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Numerical Implementation of a Unified Viscoplastic Model for Considering Solder Joint Response under Board-Level Temperature Cycling

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Computer Modeling in Engineering & Sciences 2021年第8期128卷 639-668页

作者： Hung-chun Yang Tz-Cheng chiu Department of Mechanical Engineering National Cheng Kung UniversityTainan701Taiwan

An implicit integration scheme was developed for simulating the viscoplastic constitutive behavior ofSn3.0Ag0.5Cu solder and programmed into a user material subroutine of the finite element software ANSYS. Thenumerical procedure first solves the essential state variables by using a three-level iterative procedure, and updatesthe remaining stress and state variables accordingly. The numerical implementation was applied to consider theresponses of solder joints in an electronic assembly under temperature cycling condition. The viscoplastic strainenergy density accumulation over one temperature cycle was identified as a feasible parameter for evaluating thethermomechanical reliability of the solder joints.

关键词： Pb-free hysteresis ratcheting fatigue tangent modulus

Experimental and analytical study on design performance of full-scale viscoelastic dampers

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 693-706页

作者： Shiang-Jung Wang I-Chen chiu chung-Han Yu Kuo-chun Chang Department of Civil and Construction Engineering Taiwan University of Science and Technology Taipei Chinese Taipei Department of Civil Engineering Taiwan University (NTU) Taipei Chinese Taipei Center for Research on Earthquake Engineering (NCREE) Taipei Chinese Taipei

Viscoelastic（VE） dampers, with their stiffness and energy dissipation capabilities, have been widely used in civil engineering for mitigating wind-induced vibration and seismic responses of structures, thus enhancing the comfort of residents and serviceability of equipment inside. In past relevant research, most analytical models for characterizing the mechanical behavior of VE dampers were verified by comparing their predictions with performance test results from small-scale specimens, which might not adequately or conservatively represent the actual behavior of full-scale dampers, especially with regard to the ambient temperature, temperature rise, and heat convection effects. Thus, in this study, by using a high-performance testing facility with a temperature control system, full-scale VE dampers were dynamically tested with different displacement amplitudes, excitation frequencies, and ambient temperatures. By comparing the analytical predictions with the experimental results, it is demonstrated that adopting the fractional derivative method together with considering the effects of excitation frequencies, ambient temperatures, temperature rises, softening, and hardening, can reproduce the design performance of full-scale VE dampers very well.

关键词： viscoelastic damper full-scale designperformance dynamic test fractional derivative model

Intense blue-emitting Ca_2PO_4Cl:Eu^(2+) phosphor for near-ultraviolet converting white light-emitting diodes

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Journal of Rare Earths 2010年第S1期28卷 250-253页

作者： Yi-Chen chiu chun-Kuei Chang Yao-Tsung Yeh Shyue-Ming Jang Material and Chemical Research Laboratories Industrial Technology Research Institute Phosphors Research Laboratory and Department of Applied Chemistry National Chiao Tung University

A blue phosphor Ca2PO4Cl:Eu2+(CAP:Eu2+) was synthesized by solid state *** Ca2PO4Cl:Eu2+ exhibited high quantum efficiency and excellent thermal *** luminescent intensity of Ca2PO4Cl:Eu2+ was found to be 128% under excitation at 380 nm,149% under 400 nm,and 247% under 420 nm as high as that of BaMgAl10O17:Eu2+.The optimal doping concentration was observed to 11 mol.% of CAP:Eu2+.The energy transfer between Eu2+ ions in CAP were occurred via electric multipolar interaction,and the critical transfer distance was estimated to be 1.26 nm.A mixture of blue-emitting Ca2PO4Cl:Eu2+,green-emitting(Ba,Sr)2SiO4:Eu2+ and red-emitting CaAlSiN3:Eu2+ phosphors were selected in conjunction with 400 nm chip to fabricate white LED *** average color-rendering index Ra and correlated color temperature(Tc) of the white LEDs were found to be 93.4 and 4590 K,*** results indicated that it was a promising candidate as a blue-emitting phosphor for the near-UV white light-emitting diodes.

关键词： Ca2PO4Cl:Eu2+ phosphors luminscense rare earths

Transactive Energy and Flexibility Provision in Multi-microgrids Using Stackelberg Game

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 505-515页

作者： Weiqi Hua Hao Xiao Wei pei Wei-Yu chiu Jing Jiang Hongjian Sun Peter Matthews Department of Engineering Science University of OxfordOxford OX13PJUK Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China MOCaRL Lab Department of Electrical EngineeringNational Tsing Hua UniversityHsinchu 300044Chinese Taiwan Department of Mathematics Physics and Electrical EngineeringUniversity of NorthumbriaNewcastleNE18STUK Department of Engineering Durham UniversityDurhamDH13LEUK

Aggregating demand side flexibility is essential to complementing the inflexible and variable renewable energy supply in achieving low carbon energy *** of demand side flexibility,e.g.,dispatchable generators,storage,and flexible loads,can be structured in a form of microgrids and collectively provided to utility grids through transactive energy in local energy *** paper proposes a framework of local energy markets to manage this transactive energy and facilitate the flexibility *** distribution system operator aims to achieve local energy balance by scheduling the operation of multi-microgrids and determining the imbalance *** microgrid traders aim to maximize profits for their prosumers through dispatching flexibility sources and participating in localised energy *** decision making and interactions between a distribution system operator and multiple microgrid traders are formulated as the Stackelberg game-theoretic *** studies using the IEEE 69-bus distribution system demonstrate the effectiveness of the developed model in terms of facilitating local energy balance and reducing dependency on the utility grids.

关键词： Demand side flexibility game theory multimicrogrid prosumer smart grid transactive energy

Modulation of morphological changes of microglia and neuroprotection by monocyte chemoattractant protein-1 in experimental glaucoma

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Cellular & Molecular Immunology 2010年第1期7卷 61-68页

作者： Kin chiu Sze-chun Yeung Kwok-Fai So Raymond Chuen-chung Chang Laboratory of Neurodegenerative Diseases Department of AnatomyUniversity of Hong KongPokfulamHong KongChina State Key Laboratory of Brain and Cognitive Sciences University of HongKongPokfulamHongKongChina Research Centre of Heart BrainHormone and Healthy AgingLiKa Shing Faculty of MedicineUniversity of Hong KongPokfulamHong KongChina

Monocyte chemoattractant protein-1(MCP-1)/CCL2 is a C–C chemokine involved in the activation and recruitment of monocytic cells to injury ***-1/CCL2 can induce either neuroprotection or neurodestruction in vitro,depending on the experimental *** aim to use MCP-1/CCL2 as an experimental tool to investigate the morphological changes of microglia when loss of healthy retinal ganglion cells(RGCs)is exacerbated or attenuated in an experimental glaucoma *** a high concentration(1000 ng)of MCP-1/CCL2 and lipopolysaccharide(LPS)-exacerbated RGC loss,100 ng MCP-1/CCL2 provided neuroprotection towards *** MCP-1/CCL2(100 ng)also upregulated insulin-like growth factor-1(IGF-1)immunoreactivity in the *** neuroprotective effect of MCP-1/CCL2 was not due to the massiveinfiltration of microglia/*** together,this is the first report showing that an appropriate amount of MCP-1/CCL2 can protect RGCs in experimental glaucoma.

关键词： glaucoma IGF-1 MCP-1/CCL2 microglia neuroprotection

Predictors of rebleeding after initial hemostasis with epinephrine injection in high-risk ulcers

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World Journal of Gastroenterology 2010年第43期16卷 5490-5495页

作者： Ming-Luen Hu King-Wah chiu Yi-chun chiu Yeh-Pin Chou Tsung-Hui Hu Shue-Shian Chiou Seng-Kee Chuah Division of Hepatogastroenterology Department of Internal Medicine Chang Gung Memorial Hospital-Kaohsiung Medical Center Chang Gung University College of Medicine

AIM: To identify the predictors of rebleeding after initial hemostasis with epinephrine injection (EI) in patients with high-risk ulcers. METHODS: Recent studies have revealed that endoscopic thermocoagulation, or clips alone or combined with EI are superior to EI alone to arrest ulcer bleeding. However, the reality is that EI monotherapy is still common in clinical practice. From October 2006 to April 2008, high-risk ulcer patients in whom hemorrhage was stopped after EI monotherapy were studied using clinical, laboratory and endoscopic variables. The patients were divided into 2 groups: sustained hemostasis and rebleeding. RESULTS: A total of 175 patients (144, sustainedhemostasis; 31, rebleeding) were enrolled. Univariate analysis revealed that older age (≥ 60 years), advanced American Society of Anesthesiology (ASA) status (category Ⅲ , Ⅳ and Ⅴ ), shock, severe anemia (hemoglobin < 80 g/L), EI dose ≥ 12 mL and severe bleeding signs (SBS) including hematemesis or hematochezia were the factors which predicted rebleeding. However, only older age, severe anemia, high EI dose and SBS were independent predictors. Among 31 rebleeding patients, 10 (32.2%) underwent surgical hemostasis, 15 (48.4%) suffered from delayed hemostasis causing major complications and 13 (41.9%) died of these complications. CONCLUSION: Endoscopic EI monotherapy in patients with high-risk ulcers should be avoided. Initial hemostasis with thermocoagulation, clips or additional hemostasis after EI is mandatory for such patients to ensure better hemostatic status and to prevent subsequent rebleeding, surgery, morbidity and mortality.

关键词： Epinephrine injection High-risk ulcers Initial hemostasis Predictors Rebleeding

1D-2D nanohybrid-based textile strain sensor to boost multiscale deformative motion sensing performance

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Nano Research 2022年第9期15卷 8398-8409页

作者： Xiaoting Li Keng Huat Koh Jiaqi Xue chun Ho So Na Xiao chung Tin King Wai chiu Lai Department of Biomedical Engineering City University of Hong KongKowloon TongHong KongChina

The development of strain sensors with both superior sensitivity(gauge factor(GF)>100)and broad strain-sensing range(>50%strain)is still a grand ***,which demonstrate significant structural deformation under microscale motion,are required to offer high *** connection of materials upon large-scale motion is demanded to widen strainsensing ***,it is hard to achieve both features ***,we design a crepe roll structure-inspired textile yarn-based strain sensor with one-dimensional(1D)-two-dimensional(2D)nanohybrid strain-sensing sheath,which possesses superior *** ultrastretchable strain sensor exhibits a wide and stable strain-sensing range from microscale to large-scale(0.01%–125%),and superior sensitivity(GF of 139.6 and 198.8 at 0.01%and 125%,respectively)*** strain sensor is structurally constructed by a superelastic 1D-structured core elastomer polyurethane yarn(PUY),a novel high conductive crepe roll-structured(CRS)1D-2D nanohybrid multilayer sheath which assembled by 1D nanomaterials silver nanowires(AgNWs)working as bridges to connect adjacent layers and 2D nanomaterials graphene nanoplates(GNPs)offering brittle lamellar structure,and a thin polydopamine(PDA)wrapping layer providing protection in exterior *** the stretching/deformation process,microcracks originate and propagate in the GNPs lamellar structure enable resistance to change significantly,while AgNWs bridge adjacent GNPs to accommodate applied stress partially and boost *** 1D crepe roll structure-inspired strain sensor demonstrates multifunctionality in multiscale deformative motion detection,such as respiratory motions of Sprague–Dawleyw rat,flexible digital display,and proprioception of multi-joint finger bending and antagonistic flexion/extension motions of its flexible continuum body.

关键词： crepe roll-inspired multifunctional yarn strain sensor one-dimensional silver nanowires/two-dimensional graphene nanoplates(1D AgNWs/2D GNPs)nanohybrid multi-scale motion detection e-textiles tactile sensing proprioception of the endoscopic robot

Stigmatic exudate in the Annonaceae:Pollinator reward,pollen germination medium or extragynoecial compitum?

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Journal of Integrative Plant Biology 2017年第12期59卷 881-894页

作者： Jenny Y.Y.Lau chun-chiu Pang Lawrence Ramsden Richard M.K.Saunders School of Biological Sciences the University of Hong KongPokfulam RoadHong KongChina

Although ＂dry-type＂ stigmas are widely re- garded as ancestral in angiosperms, the early-divergent family Annonaceae has copious stigmatic exudate. We evaluate three putative functions for this exudate： as a nutritive reward for pollinators; as a pollen germination medium; and as an extragynoecial compitum that enables pollen tube growth between carpels. Stigmatic exudate is fructose dominated （72.2%）, but with high levels of glucose and sucrose; the dominance of hexose sugars and the diversity of amino acids observed, including many that are essential for insects, support a nutritive role for pollinators. Sugar concentration in pre-receptive flowers is high （28.2%）, falling during the peak period of stigmatic receptivity （17.4%）, and then rising again toward the end of the pistillate phase （32.9%）. Pollen germination was highest in sugar concentrations 〈2%. Sugar concentrations during the peak pistillate phase therefore provide optimal osmolarity for pollen hydration and germination; subsequent changes in sugar concentration during anthesis reinforce protogyny （in which carpels mature before stamens）, enabling the retention of concentrated exudate into the staminate phase as a pollinator food reward without the possibility of pollen germination. Intercarpellary growth of pollen tubes was confirmed： the exudate therefore also functions as a suprastylar extragynoecial compitum, overcoming the limitations of apocarpy.

关键词： Stigmatic exudate in the Annonaceae pollen germination medium or extragynoecial compitum Pollinator reward

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儿童原发性肾病综合症治理方案(英文)

中南大学学报（医学版） 2008年第1期33卷 1-7页

作者： chiu Man-chun 香港玛嘉烈医院儿童及青少年科儿童肾病中心

皮质激素、烷基化物如环磷酰胺、苯丁酸氮芥用于原发性肾病综合症近50年,改变了肾病综合症儿童的预后。然而,长期使用激素,尤其较高剂量却引起严重副作用。较新药物如环孢A、左旋咪唑、他克莫司、霉酚酸酯可免去不少激素副作用。在选择... 详细信息

皮质激素、烷基化物如环磷酰胺、苯丁酸氮芥用于原发性肾病综合症近50年,改变了肾病综合症儿童的预后。然而,长期使用激素,尤其较高剂量却引起严重副作用。较新药物如环孢A、左旋咪唑、他克莫司、霉酚酸酯可免去不少激素副作用。在选择药物时,应衡量及平衡效益与副作用,并考虑药物价格。虽然大部份肾病综合症儿童都会复发,然而预后却良好,不少肾病综合症儿童成长后不再复发,或只间有复发,故治疗方案应以最少药物以维持缓解,以过渡儿童期,避免不必要的副作用。至于激素抵抗(SRNS)者,尤其局部节段性肾小球硬化(FSGS),预后可致终末期肾衰;治疗方面,用药可较为进取,多需较强免疫抑制剂如环孢A、他克莫司、霉酚酸酯等加以控制。治疗肾病综合症儿童的长期目标,还需考虑生长、教育与心理影响,尤其在过渡青春期时,能让他们正常地成长。

关键词：原发性肾病综合症药物治疗病程治疗方案治疗目标儿童