Spin-current Seebeck effect in quantum dot systems

We first bring up the concept of spin-current Seebeck effect based on a recent experiment [Nat. Phys. {\bf 8}, 313 (2012)], and investigate the spin-current Seebeck effect in quantum dot (QD) systems. Our results show that the spin-current Seebeck coefficient $S$ is sensitive to different polarization states of QD, and therefore can be used to detect the polarization state of QD and monitor the transitions between different polarization states of QD. The intradot Coulomb interaction can greatly enhance the $S$ due to the stronger polarization of QD. By using the parameters for a typical QD, we demonstrate that the maximum $S$ can be enhanced by a factor of 80. On the other hand, for a QD whose Coulomb interaction is negligible, we show that one can still obtain a large $S$ by applying an external magnetic field.Comment: 6 pages, 8 figure

Coherent Single Spin Source based on topological insulator

We report on the injection of quantized pure spin current into quantum conductors. In particular, we propose an on demand single spin source generated by periodically varying the gate voltages of two quantum dots that are connected to a two dimensional topological insulator via tunneling barriers. Due to the nature of the helical states of the topological insulator, one or several {\it spin pair}s can be pumped out per cycle giving rise to a pure quantized alternating spin current. Depending on the phase difference between two gate voltages, this device can serve as an on demand single spin emitter or single charge emitter. Again due to the helicity of the topological insulator, the single spin emitter or charge emitter is dissipationless and immune to disorders. The proposed single spin emitter can be an important building block of future spintronic devices.Comment: 5 pages, 4 figures, append one co-author that has been misse

A target guided subband filter for acoustic event detection in noisy environments using wavelet packets

This paper deals with acoustic event detection (AED), such as screams, gunshots, and explosions, in noisy environments. The main aim is to improve the detection performance under adverse conditions with a very low signal-to-noise ratio (SNR). A novel filtering method combined with an energy detector is presented. The wavelet packet transform (WPT) is first used for time-frequency representation of the acoustic signals. The proposed filter in the wavelet packet domain then uses a priori knowledge of the target event and an estimate of noise features to selectively suppress the background noise. It is in fact a content-aware band-pass filter which can automatically pass the frequency bands that are more significant in the target than in the noise. Theoretical analysis shows that the proposed filtering method is capable of enhancing the target content while suppressing the background noise for signals with a low SNR. A condition to increase the probability of correct detection is also obtained. Experiments have been carried out on a large dataset of acoustic events that are contaminated by different types of environmental noise and white noise with varying SNRs. Results show that the proposed method is more robust and better adapted to noise than ordinary energy detectors, and it can work even with an SNR as low as -15 dB. A practical system for real time processing and multi-target detection is also proposed in this work

Diagnostic analysis of dynamic deflection for cracked asphalt pavements under FWD impulsive loading

The falling weight deflectometer (FWD) is a non-destructive testing technology used to calculate the stiffness-related parameters of pavement structures and has been widely used in the pavement engineering field. Deflection basin testing data have an obviously affecting effect on the modulus backcalculation of an asphalt pavement. Identifying effective data of dynamic deflection basins is an important task to perform modulus backcalculation. The objective of this paper is to study the distribution features of dynamic deflection basins of cracked asphalt pavements using a three dimension dynamic finite element method. Based on the systematic analysis, the criteria used to filter effective data of FWD deflection basins were presented and verified with an in-situ case study. The study results demonstrated that the crack width of 0.2 mm was a critical value to determine the existence of contact behavior between vertical crack surfaces. The distribution characteristics of dynamic deflection basins showed a significant difference between intact and cracked pavements. The established criteria, involving surface deflection indicator and surface modulus indicator, were verified to be reasonable and viable for filtering the FWD testing data

Numerical Modelling of Structural Behavior of RC Frames With and Without Infill Walls Subjected to Progressive Collapse

This paper aims to develop a numerical model of RC frame considering the same geometrical properties, material properties and boundary conditions in ABAQUS and validated with the experimental results comparing its force-displacement curve, damage pattern and stress and strain variations with the experimental outcomes. The use of infill walls increases the progressive collapse resistance force, mainly in the CAA. This is due to the addition of compressive action of infill walls to beam bending and CAA of RC frame. Plastic hinge was observed at the beam ends in case of RC bare frame. However, in the case of RC frame with infill wall, the plastic hinge was formed at some distance from middle joint interface and near the adjacent column joint on first floor and at some distance from adjacent column joint and near middle joint interface on second floor. Furthermore, in order to examine the effect of full height infill walls on progressive collapse resistance mechanism, RC frame with full height concrete block is modeled in ABAQUS and compare the results. It is seen that the RC frame with full height infill walls provides much higher progressive collapse resistance force in all stages i.e. beam mechanism stage, transient stage and catenary action stage

Application of Painless Catheterization in Promoting Nursing Satisfaction of Elderly Patients

目的 探讨无痛导尿术提升高龄患者关怀护理满意度的应用效果。方法 将80例女性手术患者随机分为试验组和对照组，每组各40例。对照组以常规方法行术前导尿，试验组行无痛导尿术及关怀护理操作法，比较两组患者导尿前后的心率、血压、血氧饱和度、疼痛程度、关怀护理满意程度的情况。结果 两组患者导尿后血压、心率的比较有显著性差异（р<0.05）；导尿后对照组的疼痛程度高于试验组，差异有显著性（р<0.05）；试验组患者满意度高于对照组，差异有显著统计学意义（р<0.01）。结论 护士愿意在术前女性患者中采用无痛导尿术，不仅临床实施便利，增进护患交流，减少患者痛苦，拉近与患者的距离，能够提升患者对关怀护理的满意度。Objective: To explore the effect of painless catheterization on nursing care satisfaction of elderly patients. Methods: 80 cases of female patients were randomly divided into experiment group and control group, 40 cases in each group, using conventional methods of preoperative catheterization, painless catheterization and nursing care operation method. Results: The blood pressure and heart rate after catheterization were significantly different (р<0.05). The degree of pain in the experiment group was higher than that in the control group after catheterization (р<0.05). The satisfaction degree of the experiment group was higher than that of the control group (р<0.01). Conclusion: Nurses are willing to use painless catheterization in preoperative, which not only facilitates clinical practice, but also improves the communication between patients and nurses, reduces patients' pain and shortens the distance between patients and patients, and improves the patients' satisfaction with nursing car