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Analytic Formulae for Estimating Motor Proportion of Load Model Under Small Disturbance

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1599-1607页

作者： Ping Ju Shiqiu xia Yuqing Jin Lu cao School of Electrical and Power Engineering Hohai UniversityNanjing 211100China the East China Branch of the State Grid Corporation of China Shanghai 200120China

In the composite load model(CLM),which is commonly used in China,an equivalent motor and equivalent static load are used to represent all electrical equipment and networks connected to a load *** research has determined typical values of electrical and mechanical parameters for load models of different load types,which improves the basis for load ***,the motor proportion parameter is not the same for different load buses or at different times;therefore,obtaining the actual motor proportion is key to establishing an accurate load *** the existing load modeling method,motor proportion is commonly identified along with other parameters under rare large disturbances;therefore,the value of the motor proportion is fixed by the time when a large disturbance *** this paper,formulae are derived to estimate motor proportion under small disturbances,and these formulae allow direct calculation of motor proportion without using any optimization *** proposed estimation formulae do not rely on any parameters of load model or power system but instead rely only on measurement of the voltage and active power at steady-state points before and after a small *** of universality of small disturbances in power systems,estimating time-varying motor proportion under small disturbances will be helpful for solving the time-varying problem of load ***,the proposed motor proportion estimation formulae are validated by simulations,physical experiments,and field experiments.

关键词： Composite load model load modeling motor proportion parameter estimation

Exploring the ultrahigh rolling contact fatigue life of M50 bearing steel by adjusting the cryogenic sequence

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Journal of Materials Science & Technology 2024年第2期169卷 243-250页

作者： Xin cai xiaoqiang Hu Xingyu Lu Hongwei Liu Yanfei cao Dianzhong Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The influence of different cryogenic sequences on the rolling contact fatigue(RCF)life of M50-bearing steel has been *** results show that direct cryogenic treatment after quenching can effectively improve RCF *** L_(10)life is strikingly 5 times longer than that with cryogenic treatment after *** is caused by the distinct lattice construction of martensite and the transformation of retained *** secondary nanocarbides and fine twins are formed via cryogenic treatment before tem-pering compared with cryogenic treatment after *** improvement in the RCF life of the steel is attributed to the joint effects of the secondary nanocarbides and twin boundaries with a width of 5-13 nm,which delays significantly crack initiation and *** study highlights a common method to improve the service life of high-carbon and high-alloy steels by adjusting the cryogenic se-quence.

关键词： M50 steel Cryogenic treatment Rolling contact fatigue life Carbide Twin

Different lymph node staging systems for predicting the prognosis of colorectal neuroendocrine neoplasms

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1745-1755页

作者： Yuan-Yi Zhang Yue-Wei cai xia Zhang Department of Pathology Zhaoqing Medical CollegeZhaoqing 526020Guangdong ProvinceChina Department of Emergency Zhaoqing Second People’s HospitalZhaoqing 526020Guangdong ProvinceChina Department of Pathology and Physiology Zhaoqing Medical CollegeZhaoqing 526020Guangdong ProvinceChina

BACKGROUND Colorectal neuroendocrine neoplasms(NENs)are a rare malignancy that primarily arises from the diffuse distribution of neuroendocrine cells in the colon and *** studies have pointed out that the status of lymph node may be used to predict the *** To investigate the predictive values of lymph node ratio(LNR),positive lymph node(PLN),and log odds of PLNs(LODDS)staging systems on the prognosis of colorectal NENs treated surgically,and compare their predictive *** This cohort study included 895 patients with colorectal NENs treated surgically from the Surveillance,Epidemiology,and End Results *** endpoint was mortality of patients with colorectal NENs treated surgically.X-tile software was utilized to identify most suitable thresholds for categorizing the LNR,PLN,and *** were selected in a random manner to form training and testing *** prognosis of surgically treating colorectal NENs was examined using multivariate cox analysis to assess the associations of LNR,PLN,and LODDS with the prognosis of colorectal NENs.C-index was used for assessing the predictive *** conducted a subgroup analysis to explore the different lymph node staging systems’predictive *** After adjusting all confounding factors,PLN,LNR and LODDS staging systems were linked with mortality in patients with colorectal NENs treated surgically(P<0.05).We found that LODDS staging had a higher prognostic value for patients with colorectal NENs treated surgically than PLN and LNR staging *** results were obtained in the different G staging subgroup ***,the area under the receiver operating characteristic curve values for LODDS staging system remained consistently higher than those of PLN or LNR,even at the 1-,2-,3-,4-,5-and 6-year follow-up *** LNR,PLN,and LODDS were found to significantly predict the prognosis of patients with colorectal NENs treated surgically.

关键词： Positive lymph node Lymph node ratio Log odds of positive lymph nodes Prognosis Colorectal neuroendocrine neoplasms

Study on trifluoromethanesulfonic acid-promoted synthesis of daidzein: Process optimization and reaction mechanism

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Chinese Journal of Chemical Engineering 2024年第7期71卷 132-139页

作者： Hai cao Haibin Yang Yanxiong Fang Yuandi Zeng xiaolan cai Jingjing Ma School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory(Rongjiang Laboratory) Jieyang 515200China

Daidzein has been widely used in pharmaceuticals,nutraceuticals,cosmetics,feed additives,*** preparation process and related reaction mechanism need to be further investigated.A cost-effective process for synthesizing daidzein was developed in this *** this article,a two-step synthesis of daidzein(Friedel–Crafts acylation and[5+1]cyclization)was developed via the employment of trifluoromethanesulfonic acid(TfOH)as an effective promoting *** effect of reaction conditions such as solvent,the amount of TfOH,reaction temperature,and reactant ratio on the conversion rate and the yield of the reaction,respectively,was systematically investigated,and daidzein was obtained in 74.0%isolated yield under optimal *** to the facilitating effect of TfOH,the Friedel–Crafts acylation was completed within 10 min at 90℃ and the[5+1]cyclization was completed within 180 min at 25℃.In addition,a possible reaction mechanism for this process was *** results of the study may provide useful guidance for industrial production of daidzein on a large scale.

关键词： Synthesis Optimal design Chemical processes Reaction mechanism

How interfacial electron-donating defects influence the structure and charge of gold nanoparticles on TiO_(2)support

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Nano Research 2024年第7期17卷 5965-5974页

作者： Guang-Jie xia Yu Fu Wei cao Jun Li Yang-Gang Wang Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis Southern University of Science and TechnologyShenzhen 518055China School of Physical Sciences Great Bay UniversityDongguan 523000China Department of Chemistry Tsinghua UniversityBeijing 100084China

The reduction degree of TiO_(2)support is critical to the performances of metal *** many previous theoretical calculations,only the bridge oxygen vacancy(Ov)was considered as the electron-donating defect on reduced rutile TiO_(2)(r-TiO_(2−x))***,titanium adatoms(Tiad.),oxidized titanium islands(***),and acid hydroxyls(ObrH)also exist at the metal/support *** conducting density functional theory(DFT)calculations and ab initio molecular dynamics(AIMD)simulations,we compared r-TiO_(2−x)surfaces with Ov,Tiad.,***,and ObrH sites loaded with Au nanoparticles(NPs).The results showed the Au NPs were oxygen-phobic but titanium-philic,resulting in wetting of Ov and *** short contact with *** and *** Bader charges of Au NPs(QM)showed a good linear relationship with the ideal number of donating electrons(Ne)from the defective sites(QM=−KeNe+QM,S),demonstrating the intrinsic electron allocation at the *** Ov,Tiad.,and *** exhibited similar slopes(Ke),relatively steeper than that of *** means in the scope of Au NP charge state,the *** *** have a close electron-donating ability with Ov,but the ObrH donates relatively fewer *** linear relationship can be extended approximately to other *** higher the metal work function,the steeper the Ke for easier electron donation from defective *** stronger the metal oxygen affinity,the more positive the intercept(QM,S).That explains the easy generation of metallic or negative Pt and Au NPs on r-TiO_(2−x),but hard for Cu and Zn in *** provides theoretical guidance for regulating the charge of metal NPs over TiO_(2−x)supports.

关键词： metal-support interaction titanium oxide oxygen vacancy surface hydroxyl titanium adatom

Study on cumulative effects of biological craniocerebral trauma under repeated blast

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 174-183页

作者： Xingyuan Huang Bingchen xia Lijun Chang Zhikang Liao Hui Zhao Zhihua cai Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and TechnologyXiangtan 411201China School of Mechanical and Electrical Engineering Foshan UniversityFoshan 528231China Institute for Traffic Medicine PLA Army Characteristic Medical CenterChongqing 400042China

Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral *** existing studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects and cumulative effects of repeated ***,rats were used as the experimental samples to suffer from explosion blasts with different peak air overpressures(167 kPa~482 kPa)and varying number of repeated *** cumulative effect of craniocerebral trauma was most pronounced for moderate repeated blast,showing approximately 95%increase of trauma severity with penta blast,and an approximately 85%increase of trauma severity with penta minor *** cumulative effect of craniocerebral trauma from severe,repeated blast has a smaller rate of change compared to the other two *** severity of trauma from penta blast increased by approximately 69%compared to a single *** physiological,pathological and biochemical analysis show that the degree of neurological trauma caused by repeated blasts is higher than that of single blasts,and the pathological trauma to brain tissue is more extensive and *** trauma degree remains unchanged after double blast,increases by one grade after triple or quadruple blast,and increases by two grades after penta blast.

关键词： Repeated blast Craniocerebral trauma Trauma severity grade Cumulative effects

Survey of hepatitis B virus infection for liver cancer screening in China:A population-based,cross-sectional study

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Chinese Medical Journal 2024年第12期137卷 1414-1420页

作者： Yongjie Xu Changfa xia He Li Maomao cao Fan Yang Qianru Li Mengdi cao Wanqing Chen Office of Cancer Screening National Cancer Center/National Clinical Research Center for Cancer/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China Office of National Cancer Regional Medical Centre in Liaoning Province The First Affiliated Hospital of China Medical UniversityShenyangLiaoning 110001China

Background:Hepatitis B virus(HBV)infection is the primary cause of hepatocellular carcinoma(HCC)in *** target population for HCC screening comprises individuals who test positive for hepatitis B surface antigen(HBsAg).However,current data on the prevalence of HBV infection among individuals who are eligible for HCC screening in China are *** aimed to assess the seroepidemiology of HBV infection among Chinese individuals eligible for HCC screening to provide the latest evidence for appropriate HCC screening strategies in ***:Questionnaires including information of sex,age,ethnicity,marital status,educational level,source of drinking water,as well as smoking and alcohol consumption history and serum samples were collected from females aged 45-64 years and males aged 35-64 years in 21 counties from 4 provinces in eastern and central China between 2015 and ***-linked immunosorbent assay methods were used to detect the serum HBV marker ***:A total of 603,082 individuals were enrolled,and serum samples were collected for analysis from January 1,2015 to December 31,*** prevalence of HBsAg positive in the study population was 5.23%(31,528/603,082).The prevalence of HBsAg positive was greater in males than in females(5.60%[17,660/315,183]vs 4.82%[13,868/287,899],χ^(2)=187.52,P<0.0001).The elderly participants exhibited a greater prevalence of HBV infection than younger participants(χ^(2)=41.73,P<0.0001).Birth cohort analysis revealed an overall downward trend in HBV prevalence for both males and *** born in more recent cohorts exhibited a lower prevalence of HBV infection as compared to those born ***:The current prevalence of HBV infection remains above 5%in populations eligible for HCC screening in *** efforts should be made to increase the accessibility of HCC screening among individuals with HBV infection.

关键词： Hepatitis B virus Liver cancer screening China Hepatitis B surface antigens Early detection of cancer

Facile preparation of Fe/N-based biomass porous carbon composite towards enhancing the thermal decomposition of DAP-4

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Defence Technology（防务技术） 2024年第1期31卷 288-294页

作者： Er-hai An xiao-xia Li Cun-juan Yu Ying-xin Tan Zi-jun Fan Qing-xia Li Peng Deng Xiong cao School of Environment and Safety Engineering North University of ChinaTaiyuan030051PR China College of Safety and Emergency Management Engineering Taiyuan University of Science and TechnologyTaiyuan030024PR China

Fe/N-based biomass porous carbon composite(Fe/N-p Carbon) was prepared by a facile high-temperature carbonization method from biomass,and the effect of Fe/N-p Carbon on the thermal decomposition of energetic molecular perovskite-based material DAP-4 was *** porous carbonaceous materials was considered as the micro/nano support layers for in situ deposition of Fe/N ***/Np Carbon was prepared simply by the high-temperature carbonization *** was found that it showed the inherent catalysis properties for thermal decomposition of *** heat release of DAP-4/Fe/N-p Carbon by DSC curves tested had increased slightly,compared from DAP-4/Fe/N-p *** decomposition temperature peak of DAP-4 at the presence of Fe/N-p Carbon had reduced by 79°C from384.4°C(pure DAP-4) to 305.4°C(DAP-4/Fe/N-p Carbon-3).The apparent activation energy of DAP-4thermal decomposition also had decreased by 29.1 J/*** possible catalytic decomposition mechanism of DAP-4 with Fe/N-p Carbon was proposed.

关键词： Biomass materials Porous carbon DAP-4 Thermal decomposition Facile method

Modeling of multiphase flow in low permeability porous media:Effect of wettability and pore structure properties

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1127-1139页

作者： xiangjie Qin Yuxuan xia Juncheng Qiao Jiaheng Chen Jianhui Zeng Jianchao cai National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China Research Institute of Petroleum Exploration and Development Beijing10083China

Multiphase flow in low permeability porous media is involved in numerous energy and environmental ***,a complete description of this process is challenging due to the limited modeling scale and the effects of complex pore structures and *** address this issue,based on the digital rock of low permeability sandstone,a direct numerical simulation is performed considering the interphase drag and boundary slip to clarify the microscopic water-oil displacement *** addition,a dual-porosity pore network model(PNM)is constructed to obtain the water-oil relative permeability of the *** displacement efficiency as a recovery process is assessed under different wetting and pore structure *** show that microscopic displacement mechanisms explain the corresponding macroscopic relative *** injected water breaks through the outlet earlier with a large mass flow,while thick oil films exist in rough hydrophobic surfaces and poorly connected *** variation of water-oil relative permeability is significant,and residual oil saturation is high in the oil-wet *** flooding is extensive,and the residual oil is trapped in complex pore networks for hydrophilic pore surfaces;thus,water relative permeability is lower in the water-wet *** the displacement efficiency is the worst in mixed-wetting systems for poor water *** negatively correlates with invading oil volume fraction due to strong capillary resistance,and a large microporosity corresponds to low residual oil *** work provides insights into the water-oil flow from different modeling perspectives and helps to optimize the development plan for enhanced recovery.

关键词： Low permeability porous media Water-oil flow Wettability Pore structures Dual porosity pore network model(PNM) Free surface model