Study of a New Imaging Strategy Based on Compressed Sensing to Shorten the Imaging Time of a Fourier Telescope

Lei Dong,Zhenwu Lu,Xinyue Liu,Zhengwei Li,Liang Wang 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.74 No.12

A Fourier telescope (FT) is an imaging system based on laser illumination and optical aperture synthesis and is suitable for imaging distant targets with high resolution through the atmosphere. The imaging time of a conventional FT is so long (about two hours) as to limit its practical applications. In order to shorten the imaging time of a Fourier telescope, we propose a new imaging system called the compressed sensing Fourier telescope (CS-FT). The image quality, the imaging time and the effects of noise of the new system are studied in detail. Based on the analysis, we find that by reasonably choosing the total sampling rate (TSR), the imaging time of the CS-FT is obviously shorter than that of the conventional FT while the image quality of the CS-FT is near that of the conventional FT. Worth noting is that with the smaller values of the low-frequency sampling rate (LSR) and the order of the sampling probability density function (OPDF), the CS-FT can achieve a better image quality. The reconstruction results of the field data show that the CS-FT can reduce the imaging time of a FT in an actual noise environment.

Theoretical Analysis of Laser-Locked Spectroscopy Employing a Confocal Fabry-Perot Cavity

Lei Dong,Li Linfeng,suotang Jia,wangbao Yin,weiguang ma,Zhang Lei 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.I

A theoretical analysis of laser-locked enhanced absorption spectroscopy employing a confocal Fary-Perot cavity (CFPC) is presented. The signal-to-noise ratio and the minimum detectable absorbance, which are limited by either the shot noise or the amplitude noise due to the loose laser lock loop, are also discussed in detail. The results show that the effective absorption path length of a CFPC configuration is the same as that of the conventional nonconfocal Fary-Perot cavity configuration, with the CFPC configuration being more convenient to align without deliberate mode matching. Thus, the CFPC configuration should greatly simplify the complications of conventional laser-locked spectroscopy.

Analysis the role of arabidopsis CKRC6/ASA1 in auxin and cytokinin biosynthesis

Dong-Wei Di,Lei Wu,Pan Luo,Li Zhang,Tian-Zi Zhang,Xue Sun,Shao-Dong Wei,Chen-Wei An,Guang-Qin Guo 한국식물학회 2016 Journal of Plant Biology Vol.59 No.2

The crosstalk between auxin and cytokinin (CK) is important for plant growth and development, although the underlying molecular mechanisms remain unclear. Here, we describe the isolation and characterization of a mutant of Arabidopsis Cytokinin-induced Root Curling 6 (CKRC6), an allele of ANTHRANILATE SYNTHASE ALPHA SUBUNIT 1 (ASA1) that encodes the á-subunit of AS in tryptophan (Trp) biosynthesis. The ckrc6 mutant exhibits root gravitropic defects and insensitivity to both CK and the ethylene precursor 1-aminocyclopropane-1-carboxylicacid (ACC) in primary root growth. These defects can be rescued by exogenous indole-3-acetic acid (IAA) or tryptophan (Trp) supplementation. Furthermore, our results suggest that the ckrc6 mutant has decreased IAA content, differential expression patterns of auxin biosynthesis genes and CK biosynthesis isopentenyl transferase (IPT) genes in comparison to wild type. Collectively, our study shows that auxin controls CK biosynthesis based on that CK sensitivity is altered in most auxin-resistant mutants and that CKs promote auxin biosynthesis but inhibit auxin transport and response. Our results also suggest that CKRC6/ASA1 may be located at an intersection of auxin, CK and ethylene metabolism and/or signaling.

Characterization and Electrical Conductivity of Carbon-Coated Metallic (Ni, Cu, Sn) Nanocapsules

Wang, Dong Xing,Shah, Asif,Zhou, Lei,Zhang, Xue Feng,Liu, Chun Jing,Huang, Hao,Dong, Xing Long Korean Society of Microscopy 2015 Applied microscopy Vol.45 No.4

Carbon-coated Ni, Cu and Sn nanocapsules were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and a four-point probe device. All of these nanocapsules were prepared by an arc-discharge method, in which the bulk metals were evaporated under methane ($CH_4$) atmosphere. Three pure metals (Ni, Cu, Sn) were typically diverse in formation of the carbon encapsulated nanoparticles and their different mechanisms were investigated. It was indicated that a thick carbon layers formed on the surface of Ni(C) nanocapsules, whereas a thin shell of carbon with 1~2 layers covered on Cu(C) nanocapsules, and the Sn(C) nanocapsules was, in fact, a longger multi-walled carbon nanotubes partially-filled with metal Sn. As one typical magnetic/dielectric nanocomposite particles, Ni(C) nanocapsules and its counterpart of oxide-coated Ni(O) nanocapsules were compared in the electrically conductive behaviors for further applications as the electromagnetic materials.

한·중 양국어에서의 접미사 ‘-的’에 대한 비교 연구 : 형태론·통사론적 성격을 중심으로

董磊(Dong Lei) 한림대학교 아시아문화연구소 2010 아시아문화 Vol.- No.25

Study on pore evolution characteristics of gas adsorption and desorption in coal under the action of liquid nitrogen

Shuaiqi Dong,Dong Zhao,Lei Li,Xiaowei Li,Tao Chen 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.1

CBM (Coalbed methane) belongs to unconventional natural gas mineral resources. The development and utilization of CBM can greatly reduce the occurrence of mine gas accidents, and how to improve the desorption capacity of CBM has always been a hot issue for researchers. Liquid nitrogen has obvious effect on coal seam cracking and permeability improvement. The purpose of this paper is to study the cracking mechanism of liquid nitrogen on coal, and provide a theoretical basis for using liquid nitrogen freezing and thawing to treat coal so as to improve the production of coalbed methane. Coal samples from Yangquan County, Shanxi Province were pretreated. The pore structure test, microscopic observation test and methane isothermal adsorption test were carried out after the coal samples with different particle sizes were treated with different liquid nitrogen freeze-thaw cycles. According to the experimental data, the evolution law of pores of coal before and after freezing and thawing with liquid nitrogen, the cracking mechanism of coal treated with freezing and thawing with liquid nitrogen, and the optimal number of freezing and thawing cycles with liquid nitrogen are analyzed. The results show that: 1) the evolution characteristics of pore structure of lower coal after liquid nitrogen freezing and thawing are that micropores in coal are promoted to develop into transition pores and mesopores, and mesopores and transition pores develop into macropores and fractures. 2) Through the observation of a metallographic microscope, the expansion degree of coal surface crack is positively correlated with the times of liquid nitrogen freeze-thaw. 3) Liquid nitrogen freeze-thaw treatment has an optimal number of cycles for the cracking degree of coal. With the increase of freeze-thaw cycles, the final adsorption capacity of coal pillar increases first and then decreases; The adsorption capacity of granular coal first increases and then decreases. After reaching freeze-thaw saturation, continued freeze-thaw is not conducive to the increase of adsorption capacity. These research results provide theoretical support for the implementation of liquid nitrogen fracturing and permeability enhancement technology in coal reservoirs.

확장 의미 단위(EUM) 기반 한국어 어휘 교육 방안 탐구

동뢰 ( Dong Lei ) 연세대학교 언어연구교육원 한국어학당 2020 외국어로서의 한국어교육 Vol.56 No.-

본고는 확장 의미 단위(EUM) 기반 한국어 어휘 교육의 효율성을 재확인하면서 효과적인 EUM 기반 한국어 어휘 교육 방안을 마련하는 데에 목적을 둔다. 이를 위해 본 연구에서 한국어 실력이 중급 수준에 해당된 학생 28명을 연구 참여자로 택해 대조반과 실험반으로 나누어 한 학기 동안의 한국어 어휘 교육 실험을 실시하였다. 대조반에서는 교사의 교수와 사전이나 교과서에 의한 전통적인 교육법을 사용하는 반면 실험반에서는 EUM 기반 어휘 교육법으로 사용하였다. 사전과 사후 테스트 결과에 대한 분석 및 실험반 학습자에 대한 설문조사를 통해 다음 네 가지의 실험 결과를 얻었다. 첫째, EUM 기반 한국어 어휘 학습법은 한국어 실력이 고급뿐만 아니라 중급 수준의 학생에게도 적용될 수 있다. 둘째는 EUM 기반 한국어 어휘 교육법은 교사의 교수 및 사전이나 교과서에 의한 전통적인 교육법보다 어휘 습득에 더욱 적극적인 영향을 미쳤다. 셋째는 사후테스트와 학생들의 설문조사를 통해 본 실험에서 시행한 한국어 어휘 교육 수업안이 상당히 효과적이었다. 넷째는 학생들이 교실 안에서만이 아니라 교실 밖에서도 수시로 EUM 기반 한국어 어휘 교육법으로 어휘 공부를 스스로 할 수 있으므로 이는 능동적인 어휘 학습에 도움이 될 수 있다. It is well known that learning vocabulary is the most important factor when studying a foreign language. Many students who major in Korean language abroad, however, have difficulties learning Korean because they have few chances to be exposed to Korean-speaking circumstances. The purpose of this study is to reaffirm the effectiveness of EUM-based learning and propose more innovative educational methods. Two groups of students were drawn from Korean majors in a university in Qingdao for a semester. 'The experimental group' was guided by EUM, while 'the controlling group' was taught by traditional methods. Through analysing examination scores of pre-test and post-test, this study concludes as follows; First, EUM-based learning of Korean vocabulary is much effective for both intermediate and high level students. Second, EUM-based learning strategy is more effective to improve vocabulary acquisition than using traditional materials and methods. Third, the result of some tests shows that students have significantly improved their Korean language skill with this EUM-based lesson plans. Finally, the EUM-based learning method encourages students to study Korean more actively outside the classroom.

Characterization of SiC/C Nanocomposite Powders Synthesized by Arc-Discharge

Zhou, Lei,Yu, Jie Yi,Gao, Jian,Wang, Dong Xing,Gan, Xiao Rong,Xue, Fang Hong,Huang, Hao,Dong, Xing Long Korean Society of Microscopy 2015 Applied microscopy Vol.45 No.4

In this paper, three carbon sources, i.e., solid graphite, gaseous CH4 and liquid ethanol, and one solid silicon source were employed to synthesize SiC/C nanocomposite powders by arc-discharge plasma. The processing conditions such as the component ratios of raw materials, atmospheric gases, etc. were adjusted for controllable synthesis of the nanopowders. It is indicated that both of solid graphite and silicon can be co-evaporated and reacted to form nanophases of cubic ${\beta}$-SiC with ~50 nm in mean size and a little free graphite; the carbon atoms decomposed from gaseous $CH_4$ favor to combine with the evaporated silicon atoms to form the dominant SiC nanophase; liquid carbon source of ethanol can also be used to harvest the main ${\beta}$-SiC and minor 6H-SiC phases in the assembly of nanoparticles. The as-prepared SiC/C nanocomposite powders were further purified by a heat-treatment in air and their photocatalytic performances were then greatly improved.

Long-term surgical outcomes of liver resection for hepatocellular carcinoma in patients with hepatitis B virus and hepatitis C virus co-infection: A multicenter observational study

Hang-Dong JIA,Lei LIANG,Chao LI,Han WU,Hong WANG,Ying-Jian LIANG,Ya-Hao ZHOU,Wei-Min GU,Xin-Ping FAN,Wan Yee LAU,Timothy M. PAWLIK,Yong-Kang DIAO,Qiu-Ran XU,Feng SHEN,Cheng-Wu ZHANG,Dong-Sheng HUANG,T 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-

Helicobacter pylori Chaperone-Like Protein CagT Plays an Essential Role in the Translocation of CagA into Host Cells

( Ding Hong Lei ),( Hao Zeng ),( Lin Ping Huang ),( Yan Dong Dong ),( Yi Jun Duan ),( Xu Hu Mao ),( Gang Guo ),( Quan Ming Zou ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.10

Most of the Helicobacter pylori strains containing the cag pathogenicity island (PAI) have been associated with more severe gastric disease in infected humans. The cag PAI is composed of 27 proteins, and some of the components are required for CagA translocation into host cells as well as induction of proinflammatory cytokines, such as interleukin-8 (IL-8); however, the exact function of most of the components remains unknown or poorly characterized. In this study, we demonstrated that CagT (HP0532), which is an essential structural component of the cag PAI apparatus, plays an important role in the translocation of CagA into host epithelial cells. In addition to being located on the bacterial surface, CagT is also partially localized in the inner membrane, where it acts as a chaperone-like protein and promotes CagA translocation. However, CagT secretion was not detected by immunoprecipitation analysis of cell culture supernatants. Meanwhile, CagT was related to the introduction of IL-8 of the host cell. These results suggest that CagT is expressed on both the inner and outer bacterial membranes, where it serves as a unique type IV secretion system component that is involved in CagA secretion and cag PAI apparatus assembly.