Differences in Non-suicidal Self-injury Behaviors between Unipolar Depression and Bipolar Depression in Adolescent Outpatients

Objective Non-suicidal self-injury(NSSI)has a higher prevalence in adolescents with depressive disorders than in community adolescents.This study examined the differences in NSSI behaviors between adolescents with unipolar depression(UD)and those with bipolar depression(BD).Methods Adolescents with UD or BD were recruited from 20 general or psychiatric hospitals across China.The methods,frequency,and function of NSSI were assessed by Functional Assessment of Self-Mutilation.The Beck Suicide Ideation Scale was used to evaluate adolescents’suicidal ideation,and the 10-item Kessler Psychological Distress Scale to estimate the anxiety and depression symptoms.Results The UD group had higher levels of depression(19.16 vs.17.37,F=15.23,P<0.001)and anxiety symptoms(17.73 vs.16.70,F=5.00,P=0.026)than the BD group.Adolescents with BD had a longer course of NSSI than those with UD(2.00 vs.1.00 year,Z=−3.39,P=0.001).There were no statistical differences in the frequency and the number of methods of NSSI between the UD and BD groups.Depression(r=0.408,P<0.01)and anxiety(r=0.391,P<0.01)were significantly and positively related to NSSI frequency.Conclusion Adolescents with BD had a longer course of NSSI than those with UD.More importantly,NSSI frequency were positively and strongly correlated with depression and anxiety symptoms,indicating the importance of adequate treatment of depression and anxiety in preventing and intervening adolescents’NSSI behaviors.

Reduction of Unipolar Leakage Flux and Torque Ripple in Consequent-pole PM Vernier Machine

This paper proposes a new consequent-pole permanent magnet vernier machine(CPMVM),which can be regarded as a combination of two conventional CPMVM with opposite polarities.Based on the simplified axial magnetic circuit model,it is verified that the proposed CPMVM can reduce the unipolar leakage flux.In order to reduce the torque ripple of machine and improve the output torque of machine,the flux barrier is placed on the rotor of the proposed machine.Then,the parameters of the proposed CPMVM are optimized and determined.Moreover,the electromagnetic performance,including no-load air-gap flux density,average torque and torque ripple,flux linkage,back-electromotive force,cogging torque,average torque,torque ripple,power factor and loss,is compared with conventional surface-mounted permanent magnet vernier machine(SPMVM)and CPMVM.Finally,it is demonstrated that proposed CPMVM with flux barrier can effectively reduce the unipolar leakage flux and greatly reduce the torque ripple of machine.Also,compared with the SPMVM,the proposed CPMVM with flux barrier saves more than 45%of the permanent magnet material without reducing output torque.

Coexistence of unipolar and bipolar modes in Ag/ZnO/Pt resistive switching memory with oxygen-vacancy and metal-Ag filaments

In this study, the unipolar resistive switching （URS） and bipolar resistive switching （BRS） are demonstrated to be coexistent in the Ag/ZnO/Pt memory device, and both modes are observed to strongly depend on the polarity of forming voltage. The mechanisms of the URS and BRS behaviors could be attributed to the electric-field-induced migration of oxygen vacancies （Vo） and metal-Ag conducting filaments （CFs） respectively, which are confirmed by investigating the temperature dependences of low resistance states in both modes. Furthermore, we compare the resistive switching （RS） characteristics （e.g., forming and switching voltages, reset current and resistance states） between these two modes based on Vo- and Ag-CFs. The BRS mode shows better switching uniformity and lower power than the URS mode. Both of these modes exhibit good RS performances, including good retention, reliable cycling and high-speed switching. The result indicates that the coexistence of URS and BRS behaviors in a single device has great potential applications in future nonvolatile multi-level memory.

Coexistence of Bipolar and Unipolar Resistive Switching Behavior in Ag/ZnMn_2O_4/p^+-Si Device

ZnMnOthin films were deposited by a sol-gel technique onto a p+-Si substrate, and a RRAM device with the Ag/ZnMnO/p~+-Si structure was fabricated. The microstructure of ZnMnOfilms and the resistive switching behavior of Ag/ZnMnO/p~+-Si device were investigated. ZnMnOthin films had a spinel structure after annealing at 650 °C for 1 h. The Ag/ZnMnO/p~+-Si device showed unipolar and/or bipolar resistive switching behavior, exhibiting different ION/IOFF ratio and switching endurance properties. In bipolar resistive switching, high-resistance-state(HRS) conduction was dominated by the space-charge-limited conduction mechanism, whereas the filament conduction mechanism dictated the low resistance state(LRS). For unipolar resistive switching, HRS and LRS were controlled by the filament conduction mechanism. For bipolar resistive switching, the conduction process can be explained by the space-charge region of the p-n junction.

SPICE modeling of flux-controlled unipolar memristive devices

Unipolar memristive devices are an important kind of resistive switching devices. However, few circuit models of them have been proposed. In this paper, we propose the SPICE modeling of flux-controlled unipolar memristive devices based on the memristance versus state map. Using our model, the flux thresholds, ON and OFF resistance, and compliance current can easily be set as model parameters. We simulate the model in HSPICE using model parameters abstracted from real devices, and the simulation results show that the proposed model caters to the real device data very well, thus demonstrating that the model is correct. Using the same modeling methodology, the SPICE model of charge-controlled unipolar memristive devices could also be developed. The proposed model could be used to model resistive memory cells, logical gates as well as synapses in artificial neural networks.

Comparison of performance between bipolar and unipolar double-frequency sinusoidal pulse width modulation in a digitally controlled H-bridge inverter system

By deriving the discrete-time models of a digitally controlled H-bridge inverter system modulated by bipolar sinu- soidal pulse width modulation （BSPWM） and unipolar double-frequency sinusoidal pulse width modulation （UDFSPWM） respectively, the performances of the two modulation strategies are analyzed in detail. The circuit parameters, used in this paper, are fixed. When the systems, modulated by BSPWM and UDFSPWM, have the same switching frequency, the stabil- ity boundaries of the two systems are the same. However, when the equivalent switching frequencies of the two systems are the same, the BSPWM modulated system is more stable than the UDFSPWM modulated system. In addition, a convenient method of establishing the discrete-time model of piecewise smooth system is presented. Finally, the analytical results are confirmed by circuit simulations and experimental measurements.

Bias polarity-dependent unipolar switching behavior in NiO/SrTiO_3 stacked layer

The identification of the switching location has been a key technology to tune the physical properties of unipolar resistive switching（RS） cells.Here we report the RS properties of Au/Ni O/Sr Ti O3（STO）/Pt memory cells.The switching repeatability is closely related to the applied bias polarity,which is different from the scenario of the Au/STO/Pt cells reported in our previous researches.The high resistance in positive bias is greater than that in negative bias.The R（T）–R0I^2 R（T） plot of the on-state I–V curve shows a regular shape only with a slight bend and an abnormal shape with an abrupt increase and decrease under negative and positive bias,respectively.These comparative experimental results reveal that the conductance filament consisting of oxygen vacancies grows from the cathode to the anode.The spatial RS location is identified with the weaker part along the conductance filament length direction,which should be near the Ni O/STO interface and STO/Pt interface under positive and negative bias,respectively.

PHOTOACOUSTIC GENERATION OF FOCUSED QUASI-UNIPOLAR PRESSURE PULSES

The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries.In the focal region,the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface,with a time-averaged value equal to zero.This approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free boundaries.For a free boundary,the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse.

Reversible alternation between bipolar and unipolar resistive switching in La-SrTiO_3 thin films

The alternation from bipolar to unipolar resistive switching is observed in perovskite La0.01Sr0.99TiO3 thin films. These two switching modes can be activated separately depending on the compliance current （Icomp） during the electroforming process： with a higher Icomp （5 mA） the unipolar resistance switching behavior is measured, while the bipolar resistance switching behavior is observed with a lower Icomp （1 mA）. On the basis of I–V characteristics, the switching mechanisms for the URS and BRS modes are considered as being a change in the Schottky-like barrier height and/or width at the Pt/La-SrTiO3 interface and the formation and disruption of conduction filaments, respectively.

A "Superpower" instead of "Unipolarity"

The power position and influence of a country depend on its comprehensive national power based on economics. While addressing to the press in Kansas on July 6, 1971, President Nixon noted: "Comparing to our overwhelming position at the end of World War II, the United States is now facing immense challenges that we have never expected before. " He added, "In terms of economics, the United States is no longer a dominant power or an overwhelming global power. At present, there exist not only two superpowers. In consideration of eco-

Healthy individuals vs patients with bipolar or unipolar depression in gray matter volume

BACKGROUND Previous studies using voxel-based morphometry(VBM)revealed changes in gray matter volume(GMV)of patients with depression,but the differences between patients with bipolar disorder(BD)and unipolar depression(UD)are less known.AIM To analyze the whole-brain GMV data of patients with untreated UD and BD compared with healthy controls.METHODS Fourteen patients with BD and 20 with UD were recruited from the Mental Health Center of Shantou University between August 2014 and July 2015,and 20 nondepressive controls were recruited.After routine three-plane positioning,axial T2WI scanning was performed.The connecting line between the anterior and posterior commissures was used as the scanning baseline.The scanning range extended from the cranial apex to the foramen magnum.Categorical data are presented as frequencies and were analyzed using the Fisher exact test.RESULTS There were no significant intergroup differences in gender,age,or years of education.Disease course,age at the first episode,and Hamilton depression rating scale scores were similar between patients with UD and those with BD.Compared with the non-depressive controls,patients with BD showed smaller GMVs in the right inferior temporal gyrus,left middle temporal gyrus,right middle occipital gyrus,and right superior parietal gyrus and larger GMVs in the midbrain,left superior frontal gyrus,and right cerebellum.In contrast,UD patients showed smaller GMVs than the controls in the right fusiform gyrus,left inferior occipital gyrus,left paracentral lobule,right superior and inferior temporal gyri,and the right posterior lobe of the cerebellum,and larger GMVs than the controls in the left posterior central gyrus and left middle frontal gyrus.There was no difference in GMV between patients with BD and UD.CONCLUSION Using VBM,the present study revealed that patients with UD and BD have different patterns of changes in GMV when compared with healthy controls.

On the Unipolar Generator: An Experimental and Theoretical Study

When studying the phenomenon of the induced electromotive force, which originates from Faraday’s unipolar inductor, the contrast between Faraday’s view of the magnetic field dynamic lines and the theory of relativity is revealed. In order to remove this contradiction, this phenomenon was studied in depth, theoretically and experimentally, using an experimental setup similar to Faraday’s. Calculations of the induced electromotive force, based on relativity on the one hand and on Faraday’s view on the other were made with the help of measurements of the magnetic field components. Accurate magnetic field measurements are confirmed by analytical calculations. Precise-induced electromotive force measurements confirmed Faraday’s view and contradicted the theory of relativity.

Enhanced unipolar electrical fatigue resistance and related mechanism in grain-oriented Pb(Mg_(1/3)Nb_(2/3))O_(3)-Pb(Zr,Ti)O_(3)piezoceramics

Piezoceramics with high and fatigue-resisted piezoelectric properties are strongly desired for actuator ap-plications.In this work,textured Pb(Mg_(1/3)Nb_(2/3))O_(3)-Pb(Zr,Ti)O_(3)ceramics with Lotgering factor F_(001)∼98%were fabricated by templated grain growth technique.Strong[001]c-grain orientation(f∼90%and r∼0.22)of the textured ceramics effectively produced about 230%enhanced piezoelectric coefficient d_(33)^(∗)(i.e.,S_(max)/E_(max))and substantially improved unipolar electrical fatigue resistance.Unipolar polarization P max and d_(33)^(∗)of the textured ceramics were nearly maintained up to 106 unipolar cycles,while 19%and 14%degradations were respectively observed from randomly oriented counterparts.Especially,normal-ized d_(33)^(∗)of the textured ceramics shows better unipolar fatigue resistance than those of piezoceramics reported previously.Much lower bipolar strain asymmetryγs(∼4%)was observed from the textured samples fatigued after 106 unipolar cycles as compared toγs∼23%for randomly oriented counterparts.While charged defect accumulation model described the serious fatigue deteriorations in randomly ori-ented ceramics,the current work revealed that substantially enhanced unipolar fatigue resistance of the textured ceramics is mainly associated with the inherent fatigue anisotropy,weakened local bias fields owing to both enhanced domain mobility and lower defect density near grain boundaries/interfaces,and increased intrinsic contribution due to more tetragonal content.These superior characteristics suggest the great potential of textured ceramics for high-performance and robust actuator applications.

手持式心电采集仪的使用技巧

手持式心电采集仪是一款简易的双极单导联心电图记录设备,只需双手拇指紧捏正、负两极,就能方便地记录出标准Ⅰ导联心电图,多用于监测心律失常。它属于家用医疗器械,颇受广大中老年朋友的欢迎。基于单极导联与双极导联的本质及其内在联系,本文衍生出标准导联与加压单极导联的记录方法;同时,在深入探究CR导联与Wilson导联内在联系的基础上,创造性地提出了手持式心电采集仪直采CR胸导联心电图的方法。理论和实践均表明,加压单极肢体导联的等效记录法与CR胸导联的双极记录法不仅能满足临床需要,而且还有其独到之处。该方法能充分发挥家用医疗器械的医用价值,值得推广普及。

基于相互解耦四单极接收线圈的电动汽车无线充电系统的互操作性

近年来电动汽车发展迅速,而传统的有线充电方式不能满足自动化和便利性的要求。电动汽车无线充电技术因其便利性和安全性受到广泛的研究。无线充电系统中常见的线圈结构有单极型线圈、双极型线圈和田字形线圈,由于不同厂商的适配问题,要兼容这些线圈则需要设计一种新型的线圈来实现互操作性。该文提出了一种新型的相互解耦的四单极接收线圈结构,能实现与不同发射线圈之间的互操作性。通过在接收线圈内部添加解耦绕组以实现4个接收线圈之间的解耦,并且通过串联二极管整流器使得发射线圈和四单极接收线圈之间的等效总互感是发射线圈和4个单极线圈之间的互感绝对值的总和。搭建了一套实验样机,验证了该方案的有效性,所提出的四单极接收线圈可以兼容单极型和双极型线圈以及田字形线圈,实现对不同接收线圈的互操作性。

基于机器学习构建单双相抑郁鉴别诊断模型

目的构建基于临床特征及血液指标的单双相抑郁鉴别诊断模型。方法分别纳入单相抑郁和双相抑郁受试者,回顾性收集受试者的临床数据及血常规、血生化检测指标。将数据随机分为训练集和测试集。基于不同的特征组合在训练集中采用极端梯度提升法(eXtreme gradient boosting,XGBoost)进行分类模型训练,并在测试集上验证模型的性能,采用受试者操作特征(receiver operating characteristic,ROC)曲线下面积(area under curve,AUC)、敏感性、特异性和准确率进行模型效能评价,使用SHapley加法移植计算所选特征对单双相抑郁鉴别诊断的重要性。结果本研究共纳入1160例受试者,其中918例为单相抑郁,242例为双相抑郁。构建单双相抑郁分类模型,其中基于临床特征、血常规指标和生化指标的XGBoost模型的效能最佳,其AUC为0.889,敏感性为0.831,特异性为0.839,准确率为0.863。该模型中的主要特征包括病程、发病年龄、血清白蛋白、低密度脂蛋白、血钾浓度、白细胞计数、血小板/淋巴细胞比值和单核细胞。结论病程特征和血液学生物标志物等容易在临床中获得的指标可对单相抑郁与双相抑郁的鉴别诊断提供重要支持。

一种适用于介质阻挡放电负载的简易型单极性正向脉冲式供电电源

针对常用的负载谐振型波形连续式的供电电源无法充分发挥介质阻挡放电负载的性能,以及现有脉冲式供电电源拓扑结构比较复杂的不足,提出了一种由1个功率开关管、2个二极管和1个耦合电感构成的单极性正向脉冲式供电电源。通过对该供电电源工作模态的分析得出,该供电电源不仅能为介质阻挡负载提供快速上升的脉冲电压,而且功率器件工作于软开关状态。仿真和实验结果验证了该供电电源的可行性,所提出的单极性正向脉冲式供电电源对现有的介质阻挡放电负载的供电电源的升级改造有一定的借鉴意义。

Grey matter volume abnormalities in patients with bipolar I depressive disorder and unipolar depressive disorder:a voxelbased morphometry study

Bipolar disorder and unipolar depressive disorder（UD） may be different in brain structure. In the present study,we performed voxel-based morphometry（VBM） to quantify the grey matter volumes in 23 patients with bipolar I depressive disorder（BP1） and 23 patients with UD,and 23 age-,gender-,and educationmatched healthy controls（HCs） using magnetic resonance imaging. We found that compared with the HC and UD groups,the BP1 group showed reduced grey matter volumes in the right inferior frontal gyrus and middle cingulate gyrus,while the UD group showed reduced volume in the right inferior frontal gyrus compared to HCs. In addition,correlation analyses revealed that the grey matter volumes of these regions were negatively correlated with the Hamilton depression rating scores. Taken together,the results of our study suggest that decreased grey matter volume of the right inferior frontal gyrus is a common abnormality in BP1 and UD,and decreasedgrey matter volume in the right middle cingulate gyrus may be specifi c to BP1.

Unipolar electrogram in identification of successful targets for radiofrequency catheter ablation of focal atrial tachycardia

Objective To analyze the unipolar electrogram from successful and unsuccessful ablation sites of focal atrial tachycardia (AT), and to evaluate its value in the identification of successful targets.Methods Fifteen consecutive patients with focal AT were referred for radiofrequency catheter ablation (RFCA). Both unipolar (from the tip electrode of ablating catheter) and bipolar (from the distal pair of electrode of ablating catheter) electrograms were used to identify the ablation targets of focal AT.Results Successful ablation was echieved in 14 patients. Radiofrequency energy was delivered at a total of 27 sites. The bipolar electrograms associated with successful ablation sites showed earlier atrial deflection relative to P wave onset (36 ms±15 ms vs 30 ms±11 ms, P <0.05) than the electrograms associated with failed ablation sites. At the 14 successful ablation sites, the unipolar electrograms displayed a completely negative atrial wave (“QS” morphology ) beginning with intrinsic deflection. However, at the 13 unsuccessful ablation sites,a “rS” morphology of atrial wave was shown on the unipolar electrogram.Conclusion The “QS” morphology of the atrial wave on unipolar electrograms appears to represent a reliable marker for identifying the successful ablation targets of focal AT, with a high sensitivity and specificity .