Finite Frequency Phase Property Versus Achievable Control Performance in H∞ Loop Shaping Design

Shinji Hara,Masaaki Kanno,Masahiko Onishi 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Comparative Study of Tetrahydrothiophene and Thiophene Self Assembled Monolayers on Au(111): Structure and Molecular Orientation

Ito, Eisuke,Hara, Masahiko,Kanai, Kaname,Ouchi, Yukio,Seki, Kazuhiko,Noh, Jaegeun Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.8

Surface structure and molecular orientation of self-assembled monolayers (SAMs) formed by the spontaneous adsorption of tetrahydrothiophene (THT) and thiophene (TP) on Au(111) were investigated by means of scanning tunneling microscopy (STM) and carbon K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. STM imaging revealed that THT SAMs have a commensurate (3 ${\times}\;2\sqrt[]{3}$) structure containing structural defects in ordered domains, whereas TP SAMs are composed of randomly adsorbed domains and paired molecular row domains that can be described as an incommensurate packing structure. The NEXAFS spectroscopy study showed that the average tilt angle of the aliphatic THT ring and $\pi$-conjugated TP ring in the SAMs were calculated to be about $30^o\;and\;40^o$, respectively, from the surface normal. It was also observed that the $\pi$* transition peak in the NEXAFS spectrum of the TP SAMs is very weak, suggesting that a strong interaction between $\pi$-electrons and the Au surface arises during the self-assembly of TP molecules. In this study, we have clearly demonstrated that the surface structure and adsorption orientation of organic SAMs on Au(111) are strongly influenced by whether the cyclic ring is saturated or unsaturated.

Smaller cross-sectional areas of the hamstring tendon measured from preoperative ultrasonography are likely to need additional gracilis harvesting for double-bundle anterior cruciate ligament reconstructions

Goto Kazumi,Hara Masahiko,Yamazaki Yoshiyuki,Urata Taihei,Shimizu Yuki,Shimizu Naofumi 대한슬관절학회 2020 대한슬관절학회지 Vol.32 No.-

Background/Purpose: Hamstring tendon autografts are commonly used for double-bundle anterior cruciate ligament reconstruction (DB-ACLR). If the volume of the semitendinosus (ST) tendon is insufficient, the gracilis (G) tendon is also harvested. Additional harvesting of the G autograft can affect patients’ short-term postoperative outcome, such as muscle recovery; thus, preoperative information about whether an additional G autograft is needed would be useful. The purpose of this study was to investigate whether preoperative measurement of the ST tendon using ultrasonography could inform the intraoperative decision to harvest the G tendon. Methods: We enrolled 20 patients (13 men and seven women) who underwent DB-ACLR between October 2017 and March 2019. The mean patient age was 28.5 years. The ipsilateral ST tendon was measured using ultrasonography before surgery. Measurements included the diameter and breadth of the short-axis image. The cross-sectional area (CSA) was calculated from these measurements. During surgery, when two grafts with diameters of ≥ 5.0mm could not be made, the G tendon was also harvested. Patients were categorized into two groups: the ST group where only the ST tendon was harvested, and the semitendinosus gracilis tendon (STG) group where the ST and G tendons were both harvested. The CSA value was compared between the two groups, and the cutoff value was calculated. Results: In the ST group (n = 8), the mean diameter and breadth of the semitendinosus tendon were 4.21 and 2.34mm, respectively. In the STG group (n = 12), the mean diameter and breadth of the ST tendon were 3.39 and 1.78 mm, respectively. The CSAs calculated for the ST group and the STG group were 7.74mm2 and 4.79mm2, respectively. A cutoff value of 7.0mm2 was found to correspond to a specificity and sensitivity to harvest the G tendon of 87.5% and 75.0%, respectively. Conclusions: The preoperative CSA of the ST tendon determined using ultrasonography can, therefore, be informative for deciding whether to harvest the G tendon for DB-ACLR. The results of this study provide valuable information for graft selection in anterior cruciate ligament reconstruction.

Comparative Study of Tetrahydrothiophene and Thiophene Self-Assembled Monolayers on Au(111): Structure and Molecular Orientation

Eisuke Ito,Masahiko Hara,Kaname Kanai,Yukio Ouchi,Kazuhiko Seki,노재근 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.8

Surface structure and molecular orientation of self-assembled monolayers (SAMs) formed by the spontaneous adsorption of tetrahydrothiophene (THT) and thiophene (TP) on Au(111) were investigated by means of scanning tunneling microscopy (STM) and carbon K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. STM imaging revealed that THT SAMs have a commensurate (3 × 2√3) structure containing structural defects in ordered domains, whereas TP SAMs are composed of randomly adsorbed domains and paired molecular row domains that can be described as an incommensurate packing structure. The NEXAFS spectroscopy study showed that the average tilt angle of the aliphatic THT ring and π-conjugated TP ring in the SAMs were calculated to be about 30o and 40o, respectively, from the surface normal. It was also observed that the π* transition peak in the NEXAFS spectrum of the TP SAMs is very weak, suggesting that a strong interaction between π-electrons and the Au surface arises during the self-assembly of TP molecules. In this study, we have clearly demonstrated that the surface structure and adsorption orientation of organic SAMs on Au(111) are strongly influenced by whether the cyclic ring is saturated or unsaturated.

Surface Potential Change Depending on Molecular Orientation of Hexadecanethiol Self-Assembled Monolayers on Au(111)

Eisuke Ito,Takayuki Arai,Masahiko Hara,노재근 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.6

Surface potential and growth processes of hexadecanethiol (HDT) self-assembled monolayers (SAMs) on Au(111) surfaces were examined by Kelvin probe method and scanning tunneling microscopy. It was found that surface potential strongly depends on surface structure of HDT SAMs. The surface potential shift for the striped phase of HDT SAMs chemisorbed on Au(111) surface was +0.45 eV, which was nearly the same as that of the flat-lying hexadecane layer physisorbed on Au(111) surface. This result indicates that the interfacial dipole layer induced by adsorption of alkyl chains is a main contributor to the surface potential change. In the densely-packed HDT monolayer, further change of the surface potential was observed, suggesting that the dipole moment of the alkanethiol molecules is an origin of the surface potential change. These results indicate that the work function of a metal electrode can be modified by controlling the molecular orientation of an adsorbed molecule.

Formation of Ordered 4-Fluorobenzenethiol Self-Assembled Monolayers on Au(111) from Vapor Phase Deposition

Kang, Hungu,Ito, Eisuke,Hara, Masahiko,Noh, Jaegeun American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.3

<P>Self-assembled monolayers (SAMs) were formed by the spontaneous adsorption of 4fluorobenzenethiol (4-FBT) on Au(111) using both solution and ambient-pressure vapor deposition methods at room temperature. The surface structure and thermal desorption properties of 4-FBT SAMs were examined by scanning tunneling microscopy (STM) and thermal desorption spectroscopy (TDS). STM imaging showed that 4-FBT SAMs formed in solution at room temperature mainly contained disordered phase with gold adatom islands, while those formed by ambientpressure vapor deposition had well-ordered phase, which can be described as a (2x2 root 13)R45 degrees structure. In addition, thermal desorption spectroscopy (TDS) measurements showed that strong desorption peak for parent mass fragment (m/z = 128, FC6H5SH+) for 4-FBT SAMs on Au(111) was observed at 460 K, as a result of hydrogen abstract reaction of chemisorbed thiolates during desorption.</P>

Surface Potential Change Depending on Molecular Orientation of Hexadecanethiol Self-Assembled Monolayers on Au(111)

Ito, Eisuke,Arai, Takayuki,Hara, Masahiko,Noh, Jaegeun Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.6

Surface potential and growth processes of hexadecanethiol (HDT) self-assembled monolayers (SAMs) on Au(111) surfaces were examined by Kelvin probe method and scanning tunneling microscopy. It was found that surface potential strongly depends on surface structure of HDT SAMs. The surface potential shift for the striped phase of HDT SAMs chemisorbed on Au(111) surface was +0.45 eV, which was nearly the same as that of the flat-lying hexadecane layer physisorbed on Au(111) surface. This result indicates that the interfacial dipole layer induced by adsorption of alkyl chains is a main contributor to the surface potential change. In the densely-packed HDT monolayer, further change of the surface potential was observed, suggesting that the dipole moment of the alkanethiol molecules is an origin of the surface potential change. These results indicate that the work function of a metal electrode can be modified by controlling the molecular orientation of an adsorbed molecule.

Improved Structural Quality of Aromatic Thiol Self-Assembled Monolayers on Au(111) by Microwave Irradiation

Taesung Park,강훈구,Eisuke Ito,Masahiko Hara,노재근 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.8

Phase Transition of Octaneselenolate Self-assembled Monolayers on Au(111) Studied by Scanning Tunneling Microscopy

Jungseok Choi,강훈구,Eisuke Ito,Masahiko Hara,노재근 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.8

We investigated the surface structure and wetting behavior of octaneselenolate self-assembled monolayers (SAMs) on Au(111) formed in a 50 μM ethanol solution according to immersion time, using scanning tunneling microscopy (STM) and an automatic contact angle (CA) goniometer. Closely-packed, well-ordered alkanethiol SAMs would form as the immersion time increased; unexpectedly, however, we observed the structural transition of octaneselenolate SAMs from a molecular row phase with a long-range order to a disordered phase with a high density of vacancy islands (VIs). Molecularly resolved STM imaging revealed that the missing-row ordered phase of the SAMs could be assigned as a (6 × √3)R30° superlattice containing three molecules in the rectangular unit cell. In addition, CA measurements showed that the structural order and defect density of VIs are closely related to the wetting behaviors of octaneselenolate SAMs on gold. In this study, we clearly demonstrate that interactions between the headgroups and gold surfaces play an important role in determining the physical properties and surface structure of SAMs.

Autonomous Pattern Formation of Micro-organic Cell Density with Optical Interlink between Two Isolated Culture Dishes.

Ozasa, Kazunari,Lee, Jeesoo,Song, Simon,Hara, Masahiko,Maeda, Mizuo MIT Press 2015 Artificial life Vol.21 No.2

<P>Artificial linking of two isolated culture dishes is a fascinating means of investigating interactions among multiple groups of microbes or fungi. We examined artificial interaction between two isolated dishes containing Euglena cells, which are photophobic to strong blue light. The spatial distribution of swimming Euglena cells in two micro-aquariums in the dishes was evaluated as a set of new measures: the trace momentums (TMs). The blue light patterns next irradiated onto each dish were deduced from the set of TMs using digital or analogue feedback algorithms. In the digital feedback experiment, one of two different pattern-formation rules was imposed on each feedback system. The resultant cell distribution patterns satisfied the two rules with an and operation, showing that cooperative interaction was realized in the interlink feedback. In the analogue experiment, two dishes A and B were interlinked by a feedback algorithm that illuminated dish A (B) with blue light of intensity proportional to the cell distribution in dish B (A). In this case, a distribution pattern and its reverse were autonomously formed in the two dishes. The autonomous formation of a pair of reversal patterns reflects a type of habitat separation realized by competitive interaction through the interlink feedback. According to this study, interlink feedback between two or more separate culture dishes enables artificial interactions between isolated microbial groups, and autonomous cellular distribution patterns will be achieved by correlating various microbial species, despite environmental and spatial scale incompatibilities. The optical interlink feedback is also useful for enhancing the performance of Euglena-based soft biocomputing.</P>