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Orbit insertion strategy of Hayabusa2’s rover with large release uncertainty around the asteroid Ryugu

Astrodynamics 2020年第4期4卷 309-329页

作者： Yusuke Oki kent yoshikawa Hiroshi Takeuchi Shota kikuchi Hitosi Ikeda Daniel JScheeres Jay WMcMahon Junichiro kawaguchi Yuto Takei Yuya Mimasu Naoko Ogawa Go Ono Fuyuto Terui Manabu Yamada Toru kouyama Shingo k ameda kazuya Yoshida kenji Nagaoka Tetsuo Yoshimitsu Takanao Saiki Yuichi Tsuda Japan A erospace Exploration Agency T'sukuba 305-8505Japan Japan Aerospace Exploration Agency Sagamihara 252-5210Japan University of Colorado BoulderCO 80309USA Planetary Exploration Research Center Chiba Institute of TechnologyNarashino 275-0016Japan National Institute of Aduanced Industrial Science and Technology Koto-ku 135-0064Japan Rikkyo University Toshima-ku 171-8501Japan Department of A erospace Engineering Tohoku UniversitySendai 980-8579Japan kyushu Institute of Technology Kitakyusyu 804-8550Japan

This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II,installed on the Hayabusa2 *** Rover 2 did not have surface exploration capabilities,the operation team decided to experiment with a new strategy for its deployment to the *** rover was ejected at a high altitude and made a semi-hard landing on the surface of the asteroid Ryugu after several *** on the orbital analysis around Ryugu,the expected collision speed was tolerable for the rover to function *** the rover could not control its position,its motion was entirely governed by the initial ***,the largest challenge was to insert the rover into a stable orbit(despite its large release uncertainty),and avoid its escape from Ryugu due to an environment strongly perturbed by solar radiation pressure and gravitational *** study investigates the solution space of the orbit around Ryugu and evaluates the orbit’s robustness by utilizing Monte Carlo simulations to determine the orbit insertion *** analyzing the flight data of the rover operation,we verified that the rover orbited Ryugu for more than one period and established the possibility of a novel method for estimating the gravity of an asteroid.

关键词： solar radiation pressure augmented elliptic Hill three-body problem gravitational irregularity

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轧辊间钢琴丝压入法实现薄金属板的开槽、切割和平面内弯曲

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锻压技术 1989年第5期14卷 13-19页

作者： k. Yamaguchi N. Takakura Y. yoshikawa M. Fukuda 董建令京都工艺学院

本文提出一种新的薄金属板曲线开槽和切割方法。在该方法中,钢琴丝靠二辊轧机沿板厚方向压入,对板材进行开槽、切割和平面内弯曲。

关键词：钢丝压入法薄板轧制轧辊

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Effects of Orbital Motion on the Boundary Layer Flow on a Spinning Disk

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Open Journal of Fluid Dynamics 2012年第4期2卷 187-194页

作者： Mizue Munekata Naoya Jobi koichi Ikebe Hiroyuki yoshikawa Graduate School of Science and Technology Kumamoto University Kumamoto Japan Mechanical Engineering Department Kumamoto University Kumamoto Japan

The objective of this study is to experimentally examine the effects of orbital motion on the boundary layer flow on a spinning disk. The boundary layer flow on the disk is visualized by the oil flow method, and velocity in the boundary layer is measured by the hot-wire method. For the oil flow pattern in the case of spinning motion only, streaks are clearly observed on the disk as transient vortices, but by adding orbital motion to the spinning motion, we find that streaks are not observed in a certain range of orbital conditions. With increasing orbital motion speed, the laminar re- gion becomes narrower and transition is promoted from the inward region of the disk, regardless of the direction of ro- tation. Also, with the addition of orbital motion, the velocity profile in the boundary layer becomes more asymmetric with respect to the spin axis of the disk. Furthermore, stationary vortices do not appear on the disk when the orbital speed is beyond a certain critical value. Therefore, the lack of streaks in the oil film pattern when orbital motion is added is due to the spatiotemporal unsteadiness of the flow field on the disk.

关键词： Rotating Disk Transition Boundary Layer Flow Visualization Velocity Measurement

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Effects of Orbital Motion on the Velocity Field of Boundary Layer Flow over a Rotating Disk

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Open Journal of Fluid Dynamics 2017年第2期7卷 169-177页

作者： Mizue Munekata Takaomi Utatsu Hiroyuki yoshikawa Yasuhiro Okumura Department of Mechanical System Engineering Kumamoto University Kumamoto Japan

The purpose of this study is to investigate experimentally the effects of orbital motion on the velocity field of boundary layer flow over a rotating disk. The characteristics of velocity field at a fixed orbital angular section measured by a hot-wire anemometer show that the structure of the 3-dimensional boundary layer flow is deformed elliptically and displaced in a certain direction that is not in the orbital radial direction, but the direction of deformation depends on the combination of orbital and rotational directions. For coincide orbital and rotational directions, there are regions where the intensity of low-frequency disturbances increases rapidly in a certain central region (laminar region under pure rotation). The transient vortices, which form streaks on the coating film, are considered to be destroyed by low-frequency disturbances. However, for opposite orbital and rotational directions, the low-frequency disturbances are not observed in any section. As the adding orbital speed increases, the intensity of velocity fluctuations in the turbulence region becomes larger in the expected except in a certain region. This location of the region also depends on the direction of deformation or the combination of orbital and rotational directions.

关键词： Boundary Layer Flow Rotating Disk Transition Vortices Hot-Wire Anemometer

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Effects of laminin on hard tissue formation by bone marrow cells <i>in vivo</i>and <i>in vitro</i>

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Journal of Biomedical Science and Engineering 2014年第1期7卷 15-23页

作者： Masataka yoshikawa Hideyuki kakigi Takayoshi Yabuuchi Hiroyuki Hayashi Department of Endodontics Osaka Dental University Osaka Japan

The effect of laminin on hard tissue formation using rat bone marrow cells was assessed. Rat bone marrow cells were obtained from femora of 6-week-old male Fischer 344 rats. In this in vivo examination, porous cylindrical hydroxyapatite scaffolds with a hollow center were immersed in 100 mg/ml laminin solution and air-dried. Rat bone marrow cells in 200 ml culture medium at 1 × 106 cells/ml were seeded in the scaffolds. The scaffolds were implanted into the dorsal subcutis of 7-week-old male Fischer 344 rats for 6 weeks. The scaffolds were then removed and examined histologically. For in vitro examinations, 1 × 105 rat bone marrow cells in 2 ml culture medium were then cultured with the addition of dexamethasone and laminin. Rat bone marrow cells were also cultured in laminin-coated culture plates. In vitro examinations showed the effectiveness of laminin for hard tissue formation from the results of biochemical and immunochemical analysis. From the in vivo examination, laminin coating of the scaffolds induced hard tissue in the pores with the cells. It is concluded that laminin is useful for bone formation, as in an in vitro culture study using bone marrow cells, in hydroxyapatite scaffolds in vivo.

关键词： Laminin Bone Marrow Cells Scaffold Hydroxyapatite Osteogenesis

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Hybrid Scaffolds Composed of Amino-Acid Coated Sponge and Hydroxyapatite for Hard Tissue Formation by Bone Marrow Cells

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Journal of Biomedical Science and Engineering 2014年第6期7卷 316-329页

作者： Takayoshi Yabuuchi Masataka yoshikawa Hideyuki kakigi Hiroyuki Hayashi Department of Endodontics Osaka Dental University Osaka City Japan

A formalin-treated polyvinyl-alcohol (PVF) sponge is convenient as a scaffold because its configuration is easily modified. However, coating the sponge with an adhesive chemical agent is necessary to attach bone marrow cells (BMCs) to the sponge structure. Moreover, it was considered that a hybrid scaffold composed of a sponge and enveloped cylindrical porous hydroxyapatite (HA) would be convenient. In this study, the effect of leucine (Leu) coating on a PVF sponge was examined for osteogenesis on an HA/PVF hybrid scaffold by rat BMCs (rBMCs). In an in vivo assessment, the sponge immersed in Leu solution (10 mg/ml) was inserted into the hollow center of cylindrical HA. The sponge received 1.5 × 106 rBMCs obtained from male Fischer 344 rats. The hybrid scaffolds were then implanted subcutaneously of syngeneic rats for 6 weeks. In vitro assessment of Leu to hard tissue formation with coating on the well or addition in rBMC culture medium was also performed in a 6-well plate for 2 weeks. In vivo examinations showed the excellent effect of Leu coating on PVF sponge. Leu-coated PVF sponge in the scaffolds showed marked new bone formation in the pores by histological examination. Leu-coated PVF sponge showed a high quantity of osteocalcine (OC). HA might prevent the release of rBMCs from PVF as a barrier. In in vitro examinations, the quantity of OC in rBMC culture with and without the addition of Leu in culture medium showed no significant difference. However, addition of Leu showed significant ALP activity level in culture medium. Leu coating in culture plate wells showed no influence on the quantity of OC. It was concluded from the results that Leu might prevent the emigration of rBMCs to the outside of the scaffold and promote the differentiation of cells to osteoblasts in the scaffold.

关键词： Amino-Acid Bone Marrow Cells Bone Formation Hybrid Scaffold Scaffold Hydroxyapatite Formalin-Treated Polyvinyl-Alcohol Sponge

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日本制药企业在海外的研究开发活动

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药学进展 1991年第4期 237-241页

作者： A kI yoshikawa 袁静文

日本的制药企业与国外的先进制药企业相比,在国际上明显地落后。日本的巨头制药企业在国外的销售比率约为5%,而美国制药企业在国外的销售比率约为35%,欧洲则为80%以上。这是因为一方面,日本迄今还没能在海外研制开发出常用的、有效的拳... 详细信息

日本的制药企业与国外的先进制药企业相比,在国际上明显地落后。日本的巨头制药企业在国外的销售比率约为5%,而美国制药企业在国外的销售比率约为35%,欧洲则为80%以上。这是因为一方面,日本迄今还没能在海外研制开发出常用的、有效的拳头新产品,另一方面,由于日本在国内有相当广阔的市场,故在国际上的局面较为被动。但今天日本企业对国际市场的关注开始加强。因为研制、开发新药需花费庞大经费,故不得不在国际市场上获取高利润,同时本国国民医疗费用的抑制,也是使得以国内市场为中心的企业把眼光投向更加现实的国际市场的原因之一。日本的制药企业面临的首要问题:以怎样的规模,如何有效地进行海外

关键词：制药企业美国研究开发美利坚合众国北美洲日本研制开发

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Clinical utility of treatment method conversion during single-session endoscopic ultrasound-guided biliary drainage

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World Journal of Gastroenterology 2020年第9期26卷 947-959页

作者： kosuke Minaga Mamoru Takenaka kentaro Yamao ken kamata Shunsuke Omoto Atsushi Nakai Tomohiro Yamazaki Ayana Okamoto Rei Ishikawa Tomoe yoshikawa Yasutaka Chiba Tomohiro Watanabe Masatoshi kudo Department of Gastroenterology and Hepatology Kindai University Faculty of MedicineOsaka-Sayama 589-8511Japan Clinical Research Center Kindai University HospitalOsaka-Sayama 589-8511Japan

BACkGROUND Although several techniques for endoscopic ultrasound-guided biliary drainage(EUS-BD)are available at present,an optimal treatment algorithm of EUS-BD has not yet been *** To evaluate the clinical utility of treatment method conversion during single endoscopic sessions for difficult cases in initially planned *** This was a single-center retrospective analysis using a prospectively accumulated *** with biliary obstruction undergoing EUS-BD between May 2008 and April 2016 were *** primary outcome was to evaluate the improvement in EUS-BD success rates by converting the treatment methods during a single endoscopic *** outcomes were clarification of the factors leading to the conversion from the initial EUS-BD and the assessment of efficacy and safety of the conversion as judged by technical success,clinical success,and adverse events(AEs).RESULTS A total of 208 patients underwent EUS-BD during the study *** 18.8%(39/208)of the patients,the treatment methods were converted to another EUSBD technique from the initial *** obstruction was caused by pancreatobiliary malignancies,other malignant lesions,biliary stones,and other benign lesions in 22,11,4,and 2 patients,*** reasons for the difficulty with the initial EUS-BD were classified into the following 3 procedures:Target puncture(n=13),guidewire manipulation(n=18),and puncture tract dilation(n=8).Technical success was achieved in 97.4%(38/39)of the cases and clinical success was achieved in 89.5%of patients(34/38).AEs occurred in 10.3%of patients,including bile leakage(n=2),bleeding(n=1),and cholecystitis(n=1).The puncture target and drainage technique were altered in subsequent EUSBD procedures in 25 and 14 patients,*** final technical success rate with 95%CI for all 208 cases was 97.1%(95%CI:93.8%-98.9%),while that of the initially planned EUS-BD was 78.8%(95%CI:72.6%-84.2%).CONCLUSION Among multi-step pro

关键词： Endoscopic ultrasound Endoscopic ultrasound-guided biliary drainage Interventional endoscopic ultrasound Biliary drainage Biliary obstruction

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New Technologies and Systems for High Quality Citrus Fruit Production, Labor-saving and Orchard Construction in Mountain Areas of Japan

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Journal of Mountain Science 2005年第1期2卷 59-67页

作者： kunihisa MORINAGA Osamu SUMIkAWA Osamu kAWAMOTO Hiroyasu yoshikawa Seiji NAkAO Masahiko SHIMAZAkI Shin-no-suke kUSABA Norihiro HOSHI National Agricultural Research Center for Western Region NABRO2575 Ikano Zentsuji Kagawa 765-0053 JapanNational Agricultural Research Center for Western RegionNABRO2575 Ikano Zentsuji Kagawa 765-0053 JapanNational Agricultural Research Center for Western RegionNABRO2575 Ikano Zentsuji Kagawa 765-0053 JapanNational Agricultural Research Center for Western RegionNABRO2575 Ikano Zentsuji Kagawa 765-0053 JapanNational Agricultural Research Center for Western RegionNABRO2575 Ikano Zentsuji Kagawa 765-0053 JapanNational Agricultural Research Center for Western RegionNABRO2575 Ikano Zentsuji Kagawa 765-0053 JapanNational Agricultural Research Center for Western RegionNABRO2575 Ikano Zentsuji Kagawa 765-0053 JapanNational Agricultural Research Center for Western RegionNABRO2575 Ikano Zentsuji Kagawa 765-0053 Japan

Novel technologies have been necessary for improving fruit quality and productivity of citrus, labor-saving and orchard conservation on steep slope lands since aging of growers and decrease in the number of successors is remarkable in mountain areas of southwestern Japan. The purpose of this paper is to introduce new technologies for improving citrus production that have been developed in recent years. A new fruit quality control system using drip irrigation and liquid fertilization technique combined with year-round plastic mulching was developed, and it enables high quality and stable citrus fruit production. Water and/or nutrient solution is automatically supplied through drip tubes that are laid under the mulching sheets to give adequate water stress, so as to improve sugar and acid content of fruit. A new transportation system for steep sloping citrus orchards, which is a combination of the monorail system and contour narrow paths, was suggested. A small walking cultivator was developed to explain the procedure of narrow path excavation. After introducing the narrow path, working hours for fertilizer and chemical herbicide application were reduced. Disaster prevention mapping of citrus orchards on slope lands was developed based on computer-aided seepage estimation and topographic data. The mapping can show zones of both ascending flow and descending flow of underground water during heavy rains in citrus orchards. The mapping is considered to be effective for the management of orchards and prevention of erosion on slope lands.

关键词：柑橘水果生产劳动力节约日本山脉地区果园建设

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Modeling and analysis of Hayabusa2 touchdown

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Astrodynamics 2020年第2期4卷 119-135页

作者： kent yoshikawa Hirotaka Sawada Shota kikuchi Naoko Ogawa Yuya Mimasu Go Ono Yuto Takei Fuyuto Terui Takanao Saiki Seiji Yasuda kota Matsushima Tetsuya Masuda Yuichi Tsuda Japan Aerospace Exploration Agency Sagamihara252-5210Japan NEC Corporation Fuchu183-8501Japan

The Hayabusa2 asteroid explorer mission focuses principally on the touchdown and sampling on near-Earth asteroid 162173 ***2 successfully landed on its surface and ejected a projectile for sample collection on February 22,***2 later landed near a crater formed by an impactor and executed the sampling sequence again on July 11,*** a successful mission,a thorough understanding and evaluation of spacecraft dynamics during touchdown were *** most challenging aspect of this study was the modeling of such spacecraft phenomena as the dynamics of landing on a surface with unknown *** particular,a Monte Carlo analysis was used to determine the parameters of the operational design for the final descent and touchdown *** paper discusses the dynamical modeling of the simulation during the touchdown of Hayabusa2.

关键词： contact dynamics resistive force theory(RFT) astrodynamics Hayabusa2 planetary exploration

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