Abstract: In a wireless packet communication method for transmitting a plurality of wireless packets simultaneously by using multiple wireless channels determined to be idle by carrier sense, a wireless channel determined to be idle and MIMO, or the multiple wireless channel and the MIMO, a mandatory channel that is always used for transmission is set. The wireless packets are transmitted by using the wireless channel(s) including the mandatory channel only when the mandatory channel is idle. That is, in case of transmitting a plurality of wireless packets simultaneously, transmission is performed by using the wireless channel(s) including the mandatory channel, and transmission is not performed when the mandatory channel is not idle.

Abstract: In retransmission processing due to a failure of transmission of data packets, a plurality of data packets are simultaneously transmitted between two STAs by utilizing multiple wireless channels and MIMO, and the number of idle channels and the number of retransmission packets are compared. Then, when both of the numbers are different or only when the number of idle channels is larger than the number of retransmission packets, the retransmission packets are reconstructed according to the number of idle channels, and the reconstructed retransmission packets are simultaneously transmitted by using the idle channels.

Abstract: When a transmission rate of each of lines that transmit data simultaneously between two STAs by using a plurality of radio channels and/or MIMO can be set independently, one data frame is fragmented in accordance with the transmission rates of the respective lines so as to generate a plurality of data packets having the same packet time length and data sizes equal to or smaller than a maximum data size. Those data packets are transmitted simultaneously by using a plurality of radio channels, or one radio channel and MIMO, or a plurality of radio channels and MIMO.

Abstract: A plurality of types of available transmission rates to be used for transmission of data packets are individually managed for each receiver terminal. When there are a plurality of data packets to be transmitted onto a transmission buffer and when it is possible to transmit said plurality of data packets simultaneously, the packet sizes representative of the data amounts of the respective data packets are referred to as well as the transmission rates of the respective data packets associated with the receiver terminals. The packet time lengths (transmission times) defined by the packet sizes and transmission rates are checked for the respective data packets. A plurality of data packets whose packet time lengths are approximately equal to each other are selected regardless of their receiver terminals. The transmissions of the plurality of selected data packets are commenced simultaneously by use of a plurality of radio channels.

Abstract: A plurality of data packets that contain sequence numbers, respectively, are transmitted simultaneously between two STAs by using a wireless channel and MIMO. An STA receiving the plurality of data packets transmitted simultaneously by using MIMO generates a single ACK packet containing information that corresponds to a sequence number of each data packet successfully received, and transmits the single ACK packet to a transmit-side STA without using MIMO. Thus, a ratio of successful ACK packet receptions to total receptions can be increased. An effect of improving throughput achieved by simultaneous transmission can also be ensured.

Abstract: An epitaxial growth system is provided with a susceptor driving mechanism for rotationally driving a susceptor in a process chamber and this susceptor driving mechanism has a support shaft coupled to the susceptor, a driven portion, and an annular member with a plurality of permanent magnets arranged outside the driven portion. The driven portion is constructed in such structure that a coating for corrosion prevention consisting of a nickel coating, a chromium coating, and a metal oxide film formed by a passivation treatment with ozone is provided on a surface of a magnetic member.

Abstract: In a radio-frequency accelerating system, a loop antenna is coupled with at least one of a plurality of magnetic core groups each including a plurality of magnetic cores or with at least one of the plurality of magnetic cores, and an impedance adjusting means is connected to the loop antenna. A relatively low voltage is applied to the impedance adjusting means. Therefore, the impedance adjusting means may be a circuit element having a low withstand voltage and hence the radio-frequency accelerating system can be formed to have a small construction.

Abstract: Ultrasonic imaging apparatus including ultrasonic transducers for emitting acoustic wave beams of various apertures, apparatus for directing two acoustic wave beams of substantially different focussing distances on the same beam direction, circuitry for receiving the reflected waves corresponding to the beam directions, apparatus for modulating the scanning lines corresponding to the beam directions of the reflected acoustic waves, and apparatus for composing the scanning lines corresponding to the two acoustic beams directed on the same beam direction into a single scanning line for display.

Abstract: Ultrasonic imaging apparatus including ultrasonic transducers for emitting acoustic wave beams of various apertures, apparatus for directing two acoustic wave beams of substantially different focussing distances on the same beam direction, circuitry for receiving the reflected waves corresponding to the beam directions, apparatus for modulating the scanning lines corresponding to the beam directions of the reflected acoustic waves, and apparatus for composing the scanning lines corresponding to the two acoustic beams directed on the same beam direction into a single scanning line for display.

Abstract: An ultrasonic apparatus including apparatus for detecting the position of an ultrasonic probe, a memory for storing the positions of the ultrasonic probe relative to a reference point in symbolized pattern of a human body, a memory for storing tomogram signals received by the probe relative to the stored positions timing pulse generator apparatus for reading out the stored signals, and apparatus for displaying the symbolized pattern, the position of the probe and the relative tomogram data simultaneously on the screen of a monitor. The position detecting apparatus includes auto-reset circuits for arbitrarily resetting the position of the probe in the memory to the reference point regardless of the actual position of the probe.

Abstract: An ultrasonic diagnosis apparatus is provided with a plurality of phased array transducer elements arranged in a row. The number of simultaneously driven transducer elements is changed in response to a rate pulse to increase the ultrasonic scanning line density without increasing the number of the transducer elements, while the position of the focal point is adjusted to maintain the minimum width position of the ultrasonic beam provided by the group of the simultaneously driven transducer elements substantially constant irrespective of the change of the number of the simultaneously driven transducer elements by controlling the phase of transmitted and received ultrasonic waves by means of delay elements.