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991.
Sang Sun Lee Jung Hee Koo Sung Soo Lee Soo Gyum Chai Jong Chan Lim 《Progress in Organic Coatings》2003,46(4):266-272
This study describes the crucial role played by acrylic resin and curing agents in the gloss reduction of low temperature curable hybrid powder coatings. The incompatibility of the acrylic resin with the primary (epoxy/polyester) resins induces a two-phase morphology and initiates the formation of micro-structured surface. DSC measurements on various mixtures reveal the relative reactivity and the role of curing agents in the gloss reduction. These results indicate that the optimization of relative reactivity and compatibility is required to achieve low gloss coatings at low curing temperature. In addition, the gloss level is strongly affected by extruding conditions. These experimental results give a possibility to develop matt and semi-matt low temperature curable powder coatings. 相似文献
992.
Ngoc Lan Mai Sung Hoon Kim Sung Ho Ha Hwa Sung Shin Yoon-Mo Koo 《Korean Journal of Chemical Engineering》2013,30(9):1804-1809
An effective in situ recovery of acetone, butanol and ethanol (ABE) from fermentation broth is requisite to overcome the low productivity of ABE production. Pervaporation has proven to be one of the best methods for recovering ABE from fermentation broth. We fabricated an immobilized ionic liquid-polydimethylsiloxane (PDMS) membrane in which a [Tf2N]? based ionic liquid covalently bound to the PDMS backbone polymer and used it to recover ABE from aqueous solution by pervaporation. Permeate flux of immobilized IL-PDMS membrane was 7.8 times higher than that of conventional supported IL-PDMS membrane (where ILs are physically absorbed on the supported membrane). Butanol enrichment factor of immobilized IL-PDMS membrane was three-times higher than that of PDMS membrane. In addition, high enrichment factor both to acetone and ethanol as well as high operational stability of immobilized IL-PDMS membrane can enhance the efficacy of ABE recovery by employing this membrane. 相似文献
993.
The outbreak of the coronavirus disease 2019 (COVID-19) began at the end of 2019. COVID-19 is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and patients with COVID-19 may exhibit poor clinical outcomes. Some patients with severe COVID-19 experience cytokine release syndrome (CRS) or a cytokine storm—elevated levels of hyperactivated immune cells—and circulating pro-inflammatory cytokines, including interleukin (IL)-1β and IL-18. This severe inflammatory response can lead to organ damage/failure and even death. The inflammasome is an intracellular immune complex that is responsible for the secretion of IL-1β and IL-18 in various human diseases. Recently, there has been a growing number of studies revealing a link between the inflammasome and COVID-19. Therefore, this article summarizes the current literature regarding the inflammasome complex and COVID-19. 相似文献
994.
Hye Cheong Koo Yi-Yong Baek Jun-Sup Choi Young-Myeong Kim Bokyung Sung Min-Jung Kim Jae Gyu Kim Ji Chang You 《International journal of molecular sciences》2021,22(8)
It has been shown previously that a novel tetrapeptide, Arg-Leu-Tyr-Glu (RLYE), derived from human plasminogen inhibits vascular endothelial growth factor (VEGF)-induced angiogenesis, suppresses choroidal neovascularization in mice by an inhibition of VEGF receptor-2 (VEGFR-2) specific signaling pathway. In this study, we report that a modified tetrapeptide (Ac-RLYE) showed improved anti-choroidal neovascularization (CNV) efficacy in a number of animal models of neovascular age-related macular degeneration (AMD) which include rat, rabbit, and minipig. The preventive and therapeutic in vivo efficacy of Ac-RLYE via following intravitreal administration was determined to be either similar or superior to that of ranibizumab and aflibercept. Assessment of the intraocular pharmacokinetic and toxicokinetic properties of Ac-RLYE in rabbits demonstrated that it rapidly reached the retina with minimal systemic exposure after a single intravitreal dose, and it did not accumulate in plasma during repetitive dosing (bi-weekly for 14 weeks). Our results suggested that Ac-RLYE has a great potential for an alternative therapeutics for neovascular (wet) AMD. Since the amino acids in human VEGFR-2 targeted by Ac-RLYE are conserved among the animals employed in this study, the therapeutic efficacies of Ac-RLYE evaluated in those animals are predicted to be observed in human patients suffering from retinal degenerative diseases. 相似文献
995.
Kumar S Batoo KM Gautam S Koo BH Alimuddin Chae KH Chung H Lee CG 《Journal of nanoscience and nanotechnology》2011,11(1):396-401
The structural, magnetic, and electronic structural properties of Ni0.2Cd0.3Fe(2.5-x)Al(x)O4 ferrite nanoparticles were studied via X-ray diffraction (XRD), transmission electron microscopy (TEM), DC magnetization, and near-edge X-ray absorption fine-structure spectroscopy (NEXAFS) measurements. Nanoparticles of Ni0.2Cd0.3Fe(2.5x)Al(x)O4 (0 < or = x < or = 0.4) ferrite were synthesized using the sol-gel method. The XRD and TEM measurements showed that all the samples had a single-phase nature with a cubic structure, and had nanocrystalline behavior. From the XRD and TEM analysis, it was found that the particle size increases with Al doping. The DC magnetization measurements revealed that the blocking temperature increases with increased Al doping. It was observed that the magnetic moment decreases with Al doping, which may be due to the dilution of the sublattice by the doping of the Al ions. The NEXAFS measurements performed at room temperature indicated that Fe exists in a mixed-valence state. 相似文献
996.
Yong‐Koo Park Hyun‐Su Kim Dong‐Guen Lee 《The Structural Design of Tall and Special Buildings》2014,23(10):740-759
In this study, an efficient analytical model for the dynamic analysis of tall buildings with a shear wall–frame structural system has been proposed. A shear wall–frame structural system usually consists of a core wall showing flexural behavior and a frame presenting shear behavior. Therefore, the deformed shape of the shear wall–frame structural system is shown by the combination of flexural mode and shear mode. To consider this characteristic in developing an efficient analytical model, the effect of shear wall and frame on the dynamic behavior of a tall building with a dual system has been separately investigated. In order to consider the effect of the shear wall in the frame model without shear wall, a rigid body was used instead of the shear wall. Each equivalent model for the separated shear wall part and frame part has been independently developed, and two equivalent models were then combined to create an efficient analytical model for tall buildings with a shear wall–frame structural system. In order to verify the efficiency and accuracy of the proposed method, time history analyses of tall buildings with a shear wall–frame system were performed. With analytical results, it has been confirmed that the proposed method can provide accurate results with significantly reduced computational time and memory. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
997.
A novel nanophotonic method for enhancing the two-photon fluorescence signal of a fluorophore is presented. It utilizes the second harmonic (SH) of the exciting light generated by noble metal nanospheres in whose near-field the dye molecules are placed, to further enhance the dye's fluorescence signal in addition to the usual metal-enhanced fluorescence phenomenon. This method enables demonstration, for the first time, of two-photon fluorescence enhancement inside a biological system, namely live cells. A multishell hydrogel nanoparticle containing a silver core, a protective citrate capping, which serves also as an excitation quenching inhibitor spacer, a pH indicator dye shell, and a polyacrylamide cladding are employed. Utilizing this technique, an enhancement of up to 20 times in the two-photon fluorescence of the indicator dye is observed. Although a significant portion of the enhanced fluorescence signal is due to one-photon processes accompanying the SH generation of the exciting light, this method preserves all the advantages of infrared-excited, two-photon microscopy: enhanced penetration depth, localized excitation, low photobleaching, low autofluorescence, and low cellular damage. 相似文献
998.
The problem of determining the most profitable sub-process means is considered for a production process where multiple ingredients are mixed. The quantities of the ingredients are controlled through the corresponding sub-processes. The values of the sub-process means directly affect the fraction defective and the costs of production, reworking, and scrap of the mixture process. Every item accepted through screening inspection is sold to a regular market at a fixed price, and any rejected item is scrapped. It is assumed that the quantities of the multiple ingredients are normally distributed with known variances. An economic model is constructed, which involves the selling price, production costs, inspection cost, and scrap and reprocessing costs. The goal is to determine the optimum sub-process mean values maximizing expected profit function. A solution procedure is provided, and an illustrative example for the case with two main ingredients is given. 相似文献
999.
1000.
When an organization implements a new managerial practice how should timing affect its decision? Should it be among the organizations that implement the new management practices early, i.e. first movers, or wait for others to implement and implement it a later time, i.e. second movers. The literature's findings with regard to many management practices, especially those that deal with quality, such as total quality management, suggest that while first movers implement a new management practice because of real needs and a high fit between what the practice suggests and their needs (technical efficiency), second movers implement the new management practice because of customer pressure and the fear of falling behind the competition (external pressure). Second movers just mimic first movers, and the new practice does not really fit with their operations. Thus, the new management practice achieves more for the first movers than the second movers. In this paper we ask whether this premise holds for the ISO 9000 quality standard, one which was specified in considerable detail by outside forces but was implemented in many different ways by organizations. Our results are based on a survey of 1150 quality managers who implemented ISO 9000. We find that learning is a more important factor than timing in explaining ISO 9000 performance. First movers achieve a high level of performance because they learn from their own experience, and second movers achieve a high level of performance because they learn from the experience of others. Whether an organization is a first mover or second, the ones that benefit from ISO 9000 are those who learn. 相似文献