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Research on shell-side heat and mass transfer with multi-component in LNG spiral-wound heat exchanger under sloshing conditions

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Petroleum Science 2024年第2期21卷 1333-1345页

作者： Xue-ping Du Guang-Lei yu Ya-Cheng Xu Zhi-Jie Chen Nai-Liang Li Huan-Guang Wang School of Low-carbon Energy and Power Engineering China University of Mining and TechnologyXuzhou221116JiangsuChina Key Laboratory of Thermo-Fluid Science and Engineering MOEXi'an Jiaotong UniversityXi'an710049ShaanxiChina Xi'an Aerospace Propulsion Test Technology Institute Xi'an710100ShaanxiChina

The spiral-wound heat exchanger(SWHE) is the primary low-temperature heat exchanger for large-scale LNG plants due to its high-pressure resistance, compact structure, and high heat exchange efficiency. This paper studied the shell-side heat and mass transfer characteristics of vapor-liquid two-phase mixed refrigerants in an SWHE by combining a multi-component model in FLUENT software with a customized multicomponent mass transfer model. Besides, the mathematical model under the sloshing condition was obtained through mathematical derivation, and the corresponding UDF code was loaded into FLUENT as the momentum source term. The results under the sloshing conditions were compared with the relevant parameters under the steady-state condition. The shell-side heat and mass transfer characteristics of the SWHE were investigated by adjusting the component ratio and other working conditions. It was found that the sloshing conditions enhance the heat transfer performance and sometimes have insignificant effects. The sloshing condition is beneficial to reduce the flow resistance. The comprehensive performance of multi-component refrigerants has been improved and the improvement is more significant under sloshing conditions, considering both the heat transfer and pressure *** results will provide theoretical support for the research and design of multi-component heat and mass transfer enhancement of LNG SWHE under ocean sloshing conditions.

关键词： Spiral-wound heat exchanger Sloshing conditions Two-phase flow Multi-component Heat and mass transfer

Poly(3-hexylthio) thiophene Field-effect Transistor Device Performance: Impact of the Content of Hexylthio Side Chain on Backbone

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Chinese Journal of Polymer Science 2024年第1期42卷 14-23,I0005页

作者： Hao-yu Liu Lian-He Han Ling-Wei Kong Li-ping Zhu Xiao-Lan Qiao Mei-Fang Zhu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Regioregular poly(3-hexylthio)thiopene(P3HTT) has emerged tremendous potential in organic electronic applications due to the strong noncovalent interactions from the sulfur atom linked to thiophene. however, P3HTT generally exhibits low charge mobility mostly due to poor solution processability attributed to dense arrangement of hexylthio side chain in polymer, which led to strong noncovalent interactions among sulfur atoms. To balance the nonvalent interaction and aggregation for P3HTT, herein, we systematically study the effect of hexylthio side chain content in polymer backbone on the structure and properties. A series of regioregular P3HTT-based homopolymers(P3HTT, P3HTT-50,P3HTT-33 and P3HTT-25) were prepared via Kumada catalyst transfer polycondensation method from a set of mono-, bi-, ter-and quarterthiophenes containing different contents of hexylthio side chain. The DFT calculation shows the planarity of polymers backbone could be improved through reducing the density of hexylthio side chain in polymer mainchain. And significant changes in their crystallinity, aggregation and optical properties were observed with the content of hexylthio side chain reducing. The P3HTT-33 displayed the highest field-effect transistor hole mobility of 2.83×10^(-2) cm^(2)·V^(-1)·s^(-1) resulting from a balance between the crystallinity and planarity. This study demonstrates modulating the content of hexylthio side chain in P3HTT is an effective strategy to optimize the opto-electronic properties of polymer obtaining excellent semiconductor device performance.

关键词： Conjugated polymer Polythiophene Noncovalent interaction Molecular aggregation Organic field-effect transistor

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跳跃机构与低渗杂半导体杂质电导

物理学报 1963年第12期 791-806页

作者：霍裕平

在渗杂度很低时,由于少数杂质电离后引起场的起伏,电子在杂质上主要处于局域状态,电声子作用使电子能够在不同杂质上跳跃,但由于电子坐标算符与电声子作用交换,在电场中电子的运动实际上是一种击穿效应,而由声子束补偿能量。针对低补偿... 详细信息

在渗杂度很低时,由于少数杂质电离后引起场的起伏,电子在杂质上主要处于局域状态,电声子作用使电子能够在不同杂质上跳跃,但由于电子坐标算符与电声子作用交换,在电场中电子的运动实际上是一种击穿效应,而由声子束补偿能量。针对低补偿情况,略去复杂能带结构,我们由刘维方程出发,把密度矩阵对电场,然后对电声子作用展开,得到电流表达式及密度矩阵对角元所满足的玻茲曼型方程.只取到重迭积分二次项,我们得到了Miller等的网络方程,可以简单地求出平均阻抗,在低温极限下,得到βε3=βe2/εrd-1.93（βEA）3/4 。借助网络模型,我们分析了密度矩阵各部分的贡献,特别是与通常输运过程的差别。最后利用Anderson的结果,若K<10（-2）,在对电导起主要作用的链上,在Ge,Si中浓度要在1014及1016cm-3以下才能形成局域态,我们认为,考虑了电子间库仑作用后,载流子非局域并不与目前实验矛盾。

关键词：杂质带导体导电体跳跃机构准粒子声子局域态波动力学波函数电子状态轻子电子算符低渗

Asymptomatic low-grade appendiceal mucinous neoplasm:A case report

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World Journal of Clinical Cases 2024年第2期12卷 361-366页

作者： Min-Quan Yao yu-Peng Jiang yuan-yu Wang Yi-ping Mou Jin-Xing Fan Department of Gastrointestinal Surgery Tongxiang First People’s HospitalJiaxing 314500Zhejiang ProvinceChina Department of General Surgery Zhejiang Provincial People’s HospitalHangzhou 310014Zhejiang ProvinceChina Endoscopy Center Tongxiang First People’s HospitalJiaxing 314500Zhejiang ProvinceChina

BACKGROUND Low-grade appendiceal neoplasms(LAMN)are characterized by low incidence and atypical clinical presentations,often leading to misdiagnosis as acute or chronic appendicitis before *** primary diagnostic tool for LAMN is abdominal computed tomography(CT)*** resection remains the cornerstone of LAMN management,necessitating en bloc tumor excision to minimize the risk of iatrogenic ***,known for its minimal invasiveness,reduced postoperative discomfort,and expedited recovery,is a safe and reliable approach for LAMN *** the possibility of pseudomyxoma peritonei development,appendectomy and partial appendectomy generally result in negative tumor margins and favorable outcomes,which can be attributed to the disease’s slow growth and lower *** SUMMARY A 71-year-old male patient was admitted to our hospital with a pelvic spaceoccupying lesion detected 1 mo *** examination showed a soft abdomen without tenderness or rebound and no palpable *** shifting dullness was noted,and digital rectal examination revealed no palpable *** revealed a raised,smooth-surfaced mass measuring 3.0 cm in the *** contrast-enhanced CT showed a markedly thickened and dilated appendix with visible cystic *** surgery was performed and revealed a significantly dilated appendix,leading to laparoscopic resection of the appendix and part of the ***-surgical pathologic analysis confirmed *** patient received symptomatic and supportive post-operative care and was discharged on postoperative day 4 without complications such as abdominal bleeding,intestinal obstruction,or incision *** tumor recurrence was observed during a 7-mo follow-up *** LAMN is a rare disease that lacks specific clinical *** CT plays a crucial role in diagnosing LAMN,and laparoscopic surgery is a safe and effective diagnostic and therapeutic approach.

关键词： Low-grade appendiceal mucinous neoplasm Pseudomyxoma peritonei Computed tomography Laparoscopy appendectomy Case report

Automatic fovea detection and choroid segmentation for choroidal thickness assessment in optical coherence tomography

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International Journal of Ophthalmology(English edition) 2024年第10期17卷 1763-1771页

作者： Chen yu Lin Hung Ju Chen Yi Kit Chan Wei ping Hsia yu Len Huang Chia Jen Chang Department of Ophthalmology Taichung Veterans General HospitalTaichung 407TaiwanChina Department of Computer Science Tunghai UniversityTaichung 407TaiwanChina

AIM:To develop an automated model for subfoveal choroidal thickness(SFCT)detection in optical coherence tomography(OCT)images,addressing manual fovea location and choroidal contour ***:Two procedures were proposed:defining the fovea and segmenting the *** localization from B-scan OCT image sequence with three-dimensional reconstruction(LocBscan-3D)predicted fovea location using central foveal depression features,and fovea localization from two-dimensional en-face OCT(LocEN-2D)used a mask region-based convolutional neural network(Mask R-CNN)model for optic disc detection,and determined the fovea location based on optic disc relative *** segmentation also employed Mask ***:For 53 eyes in 28 healthy subjects,LocBscan-3D’s mean difference between manual and predicted fovea locations was 170.0μm,LocEN-2D yielded 675.9μ***-2D performed better in non-high myopia group(P=0.02).SFCT measurements from Mask R-CNN aligned with manual ***:Our models accurately predict SFCT in OCT ***-3D excels in precise fovea localization even with high ***-2D shows high detection rates but lower accuracy especially in the high myopia *** both models offers a robust SFCT assessment approach,promising efficiency and accuracy for large-scale studies and clinical use.

关键词： subfoveal choroidal thickness optical coherence tomography automatic foveal detection automatic choroid segmentation

Features and formulae of sediment incipient motion in vegetated flow environment

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Journal of Hydrodynamics 2024年第2期36卷 331-339页

作者： yu-xuan Xu Wei-jie Wang Shi-bao Zhang Han-qing Zhao Xue-kai Chen Hai-ping Zhang School of Water Conservancy North China University of Water Resources and Electric PowerZhengzhou450045China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100038China China Three Gorges Corporation Wuhan430010China

Aquatic vegetation is a vital component of natural river ecosystems,playing a crucial role in maintaining ecological balance,providing habitat and improving water ***,the presence of vegetation results in increased resistance in vegetated channels compared with non-vegetated channels,rendering traditional sediment movement predictions inadequate for the ***,the concept of a vegetation influence factor,denoted by CDah,has been proposed by previous researchers to represent the effect of vegetation on sediment movement in *** this study,we focus on exploring the vegetation resistance coefficient(CD)among the vegetation influence factors,evaluating two different calculation methods for vegetation resistance coefficient,and presenting two expressions through genetic algorithm analysis to predict the incipient flow velocity of sediment in vegetated *** predicted values from the new formulae show excellent agreement with measured data,highlighting the high accuracy of the proposed methods in predicting the incipient flow velocity of *** results provide a solid theoretical basis for understanding the influence of aquatic vegetation on sediment particle movement.

关键词： Vegetation flow vegetation resistance coefficient genetic algorithm sediment initiation

Two sandwich-type uranyl-containing polytungstates catalyze aerobic synthesis of benzimidazoles

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Rare Metals 2024年第3期43卷 1316-1322页

作者： yu-Feng Liu Qi-Long Hu Xue-Jiao Chen Ke Li Pei Luo Guo-ping Yang School of Chemistry and Material Science Jiangxi Province Key Laboratory of Synthetic ChemistryJiangxi Key Laboratory for Mass Spectrometry and InstrumentationEast China University of TechnologyNanchang330013China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China

Diversified synthetic strategies are extremely important for the structural diversity of uranium-containing polyoxometalates(U-POMs)and their functional ***,two sandwich-type U-POMs were reported,which are Na_(5.6)K_(6.4)[(UO_(2))(H_(2)O)(TeW_(9)O_(33))]_(2)·21H_(2)O(UTeW_(9))and Na_(8.9)K_(2.7)H_(1.19)[K_(0.79)(UO_(2))_(2.21)(PW_(9)O_(34))_(2)]·12H_(2)O(UPW_9)using in-situ strategy and lacunary precursor strategy,***_9 shows a typical Keggin-typeopen or half-sandwich configuration.

关键词： configuration expansion sandwich

Socioeconomic traits and the risk of Barrett’s esophagus and gastroesophageal reflux disease: A Mendelian randomization study

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World Journal of Gastrointestinal Oncology 2024年第6期16卷 2631-2645页

作者： yu-Xin Liu Cheng-Li Bin Lu Zhang Wen-Tao Yang Bai-ping An Department of Oncology Hospital of Chengdu University of Traditional Chinese MedicineChengdu 610072Sichuan ProvinceChina Department of Gynecology and Obstetrics Hospital of Chengdu University of Traditional Chinese MedicineChengdu 610072Sichuan ProvinceChina Department of Endocrine Hospital of Chengdu University of Traditional Chinese MedicineChengdu 610072Sichuan ProvinceChina Department of Cardiovascular Chengdu Integrated TCM&Western Medicine HospitalChengdu 610041Sichuan ProvinceChina

BACKGROUND Previous observational studies have shown that the prevalence of gastroesophageal reflux disease(GERD)and Barrett’s esophagus(BE)is associated with socioeconomic ***,due to the methodological limitations of traditional observational studies,it is challenging to definitively establish *** To explore the causal relationship between the prevalence of these conditions and socioeconomic status using Mendelian randomization(MR).METhoDS We initially screened single nucleotide polymorphisms(SNPs)to serve as proxies for eight socioeconomic status phenotypes for univariate MR *** inverse variance weighted(IVW)method was used as the primary analytical method to estimate the causal relationship between the eight socioeconomic status phenotypes and the risk of GERD and *** then collected combinations of SNPs as composite proxies for the eight socioeconomic phenotypes to perform multivariate MR(MVMR)analyses based on the IVW MVMR ***,a two-step MR mediation analysis was used to examine the potential mediation of the associations by body mass index,major depressive disorder(MDD),smoking,alcohol consumption,and sleep *** The study identified three socioeconomic statuses that had a significant impact on *** included household income[odds ratio(OR):0.46;95% confidence interval(95%CI):0.31-0.70],education attainment(OR:0.23;95%CI:0.18-0.29),and the Townsend Deprivation Index at recruitment(OR:1.57;95%CI:1.04-2.37).These factors were found to independently and predominantly influence the genetic causal effect of ***,the mediating effect of educational attainment on GERD was found to be mediated by MDD(proportion mediated:10.83%).Similarly,the effect of educational attainment on BE was mediated by MDD(proportion mediated:10.58%)and the number of cigarettes smoked per day(proportion mediated:3.50%).Additionally,the mediating effect of household income on GERD was observed to be mediated by sleep dur

关键词： Socioeconomic status Gastroesophageal reflux disease Barrett’s esophagus Two-step Mendelian randomization Multivariate Mendelian randomization

Core-shell heterostructure by coupling layered ReS_(2) with Co_(9)S_(8) nanocubes for boosted oxygen evolution reaction

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Chinese Chemical Letters 2024年第3期35卷 518-522页

作者： Xu yu Zhiqiang Pan Chengang Pei Longjie Lin Yanhui Lu ho Seok Park Huan Pang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225009China School of Chemical Engineering Sungkyunkwan University2066Seobu-roJangan-guSuwon-siGyeonggi-do 440-746Republic of Korea

The controllable morphology and composition of catalysts are crucial to improving the electrocatalytic activity of oxygen evolution reaction(OER).Herein,we construct a bimetallic heterostructure by sulfidation and hydrothermal methods,and the layered ReS_(2)is vertically aligned on Prussian blue-derived hollow Co_(9)S_(8)nanocubes(Co_(9)S_(8)@ReS_(2)).The core-shell structure of Co_(9)S_(8)@ReS_(2)can effectively prevent the restacking of layered ReS_(2),expose the abundant surface area and improve the utilization of electrocatalytic sites,resulting in fast electrolyte diffusion and charge transfer during *** to the synergistic effect of the core-shell morphology and the formed bimetallic heterostructure,Co_(9)S_(8)@ReS_(2)exhibits excellent catalytic OER *** 10 mA/cm^(2),only 288 mV of overpotential is required with the Tafel slope of 73.3 mV/dec for Co_(9)S_(8)@ReS_(2),which are both lower than that of Co_(9)S_(8)and ReS_(2).Meanwhile,Co_(9)S_(8)@ReS_(2)exhibits high catalytic stability and low charge transfer resistance and the boosted active sites are confirmed by density functional *** work provides a rational design of the OER catalysts by constructing the bimetallic heterostructure.

关键词： Oxygen evolution reaction Rhenium disulfide Metal-organic framework Heterostructure Core-shell