Источник двухчастотного перестраиваемого СВЧ-излучения на основе гироклистрона в режиме биений с входным сигналом

A new scheme of a two-frequency radiation source based on a gyroklystron amplifier operating in the self-excitation mode and controlled by the input signal is proposed. Using a powerful 3-mm gyroklystron as an example, it is shown that, when operating in the beat mode (i.e., outside the synchronization band), by varying the frequency and power level of the input signal, it is possible to implement continuous independent tuning of the distance between spectral components in the 10-150 MHz range. and the ratio of their amplitudes in the range from -10 to 0 dB.

Introducing coherent time control to cavity magnon-polariton modes

By connecting light to magnetism, cavity magnon-polaritons (CMPs) can link quantum computation to spintronics. Consequently, CMP-based information processing devices have emerged over the last years, but have almost exclusively been investigated with single-tone spectroscopy. However, universal computing applications will require a dynamic and on-demand control of the CMP within nanoseconds. Here, we perform fast manipulations of the different CMP modes with independent but coherent pulses to the cavity and magnon system. We change the state of the CMP from the energy exchanging beat mode to its normal modes and further demonstrate two fundamental examples of coherent manipulation. We first evidence dynamic control over the appearance of magnon-Rabi oscillations, i.e., energy exchange, and second, energy extraction by applying an anti-phase drive to the magnon. Our results show a promising approach to control building blocks valuable for a quantum internet and pave the way for future magnon-based quantum computing research.

Research of Stepper Motor Control Based on SCM

The control principle of stepper motor which is widely used at present has been analyzed. It adopts 8051 single-chip microcomputer to achieve stepper motor the pulse distribution control, acceleration and deceleration control in the four phase eight beat mode. This study has avoided complex circuit design, solved the stepper motor "step", "overshoot" phenomenon, promoted step motor to be more stable, faster response, more accurate positioning. This control which has the versatility can be achieved by modifying the corresponding circuit and related procedures for different stepper motor. The control which is flexible and convenient, low cost, has the very high use value in the practical application.

Stimulation of Human Spermatozoa with Progesterone Gradients to Simulate Approach to the Oocyte

Progesterone is present at micromolar concentrations in the cumulus matrix, which surrounds mammalian oocytes. Exposure of human spermatozoa to a concentration gradient of progesterone (0–3 μm) to simulate approach to the oocyte induced a slowly developing increase in [Ca2+]iupon which, in many cells, slow oscillations were superimposed. [Ca2+]ioscillations often started at very low progesterone (<10 nm), and their frequency did not change during the subsequent rise in concentration. Oscillations also occurred, but in a much smaller proportion of cells, in response to stepped application of progesterone (3 μm). When progesterone was removed, [Ca2+]ioscillations often persisted or quickly resumed. Superfusion with low-Ca2+bathing medium (no added Ca2+) did not prevent [Ca2+]ioscillations, but they could be abolished by addition of EGTA or La3+. Inhibitors of sarcoplasmic/endoplasmic reticulum Ca2+-ATPases or inositol trisphosphate signaling had no effect on [Ca2+]ioscillations, but pharmacological manipulation of ryanodine receptors affected both their frequency and amplitude. Staining of live spermatozoa with BODIPY FL-X ryanodine showed localization of ryanodine binding primarily to the caudal part of the head and mid-piece. [Ca2+]ioscillations did not induce acrosome reaction, but in cells generating oscillations, the flagellar beat mode alternated in synchrony with the oscillation cycle. Flagellar bending and lateral movement of the sperm head during [Ca2+]ipeaks were markedly increased compared with during [Ca2+]itroughs. This alternating pattern of activity is likely to facilitate zona penetration. These observations show that progesterone initiates unusual and complex store-mediated [Ca2+]isignaling in human spermatozoa and identify a previously unrecognized effect of progesterone in regulating sperm “behavior” during fertilization.

Oxygen Saturation and Breathing Patterns in Children

Objective. To obtain information on breathing patterns and oxygenation in children. Design. Overnight tape recordings of arterial oxygen saturation (Sao2 Nellcor N200 in beat-to-beat mode), photoplethysmographic waveforms, and breathing movements in 70 healthy children (mean age 8.0 years, range 2 through 16). Analysis of recordings for pauses in breathing movements of ≥4 seconds (apneic pauses), for episodes in which Sao2 fell to ≤90% (desaturations) and, only during the state of regular breathing, for baseline Sao2 heart rate, and respiratory rate. Results. Both baseline heart rate and respiratory rate decreased with increasing age (r = –.7 and –.3, respectively, P &lt; .01). Baseline Sao2 was similar to that previously observed in infants (median 99.5%, range 95.8 to 100, 5th centile 96.6%). Every recording showed apneic pauses, with a frequency that did not vary consistently with age (median 7.7/h, range 0.6 to 25.5). One hundred nineteen apneic pauses in 43 recordings lasted for 15 to 19.9 seconds, and 23 lasted for ≥20 seconds (longest 28.8 seconds). The number of episodic falls in Sao2 to ≥90% decreased with age (r = –.3, P &lt; .01); such episodes were found in 47% of children aged 2 through 6 years, but in only 13% of those aged 12 through 16 years. The 95th centile for desaturation frequency in the total group was 0.6/h. In six episodes in four patients, Sao2 fell to ≤80%. Conclusions. Apneic pauses, some of which can last for more than 20 seconds, are a normal phenomenon in healthy children and adolescents, but only a small minority of apneic pauses affect blood gas homeostasis. Information concerning oxygenation may be more relevant to our understanding of the maturation of respiratory control than the recording of breathing signals alone.