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Achieving Enhanced Thermoelectric Performance in Multiphase Materials

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Accounts of Materials Research 2022年第2期3卷 237-246页

作者： Ning Jia Xian yi tan Jianwei Xu Qingyu Yan Mercouri G.Kanatzidis School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798 Institute of Materials Research and Engineering Singapore 138634 Department of Chemistry Northwestern UniversityEvanstonIllinois 60208United States

CONSPECTUS:Thermoelectric(TE)devices enable direct solid-state energy conversion from heat to electricity and vice versa,thereby showing great potential in warranting the supply of sustainable energy and mitigating the potentially catastrophic effects of climate ***,as a clean-energy-generation technology,TE materials have received tremendous research efforts in both industrial and academic communities for applications in the recovery of ubiquitous low-grade waste *** high efficiency in TE materials is an ongoing pursuit of the TE research community,considering approximately 90%of all waste heat in the USA comes from medium-temperature(e.g.,from 573 to 873 K)heat ***,synergistic enhancements in the figures-of-merit(ZT)are still highly desired and remain a key task for improving commercial applications of TE materials.

关键词： thereby pursuit enable

A Facile Strategy for Intrinsic Low-Dk and Low-Df Polyimides Enabled by Spirobifluorene Groups

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高分子科学：英文版 2023年第2期41卷 288-296页

作者： Wan-yi tan Ling-Feng Jian Wei-Peng Chen Yong-Wen Zhang Xiao-Chuang Lu Wan-Jun Huang Ji-Sheng Zhang Jing-Wu Wu Jun-Li Feng yi-Dong Liu Ting-Ting Cui Yong-Gang Min Guangdong University of Technology(GDUT) Guangzhou510006China Huimai Materials Technology(Guangdong)Co. Ltd.Foshan528200China Shenzhen Customs Industrial Product Inspection Technology Center Shenzhen518026China

Modified polyimides(MPIs)show great potential towards 5G communication applications,due to its excellent thermal stability,mechanical property and chemical stability as compared to most of *** fluoride groups or porous structure is favorable to ultra-low dielectric constant(D_(k))and dielectric loss(D_(f)).However,the cost of the fluorinated MPIs is high and their synthetic processes are complicated,and porous MPIs suffer poor mechanical ***,increasing the fraction of free volume is a very effective way to lower D_(k)through introducing more ultra-low-D_(k)air ***,most of this kind of MPIs lag far behind the fluorinated MPIs and the porous MPIs in terms of ultra-low D_(f),hindering the application of MPIs in high-speed communication ***,it is highly desirable to develop intrinsic ultra-low-D_(k)/D_(f)MPIs at high frequency with less fluoric groups and nonporous ***,we introduce a facile and effective strategy to lower D_(k)and D_(f)through introducing rigid and large sterically hindered aromatic groups into *** the one hand,their large steric hindrance effect leads to low D_(k)by increasing intrinsic free *** the other hand,the resulting highly stiff polymer chain and strong intermolecular interaction are favorable to reduce D_(f)by inhibiting dipole *** on this strategy,the spirobifluorene groups are *** as-prepared MPIs show excellent dielectric performance with low D_(k)of 2.74–2.76 and low D_(f)of 0.00599 at 10 GHz,to some extent,exceeding the multiple fluorinated MPI with D_(k)/D_(f)of 2.67/0.00663 at 10 GHz.

关键词： Polyimide High speed communication Low dielectric constant Low dielectric loss

Linear Time Algorithms for Parallel Machine Scheduling

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Acta Mathematica Sinica,English Series 2007年第1期23卷 137-146页

作者： Zhi yi tan Yong HE Department of Mathematics State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 P. R. China Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

This paper addresses linear time algorithms for parallel machine scheduling problems. We introduce a kind of threshold algorithms and discuss their main features. Three linear time threshold algorithm classes DT, PT and DTm are studied thoroughly. For all classes, we study their best possible algorithms among each class. We also present their application to several scheduling problems, The new algorithms are better than classical algorithms in time complexity and/or worst-case ratio. Computer-aided proof technique is used in the proof of main results, which greatly simplifies the proof and decreases case by case analysis.

关键词： scheduling design and analysis of algorithm worst-case ratio computer-aided proof

A Two-layer Framework for Mitigating the Con-gestion of Urban Power Grids Based on Flexible Topology with Dynamic Thermal Rating

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Protection and Control of Modern Power Systems 2024年第4期9卷 83-95页

作者： yi Su Jiashen Teh Qian Luo Kangmiao tan Jiaying Yong the School of Automation and Electronic In-formation Xiangtan Universityxiangtan 411100China IEEE the School of Electrical and Electronic Engineering Universiti Sains Malaysia(USM)Penang 11800Malaysia the School of Computer Sciences Universiti Sains Malaysia(USM)Penang 11800Malaysia the Institute of Power Engineering College of EngineeringUniversiti Tenaga Nasional(UNITEN)Kajang 43000Malaysia

The urban power grid(UPG)combines transmission and distribution *** studies on UPG congestion mitigation have primarily focused on relieving local congestion while ignoring large-scale energy transfer with safety margins and load *** situation is expected to worsen with the proliferation of renewable energy and electric *** this paper,a two-layer congestion mitigation framework is proposed,one which considers the congestion of the UPG with flexible *** the upper-layer,the particle swarm optimization algorithm is employed to optimize the power supply distribution(PSD)of substation *** is known as the upper-layer *** lower-layer model recalculates the new PSD,known as the lower-layer PSD,based on the topology candidates.A candidate topology is at an optimum when the Euclidean distance mismatch between the upper-and lower-layer PSDs is the *** optimum topology is tested by standard power flow to ascertain its *** optimum transitioning sequence between the initial and optimum topologies is also determined by the two-layer framework to minimize voltage deviation and line overloading of the UPG considering dynamic thermal *** proposed framework is tested on a 56-node test *** show that the proposed framework can significantly reduce congestion,maintain safety margins,and determine the optimum transitioning sequence.

关键词： Congestion mitigation urban power grid two-layer framework transitioning sequence dynamic thermal rating

电子束精炼FGH4097母合金夹杂物迁移行为研究

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铸造技术 2024年第7期45卷 659-671页

作者：夏福宽谭毅白如圣张雪良李鹏廷常凯大连理工大学材料科学工程学院辽宁大连116024 大连理工大学辽宁省载能束冶金与先进材料制备重点实验室辽宁大连116024 北京钢研高纳科技股份有限公司北京100081

采用电子束熔炼技术精炼FGH4097母合金,分析了熔炼过程中非金属夹杂物的迁移行为。结果显示,电子束精炼技术可以使FGH4097合金中Al_(2)O_(3)、SiO_(2)、Ce_(2)O_(3)等低密度(<8.30 g/cm^(3))非金属夹杂物上浮并保留在最后凝固区。夹杂... 详细信息

采用电子束熔炼技术精炼FGH4097母合金,分析了熔炼过程中非金属夹杂物的迁移行为。结果显示,电子束精炼技术可以使FGH4097合金中Al_(2)O_(3)、SiO_(2)、Ce_(2)O_(3)等低密度(<8.30 g/cm^(3))非金属夹杂物上浮并保留在最后凝固区。夹杂物的上浮行为主要与夹杂物的尺寸和密度有关,尺寸越大、密度越小的夹杂物上浮速度越快。根据计算结果显示,本实验工艺可使尺寸大于6.5μm的低密度夹杂物有效上浮,熔体表面存在马兰戈尼效应产生的液流,能够带动上浮的夹杂物向熔池中心运动,并聚集形成夹杂物浮筏。当母合金O含量略高于4×10^(-4)%时,能在铸锭上观察到面积不大于10 mm^(2)的夹杂物聚集区,而当母合金存在缩孔时,夹杂物聚集的面积则急剧增大至100 mm^(2)以上。

关键词： FGH4097 母合金电子束精炼夹杂物

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Enhanced near-room-temperature thermoelectric performance in GeTe

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Rare Metals 2022年第9期41卷 3027-3034页

作者： Xian yi tan Jin-Feng Dong Ning Jia Hong-Xia Zhang Rong Ji Ady Suwardi Zhi-Liang Li Qiang Zhu Jian-Wei Xu Qing-Yu Yan School of Materials Science and Engineering Nanyang Technological UniversitySingapore639798Singapore Institute of Materials Research and Engineering Agency for ScienceTechnology and ResearchSingapore138634Singapore Key Laboratory of High-Precision Computation and Application of Quantum Field Theory of Hebei Province College of Physics Science and TechnologyHebei UniversityBaoding071002China

GeTe is an excellent mid-temperature thermoelectric material with high dimensionless figure of merit(ZT)values at temperatures over 600 *** near-room-temperature performance is less studied due to the intrinsic high carrier ***,we successfully enhance the Seebeck coefficient of GeTe from~30 to 220μV·K^(−1) at 300 K,which is achieved by AgInSe2 alloying and Bi *** is demonstrated that Bi doping helps to optimize the Seebeck coefficient without deteriorating the intrinsic electrical transport properties of the matrix.A high room-temperature power factor(PF)of~11μW·cm^(−1)·K^(−2) is achieved for a wide range of Bi-doped *** simultaneously introduced abundant point defects cause mass and strain fluctuations,which decrease the lattice thermal conductivity(κ_(L))to a low value of 0.6 W·m^(−1)·K^(−1) at 300 *** to the synergetic effects of Bi doping in AgInSe2-alloyed GeTe,a high room-temperature ZT value of 0.46 is obtained together with a high ZT value of 1.1 at 523 K.

关键词： Thermoelectric GeTe Thermal conductivity Room-temperature ZT

Projections of the transmission of the Omicron variant for Toronto,Ontario,and Canada using surveillance data following recent changes in testing policies

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Infectious Disease Modelling 2022年第2期7卷 83-93页

作者： Pei Yuan Elena Aruffo yi tan Liu Yang Nicholas HOgden Aamir Fazil Huaiping Zhu Laboratory of Mathematical Parallel Systems(LAMPS) Centre for Diseases ModellingDepartment of Mathematics and StatisticsYork UniversityTorontoONCanada Public Health Agency of Canada(PHAC) OttawaONCanada

At the end of 2021,with the rapid escalation of COVID19 cases due to the Omicron variant,testing centers in Canada were *** alleviate the pressure on the PCR testing capacity,many provinces implemented new strategies that promote self testing and adjust the eligibility for PCR tests,making the count of new cases *** designed a novel compartmental model which captures the new testing guidelines,social behaviours,booster vaccines campaign and features of the newest variant *** better describe the testing eligibility,we considered the population divided into high risk and non-highrisk *** model is calibrated using data from January 1 to February 9,2022,on cases and severe outcomes in Canada,the province of Ontario and City of *** conduct analyses on the impact of PCR testing capacity,self testing,different levels of reopening and vaccination coverage on cases and severe *** results show that the total number of cases in Canada,Ontario and Toronto are 2.34(95%CI:1.22e3.38),2.20(95%CI:1.15e3.72),and 1.97(95%CI:1.13e3.41),times larger than reported cases,*** current testing strategy is efficient if partial restrictions,such as limited capacity in public spaces,are *** more people to have access to PCR reduces the daily cases and severe outcomes;however,if PCR test capacity is insufficient,then it is important to promote self ***,we found that reopening to a pre-pandemic level will lead to a resurgence of the infections,peaking in late March or April *** and adherence to isolation protocols are important supports to the testing policies to mitigate any possible spread of the virus.

关键词： PCR testing Self-testing Booster dose Social behavior Mathematical model COVID-19 Omicron Exit strategy

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血管栓塞用明胶海绵微球的制备及表征

中国医疗器械信息 2024年第7期30卷 25-28,37页

作者：谭奕勋云晓王春曼吴芬敏杨顶建海南百迈科医疗科技股份有限公司海南定安571200

目的:制备一种可用于血管栓塞的明胶海绵微球,表征其理化性能,并通过动物试验初步验证其用于体内栓塞的安全性和有效性。方法:在制备明胶海绵微球时,将含有明胶的水相,添加到含有乳化剂的油相中,构建油包水的乳化体系,随后加入交联剂固... 详细信息

目的:制备一种可用于血管栓塞的明胶海绵微球,表征其理化性能,并通过动物试验初步验证其用于体内栓塞的安全性和有效性。方法:在制备明胶海绵微球时,将含有明胶的水相,添加到含有乳化剂的油相中,构建油包水的乳化体系,随后加入交联剂固化得到明胶海绵微球;对制得的微球开展了包括显微外观、粒径、溶胀率、弹性在内的理化性能表征;将制得的明胶海绵微球通过微导管注入猪肾脏血管,观察栓塞效果以及术后的并发症等情况以验证微球用于体内栓塞的安全性和有效性。结果:以此法制得的明胶海绵微球,表面光滑,呈规则球形;溶胀后的粒径呈类正态分布,粒径范围50~2000μm,平均溶胀率为355%,通过质构仪对微球施加粒径50%的压缩形变后,微球不破碎,不变形;猪肾脏栓塞动物试验表明,微球能够有效栓塞靶血管,引起靶组织的缺血梗死,体内降解时长约为28d,降解后血管可复通,试验过程中未见与明胶海绵微球相关的并发症。结论:该方法制得的明胶海绵微球呈完整球形,形状规则,粒径分布范围广,经筛分后具有可用于不同尺寸血管栓塞的潜力。微球具有适中的溶胀率与良好的弹性,便于在术中通过导管进行输送并能够与靶血管紧密嵌合;猪肾脏栓塞动物试验的结果亦表明制得的明胶海绵微球安全性和有效性良好,降解时长适中,运用于血管栓塞具有较大的市场前景。

关键词：明胶海绵微球血管栓塞猪肾脏动物试验

Low-molecular-weight heparin and preeclampsia—does the sword cut both ways?Three case reports and review of literature

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World Journal of Clinical Cases 2024年第9期12卷 1634-1643页

作者： Dan Shan Tao Li Xi tan Ya-yi Hu Department of Obstetrics and Gynecology West China Second University HospitalSichuan UniversityChengdu 610000Sichuan ProvinceChina Key Laboratory of Birth Defects and Related Diseases of Women and Children Sichuan UniversityMinistry of EducationChengdu 610000SichuanChina

BACKGROUND Low-molecular-weight heparins(LMWH)are the most commonly used anticoagulants during *** is considered to be the drug of choice due to its safety in not crossing *** the beneficial effect in the improvement of microcirculation,prophylactic application of LMWH in patients with preeclampsia became a ***,the bleeding risk related with LMWH in preeclampsia patients has seldomly been *** current study aimed to identify the potential risks regarding LMWH application in patients with *** SUMMARY Herein we present a case series of three pregnant women diagnosed with preeclampsia on LMWH therapy during *** the cases experienced catastrophic hemorrhagic *** reviewing the twenty-one meta-analyses,the bleeding risk related with LMWH seems *** one study analyzed the bleeding risk of LMWH and found a significantly higher risk of developing PPH in women receiving *** studies reported minor bleeding risks,none of these were serious enough to stop LMWH *** of bleeding either from uterus or from intrabdominal organs in preeclampsia patients on LMWH therapy should not be *** management of blood pressure even after delivery and homeostasis suture in surgery are *** Consideration should be given to the balance between benefits and risks of LMWH in patients with preeclampsia.

关键词： Pregnancy Preeclampsia Low-molecular-weight heparin Hemorrhage Case report