A new fast rangefinding method based on a non-mechanical scanning mechanism and a high-speed image sensor

In this paper, we present a new fast rangefinding method based on a non-mechanical scanning mechanism and a high-speed image sensor. Although the light stripe rangefinding method often is utilized to measure three dimensional shape of an object, it is difficult to acquire dense range data at high-speed with conventional light stripe rangefinders. We proposed a fast rangefinding method based on two new ideas unlike conventional methods: (1) to move a parabolic light pattern onto the object by means of a non-mechanical mechanism; (2) to detect a true peak value using a high-speed image sensor. We have designed and built a prototype rangefinder. The rangefinder was able to acquire three-dimensional position at 500 ns which is faster than conventional rangefinders. As a result, the proposed method is effective for high-speed three-dimensional measurement </p

Observation of superconductivity and its enhancement at the charge density wave critical point in LaAgSb 2

We discover superconductivity (SC) in LaAgSb2 at ambient pressure and its close correlation with a charge density wave (CDW) under pressure. The superconducting transition temperature (Tc) exhibits a sharp peak at a CDW critical pressure of 3.2 GPa. We demonstrate that the carriers inhabiting the Sb-square net are crucial not only in the formation of CDW but also in SC for their relatively strong electron-phonon coupling (EPC). Furthermore, theoretical EPC strength in pristine LaAgSb 2 cannot explain the observed peak with Tc∼1 K, which indicates that an additional mechanism reinforces SC only around the CDW critical pressure

Magnetotransport studies of the Sb square-net compound LaAgSb2 under high pressure and rotating magnetic fields

Square-net-layered materials have attracted attention as an extended research platform of Dirac fermions and of exotic magnetotransport phenomena. In this study, we investigated the magnetotransport properties of LaAgSb2, which has Sb-square-net layers and shows charge density wave (CDW) transitions at ambient pressure. The application of pressure suppresses the CDWs, and above a pressure of 3.2 GPa a normal metallic phase with no CDWs is realized. By utilizing a mechanical rotator combined with a high-pressure cell, we observed the angular dependence of the Shubnikov–de Haas (SdH) oscillation up to 3.5 GPa, and we confirmed the notable two-dimensional nature of the Fermi surface. In the normal metallic phase, we also observed a remarkable field-angular-dependent magnetoresistance (MR), which exhibited a “butterflylike” polar pattern. To understand these results, we theoretically calculated the Fermi surface and conductivity tensor at the normal metallic phase. We showed that the SdH frequency and Hall coefficient calculated based on the present Fermi surface model agree well with the experiment. The transport properties in the normal metallic phase are mostly dominated by the anisotropic Dirac band, which has the highest conductivity due to linear energy dispersions.We also proposed that momentum-dependent relaxation time plays an important role in the large transverse MR and negative longitudinal MR in the normal metallic phase, which is experimentally supported by the considerable violation of Kohler’s scaling rule. Although quantitatively complete reproduction was not achieved, the calculation showed that the elemental features of the butterfly MR could be reasonably explained as the geometrical effect of the Fermi surface

<原著>肝右葉切除における短肝静脈, 右肝静脈処理のための前方アプローチ

A simple procedure of right hepatic lobectomy for bulky liver tumors is proposed. The procedure is named "Anterior approach", which is characterized by transection of hepatic parenchyma without mobilization and rotation of the right hepatic lobe. The transection directly reaches the ventral surface of the retrohepatic inferior vena cava first at the portion of caudate process. The hepatic parenchymal transection proceeds from ventral to dorsal and from caudal to cranial. Several dorsal short hepatic veins are severed on the ventral surface of the IVC and the right hepatic vein is finally severed from inside. This method enables the minimization of operative stress and is especially useful for cases with a huge tumor in the right hepatic lobe which invades the diaphragm or thoraco-abdominal wall.巨大肝腫瘍に対する合理的な肝右葉切除法としての前方アプローチを紹介する. 肝右葉切除の標準手技として, 右葉の授動と脱転がある. これは肝の右側から, 肝部下大静脈に注ぐ短肝静脈や右肝静脈の剥離と切離を行う方法であるが, 後区域や右葉全体を占める巨大肝腫瘍の場合には, それらの手技は困難なことが多く, また腫瘍の破裂をきたす恐れもあり危険を伴う. 前方アプローチは, 右葉の脱転を行わずに直接肝実質を切離して, 肝部下大静脈腹側面に到達し, 尾状葉突起から頭側に向かつて肝実質の離断を進める方法である. 肝部下大静脈腹側面に注ぐ短肝静脈を, 順次肝離断面側から剥離処理し, 最後に右肝静脈の離断も同様に行う. 横隔膜浸潤, 胸壁, 腹壁浸潤がある場合には, 肝切離が終了してから合併切除として最後に行う. また本法は, 脱転による残存肝の阻血, 門脈血液鬱滞を回避出来る利点があり, 肝ミトコンドリアの酸化還元状態を反映する動脈血中ケトン体比(AKBR)の術中低下も軽微であることが判明しており, 手術侵襲の点からみても有用である前方アプローチの良い適応は, 1)後区域, 又は右葉全体を占拠するような巨大肝腫瘍の場合, 2)腫蕩が右横隔膜, 胸壁, 腹壁に浸潤している場合, 3)右葉の腫瘍の下大静脈への浸潤が疑われ, 下大静脈合併切除の要否を判定する場合, 4)肝障害のために右葉切除を行うには機能的予備力の点で不安がある場合, などである

Successive destruction of charge density wave states by pressure in LaAgSb2

We comprehensively studied the magnetotransport properties of LaAgSb2 under high pressure up to 4 GPa, which showed unique successive charge density wave (CDW) transitions at TCDW1∼210 K and TCDW2∼190 K at ambient pressure. With the application of pressure, both TCDW1 and TCDW2 were suppressed and disappeared at the critical pressures of PCDW1=3.0–3.4 GPa and PCDW2=1.5–1.9 GPa, respectively. At PCDW1, the Hall conductivity showed a steplike increase, which is consistently understood by the emergence of a two-dimensional hollow Fermi surface at PCDW1. We also observed a significant negative magnetoresistance effect when the magnetic field and current were applied parallel to the c axis. The negative contribution was observed in the whole pressure region from 0 to 4 GPa. Shubnikov–de Haas (SdH) oscillation measurements under pressure directly showed the changes in the Fermi surface across the CDW phase boundaries. In PPCDW1, we observed a single frequency of ∼48 T with a cyclotron effective mass of 0.066m0, whose cross section in the reciprocal space corresponded to only 0.22% of the first Brillouin zone. Besides, we observed another oscillation component with frequency of ∼9.2 T, which is significantly enhanced in the limited pressure range of PCDW2<P<PCDW1. The amplitude of this oscillation was anomalously suppressed in the high-field and low-temperature region, which cannot be explained by the conventional Lifshitz-Kosevich formula

Removal of detergents and fats from waste water using allophane

Micelles, consisting of an anionic surfactant and a fatty acid released from fat, were removed from an aqueous phase using the ion exchange characteristics of a natural clay mineral, allophane. The UV spectral measurements revealed that the concentrations of the anionic surfactant and the fatty acid in the aqueous phase decreased and that these species were removed from the aqueous phase. The adsorption of the surfactant and the fatty acid onto the allophane was confirmed by FT-IR spectroscopy. Furthermore, this adsorption was confirmed by the adsorption of anthracene added as a probe molecule.ArticleAPPLIED CLAY SCIENCE. 47(3-4):325-329 (2010)journal articl

Preliminary result of the relationship between the breathing frequency and dynamic body acceleration

March 5-6, 2009, Bangkok, ThailandIn this study, the relationship between the breathing frequency and the dynamic body acceleration (DBA) of one hatchery-reared loggerhead turtle Carretta carretta was examined using acceleration data loggers. Two acceleration data loggers (M190L-D2GT, W1000-3MPD3GT, Little Leonard, Japan) were attached on the lower-beak and carapace of a hatchery-reared loggerhead turtle, respectively. Breathing was successfully detected from the angle and depth of the beak-attached data logger and DBA, which has been used as an index of activity levels (Wilson et al., 2006), was calculated from the forward acceleration of the carapace-attached logger. There was a positive correlation between the DBA in the previous dive and the breathing frequency; the relationship was exponential. The result suggests that the number of breaths increased exponentially after a more active dive