Development of SPring-8 vacuum system

SPring-8 storage ring has been available for user operation with low emittance and extreme stability for over 10 years. However there occurred some problems in the components of the storage ring due to high-brightness synchrotron radiation (SR) and low-emittance operation. On the vacuum system of the storage ring, an accurate pressure could not be measured near the photon absorber due to scattered high-energy SR to the gauge head. High-energy SR activated dissolved oxygen in cooling water, and the activated dissolved oxygen corroded the inside of the photon absorbers in SR irradiation part. Air leakage occurred at an injection chamber due to impact by a small-size electron beam produced by low-emittance operation.We investigated the cause of the aforementioned difficulties with the vacuum system and prescribed the treatments described in this paper. In addition, we are making continual efforts at further system upgrades such as developing an RF shield that suppresses temperature increase in the shield in possible high-current operation.     

Erbium-doped fibre amplifiers with an extremely high gain coefficient of 11.0 dB/mW

A gain coefficient of 11.0 dB/mW is obtained using 0.98 mu m laser diode pumped erbium-doped fibre amplifiers with a low erbium concentration of 81 p.p.m. and a high relative refractive index difference of 1.88%.<>     

Bacterial invasion into the colonic mucosa in ulcerative colitis

This study investigated interactions between mucosal lesions and bacterial invasion in ulcerative colitis using the acridine-orange staining method. In all 16 cases of ulcerative colitis, the mucosa was found to be invaded by small rods and cocci. In five of 10 controls, bacteria were seen only adhering to the mucosa and no bacteria were detected in the five remaining cases. It is suggested that the presence of bacteria in the colonic mucosa may be a factor responsible for the persistence or aggravation of ulcerative colitis.     

The development of a visual system for the detection of obstructions for visually impaired people

In this paper, the author presents a new visual system that can aid visually impaired people in walking. The system provides object information (that is, shape and location) through the sense of touch. This visual system depends on three different components: (i) an infrared camera sensor that detects the obstruction, (ii) a control system that measures the distance between the obstruction and the sensor, and (iii) a tooling apparatus with small pins (ϕ1 mm) used in forming a three-dimensional shape of the obstruction. The pins, arranged on a 6×6 matrix, move longitudinally between the retracted and extended positions based on the distance data. The pin extends individually, while the pin tip reflects the object’s outer surface. The length of the pin from the base surface is proportional to the distance of the sensor from the obstruction. An ultrasonic actuator, controlled at a 15Hz frame rate, is the driving force for the pin movement. The tactile image of the 3D shape can provide information about the obstruction.