Dynamical behaviors in discrete memristor-coupled small-world neuronal networks

The brain is a complex network system in which a large number of neurons are widely connected to each other and transmit signals to each other.The memory characteristic of memristors makes them suitable for simulating neuronal synapses with plasticity.In this paper,a memristor is used to simulate a synapse,a discrete small-world neuronal network is constructed based on Rulkov neurons and its dynamical behavior is explored.We explore the influence of system parameters on the dynamical behaviors of the discrete small-world network,and the system shows a variety of firing patterns such as spiking firing and triangular burst firing when the neuronal parameterαis changed.The results of a numerical simulation based on Matlab show that the network topology can affect the synchronous firing behavior of the neuronal network,and the higher the reconnection probability and number of the nearest neurons,the more significant the synchronization state of the neurons.In addition,by increasing the coupling strength of memristor synapses,synchronization performance is promoted.The results of this paper can boost research into complex neuronal networks coupled with memristor synapses and further promote the development of neuroscience.

Preliminary analysis of the shear-wave splitting observations from the Qiaojia seismic array

A total of 351 shear-wave splitting results at 25 stations were obtained from the seismic data recorded in period of January,2013 to December,2016,by a broadband seismic array deployed in the northern segment of Xiaojiang Fault Zone(n-XJFZ).Meanwhile,the stress field of the n-XJFZ was determined by inverting 140 focal mechanism solutions of the small earthquakes within the study area which were recorded in the same period.This determination confirmed a compressive stress in NW-SE orientation and an extensional stress in the NE-SW orientation,with little difference from those released by previous studies.The shear-wave splitting results show a spatial complexity in polarization orientation,different from one site to another.How-ever,the polarization orientations integrated for the subareas suggest that the fault trends seemingly played important roles.All the subareas bear two dominant orientations,N10°E and N90°E,both of which are different from the azimuths of the principal compressive stress,due to the fault distribution.The time delay averaged over the entire region is 4.56 ms/km,close to that of the upper boundary of the generally accepted interval worldwide but larger than those in most of the investigated regions in the Chinese mainland,which probably implies an alignment of more micro-cracks in the n-XJFZ.Interestingly,the 2014 Ms6.5 Ludian earthquake was found to have caused a variation in the time delays of the slow shear waves within the study area though its epicenter was outside.This earthquake resulted in an evident drop of the time delays remaining for 4 months,however,lifted a bit the time-delay level with respect to that prior to the earthquake.

Shadow–highlight feature matching automatic small crater recognition using high-resolution digital orthophoto map from Chang’E Missions

This paper introduces a new method of small lunar craters’ automatic identification, using digital orthophoto map(DOM) data. The core of the approach is the fact that the lunar exploration DOM data reveal contrasting highlight and shadow characteristics of small craters under sunlight irradiation. This research effort combines image processing and mathematical modeling. Overall it proposes a new planetary data processing approach, to segment and extract the highlight and shadow regions of small craters,using the image gray frequency(IGF) statistical method.IGF can also be applied to identify the coupling relationships between small craters’ shape and their relative features. This paper presents the highlight and shadow pair matching(HSPM) model which manages to perform highprecision automatic recognition of small lunar craters.Testing was performed using the DOM data of Chang’E-2(CE-2). The results have shown that the proposed method has a high level of successful detection rate. The proposed methodology that uses DOM data can complement the drawbacks of the digital elevation model(DEM) that has a relatively high false detection rate. A hybrid fusion model(FUM) that combines both DOM and DEM data, was carried out to simultaneously identify small, medium, and large-sized craters. It has been proven that the FUM generally shows stronger recognition ability compared to previous approaches and it can be adapted for high precision identification of craters on the whole lunar surface.The results meet the requirements for a reliable and accurate exploration of the Moon and the planets.

SEVAR: a stereo event camera dataset for virtual and augmented reality

Event cameras,characterized by their low latency,large dynamic range,and extremely high temporal resolution,have recently received increasing attention.These features make them particularly well-suited for virtual/augmented reality(VR/AR)applications.To facilitate the development of three-dimensional(3D)perception and navigation algorithms in VR/AR applications using event cameras,we introduce the Stereo Event camera dataset for Virtual and Augmented Reality(SEVAR),which comprises a wide variety of head-mounted indoor sequences,including scenarios with rapid motion and a large dynamic range.

Rice DENSE AND ERECT PANICLE 2 is essential for determining panicle outgrowth and elongation

包括谷物尺寸和圆锥花序形态学，圆锥花序的建筑学直接决定谷物产量。圆锥花序直立，为在中国的北部分完成理想的植物建筑学被选择，引起了米饭 breeders 的增加的注意。这里，稠密、直立的圆锥花序 2 (dep2 ) 异种，显示出稠密、直立的圆锥花序显型，被识别。没有任何已知的功能的领域， DEP2 编码植物特定的蛋白质。表示介绍 DEP2 表明它高度在年轻纸巾被表示，与在年轻圆锥花序的大多数丰富。词法并且表示分析显示在 DEP2 的那个变化主要影响脊柱和主要、第二等的分支的快速的延伸，但是不损害圆锥花序 primordia 的开始或形成。进一步的分析建议在 dep2 的圆锥花序长度的减少被一个缺点在圆锥花序的指数的延伸期间在房间增长引起。尽管有在 dep2 异种的一种更紧缩的植物类型，在谷物生产的重要改变都没在野类型和 dep2 异种之间被发现。因此， DEP2 的学习不仅加强我们圆锥花序建筑学的分子的基因基础的理解而且为米饭繁殖有重要含意。

The 2018 M_S 5.9 Mojiang Earthquake:Source model and intensity based on near-field seismic recordings

On September 8, 2018, an M_S 5.9 earthquake struck Mojiang, a county in Yunnan Province, China. We collect near-field seismic recordings(epicentral distances less than 200 km) to relocate the mainshock and the aftershocks within the first 60 hours to determine the focal mechanism solutions of the mainshock and some of the aftershocks and to invert for the finite-fault model of the mainshock.The focal mechanism solution of the mainshock and the relocation results of the aftershocks constrain the mainshock on a nearly vertical fault plane striking northeast and dipping to the southeast. The inversion of the finite-fault model reveals only a single slip asperity on the fault plane. The major slip is distributed above the initiation point, ～14 km wide along the down-dip direction and ～14 km long along the strike direction, with a maximal slip of ～22 cm at a depth of ～6 km. The focal mechanism solutions of the aftershocks show that most of the aftershocks are of the strike-slip type, a number of them are of the normal-slip type, and only a few of them are of the thrust-slip type.On average, strike-slip is dominant on the fault plane of the mainshock, as the focal mechanism solution of the mainshock suggests, but when examined in detail, slight thrust-slip appears on the southwest of the fault plane while an obvious part of normal-slip appears on the northeast, which is consistent with what the focal mechanism solutions of the aftershocks display. The multiple types of aftershock focal mechanism solutions and the slip details of the mainshock both suggest a complex tectonic setting, stress setting, or both. The intensity contours predicted exhibit a longer axis trending from northeast to southwest and a maximal intensity of Ⅷ around the epicenter and in the northwest.

Which velocity model is more suitable for the 2017 M_S7.0 Jiuzhaigou earthquake?

On Aug.8, 2017, an M_S 7.0 earthquake struck Jiuzhaigou, a county of Sichuan province, China. A number of investigations and studies have been conducted, some of which involved local velocity models. However, the suitability of these models has not been properly addressed. Here we collect 11 already-existing models, including those used in studies of the 2017 M_S 7.0 Jiuzhaigou earthquake,choose 10 local stations surrounding the earthquake, and employ the same technique(TRIT) to relocate the hypocenter. And furthermore, we choose a more suitable model from the 11 already-existed models by analyzing the relocation process and the relocated results for reasonability. Finally, our conclusion is that the model Fang 2018 is more suitable and the hypocenter parameters, 103.801°E,33.192°N and 15.8 km for longitude, latitude and depth, respectively, and 2017-08-08 13:19:46.66 for its origin time, based on this model should be recommended for the 2017 M_S7.0 Jiuzhaigou earthquake.

The payloads of planetary physics research onboard China’s First Mars Mission (Tianwen-1)

Mars is not only our nearby but also the most Earth-like planetary neighbor.Scientific exploration of Mars is thus of crucial value to our understanding of the solar system.The existence of abundant evidence for the former presence of water on Mars demands further exploration for signs of life on our sister planet,and investigations that could shed light on conditions favorable to the origin of life.For nearly 60 years,humans have conducted orbitally-based remote sensing and in-situ surface exploration of Mars,leading to many significant scientific discoveries.But much remains to be done before we can be sure that we truly and fully understand Mars.Key research topics include the history of water on Mars and how that history relates to the planet’s habitable environment-past,present,and future;the distribution and evolution of waterbearing and evaporative salt minerals on the planet’s surface;the history of volcanic activity on Mars;the Martian magnetic field and its effect on the escape of water and atmosphere from the planet;interactions between the solar wind and the Martian atmosphere and ionosphere;atmospheric characteristics and climate change on Mars;and so on(Li CL et al.,2018;Liu JJ et al.,2018).Based on the above scientific questions about life,climate,and geology on Mars,the international planetary science community has formulated ambitious Mars exploration programs.

Nomenclature for lunar features at the Chang＇e-3 landing site

Nomenclatures for lunar features always accompany the progresses of human lunar exploration,which has an important dual meaning in culture and science. The naming of lunar features not only can commemorate the outstanding contributions of academics,masters in various fields, and popularize the traditional cultures of ethnic groups all over the world, but also have a critical function of providing accurate indicative information on features with special morphology, origin, nature and scientific value. However, nomenclature for features at the Chang'e-3 landing site, which has a more arbitrary form without many constrains posed by a uniformed system, is unlike the features for other morphological units.This paper originated from the actual needs for the description of scientific exploration activities, interpretation of scientific research and dissemination of scientific results. Some prominent morphological units with great scientific importance and identification purpose were chosen from the images taken by the terrain camera, panorama cameras and landing camera onboard the Chang'e lander and Yutu rover. A nomenclature system was established under the three enclosures, four quadrants and twenty-eight lunar lodges' system of the Chinese ancient sky division method. Finally, a standard feature names set waspublished after some necessary approval procedures by the International Astronomical Union.

Innovative developments in lunar and planetary science promoted by China's lunar exploration

As the only natural satellite of the earth, the Moon has always been the first choice for human exploration of the solar system. China's lunar exploration project(Chang'e project) was launched in 2004. At present, it has created a perfect end to the three phases of “orbiting, landing and returning”. A series of remarkable research achievements have been made on the basic issues of current lunar scientific research, such as the Earth-Moon space environment, lunar surface material, morphology,geological structure, lunar subsurface and internal structure, and the origin and evolution of the Moon, further deepening the human understanding of the Moon. This paper briefly reviews the development process of China's lunar exploration project,summarizes the main research results and scientific understanding, and finally prospects to the future development of China's lunar and planetary exploration.

Optimal dispatch of zero-carbon-emission micro Energy Internet integrated with non-supplementary fired compressed air energy storage system

To utilize heat and electricity in a clean and integrated manner,a zero-carbon-emission micro Energy Internet(ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage(NSF-CAES) hub.A typical ZCE-MEI combining power distribution network(PDN) and district heating network(DHN) with NSF-CAES is considered in this paper.NSF-CAES hub is formulated to take the thermal dynamic and pressure behavior into account to enhance dispatch flexibility.A modified Dist Flow model is utilized to allow several discrete and continuous reactive power compensators to maintain voltage quality of PDN.Optimal operation of the ZCE-MEI is firstly modeled as a mixed integer nonlinear programming(MINLP).Several transformations and simplifications are taken to convert the problem as a mixed integer linear programming(MILP)which can be effectively solved by CPLEX.A typical test system composed of a NSF-CAES hub,a 33-bus PDN,and an 8-node DHN is adopted to verify the effectiveness of the proposed ZCE-MEI in terms of reducing operation cost and wind curtailment.

表面微结构研究揭示了太空风化作用下嫦娥5号月壤演化的中间阶段

月球土壤的组份和微结构会随时间推移发生明显变化,主要原因是其受到微陨石轰击、太阳风或宇宙射线中的带电粒子辐射等太阳风化作用.前期研究表明,太空风化会造成月壤样品表面形成50~200 nm厚的非晶层,层内包裹着大量2~10 nm的金属铁,但该类表面形貌和组成的起源仍存在争议.嫦娥5号取回的月壤样品属于最年轻的玄武岩,并且取样点的纬度最高,为理解月壤在太空风化作用下的演化规律提供了新的机会和线索.本文系统研究了月壤如铁橄榄石、辉石、长石和玻璃珠的表面形貌及化学组成.与以往报道不同的是,仅在铁橄榄石表面观察到了薄的SiO_(2)非晶层(厚度大约10 nm),发现其中包裹着2~12 nm的方铁矿FeO,并且没有观察到任何纳米金属铁颗粒.同时,在所研究的5种样品表面和内部,没有观察到任何易挥发的外来化学元素(如硫、氯等)和太阳耀斑穿过的痕迹.方铁矿FeO和表面微结构的确立暗示着本研究的月壤可能处于太阳风化所引起的热分解中间阶段.