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排序方式: 共有4954条查询结果,搜索用时 31 毫秒
1.
2.
Kazuo Tsubota Stephen C. Pflugfelder Zuguo Liu Christophe Baudouin Hyo Myung Kim Elisabeth M. Messmer Friedrich Kruse Lingyi Liang Jimena Tatiana Carreno-Galeano Maurizio Rolando Norihiko Yokoi Shigeru Kinoshita Reza Dana 《International journal of molecular sciences》2020,21(23)
Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: “Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities.” The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint. 相似文献
3.
Muhammad Sheeraz Mamoon Ur Rashid Asad Ali Fazli Akram Ho Jeong Lee Jin San Choi Jong-Seong Bae Yong Soo Kim Young-Han Shin Chang Won Ahn Tae Heon Kim 《Journal of the European Ceramic Society》2021,41(10):5155-5162
We demonstrate the structural evolution of polymorphic phases in Al2O3-inserted SrMnO3 ceramics synthesized by solid state reaction. While the 4H-hexagonal phase is predominant in pure SrMnO3 ceramics, a small amount of 6H-hexagonal polymorph is identified in addition to the primary 4H-hexagonal SrMnO3 and the secondary hexagonal SrAl2O4 phases in the as-sintered ceramics, evidenced by x-ray diffraction and subsequent Rietveld refinement analyses. The existence of the 6H-hexagonal SrMnO3 phase is corroborated using Raman spectroscopy. The chemical compositions and electronic structures of the Al2O3-inserted SrMnO3 compounds are also examined using energy dispersive spectroscopy and x-ray photoelectron spectroscopy, respectively. The first-principles calculations reveal that there is no clear difference between the total energies of 4H- and 6H-hexagonal polymorphs regardless of the presence/absence of Sr and oxygen vacancies. Possible origins are discussed with the estimation of actual strain based on the refined lattice parameter of 6H SrMnO3. 相似文献
4.
Frequency Insertion Strategy for Channel Assignment Problem 总被引:1,自引:0,他引:1
This paper presents a new heuristic method for quickly finding a good feasible solution to the channel assignment problem
(CAP). Like many other greedy-type heuristics for CAP, the proposed method also assigns a frequency to a call, one at a time.
Hence, the method requires computational time that increases only linear to the number of calls. However, what distinguishes
the method from others is that it starts with a narrow enough frequency band so as to provoke violations of constraints that
we need to comply with in order to avoid radio interference. Each violation is then resolved by inserting frequencies at the
most appropriate positions so that the band of frequencies expands minimally. An extensive computational experiment using
a set of randomly generated problems as well as the Philadelphia benchmark instances shows that the proposed method perform
statistically better than existing methods of its kind and even yields optimum solutions to most of Philadelphia benchmark
instances among which two cases are reported for the first time ever, in this paper.
Won-Young Shin was born in Busan, Korea in 1978. He received B.S. in industrial engineering from Pohang University of Science and Technology
(POSTECH) in 2001 and M.S in operation research and applied statistics from POSTECH in 2003. Since 2003 he has been a researcher
of Agency for Defense Development (ADD) in Korea. He is interested in optimization of communication system and applied statistics.
Soo Y. Chang is an associate professor in the Department of Industrial Engineering at Pohang University of Science and Technology (POSTECH),
Pohang, Korea. He teaches linear programming, discrete optimization, network flows and operations research courses. His research
interests include mathematical programming and scheduling. He has published in several journals including Discrete Applied
Mathematics, Computers and Mathematics with Application, IIE Transactions, International Journal of Production Research, and
so on. He is a member of Korean IIE, and ORMSS.
Jaewook Lee is an assistant professor in the Department of Industrial Engineering at Pohang University of Science and Technology (POSTECH),
Pohang, Korea. He received the B.S. degree in mathematics with honors from Seoul National University, and the Ph.D. degree
from Cornell University in applied mathematics in 1993 and 1999, respectively. He is currently an assistant professor in the
department of industrial engineering at the Pohang University of Science and Technology (POSTECH). His research interests
include nonlinear systems, neural networks, nonlinear optimization, and their applications to data mining and financial engineering.
Chi-Hyuck Jun was born in Seoul, Korea in 1954. He received B.S. in mineral and petroleum engineering from Seoul National University in
1977, M.S. in industrial engineering from Korea Advanced Institute of Science and Technology in 1979 and Ph.D. in operations
research from University of California, Berkeley, in 1986. Since 1987 he has been with the department of industrial engineering,
Pohang University of Science and Technology (POSTECH) and he is now a professor and the department head. He is interested
in performance analysis of communication and production systems. He has published in several journals including IIE Transactions,
IEEE Transactions, Queueing Systems and Chemometrics and Intelligent Laboratory Systems. He is a member of IEEE, INFORMS and
ASQ. 相似文献
5.
Soo Jin Kim Wha Young Lee Yeungho Park Wansoo Huh Young Gwan Ko 《Polymer Engineering and Science》2003,43(5):1011-1017
Supported zirconcene catalysts on a new support, MgO, were prepared and tested in ethylene polymerization. Three types of impregnation methods were employed to find an optimum supporting method for MgO. The direct impregnation of Cp2ZrCl2 on MgO showed low metal loading and polymerization activity, while the catalyst had a higher metal loading and polymerization activity when MgO was treated with methylaluminoxane (MAO) before supporting. Treatment of MgO with MAO during the supporting step invoked two types of catalytic sites, which was evidenced by the bimodal molecular weight distribution of the polymer products. MgO is considered to have potential as a support for metallocenes. 相似文献
6.
Panagiotis N. Zarros Myung J. Lee Tarek N. Saadawi 《Journal of Network and Systems Management》1994,2(4):361-382
In this paper, an algorithm to determine the set of packets generated continuously and periodically from different participants that are arriving at a node either for mixing at the master of a conference, or for simply playing back at a regular participant of a conference, is proposed. The essence of the algorithm is to estimate the expected packet arrival time (or reference time) for each participant. With the reference time at hand, the maximum jitter and the optimum waiting time for a mixer to wait packets from all participants can be determined. An enhancement to improve synchronization which deals with the estimation of the time offsets between the individual periods of the sources and the period of the receiver is also presented. The error of the proposed algorithm is enumerated by the Chernoff bound and demonstrated by simulation and is shown to be acceptable in practical application. The algorithm can also be employed when traffic sources operate with different periods. 相似文献
7.
Hyun-Goo Kim Wha-Nam Myung K. Sumiyama K. Suzuki 《Journal of Alloys and Compounds》2002,340(1-2):270-274
We report upon the chemical leaching and magnetic properties of nanoscale crystalline Al0.6(Co25Cu75)0.4 alloy powders produced by rod milling. X-Ray diffractometry (XRD), transmission electron microscopy, differential scanning calorimetry, vibrating sample magnetometry, and superconducting quantum interference device magnetometry were used to characterize the as-milled and leached specimens. After 400 h of milling, only the b.c.c. phase of the intermetallic compound γ-Al3.892Cu6.10808 was detected by XRD. After annealing the leached specimen at 600 °C for 1 h, the nanoscale crystalline phase was transformed into the f.c.c. Cu phase, and this was accompanied by a change in the magnetic properties. The peaks of the magnetization shifted towards lower temperature with increasing external field. The temperature behavior at Tf (45 K) for direct current (d.c.) magnetic susceptibility measurements was quite different for field cooling and zero-field cooling. After cooling the leached specimen from 800 °C, magnetization increased gradually. 相似文献
8.
Biodegradable multiblock poloxamers (BMPs) with gel duration of 8 h to several weeks were prepared by varying their molecular weights from 4000 to 40 000 g mol?1. The molecular weight of the BMP was controlled by changing the poloxamer to coupling agent ratio. Assuming a micelle packing model of the BMP gel, as in the case of a poloxamer gel, the micelle properties and critical gel concentration of BMPs were investigated on the basis of the scaling concept. The findings suggest that the control of molecular weight by hydrolyzable groups can be a facile approach to optimize the gel properties for biomedical applications. Copyright © 2005 Society of Chemical Industry 相似文献
9.
10.
Fast DCT algorithm with fewer multiplication stages 总被引:1,自引:0,他引:1
Yeonsik Jeong Imgeun Lee Hak Soo Kim Kyu Tae Park 《Electronics letters》1998,34(8):723-724
A novel fast DCT scheme with reduced multiplication stages and fewer additions and multiplications is proposed. The proposed algorithm is structured so that most multiplications tend to be performed at the final stage, which reduces the propagation error that could occur in the fixed-point computation. Minimisation of the multiplication stages can further decrease the error 相似文献