2020-03 http://hdl.handle.net/11133/3569 2026-04-04T12:39:57Z 2026-04-04T12:39:57Z 小森, 大喜 木村, 悠人 森, 正和 http://hdl.handle.net/11133/3578 2023-07-10T02:58:25Z 2020-03-30T15:00:00Z

タイトル: ファイバ型位相変調素子を用いたスペクトル線幅測定法におけるプッシュプル駆動方式 著者: 小森, 大喜; 木村, 悠人; 森, 正和 抄録: Push-pull drive method in linewidth measurement systems with fiber type phase modulators is developed. Firstly, we discuss the operation of a fiber type phase modulator. Then the principle of a frequency shifter, which consists of a fiber type phase modulator and a fiber coupler, is described. Secondly, we describe the operation of the push-pull drive method, which arranges an ultrasonic transducer at each end of a fiber loop. Finally, the performance of the push-pull drive method is evaluated by measuring linewidths of several laser diodes. With the push-pull drive method, the carrier component and the second side band components are suppressed by about 10dB.

2020-03-30T15:00:00Z 福澤, 和久 http://hdl.handle.net/11133/3579 2023-07-10T02:57:16Z 2020-03-30T15:00:00Z

タイトル: Wireless Environmental Data Tracking System Design and Evaluation with a Multifunctional Device 著者: 福澤, 和久 抄録: Wireless environmental monitoring devices are in demand. These devices, which are also referred to as IoT (Internet of Things) devices, will be of vital importance in the next decade. The objective of this study is to propose a prototype system that can collect the environmental data using sensors, and transfers the data using a wireless network to a remote database for storage. The system was tested and verified by confirming that the monitoring data was stored in the remote database server. As a result, despite the set temperature of 20 degrees, the temperature fluctuated between 21 to 23 degrees. Our future work will involve using more sensors in the device so that it can collect multiple data, such as humidity, images, and the location. Furthermore, the author needs to deploy an actuator for physical control and improve the system’s power supply so that it can be used outdoors.

2020-03-30T15:00:00Z 横浜, 良祐 宇佐見, 亜希子 八木, 明彦 城戸, 由能 http://hdl.handle.net/11133/3580 2023-07-10T04:44:03Z 2020-03-30T15:00:00Z

タイトル: 牧尾ダムによる王滝川の水質変化と用水への影響 著者: 横浜, 良祐; 宇佐見, 亜希子; 八木, 明彦; 城戸, 由能 抄録: The water quality of the Ohtakigawa River has been influenced by volcanic activities of Mount Ontake in Japan. In this study, in order to analyze Ohtakigawa water quality affected by artificial infrastructures such as the Makio Dam, we mainly observed suspended solids (SS), Aluminum (Al) and Chlorophyll-a (Chl.a) in the Ohtakigawa river, where SS and Al prevent algae from growing, and Chl.a is contained in algae. In usual discharge cases from the Makio Dam through water pipes, the concentrations of Al and SS were decreased 0.1 times and 0.2 times, respectively, and the concentration of Chl.a was increased 3.3 times. In heavy rain cases, where overflow discharge through flood sluice gates were carried out, their concentrations showed the tendency similar to the above usual cases. And, laboratory experiments showed 80% of SS was deposited. Thereby, it is implied that both sedimentation and dilution effects caused algae inhibitors such as SS and Al to decrease and hence algae grew in the Makio Dam. In conclusion, the Makio Dam is capable of rehabilitation of the Ohtakigawa river water quality.

2020-03-30T15:00:00Z 市川, 隼也 内田, 臣一 伊藤, 誠記 http://hdl.handle.net/11133/3581 2023-07-10T04:45:13Z 2020-03-30T15:00:00Z

タイトル: 矢作川水系および周辺河川におけるカワゲラ類（特にキカワゲラ属）の分布と生活史 著者: 市川, 隼也; 内田, 臣一; 伊藤, 誠記 抄録: Stonefly nymphs (Insecta, Plecoptera) were collected at 80 sites in the Yahagi River system and in its surrounding rivers, central Honshu, Japan, in addition to our previous studies. The genera Kamimuria and Paragnetina were widely distributed in both upstream and downstream of the Yahagi Dam. Isoperla nipponica was widely distributed in upstream of the Yahagi Dam, but it tended to be few in downstream of the Yahagi Dam. The genus Xanthoneuria was widely distributed and abundant in upstream of the Yahagi Dam, but, in contrast, it was not collected at all in the main stem of the Yahagi River downstream of the Yahagi Dam (alt. 15-183 m, catchment area 513-1428 k㎡). In the surrounding areas of the Yahagi River system, Xanthoneuria nymphs were widely collected in the rivers of the Kiso River system and the Tenry? River system, although they were not collected in the rivers of the Toyo River system. In the Nagara River system, the nymphs were found in the rivers at altitudes of 64-104 m and with catchment areas of 278-1079k㎡. From these distribution patterns, it is considered that Xanthoneuria used to be distributed in the main stem of the Yahagi River below the Yahagi Dam, but the construction of the Dam would have changed the downstream environment and consequently Xanthoneuria has become uninhabitable there. By rearing of the nymphs, it was found that all three known species of Xanthoneuria from Japan, X. fulva, X. jouklii and X. bolivari inhabited the Yahagi River system. Xanthoneuria fulva tended to inhabit upper streams of the Yahagi River system, whereas X. jouklii tended to be collected in the rivers below the habitat of X. fulva, above the Yahagi Dam. X. bolivari was collected only in a tributary, the Ai River. The life cycle of X. jouklii was investigated at Sumigase (alt. 326 m). The eggs needed more than half a year to hatch. The change in size frequency of the nymphs indicates that the nymphs spent about one year underwater. Large nymphs of X. jouklii were collected from October through winter to May. The adults emerged simultaneously in late May. The life cycle of X. jouklii seems to be hemivoltine with very long hatching time. The life cycle of X. fulva was studied at Utsubo (alt. 980 m). The nymphs of X. fulva seems to need longer larval periods than those of X. jouklii, and the large nymphs were collected throughout the year.

2020-03-30T15:00:00Z