Unidirectional Operation of p-GaN Gate AlGaN/GaN Heterojunction FET Using Rectifying Drain Electrode

In this study, we proposed a rectifying drain electrode that was embedded in a p-GaN gate AlGaN/GaN heterojunction field-effect transistor to achieve the unidirectional switching characteristics, without the need for a separate reverse blocking device or an additional process step. The rectifying drain electrode was implemented while using an embedded p-GaN gating electrode that was placed in front of the ohmic drain electrode. The embedded p-GaN gating electrode and the ohmic drain electrode are electrically shorted to each other. The concept was validated by technology computer aided design (TCAD) simulation along with an equivalent circuit, and the proposed device was demonstrated experimentally. The fabricated device exhibited the unidirectional characteristics successfully, with a threshold voltage of ~2 V, a maximum current density of ~100 mA/mm, and a forward drain turn-on voltage of ~2 V.

Structural Design and Performance of the First Hepatic Portal Blood Flow Blocker

Laparoscopic surgery has been gradually promoted by people because of its advantages of small trauma and quick recovery. However, the operation is difficult, the first hepatic portal should be completely fastened during the operation. In this paper, through the study of the existing structure of the blocker, a kind of blood flow blocker for the first hepatic hilum blocking under laparoscope is designed. All kinds of parameters were calibrated through equation calculation, and the pressure guiding the blood flow blocking of hepatic portal during operation was calculated. The dynamic analysis was carried out with ANSYS software, and it was found that the fluid movement state was most uniform when the airflow velocity reached 8m/s. The experimental apparatus was set up to simulate the process of hepatic portal vein being blocked in vitro, then the feasibility of blocking effect was evaluated. Finally, it is concluded that the designed blood flow blocking device can have good blocking effect on blood vessels.

MULTIPOSITION TELECOMMUNICATION SYSTEM OF ELECTROMAGNETIC EMISSION INFLUENCE ON SATELLITE BROADBAND LINES OF RADIO COMMUNICATION

The structure of construction of a multiposition system (BS) of electromagnetic radiation influence on satellite broadband radio channels, consisting of synchronously operating spatially spaced low-power transceivers N_ts and having a fully connected topology network (similar to B) . As a result, it is possible to concentrate the radiating power in a given direction. By increasing the base of the transmission system, when its dimensions become comparable to the distance to the object under study, the wave front is no longer planar and the radiating power can be concentrated not only in the direction but also in the distance (focus in a certain area of space). Along with the N_ts collaboration mode, the transceivers of the satellite television telecommunication system can operate autonomously (independently of each other) and alternately, in accordance with the control law, which increases the flexibility of the BS operation. In addition, the use of several simultaneously working emitters can increase the range of BS. Reducing the power level of the signals emitted by individual positions increases the secrecy of the system, since the value of the resulting component of the electric field, determined by the geometric sum of the fields of individual emitters, will be high in a limited area of space, as well as electromagnetic compatibility with other electronic and electronic means one area in the common frequency band. The method of calculation of mutual interference with the sharing of frequencies of the satellite network and the multipoint satellite telecommunication system is presented and a practical experiment will be conducted to block the operation of the terrestrial satellite receiving station by external radio interference. The results of experimental studies have shown that the radiation power of this instance of the microwave blocking device is sufficient to block the operation of the terrestrial satellite receiving station at a distance of up to 30 km, in the presence of direct visibility between the antenna of the blocking device and the satellite receiving transceiver, which can have both a positive and a negative effect on the practical application of a microwave blocking device..

The Effectiveness of a Non-Invasive Shot Blocking Device for Reducing Pain of In-office Injections in Hand Surgery

Background: The gate control theory asserts that non-painful stimuli can block pain perception. The ShotBlocker™ device is a plastic disk with blunt projections that rests on the skin, and we hypothesize that it will reduce pain during hand injections. Methods: This is a prospective randomized trial of 117 patients undergoing injections for common hand conditions. Patients were randomized into 3 groups: device, placebo (device with projections removed), and control. Patients recorded on an analog pain scale the pain severity of the injection, as well as their most recent tetanus shot. A normalized pain score was obtained from the difference between the injection and tetanus shot pain scores. The mean non-normalized and normalized scores for each treatment group were compared to the control group using the Wilcoxon signed rank test. Results: There were 91 women and 26 men. Common diagnoses included trigger finger (n = 53), DeQuervain’s tendonitis (n = 33), and basal joint arthritis (n = 22). The groups did not differ significantly in age, gender, or diagnosis. Mean pain score in the device group was 5.2 out of 10, and it was 5.7 for the control group. The normalized pain score in the device group was significantly lower than the control group. Normalized and non-normalized pain scores for the placebo group were not significantly lower than the control group. Conclusions: The shot blocking device effectively reduced pain of injection versus controls when pain scores were normalized for pain tolerance. The modified device did not reduce the pain of injection, suggesting that gate control is the mechanism of action.