Neural correlates underlying humans’ differential sensitivity to emotionally negative stimuli of varying valences: an ERP study

The present study aims to investigate the neural correlates underlying humans’ sensitivity to valence differences in negative stimuli. Event-related potentials (ERPs) for highly negative (HN), moderately negative (MN), and Neutral pictures were recorded while subjects perform a standard/deviant categorization task, irrespective of the emotional valence of the deviants. The results show more negative ERP deflections during HN condition than during MN condition at each 50 ms interval from 350 to 650 ms after stimulus onset (at P3 and slow negative wave (SNW) components). Moreover, emotional effect was also observed for MN stimuli at P3 component (350—450 ms interval). Dipole analyses on the HN-MN difference wave during 350—450 ms interval (P3 component) and that during 450—650 ms interval (SNW component) were both localized to the right medial temporal lobe. Thus, the present study confirmed the human sensitivity to valence variations in emotionally negative stimuli, and further showed that the right medial temporal lobe, in particular, the right hippocampus/amygdala complex, may be the critical neural substrates underlying humans’ differential sensitivity to emotionally negative stimuli of varying valences.     

Ultrathin wavy nanowires of high-entropy alloy as cocktail solution in methanol oxidation reaction

High entropy alloys(HEAs) with adjustable composition and diverse surface active sites show good catalytic performance of methanol oxidation reaction(MOR). However, the synthesis and morphology control of HEA remains a challenge. Herein, we use a fast co-reduction method to synthesize a series of ultrathin wavy nanowires(WNWs) with an average diameter of 3–5 nm, including Pt-based and Pd-based binary alloys, and HEA with different pairs of immiscible elements. The catalytic properties of Pt Pd A...     

Different types of La Niña events and different responses of the tropical atmosphere

Historical La Nia events since 1950 are divided into Eastern Pacific(EP) type and Central Pacific(CP) type,and the SSTA developing features as well as the different responses of the tropical atmosphere are further analyzed by using multiple datasets.Classification of different types La Nia is based on the normalized Ni o3 and Ni o4 indices and the SSTA distribution pattern during the mature phase.The minimum negative SSTA for CP La Nia is located over the equatorial central Pacific near the dateline,more westward than that of EP La Nia.It has stronger intensity and larger east-west zonal difference of SSTA over the equatorial Pacific than EP La Nia.Influenced by the different SSTA distribution pattern,CP La Nia induces more westward location of the anomalous sinking motion and the anomalous low-level divergent and high-level convergent winds over the equatorial eastern Pacific.The different response of the tropical atmospheric circulation between EP and CP La Nia is more significant in the upper troposphere than in the lower troposphere.However,the tropical precipitation patterns during the mature phase of EP and CP La Nia are much similar,except the less(more) precipitation over the equatorial central Pacific(eastern Indian Ocean-western Pacific) during CP La Nia than during EP La Nia.     

混沌相位编码信号成像与反欺骗干扰仿真

混沌相位编码信号具有良好的自相关特性,又兼具有类随机信号的特点,这使得它们具有较强的电子反干扰(ECCM)能力.将基于logistic映射的混沌二相编码信号引入合成孔径雷达(SAR),在考虑距离徙动的情况下,对点目标成像和反欺骗干扰进行了仿真.结果表明混沌二相码可以成像,而且具有反欺骗干扰的性能.     

The Relevant Analysis on the Stop Time in Winter and Times of Plateau and the Index in Early Days for Garrisonned Plateau Constructors

1IntroductionThe constructors entering the plateau fromthehinterland,a series of compensation andadaptability and change in its organism will takeplace[1-5],because of the coldinfluence whichisshort of suchabominable environments as oxygen,low pressure,et…     

Relaxation of Deformed Austenite and Refinement of Bainite in a Nb-Containing Microalloyed Steel

By means of stress relaxation and strain-induced precipitation in deformed austenite, bainite with micron sheaves size was obtained in Nb-containing steel. Microstructures of deformed samples isothermally relaxed for various time followed by cooling in water were examined. Stress relaxation test and transmission electron microscopy (TEM) were employed to detect precipitation of microalloy elements, such as Nb, Ti, during isothermal holding after deformation. All the samples were constituted by lath-like bainite along with acicular ferrite, but the size of bainitic sheaves and the amount of acicular ferrite were changed with relaxation time. To achieve optimum refinement, relaxation should be confined in the stage when the precipitates have sufficiently grown and started to coarsen. The sample having not undergone relaxation does not exhibit obvious refinement despite of its higher dislocation density. These results indicate that relaxation promotes bainite to refine, which is because deformed austenitic grains are divided by dislocation walls formed during relaxation and acicular ferrite formed before bainitic transformation.     

A Special TMCP Used to Develop a 800MPa Grade HSLA Steel

The effect of relaxation after finished rolling on structures and properties of four microalloyed steel with different content of Nb and Ti was investigated. By alloy designing and control rolling + relaxation-precipitation-control phase trail storm ati on (RPC) process, a new 800 MPa grade HSLA plate steel could be obtained, the microstructure is composite ultra-fine lath bainite/martensite. The tempering process and mechanical properties of this kind of HSLA steel were investigated. The yield strength can achieve 800 MPa, and the ductility and impact toughness is satisfied.     

Dissolving of Nb and Ti carbonitride precipitates in microalloyed steels

The dissolving behaviour of Nb and Ti carbonitride precipitates in microalloyed steels during isothermal holding at 1300℃ was investigated by Transmission electron microscopy (TEM) and energy dispersion x-ray spectrum (EDX). It was found that all precipitates in Nb-Ti microalloyed steel are (Nb, Ti)(C,N). With holding time increasing, the atomic ratio of Nb/Ti in precipitates decrease gradually. These precipitates still existe even after holding for 48 h at 1300℃ while Nb(C,N) precipitates dissolve away in Nb microalloyed steel only after 4 h at the same temperature. These results show that formation and thermostability of precipitates are considerably influenced by interaction between Nb and Ti.     

Effect of tempering temperature on the mechanical properties and microstructure of an copper-bearing low carbon bainitic steel

The effect of tempering temperature on the microstructure and mechanical properties of ultra-high strength, copperbearing, low-carbon bainitic steel has been investigated in the experiment. The results showed that the microstructure was mainly the laths of bainite in the as-quenched steel. The bainitic laths were restored and combined after the steel tempered at various temperatures. There were rnartensite/austenite (M/A) islands and numerous dislocations within and between the bainitic laths, while very t-me precipitates of ε-Cu were also observed within the laths. With increasing the tempered temperature from 400 to 600℃, the yield strength (YS) increased from 877 to 957 MPa, whereas the ultimate tensile strength (UTS) decreased from 1020 to 985 MPa. The Charpy V-notch (CVN) varied from 68.5 to 42 J, and the value was minimal for the steel tempered at 500℃.     

Theoretical and experimental analysis on the mechanism of the Kaiser effect of acoustic emission in brittle rocks

The Kaiser effect is formally described as the absence of detectable acoustic emission (AE) events until the load imposed on the material exceeds the previous applied level and is usually used to estimate geostress. By focusing on the heterogeneity of rock material, the mechanism of the Kaiser effect under cyclic loading is analyzed based on statistic damage mechanics. Two groups of granite specimens have been cyclically loaded with two different loading paths to verify the theoretical results. The heterogeneity of rock is the real reason that causes irrecoverable damage on the Kaiser effect of acoustic emission in cyclic loading. The Kaiser effect reflects the damaged state in rocks rather than the previous stress imposed on it. Applications for using the Kaiser effect to estimate geostress were discussed here. It is shown that the commonly used uniaxial loading method for estimating geostress is not in accor-dance with the theoretical and experimental results. The analysis is of importance to use the Kaiser effect correctly for estimating geostress or in other fields.