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Improved Hybrid Beamforming for mmWave Multi-User Massive MIMO

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Computers, Materials & Continua 2021年第6期67卷 3057-3070页

作者： Ji-Sung Jung Won-Seok Lee Yeong-Rong Lee Jaeho kim Hyoung-Kyu Song Department of Information and Communication Engineering and Convergence Engineering for Intelligent Drone Sejong UniversitySeoul05006Korea Department of Electrical Engineering Sejong UniversitySeoul05006Korea

Massive multiple input multiple output(MIMO)has become essential for the increase of capacity as the millimeter-wave(mmWave)communication is ***,hybrid beamforming systems have been studied since full-digital beamforming is impractical due to high cost and power consumption of the radio frequency(RF)*** paper proposes a hybrid beamforming scheme to improve the spectral efciency for multi-user MIMO(MU-MIMO)*** a frequency selective fading environment,hybrid beamforming schemes suffer from performance degradation since the analog precoder performs the same precoding for all *** mitigate performance degradation,this paper uses the average channel covariance matrix for all subcarriers and considers an iterative algorithm to design analog precoder using approximation *** analog precoder is iteratively updated for each column until it *** proposed scheme can reduce errors in the approximating process of the overall spectral *** scheme can be applied to fully-connected and partially-connected *** simulation results show that spectral efciency performance for the proposed scheme is better than the conventional *** proposed scheme can achieve similar performance with full-digital beamforming by using a sufciently large number of RF ***,this paper shows that the proposed scheme outperforms other schemes in the frequency selective fading *** performance improvement can be achieved in both structures.

关键词： Hybrid precoding massive MIMO MU-MIMO mmwave frequency selective fading

Energy harvesting model of moving water inside a tubular system and its application of a stick-type compact triboelectric nanogenerator

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Nano Research 2015年第8期8卷 2481-2491页

作者： Dongwhi Choi Sangmin Lee Sang Min Park Handong Cho Woonbong Hwang Dong Sung kim Department of Mechanical Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam-ro Pohang Gyeongbuk 790-784 Republic of Korea School of Mechanical Engineering Chung-Ang University 84 Heukseok-ro Dongjak-gu Seoul 156-756 Republic of Korea

As the first invention to efficiently harvest electricity from ambient mechanical energy by using contact electrification, the triboelectric nanogenerator has elicited worldwide attention because of its cost-effectiveness and sustainability. This study exploits a superhydrophobic nanostructured aluminum tube to estimate electrical output for solid-water contact electrification inside a tubular system. The linearly proportional relationship of short-circuit current and open-circuit voltage to the detaching speed of water was determined by using a theoretical energy harvesting model and experimentation. A pioneering stick-type solid-water interacting triboelectric nanogenerator, called a SWING stick, was developed to harvest mechanical energy through solid-water contact electrification generated when the device is shaken by hand. The electrical output generated by various kinds of water from the environment was also measured to demonstrate the concept of the SWING stick as a compact triboelectric nanogenerator. Several SWING sticks were connected to show the feasibility of the device as a portable and compact source of direct power. The developed energy harvesting model and the SWING stick can provide a guideline for the design parameters to attain a desired electrical output; therefore, this study can significantly increase the applicability of a water-driven triboelectric nanogenerator.

关键词： contact electrification triboelectric nanogenerator anodized aluminum xide superhydrophobic tubular system compact design

Teleconnections:Summer Monsoon over Korea and India

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Advances in Atmospheric Sciences 2002年第4期19卷 665-676页

作者： Baek-Jo kim Sung-Euii Moon 陆日宇 R.H.Kripalani Meteorological Research Institute Korea Meteorological Administration Seoul 156-720 Korea Korea Meteorological Administration Seoul 156-720 Korea LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100080 Indian Institute of Tropical Meteorology Pune 411008 India

This study investigates the relationship between the summer monsoon rainfall over Korea and India, by using correlation analysis and Singular Value Decomposition (SVD).Results reveal that summer monsoon rainfall over Korea is negatively (significant at the 99% level) cor-related with the rainfall over the northwest and central parts of India. In addition, coupled spatial modes be-tween the rainfall over Korea and India have been identified by the SVD analysis. The squared covariance fraction explained by the first mode is 70% and the correlation coefficient between the time coefficients of the two fields is significant at the 99% level, indicating that the coupled mode reflects a large part of the interaction between the summer monsoon rainfall over Korea and India. The first mode clearly demon-strates the existence of a significant negative correlation between the rainfall over the northwest and central parts of India and the rainfall over *** mechanisms of this correlation are investigated by analyzing the variation of upper-level at-mospheric circulation associated with the Tibetan high using NCEP/NCAR Reanalysis data.

关键词： summer monsoon rainfall tibetan high singular value decomposition (SVD)

Synthesis of 3-Benzyloxy-6-methyl-7-methoxyphenanthrene-9-carboxaldehyde with Utilize Intramolecular Heck Reaction as the Key Step

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Chemical Research in Chinese Universities 2008年第4期24卷 445-448页

作者： SONG Yan-ling ZHAI Xin SUN Zhi-feng kim Sang-hee GONG Ping School of Pharmaceutical Engineering Shenyang Pharmaceutical University Shenyang 110016 P. R. China School of Chemical Engineering Shenyang Institute of Chemical Technology Shenyang 110042 P. R. China College of Pharmacy Seoul National University San 56-1 Shilim Kwanak Seoul 151-742 Korea

The substituted phenanthrene-9-carboxyaldehydes are very important intermediates for the syntheses of phenanthroindolizidine and phenanthroquinolizidine alkaloids. The novel title compound was prepared from the reaction of 5 steps starting from the condensation of 3-methoxyl-4-methyl-phenylacetic acid and 4-（benzyloxy）-2-iodobenzaldehyde, followed by esterification, cyclization, reduction, and oxidation. A new method for the preparation of phenanthrene ring via palladium-catalyzed intramolecular Heck reaction was described. The title compound was characterized by IR, ^1H NMR, ^13C NMR, elemental analysis, and MS.

关键词： Phenanthrene-9-carboxyaldehyde Synthesis Heck reaction

Fitness consequences of a clock pollinator filter in Nicotiana attenuata flowers in nature

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Journal of Integrative Plant Biology 2017年第11期59卷 805-809页

作者： felipe yon danny kessler youngsung joo sang-gyu kim ian t.baldwin department of molecular ecology max planck institute for chemical ecologyHans-Knoll-StraBe 8D-07745 JenaGermany center for genome engineering institute for basic scienceYuseong-gu34047 DaejeonSouth Korea

Nicotiana attenuata flowers, diurnally open,emit scents and move vertically to interact with nocturnal hawkmoth and day-active hummingbird pollinators. To examine the fitness consequences of these floral rhythms, we conducted pollination trials in the plant’s native habitat with phase-shifted flowers of plants silenced in circadian clock genes. The results revealed that some pollination benefits observed under glasshouse conditions were not reproduced under natural field conditions. Floral arrhythmicity increased pollination success by hummingbirds, while reducing those by hawkmoths in the field. Thus, floral circadian rhythms may influence a plant’s fitness by filtering pollinators leading to altered seed set from outcrossed pollen.

关键词： Fitness consequences a clock pollinator filter in Niicotiana attenuata flowers in nature

Complete response to radiation therapy of orbital metastasis from hepatocellular carcinoma

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World Journal of Gastroenterology 2009年第47期15卷 6000-6003页

作者： Allison M Quick Mark Bloomston Edward Y kim Nathan C Hall Nina A Mayr Department of Radiation Medicine Arthur G.James Cancer HospitalThe Ohio State University Medical CenterColumbusOH 43210 United States Department of Surgical Oncology The Ohio State University Medical CenterColumbusOH 43210 United States Department of Radiology The Ohio State University Medical CenterColumbusOH 43210United States

The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely *** report the case of a 52-year-old male with known metastatic HCC,who presented with severe proptosis and *** orbital mass was identified on magnetic resonance imaging(MRI)and confirmed to have hypermetabolic activity on positron emission tomography/computed *** received a palliative course of external beam radiation therapy to the right *** modulated radiation therapy (IMRT)was used to allow sparing of critical norma tissues in close proximity to the *** month after completion of IMRT to 58 Gray in 30 fractions delivered over 6 wk,the patient had a complete clinical,radiologic(MRI)and symptomatic response The patient continues to have local control in the orbi 1.7 years after therapy *** critical norma structures were kept below the tolerance dose using IMRT,and no toxicities were observed.

关键词： Hepatocellular carcinoma Eye neoplasms Metastasis Intensity modulated radiation therapy Palliative therapy

Biochemical Characterization of Soluble Acid and Alkaline Invertases from Shoots of Etiolated Pea Seedlings

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Journal of Integrative Plant Biology 2010年第6期52卷 536-548页

作者： Donggiun kim So Yun Park youngjae Chung Jongbum Park Sukchan Lee Taek-Kyun Lee Department of Biological Science Silla University South Sea Environment Research Department Korea Ocean Research and Development Institute Department of Life Science and Biotechnology Shin Gyeong University Department of Genetic Engineering Sungkyunkwan University

Soluble invertase was purified from pea （Pisum sativum L.） by sequential procedures entailing ammonium sulfate precipitation, DEAE-Sepharose column, Con-A- and Green 19-Sepharose affinity columns, hydroxyapatite column, ultra-filtration, and Sephacryl 300 gel filtration. The purified soluble acid （SAC） and alkaline （SALK） invertases had a pH optimum of 5.3 and 7.3, respectively. The temperature optimum of two invertases was 37 ℃. The effects of various concentrations of Tris-HCI, HgCI2, and CuSO4 on the activities of the two purified enzymes were examined. Tris-HCI and HgCI2 did not affect SAC activity, whereas 10 mM Tris-HCI and 0.05 mM HgCI2 inhibited SALK activity by about 50%. SAC and SALK were inhibited by 4.8 mM and 0.6 mM CuSO4 by 50%, respectively. The enzymes display typical hyperbolic saturation kinetics for sucrose hydrolysis. The Kms of SAC and SALK were determined to be 1.8 and 38.6 mM, respectively. The molecular masses of SAC shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting were 22 kDa and 45 kDa. The molecular mass of SALK was 30 kDa. Iso-electric points of the SAC and SALK were estimated to be about pH 7.0 and pH 5.7, respectively.

关键词： SAC Biochemical Characterization of Soluble Acid and Alkaline Invertases from Shoots of Etiolated Pea Seedlings

Identifying Pb-free perovskites for solar cells by machine learning

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npj Computational Materials 2019年第1期5卷 828-835页

作者： Jino Im Seongwon Lee Tae-Wook Ko Hyun Woo kim YunKyong Hyon Hyunju Chang Korea Research Institute of Chemical Technology(KRICT) Daejeon 34114Republic of Korea National Institute for Mathematical Sciences(NIMS) Daejeon 34047Republic of Korea

Recent advances in computing power have enabled the generation of large datasets for materials,enabling data-driven approaches to problem-solving in materials science,including materials *** learning is a primary tool for manipulating such large datasets,predicting unknown material properties and uncovering relationships between structure and *** state-of-the-art machine learning algorithms,gradient-boosted regression trees(GBRT)are known to provide highly accurate predictions,as well as interpretable analysis based on the importance of ***,in a search for lead-free perovskites for use in solar cells,we applied the GBRT algorithm to a dataset of electronic structures for candidate halide double perovskites to predict heat of formation and *** analysis of the selected features identifies design guidelines for the discovery of new lead-free perovskites.

关键词： learning perovskite computing

Classifying extrahepatic bile duct metachronous carcinoma by de novo neoplasia site

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World Journal of Gastroenterology 2014年第11期20卷 3050-3055页

作者： Hyung Jun Kwon Sang Geol kim Jae Min Chun Yoon Jin Hwang Department of Surgery Kyungpook National University Medical CenterDaegu 702-210South Korea

Extrahepatic bile duct(EHBD)cancer may occur metachronously,and these cancers are resectable with a favorable *** aimed to identify the pattern of metachronous EHBD *** classified the cases of metachronous EHBD cancer reported in the literature thus far and investigated two new cases of metachronous EHBD cancer.A 70-year-old female underwent R0 bile duct resection for a type 1 Klatskin tumor(pT-1N0M0).A 70-year-old male patient underwent R0 bile duct resection for a middle bile duct cancer(pT2N1M0).Imaging studies of both patients taken at 14 and 24mo after first surgery respectively revealed a metachronous cholangiocarcinoma that required pancreaticoduodenectomy(PD).Histopathology of the both tumors after PD revealed cholangiocarcinoma invading the pancreas(pT3N0M0).Both patients have been free from recurrence for 6 years and 16 mo respectively after the second *** a review of the literature on these cases,we classified the pattern of metachronous EHBD cancer according to the site of de novo *** proximal remnant bile duct was most commonly *** EHBD cancer should be distinguished from an unresectable recurrent *** metachronous EHBD cancer may be helpful in identifying rare metachronous tumors.

关键词： Metachronous Extrahepatic bile duct Cancer Prognosis Recurrence