MAVEN observation of magnetosonic waves in the Martian magnetotail region

Magnetosonic waves are an important medium for energy transfer in collisionless space plasma.Magnetosonic waves have been widely investigated in the upstream of the bow shock at Mars.These waves are believed to originate from pickup ions or reflected particles.By utilizing MAVEN spacecraft data,we have observed the occurrence of quasi-perpendicularly propagating magnetosonic emissions near the proton gyrofrequency in the Martian magnetotail region.These plasma waves are associated with a significant enhancement of proton and oxygen flux.The excited magnetosonic waves could possibly heat the protons through resonance and facilitate the ionospheric plasma escape.Our results could be helpful to better understand the Mars’magnetospheric dynamics and offer insights into possible energy redistribution between waves and plasma in the Martian nightside magnetosphere.

Inorganic Colloidal Electrolyte for Highly Robust Zinc‑Ion Batteries

Zinc-ion batteries(ZIBs)is a promising electrical energy storage candidate due to its eco-friendliness,low cost,and intrinsic safety,but on the cathode the element dissolution and the formation of irreversible products,and on the anode the growth of dendrite as well as irreversible products hinder its practical application.Herein,we propose a new type of the inorganic highly concentrated colloidal electrolytes(HCCE)for ZIBs promoting simultaneous robust protection of both cathode/anode leading to an effective suppression of element dissolution,dendrite,and irreversible products growth.The new HCCE has high Zn^(2+)ion transference number(0.64)endowed by the limitation of SO4^(2−),the competitive ion conductivity(1.1×10^(–2) S cm^(−1))and Zn2+ion diffusion enabled by the uniform pore distribution(3.6 nm)and the limited free water.The Zn/HCCE/α-MnO2 cells exhibit high durability under both high and low current densities,which is almost 100%capacity retention at 200 mA g^(−1) after 400 cycles(290 mAh g^(−1))and 89%capacity retention under 500 mA g^(−1) after 1000 cycles(212 mAh g^(−1)).Considering material sustainability and batteries’high performances,the colloidal electrolyte may provide a feasible substitute beyond the liquid and all-solid-state electrolyte of ZIBs.

Study on the Physiological,Cellular,and Morphological Aspects of the Postharvest Development of Cut Lily Flowers

It is of great practical significance to study the development process of cut lily for regulating flowering and preservation.In this study,the developmental process of lily cut flower was explored from cellular,morphological,and physiological aspects.Froma morphological aspect,the tepal edge grows faster than the midrib.The midrib groove of the flowering stage is wider than that of bud stage.The fast-growing edge of the petals results in the midrib bending outward.Moreover,the rapid growth of the stamens and stigmas also contributes to bud cracking.From the cellular aspect,in the bud stage there were more wrinkles in the outer epidermal cell wall of the tepal than those in the inner epidermal cell wall,indicating that asymmetric structural differences exist from the beginning of lily development.From a physiological aspect,from the bud cracking stage to the senescence stage,a variety of substances in the tepal cells gradually decreased,including total nitrogen,total phosphorus,total potassium,total calcium,starch,soluble sugar,and soluble protein,but not malondialdehyde.These results indicate that the asymmetric growth caused by this structural difference is responsible for flowering.The wrinkles in the cell wall can be regarded as indicators of senescent cells and are caused by the degradation of the cell wall and the loss of intracellular turgor pressure.The differences in the epidermal cells between the inner and outer tepal indicated ultrastructural changes in the tepal cells.The bud and flowering stages are maintained by the tepals acting as a sink.After flowering,the tepals gradually change from a sink to a source organ.Senescence of the cut lily flowers was caused by the decomposition of intracellular compounds in the tepals and the remobilization of nutrients from the tepals to the developing organs.

A local Martian crustal field model: Targeting the candidate landing site of the 2020 Chinese Mars Rover

Unlike Earth,Mars lacks a global dipolar magnetic field but is dominated by patches of a remnant crustal magnetic field.In 2021,the Chinese Mars Rover will land on the surface of Mars and measure the surface magnetic field along a moving path within the possible landing region of 20°W-50°W,20°N-30°N.One scientific target of the Rover is to monitor the variation in surface remnant magnetic fields and reveal the source of the ionospheric current.An accurate local crustal field model is thus considered necessary as a field reference.Here we establish a local crust field model for the candidate landing site based on the joint magnetic field data set from Mars Global Explorer(MGS)and Mars Atmosphere and Volatile Evolution(MAVEN)data combined.The model is composed of 1,296 dipoles,which are set on three layers but at different buried depths.The application of the dipole model to the joint data set allowed us to calculate the optimal parameters of their dipoles.The calculated results demonstrate that our model has less fitting error than two other state-of-the art global crustal field models,which would indicate a more reasonable assessment of the surface crustal field from our model.

Development Strategy of Soundscape in Rural Tourism Based on Tourist Perception:A Case Study of Some Villages in Jiangxi Province

In the context of the development of rural tourism,through the field investigation of several rural tourism destinations in Jiangxi,and from the perspective of tourist perception,this paper discusses the development strategy of soundscape in rural tourism,so as to promote the inheritance and development of rural soundscape design.

Discussion on pile axial load test methods and their applicability in cold regions

The measurement of pile axial load is of great significance to determining pile foundation design parameters such as skin friction and end bearing capacity and analyzing load transfer mechanisms.Affected by the temperature and ice content of frozen ground,the interface contact relationship between pile foundation and frozen soil is complicated,making pile axial load measurements more uncertain than that in non-frozen ground.Therefore,it is necessary to gain an in-depth understanding of the current pile axial load test methods.Four methods are systematically reviewed:vibrating wire sensors,strain gauges,sliding micrometers,and optical fiber strain sensors.At the same time,the applicability of the four test methods in frozen soil regions is discussed in detail.The first two methods are mature and commonly used.The sliding micrometer is only suitable for short-term measurement.While the Fiber Bragg grating(FBG)strain gauge meets the monitoring requirements,the Brillouin optical time-domain reflectometer(BOTDR)needs further verification.This paper aims to provide a technical reference for selecting and applying different methods in the pile axial load test for the stability study and bearing capacity assessment of pile foundations in cold regions.

我国未来在轨监测火星沙尘暴的设想和方案

火星是地球的近邻,它的自转周期(约为24.6 h)及自转倾角(约为25°)都与地球的接近.火星公转周期为687 d,有稀薄的大气(主要成分为CO_(2)),有四季交替的气候变化,表面温度(夏天)最高时可达20°C.火星两极被冰(干冰和水冰的混合物)所覆盖,并有着消融和冰冻的季节周期变化.火星表面布满河道、峡谷、沟壑、冲积平原等地貌特征.在太阳系行星系统中,火星的气候环境最为接近地球.

Integrated bioinformatics identifies the dysregulation induced by aberrant gene methylation in colorectal carcinoma

Colorectal carcinoma(CRC)is one of the most common cancers,and is associated with a poor dlinical outcome.The key genes and potential prognostic markers in colorectal carcinoma remain to be identfed and explored for clinical application.DNA expression/methyl-ation profles were downloaded from the Gene Expression Omnibus(GEO)database to identify differentially expressed/methylated genes(DEGs and DEMs).A total of 255 genes and 372 genes were identified as being up-regulated and down-regulated,respectively,in GSE113513,GSE81558,and GSE89076.There were a total of 3350 hypermethylated genes and 443 hypomethylated genes identifed in GSE 48684.Twenty genes were found to be hypermethylated as well as down-regulated,and a functional enrichment analysis revealed that these genes were mainly involved in cancer-related pathways.Among these 20 genes,GPM6A,HAND2 and C2orf40 were related to poor outcomes in cancer patients based on a survival analysis.Concurrent decreases of GPM6A,HAND2 and C2orf40 protein expression were observed in highly-dif ferentiated colorectal carcinoma tissues,and higher expression levels were found in undifferentiated or minimally-differentiated colorectal carcinoma tissues.In conclusion,20 genes were found to be downregulated and hypermethylated in CRC,among which GPM6A,HAND2 and C2orf40 were explored for their potential prognostic value.