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Adversarial data splitting for domain generalization

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Science China(Information Sciences) 2024年第5期67卷 28-42页

作者： Xiang gu jian SUN Zongben XU School of Mathematics and Statistics Xi'an Jiaotong University

Domain generalization aims to learn a model that is generalizable to an unseen target domain,which is a fundamental and challenging task in machine learning for out-of-distribution generalization. This paper proposes a novel domain generalization approach that enforces the learned model to be able to generalize well over the train/val subset splitting of the training dataset. This idea is modeled herein as an adversarial data splitting framework, formulated as a min-max optimization problem inspired by the metalearning approach. The min-max optimization problem is solved by iteratively splitting the training dataset into the training and val subsets to maximize the domain shift measured by the objective function and updating the model parameters to enable the model to generalize well from the training subset to the val subset by minimizing the objective function. This adversarial training approach does not assume the known domain labels of the training data; instead, it automatically investigates the “hard” splitting of the train/val subsets to learn the generalizable model. Extensive experimental results using three benchmark datasets demonstrate the superiority of this approach. In addition, we derive a generalization error bound for the theoretical understanding of our proposed approach.

关键词： domain generalization adversarial learning data splitting meta-learning out of distribution

Experimental Investigation on Heat Transfer and Combustion of a Stirling Engine Combustor Fueled by Reformed Gas and Diesel Fuel

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Journal of Thermal Science 2024年第5期33卷 1907-1919页

作者： LAN jian ZHAO Yanchun lin guangtao LI Yelin REN Zhe LYU Tian SHEN Mengmeng gu Genxiang HAN Dong Key Laboratory for Power Machinery and Engineering Ministry of EducationShanghai Jiao Tong UniversityShanghai200240China Shanghai Marine Diesel Engine Research Institute Shanghai 201108China

Thermochemical recuperation heat recovery is an advanced waste heat utilization technology that can effectively recover exhaust waste heat from oxy-fuel Stirling *** novel combustor of a Stirling engine with thermochemical recuperation heat recovery system is expected to utilize both reformed gas and diesel fuels as sources of *** this research,the effects of various factors,including the H_(2)O addition,fuel distribution ratio(FDR),excess oxygen coefficient,and cyclone structure on the temperature distribution in the combustor,combustion emissions,and external combustion system efficiency of the Stirling engine were experimentally *** the increase of steam-to-carbon ratio(S/C),the temperature difference between the upper and lower heating tubes reduces and the circumferential temperature fluctuation decreases,and the combustion of diesel and reformed gas remains close to complete *** S/C=2,the external combustion efficiency is 80.6%,indicating a 1.6%decrease compared to conventional *** the increase of FDR,the temperature uniformity of the heater tube is improved,and the CO and HC emissions ***,the impact of the FDR on the maximum temperature difference and temperature fluctuation across the heater is *** the FDR rises from 21%to 38%,the external combustion efficiency increases from 87.4%to92.3%.The excess oxygen coefficient plays a secondary role in influencing temperature uniformity and temperature difference,and the reformed gas and diesel fuel can be burned efficiently at a low excess oxygen coefficient of *** an increase in the cyclone angle,the heater tube temperature increases,while the maximum temperature difference at the lower part decreases,and the temperature fluctuation ***,the CO and HC emissions increase,and the external combustion efficiency experiences a decrease.A cyclone angle of 30°is found to be an appropriate value for achieving optimal

关键词： Stirling engine fuel reforming synthetic gas oxy-combustion external combustion efficiency

Study of primordial deuterium abundance in Big Bang nucleosynthesis

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Nuclear Science and Techniques 2024年第3期35卷 208-215页

作者： Zhi-lin Shen jian-Jun He Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China

Big Bang nucleosynthesis(BBN)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early *** these,deuterium,the first nuclide produced by BBN,is a key primordial material for subsequent *** date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational *** this study,the Monte Carlo simulation code PRIMAT was used to investigate the sensitivity of 11 important BBN reactions to deuterium *** found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H ***,the calculated D/H uncertainty cannot reach observational precision even with the recent LUNA precise d(p,γ)^(3) He *** the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBN are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electron Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.

关键词： Big Bang nucleosynthesis Abundance of deuterium Reaction cross section Reaction rate Monte Carlo method

Recent progress in self-propelled particles

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Journal of Hydrodynamics 2024年第1期36卷 61-77页

作者： Zhen-yu Ouyang jian-zhong lin Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo315201China Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou310027China

Self-propelled particles are commonly found in a large number of planktonic organisms such as bacteria,fungi,and algae in nature,and researchers have taken a long interest in exploring their swimming mechanisms for more than a *** in the past 20 years,with the development of computational fluid dynamics and flow display technology,as well as the need for the design of synthetic self-propelled particles and micro-swimming devices,self-propelled particles have become the forefront and hotspot of current research in the field of fluid *** paper first introduces the swimming characteristics of common self-propelled particles,leading to a classic“squirmer”type self-propelled particle *** this basis,a systematic introduction and summary of the theoretical and numerical simulation research of“squirmer”will be ***,the main challenges and opportunities faced by the current research will be summarized.

关键词： Self-propelled particles multiphase flow hydrodynamic interaction

Individualized Traditional Chinese Medicine treatment vs antibiotics for recurrent urinary tract infections: a multicenter, randomized controlled study

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Journal of Traditional Chinese Medicine 2024年第3期44卷 524-529页

作者： gu Xiangchen QIU Meisi XIE lin CHEN Min DENG Yueyi ZHANG Changming jian guihua WANG Chen WANG Yi Department of Nephrology Yueyang Hospital of Integrated Traditional Chinese and Western Medicine Affiliated to Shanghai University of Traditional Chinese MedicineShanghai 200437China Department of Nephrology Rizhao Hospital of Traditional Chinese MedicineShanghai 200437China Department of Nephrology Longhua Hospital Affiliated to Shanghai University of Traditional Chinese MedicineShanghai200032China Department of Nephrology Shanghai Municipal Traditional Chinese Medicine Hospital Affiliated to Shanghai University of Traditional Chinese MedicineShanghai 200071China Department of Nephrology the Sixth People's Hospital Affiliated Shanghai Jiaotong UniversityShanghai 200233China Department of Nephrology Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese MedicineShanghai 201203China

OBJECTIVE: To systematically assess the effects of individualized Chinese medicines on recurrent urinary tract infections(rUTIs).METHODS: This study recruited 230 adult female patients in the remission phase of rUTIs from five hospitals in China. The patients were randomly allocated to two groups: an individualized Chinese medicine group(n = 114) and a control group(n = 116). Patients in the Chinese medicine group received individualized Chinese herbs, which were evaluated for syndrome *** in the control group received antibiotic treatment combined with a Chinese medicine placebo. The duration of treatment was three courses of four weeks each, with a three-month subsequent follow-up. UTI recurrence rate,Traditional Chinese Medicine(TCM) syndrome scores,36-item Short Form Survey(SF-36) score, and urine secretory immunoglobulin A(SIgA) were measured and analyzed before and after treatment in each group. RESULTS: Patients from the Chinese medicine group exhibited significant decreases in both short-and longterm UTI recurrence rates compared with the control group(P < 0.05). The changes in TCM syndrome scores between the Chinese medicine and control groups were significant(P < 0.05). The changes in the average SF-36 quality-of-life scores in the Chinese medicine group were also significantly higher than those in the control group after treatment(P < 0.05). The Chinese medicine group also demonstrated a significant increase in urine SIg A expression. CONCLUSION: Taken together, compared to the oftenused long-term antimicrobial prophylaxis during the remission stage of r UTIs, treating patients with an individualized Chinese medicine decoction by syndrome differentiation could effectively reduce the recurrence rate, improve the patients' TCM syndrome scores and quality of life, and enhance immunity, which in turn helps to prevent antibiotic resistance.

关键词： urinary tract infections medicine Chinese traditional syndrome differentiation quality of life immunoglobulin A secretory randomized controlled trial

An Image Fingerprint and Attention Mechanism Based Load Estimation Algorithm for Electric Power System

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 577-591页

作者： Qing Zhu linlin gu Huijie lin Electricity Technology Branch Nari Technology Co.Ltd.Nanjing211106China NARI-TECH Nanjing Control Systems Co. Ltd.Nanjing211106China

With the rapid development of electric power systems,load estimation plays an important role in system operation and ***,load estimation techniques contain traditional,time series,regression analysis-based,and machine learning-based *** the machine learning-based method can lead to better performance,in this paper,a deep learning-based load estimation algorithm using image fingerprint and attention mechanism is ***,an image fingerprint construction is proposed for training *** the data preprocessing,the training data matrix is constructed by the cyclic shift and cubic spline ***,the linear mapping and the gray-color transformation method are proposed to form the color image ***,a convolutional neural network(CNN)combined with an attentionmechanism is proposed for training performance *** last,an experiment is carried out to evaluate the estimation *** with the support vector machine method,CNN method and long short-term memory method,the proposed algorithm has the best load estimation performance.

关键词： Load estimation deep learning attention mechanism image fingerprint construction

Tuning Surface Molecular Design of Porous Carbon for Blue Energy Harvesting

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Research 2024年第1期2023卷 651-662页

作者： jian Yu Zhong-lin Wang Tianwei Ma Department of Civil and Environmental Engineering University of Hawaii at MānoaHonoluluHI 96822USA Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China College of Engineering Texas A&M University-Corpus ChristiCorpus ChristiTX 78412USA

Capacitive mixing is a promising blue energy technology due to its membrane-free electricity generation and long electrode life ***,because of limited performance,existing systems do not lend themselves to practical *** it is a crucial factor directly influencing electrode behavior,surface chemistry has largely been overlooked in capacitive ***,we show that manipulating surface functionalization alone can tune the responses of electrodes to produce a high voltage rise without altering the pore structure of the *** findings reveal that the spontaneous electrode potential of a surface-modified carbon electrode shifts negatively proportional to the surface charge due to the surface groups,which explains why and how manipulating the surface chemistry can improve the power generation capacity.

关键词： electrode Porous mixing

Compressed Data Separation via ℓ_(q)-Split Analysis with ℓ_(∞)-Constraint

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1655-1673页

作者： Ming Yang gu Song Li Jun Hong lin School of Mathematical Science Zhejiang UniversityHangzhou310027P.R.China Center for Data Science Zhejiang UniversityHangzhou310027P.R.China

In this paper,we study compressed data separation(CDS)problem,i.e.,sparse data separation from a few linear random *** propose the nonconvex ℓ_(q)-split analysis with ℓ_(∞)-constraint and 0 详细信息

In this paper,we study compressed data separation(CDS)problem,i.e.,sparse data separation from a few linear random *** propose the nonconvex ℓ_(q)-split analysis with ℓ_(∞)-constraint and 0

关键词： Data separation ℓ_(q)-split analysis Dantzig selector frames restricted isometry property compressed sensing

Grain refinement of 5A06 aluminum alloy welds caused by tungsten inert gas welding arc characteristics under Ar-He alternating gas supply conditions:a coupled method of water-cooled copper plate test/numerical simulation

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Journal of Iron and Steel Research International 2024年第3期31卷 767-777页

作者： Hong-bin Dai jian Miao Jia-xin lin School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040HeilongjiangChina

The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and *** the tungsten inert gas(TIG)welding process under the condition of Ar-He alternating gas supply,the arc is alternately converted between Ar arc and He arc with an alternating gas supply cycle,which has obvious arc change *** FLUENT software was used to numerically simulate the characteristics of the TIG arc under the condition of alternating gas supply,and the arc temperature field,arc pressure,electric potential and current density distribution under the condition of alternating gas supply were *** with the real-time data of arc pressure measured by the water-cooled copper plate with holes,it is proved that the TIG arc has obvious dynamic characteristics under the condition of Ar-He alternating gas *** unique dynamic TIG arc acts on the 5A06 aluminum alloy weld,causing the molten pool to stir,resulting in uniform microstructure and grain refinement at the weld,and thereby improving the mechanical properties of the welded joint.

关键词： Alternating gas supply Grain refinement Numerical simulation Tungsten argon arc morphology Microstructure Mechanical property