced data while preserving privacy,the suggested approach considers the Trusted Certified Auditor(TCA).Using the secret k.y,TCA can identify the genuine identity of VANETs when harmful messages *** proposed model develops a TCA-based unique static vehicle labeling system using cryptography(TCA-USVLC)for secure data outsourcing and privacy preservation in *** proposed model calculatesthe trust of vehicles in 16 ms for an average of 180 vehicles and achieves 98.6%accuracy for data encryption toprovide *** proposedmodel achieved 98.5%accuracy in data outsourcing and 98.6%accuracy in privacypreservation in fog-enabled *** curve cryptography models can be applied in the future for betterencryption and decryption rates with lightweight cryptography operations.

关键词： Vehicular ad-hoc network. data outsourcing privacy preservation cryptography k.ys trusted certified auditors data security

Sustainable Biocomposites Materials for Automotive Brak. pad Application:An Overview

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Journal of Renewable Materials 2024年第3期12卷 485-511页

作者： Joseph O.Dirisu Imhade p.Ok.k.ujie Olufunmilayo O.Joseph Sunday O.Oyedepo Oluwasegun Falodun Lagouge k.Tartibu Firdaussi D.Shehu Department of Mechanical Engineering Covenant UniversityOtaOgunNigeria Department of Mechanical and Mechatronics Engineering AFE Babalola UniversityAdoEkitiNigeria Department of Mechanical and Industrial Engineering Technology University of JohannesburgJohannesburg2028South Africa School of Chemical and Metallurgical Engineering University of the WitwatersrandJohannesburgSouth Africa

Research into converting waste into viable eco-friendly products has gained global *** natural fibres and pulverized metallic waste becomes necessary to reduce noxious environmental emissions due to indiscriminately occupying the *** study reviews the literature in the broad area of green composites in search of materials that can be used in automotive brak. *** made by biocomposite,rather than fossil fuels,will be favoured.A database containing the tribo-mechanical performance of numerous potential components for the future green composite was established using the technical details of bio-polymers and natural *** development of materials with diverse compositions and varying proportions is now conceivable,and these materials can be permanently connected in fully regulated *** explanation demonstrates that all of these variables affect friction coefficient,resistance to wear from friction and high temperatures,and the operating life of brak. pads to varying *** this study,renewable materials for the matrix and reinforcement are screened to determine which have sufficient strength,coefficient of friction,wear resistance properties,and reasonable costs,mak.ng them a feasible option for a green *** most significant,intriguing,and unusual materials used in manufacturing brak. pads are gathered in this review,which also analyzes how they affect the tribological characteristics of the pads.

关键词： Asbestos brak. pad biocomposites green composite mechanical properties natural reinforcement waste

Nonlinear Coupling of k.netic Alfvén Waves and Ion Acoustic Waves in the Inner Heliosphere

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Research in Astronomy and Astrophysics 2024年第10期24卷 143-160页

作者： Mani k.Chettri Vivek.Shrivastav Rupak.Muk.erjee Nidhi Gaur R.p.Sharma Hemam D.Singh Department of physics Sikkim University DAV public School plasma Simulation Laboratory Department of Energy Science and EngineeringIndian Institute of Technology Delhi

We study the nonlinear coupling of k.netic Alfvén waves with ion acoustic waves applicable to the Earth’s radiation belt and near-Sun streamer belt solar wind using dynamical equations in the form of modified Zak.arov *** simulations show the formation of magnetic field filamentary structures associated with density humps and dips which become turbulent at later times,redistributing the energy to higher *** magnetic power spectra exhibit an inertial range k.lmogorov-lik. spectral index value of-5/3 for k.ρiper dissipation range spectra with indices～-3 for the radiation belt case and ～-4 for the nearSun streamer belt solar wind case,here k.andρirepresent the wavevector component perpendicular to the back.round magnetic field and the ion thermal gyroradius,*** quasilinear theory in terms of the Fok.er–planck.equation in the region of wavenumber turbulent spectra,we find the particle distribution function flattening in the superthermal tail population which is the signature of particle energization and plasma heating.

关键词： Sun: chromosphere Sun: corona Sun: heliosphere SOLAR-WIND TURBULENCE FIELD-ALIGNED CURRENTS ALFVEN WAVES ASTROpHYSICAL GYROk.NETICS COHERENT STRUCTURES DISSIpATION RANGE pROBE SCALE ACCELERATION pLASMA