Unidirectional Circuit Research Articles

Analytical modeling of piezoelectric meta-beams with unidirectional circuit for broadband vibration attenuation

Broadband vibration attenuation is a challenging task in engineering since it is difficult to achieve low-frequency and broadband vibration control simultaneously. To solve this problem, this paper designs a piezoelectric meta-beam with unidirectional electric circuits, exhibiting promising broadband attenuation capabilities. An analytical model in a closed form for achieving the solution of unidirectional vibration transmission of the designed meta-beam is developed based on the state-space transfer function method. The method can analyze the forward and backward vibration transmission of the piezoelectric meta-beam in a unified manner, providing reliable dynamics solutions of the beam. The analytical results indicate that the meta-beam effectively reduces the unidirectional vibration across a broad low-frequency range, which is also verified by the solutions obtained from finite element analyses. The designed meta-beam and the proposed analytical method facilitate a comprehensive investigation into the distinctive unidirectional transmission behavior and superb broadband vibration attenuation performance.

Noncanonical projections to the hippocampal CA3 regulate spatial learning and memory by modulating the feedforward hippocampal trisynaptic pathway.

The hippocampal formation (HF) is well documented as having a feedforward, unidirectional circuit organization termed the trisynaptic pathway. This circuit organization exists along the septotemporal axis of the HF, but the circuit connectivity across septal to temporal regions is less well described. The emergence of viral genetic mapping techniques enhances our ability to determine the detailed complexity of HF circuitry. In earlier work, we mapped a subiculum (SUB) back projection to CA1 prompted by the discovery of theta wave back propagation from the SUB to CA1 and CA3. We reason that this circuitry may represent multiple extended noncanonical pathways involving the subicular complex and hippocampal subregions CA1 and CA3. In the present study, multiple retrograde viral tracing approaches produced robust mapping results, which supports this prediction. We find significant noncanonical synaptic inputs to dorsal hippocampal CA3 from ventral CA1 (vCA1), perirhinal cortex (Prh), and the subicular complex. Thus, CA1 inputs to CA3 run opposite the trisynaptic pathway and in a temporal to septal direction. Our retrograde viral tracing results are confirmed by anterograde-directed viral mapping of projections from input mapped regions to hippocampal dorsal CA3 (dCA3). We find that genetic inactivation of the projection of vCA1 to dCA3 impairs object-related spatial learning and memory but does not modulate anxiety-related behaviors. Our data provide a circuit foundation to explore novel functional roles contributed by these noncanonical hippocampal circuit connections to hippocampal circuit dynamics and learning and memory behaviors.

Optimization of mine ventilation network feature graph.

A ventilation network feature graph can directly and quantitatively represent the features of a ventilation network. To ensure the stability of airflow in a mine and improve ventilation system analysis, we propose a new algorithm to draw ventilation network feature graphs. The independent path method serves as the algorithm's main frame, and an improved adaptive genetic algorithm is embedded so that the graph may be drawn better. A mathematical model based on the node adjacency matrix method for unidirectional circuit discrimination is constructed as the drawing algorithm may not be valid in such cases. By modifying the edge-seeking strategy, the improved depth-first search algorithm can be used to determine all of the paths in the ventilation network with unidirectional circuits, and the equivalent transformation method of network topology relations is used to draw the ventilation network feature graph. Through the analysis of the topological relation of a ventilation network, a simplified mathematical model is constructed, and network simplification technology makes the drawing concise and hierarchical. The rapid and intuitive drawing of the ventilation network feature graphs is significant for optimization of the ventilation system and day-to-day management.

Noncanonical connections between the subiculum and hippocampal CA1.

The hippocampal formation is traditionally viewed as having a feedforward, unidirectional circuit organization that promotes propagation of excitatory processes. While the substantial forward projection from hippocampal CA1 to the subiculum has been very well established, accumulating evidence supports the existence of a significant backprojection pathway comprised of both excitatory and inhibitory elements from the subiculum to CA1. Based on these recently updated anatomical connections, such a backprojection could serve to modulate information processing in hippocampal CA1. Here we review the published anatomical and physiological studies on the subiculum to CA1 backprojection, and present recent conclusive anatomical evidence for the presence of noncanonical subicular projections to CA1. New insights into this understudied pathway will improve our understanding of reciprocal CA1-subicular connections and guide future studies on how the subiculum interacts with CA1 to regulate hippocampal circuit activity and learning and memory behaviors. J. Comp. Neurol. 524:3666-3673, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

Bidirectional global spontaneous network activity precedes the canonical unidirectional circuit organization in the developing hippocampus

Spontaneous network activity is believed to sculpt developing neural circuits. Spontaneous giant depolarizing potentials (GDPs) were first identified with single-cell recordings from rat CA3 pyramidal neurons, but here we identify and characterize a large-scale spontaneous network activity we term global network activation (GNA) in the developing mouse hippocampal slices, which is measured macroscopically by fast voltage-sensitive dye imaging. The initiation and propagation of GNA in the mouse is largely GABA-independent and dominated by glutamatergic transmission via AMPA receptors. Despite the fact that signal propagation in the adult hippocampus is strongly unidirectional through the canonical trisynaptic circuit (dentate gyrus [DG] to CA3 to CA1), spontaneous GNA in the developing hippocampus originates in distal CA3 and propagates both forward to CA1 and backward to DG. Photostimulation-evoked GNA also shows prominent backward propagation in the developing hippocampus from CA3 to DG. Mouse GNA is strongly correlated to electrophysiological recordings of highly localized single-cell and local field potential events. Photostimulation mapping of neural circuitry demonstrates that the enhancement of local circuit connections to excitatory pyramidal neurons occurs over the same time course as GNA and reveals the underlying pathways accounting for GNA backward propagation from CA3 to DG. The disappearance of GNA coincides with a transition to the adult-like unidirectional circuit organization at about 2 weeks of age. Taken together, our findings strongly suggest a critical link between GNA activity and maturation of functional circuit connections in the developing hippocampus.

A Study of Unidirectional Driving Circuit of Piezoelectric Device Considering Energy Recovery

Common R or R-L load do not need special inverter circuits, however piezoelectric load can be considered as R-C load and its voltage does not become 0 even though the applied voltage is 0. Therefore it needs some special inverter with circuit that can discharge the capacitive energy. Especially for unidirectional square-wave voltage driving, it becomes more serious problem. In this paper, an energy recovery circuit for unidirectional square-wave voltage driving for piezoelectric load is proposed. With the circuit, the peak load current and the power supply capacity can be reduced because the energy in the load capacitor is saved to a capacitor for energy recovery and recharged from the capacitor. The appropriateness is proved from the simulation of the proposed circuit.

Study on unidirectional circuit problem in multi-fan-station ventilation type of Jinchuan No.2 mine

The calculating methods for path number and path matrix of ventilation networks without unidirectional circuits were introduced, and the inapplicability problem of the matrix algorithm to determine paths in a ventilation network with unidirectional circuit was brought forward, and a depth-first search method based algorithm to determine path matrix by means of modifying search strategies was discussed. The method is suitable for ventilation networks with unidirectional circuits and ventilation networks without unidirectional circuits, moreover the complexity is less than the complexities of matrix based algorithms. A series of methods and means to avoid and to reduce the negative effects of unidirectional circuits such as the optimum of the positions of fan stations, the increase or de-crease of fan station numbers, the optimum regulation of network and the analysis of diagonal structures were put forward.

Performance Characteristics of the Second-Generation Remote Emergency Medical Oxygen Closed-Circuit Rebreather

Closed-circuit oxygen rebreathers may provide high concentrations of oxygen at extremely low flow rates appropriate for field use with limited oxygen supplies. The performance of the preproduction, second-generation remote emergency medical oxygen (REMO(2)) system developed for Divers Alert Network was evaluated. The unidirectional circuit was made up of a solid, prepackaged CO(2) scrubber canister (984 +/- 14 [SD] g scrubber mass), standard 22-mm-inside-diameter anesthesia circuit hoses, 5-L breathing bag, 5-cm H(2)O positive end-expiratory pressure valve, and oronasal mask. Oxygen flow, inspired oxygen, expired CO(2), peak inspired and expired mask pressures, time to reach scrubber canister saturation or "breakthrough" (postscrubber CO(2) concentration reaching 3.8 mm Hg), and subject tolerance were measured under standard laboratory conditions. Six trials were completed using healthy volunteers (94.7 +/- 19.6 kg). Five of the 6 completed trials did not reach breakthrough at the planned trial limit of 8 hours. Mean average oxygen flow rate was 1.00 +/- 0.17 L x min(-1). Mean peak inspired and expired mask pressures were -5.0 +/- 1.9 and 6.5 +/- 1.9 cm H(2)O, respectively. Subjects generally reported good tolerance to circuit breathing. The second-generation REMO(2) was well tolerated by healthy subjects during 8-hour laboratory evaluation trials. The device provided high mean inspired oxygen fractions at low mean oxygen flow rates, relatively modest mean maximal inspired and expired pressures, and excellent scrubber canister duration. Further evaluation of field performance with a patient population is warranted.

Systolic inner product arrays with automatic word rounding

In this paper, we show how word rounding techniques can be efficiently used to reduce/eliminate the guard band in systolic Inner Product Array (IPA) circuits. This results in a significant improvement in circuit throughput rate. By incorporating a shift-truncation module either in the main array cells or in the accumulator cells, two different versions of an Automatic-Rounding IPA can be produced--the unidirectional ARIPA circuit and the orthogonal ARIPA circuit. It is shown that the proposed method requires considerably less hardware and has a higher degree of regularity when compared with techniques previously proposed. Maximum system word length reduction can be achieved with the modified unidirectional ARIPA circuit at a slight increase in overall circuit complexity. This allows maximum performance to be achieved.

Naloxone blocks opioid peptide release in N. Accumbens and amygdala elicited by morphine injected into periaqueductal gray

It has been proposed that a serial, unidirectional circuit from the PAG to the N. accumbens and the amygdala are involved in antinociception and that enkephalins (ENK) and β-endorphin (β-EP) act as neurotansmitters in this circuitry. In the present study, we measured the release of ENK and β-EP by simultaneous push-pull perfusion of the N. accumbens and amygdala after microinjection of morphine into the PAG. Morphine administration elicited an increase in immunoreactive ENK and β-EP in both the N. accumbens and the amygdala, which was antagonized in each nucleus by perfusion with naloxone. These data suggest that the three nuclei were not serially connected and that they may take part in one and the same antinociceptive system with an “all or none” character.

Diagnosis of Rectifier Ailments

THE MERCURY-POOL rectifier is a thoroughly reliable machine when properly protected and applied with the understanding that it is subject to infrequent, randomly occurring, internal faults known as arc-backs. An arc-back is a failure of an anode to block the flow of current from cathode to anode, resulting in a unidirectional short circuit between that anode and all normal anodes.