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81.
Jaecheon Han Gucheol Kang Daesung Kang Yongtae Moon Hwanhee Jeong June-O Song Tae-Yeon Seong 《Journal of Electronic Materials》2013,42(10):2876-2880
We investigated the effect of two different quantum well (QW) structures having different indium contents on the optical performance of fully packaged GaN-based light-emitting diodes (LEDs). Dual-spectrum QW LEDs exhibit ~4% higher external quantum efficiency (at 350 mA) than single-spectrum QW LEDs. However, the two types of LEDs exhibit similar efficiency droop behavior. For both types of LEDs, the output power decreases with increasing junction temperature. When the junction temperature exceeds 70°C, the dual-spectrum QW LEDs exhibit lower output power than the single-spectrum QW LEDs. The wavelength dependence of the output power (at 350 mA) of single-spectrum QW LEDs shows that the LEDs with shorter wavelengths experience more rapid optical degradation than the LEDs with longer wavelengths. Based on the wavelength- and junction-temperature-dependent output power, the droop behavior of the dual-spectrum QW LEDs is described and discussed. 相似文献
82.
Boeun Cho Seong Hun Yu Moo Hyung Lee Juhee Lee Jun Young Lee Jeong Ho Cho Moon Sung Kang 《Organic Electronics》2014,15(12):3439-3444
We demonstrate the versatility of the threshold voltage control for organic thin-film transistors (OTFTs) based on formation of discontinuous pn-heterojunction on the active channel layer. By depositing n-type dioctyl perylene tetracarboxylic diimide molecules discontinuously onto base p-type pentacene thin films (the formation of the discontinuous pn-heterojunction), a positive shift of the threshold voltage was attained which enabled realizing a depletion-mode transistor from an original enhancement-mode pristine pentacene transistor. Careful control of the threshold voltage based on this method led assembling a depletion-load inverter comprising a depletion-mode transistor and an enhancement-mode transistor connected in series that yielded tunable signal inversion voltage approaching 0 V. In addition, the tunability could be applied to improve the program/erase signal ratio for non-volatile transistor memories by more than 4 orders of magnitude compared to reference memory devices made of pristine pentacene transistors. 相似文献
83.
Characterization of Fluxing and Hybrid Underfills with Micro‐encapsulated Catalyst for Long Pot Life
Yong‐Sung Eom Ji‐Hye Son Keon‐Soo Jang Hak‐Sun Lee Hyun‐Cheol Bae Kwang‐Seong Choi Heung‐Soap Choi 《ETRI Journal》2014,36(3):343-351
For the fine‐pitch application of flip‐chip bonding with semiconductor packaging, fluxing and hybrid underfills were developed. A micro‐encapsulated catalyst was adopted to control the chemical reaction at room and processing temperatures. From the experiments with a differential scanning calorimetry and viscometer, the chemical reaction and viscosity changes were quantitatively characterized, and the optimum type and amount of micro‐encapsulated catalyst were determined to obtain the best pot life from a commercial viewpoint. It is expected that fluxing and hybrid underfills will be applied to fine‐pitch flip‐chip bonding processes and be highly reliable. 相似文献
84.
Kwang‐Seong Choi Ki‐Jun Sung Byeong‐Ok Lim Hyun‐Cheol Bae Sunghae Jung Jong‐Tae Moon Yong‐Sung Eom 《ETRI Journal》2010,32(2):342-344
A novel, maskless, low‐volume bumping material, called solder bump maker, which is composed of a resin and low‐melting‐point solder powder, has been developed. The resin features no distinct chemical reactions preventing the rheological coalescence of the solder, a deoxidation of the oxide layer on the solder powder for wetting on the pad at the solder melting point, and no major weight loss caused by out‐gassing. With these characteristics, the solder was successfully wetted onto a metal pad and formed a uniform solder bump array with pitches of 120 µm and 150 µm. 相似文献
85.
Thin‐Film Transistors: Synthesis of Ultrathin,Homogeneous Copolymer Dielectrics to Control the Threshold Voltage of Organic Thin‐Film Transistors (Adv. Funct. Mater. 36/2016) 下载免费PDF全文
Kwanyong Pak Hyejeong Seong Junhwan Choi Wan Sik Hwang Sung Gap Im 《Advanced functional materials》2016,26(36):6672-6672
86.
87.
Dae Gyu Kwon Myung Ku Kim Yoon Sang Jeon Yoon Cheol Nam Jin Seong Park Dong Jin Ryu 《International journal of molecular sciences》2022,23(3)
Osteoarthritis (OA) has generally been introduced as a degenerative disease; however, it has recently been understood as a low-grade chronic inflammatory process that could promote symptoms and accelerate the progression of OA. Current treatment strategies, including corticosteroid injections, have no impact on the OA disease progression. Mesenchymal stem cells (MSCs) based therapy seem to be in the spotlight as a disease-modifying treatment because this strategy provides enlarged anti-inflammatory and chondroprotective effects. Currently, bone marrow, adipose derived, synovium-derived, and Wharton’s jelly-derived MSCs are the most widely used types of MSCs in the cartilage engineering. MSCs exert immunomodulatory, immunosuppressive, antiapoptotic, and chondrogenic effects mainly by paracrine effect. Because MSCs disappear from the tissue quickly after administration, recently, MSCs-derived exosomes received the focus for the next-generation treatment strategy for OA. MSCs-derived exosomes contain a variety of miRNAs. Exosomal miRNAs have a critical role in cartilage regeneration by immunomodulatory function such as promoting chondrocyte proliferation, matrix secretion, and subsiding inflammation. In the future, a personalized exosome can be packaged with ideal miRNA and proteins for chondrogenesis by enriching techniques. In addition, the target specific exosomes could be a gamechanger for OA. However, we should consider the off-target side effects due to multiple gene targets of miRNA. 相似文献
88.
Myeong Seong Sim Hye Jeong Kim Sang Hee Jo Chun Kim Il Yup Chung 《International journal of molecular sciences》2022,23(7)
Lysophosphatidylserine (LysoPS) is an amphipathic lysophospholipid that mediates a broad spectrum of inflammatory responses through a poorly characterized mechanism. Because LysoPS levels can rise in a variety of pathological conditions, we sought to investigate LysoPS’s potential role in airway epithelial cells that actively participate in lung homeostasis. Here, we report a previously unappreciated function of LysoPS in production of a mucin component, MUC5AC, in the airway epithelial cells. LysoPS stimulated lung epithelial cells to produce MUC5AC via signaling pathways involving TACE, EGFR, and ERK. Specifically, LysoPS- dependent biphasic activation of ERK resulted in TGF-α secretion and strong EGFR phosphorylation leading to MUC5AC production. Collectively, LysoPS induces the expression of MUC5AC via a feedback loop composed of proligand synthesis and its proteolysis by TACE and following autocrine EGFR activation. To our surprise, we were not able to find a role of GPCRs and TLR2, known LyoPS receptors in LysoPS-induced MUC5AC production in airway epithelial cells, suggesting a potential receptor-independent action of LysoPS during inflammation. This study provides new insight into the potential function and mechanism of LysoPS as an emerging lipid mediator in airway inflammation. 相似文献
89.
The effect of coal size (0.73–1.03 mm), excess air ratio (1.0–1.4), operating bed temperature (750–900‡C), coal feeding rate
(1–3 kg/h), and coal recycle rate (20–40 kg/h) on combustion efficiency, temperature profiles along the bed height and flue
gas composition have been determined in a bubbling and circulating fluidized bed combustor (7.8 cm-ID x 2.6 m-high).
Combustion efficiency increases with increasing excess air ratio and operating bed temperature and it decreases with increasing
particle size in the bubbling and circulating fluidzing beds. In general, temperature profiles and combustion efficiency are
more uniform and higher in a circulating bed than those in bubbling bed. Combustion efficiency also increases with increasing
recycle rate of unburned coal in the circulating bed.
The ratio of CO/CO2 of flue gas decreases with increasing bed temperature and excess air ratio, whereas the ratio of O2(CO + CO2) decreases with bed temperature in both bubbling and circulating fluidized beds. 相似文献
90.
Sangbaek Park Hae Jin Kim Chan Woo Lee Hee Jo Song Seong Sik Shin Se Won Seo Hoon Kee Park Sungjun Lee Dong-Wan Kim Kug Sun Hong 《International Journal of Hydrogen Energy》2014
We produced hierarchically branched Fe2O3 nanorods on a Sb:SnO2 transparent conducting oxide (TCO) nanobelt structure as photoanodes for photoelectrochemical water splitting. Single-crystalline SnO2 nanobelts (NBs) surrounded by Fe2O3 nanorods (NRs) were synthesized by thermal evaporation, then underwent chemical bath deposition and annealing. When Fe2O3 was crystallized by annealing, Sn was diffused from SnO2 NBs and incorporated to Fe2O3 NRs, which was confirmed through Energy dispersive spectroscopy. Unlike previous high temperature sintering (∼800 °C), Sn doped hematite NRs were obtained at a low temperature (∼650 °C). This occurred since SnO2 NBs directly connected to Fe2O3 NRs are an abundant source of Sn dopant. The 3D hematite NRs on SnO2 NBs annealed at 650 °C produce a photocurrent density of 0.88 mA/cm2 at 1.23 V vs. RHE, which is 3 times higher than that of hematite NRs on a fluorine doped tin oxide (FTO) glass substrate annealed at the same temperature. The enhanced photocurrent is attributed to the improved electrical conductivity of Fe2O3 NRs by Sn doping, the efficient electron transport pathway by TCO nanowire and the increased surface area by hierarchically branched structure. 相似文献