Frustrated Altermagnetism and Charge Density Wave in Kagome Superconductor CsCr3Sb5

Using first-principles density-functional calculations, we investigate the electronic structure and magnetism of the kagome superconductor CsCr$_3$Sb$_5$. At the ambient pressure, its ground state is found to be $4\times2$ altermagnetic spin-density-wave (SDW) pattern, with an averaged effective moment of $\sim$1.7$\mu_B$ per chromium atom. The magnetic long range order is coupled to the lattice structure, generating 4$a_0$ structural modulation. However, multiple competing SDW phases are present and energetically very close, suggesting strong magnetic fluctuation and frustration. The electronic states near the Fermi level are dominated by Cr-3d orbitals, and flat band or van Hove singularities are away from the Fermi level. When external pressure is applied, the energy differences between competing orders and the structural modulations are suppressed by external pressure. The magnetic fluctuation remains present and important at high pressure because the non-magnetic phase is unstable up to 30 GPa. In addition, a bonding state between Cr-3d$_{xz}$ and Sb$^{\mathrm{II}}$-p$_z$ quickly acquires dispersion and eventually becomes metallic around 5 GPa, leading to a Lifshitz transition. Our findings strongly support unconventional superconductivity in the CsCr$_3$Sb$_5$ compound above 5 GPa, and suggest crucial role of magnetic fluctuations in the pairing mechanism

Research 3D location technique using wireless sensor networks

The rapid progress of wireless communication and the availability of many small-sized, light-weighted and low-cost communication and computing devices nowadays have greatly impacted the research and development of wireless sensor networks. Target localization using wireless sensor network has attracted much attention for its comparable low cost and great number of possible applications with monitoring and targeting purposes. This paper will discuss the characteristics of wireless sensor network three dimensional grid-based localization techniques in details from the simulation results obtained from different models. The discussion will be carried out in both ideal cases and the actual cases with localization error. The robustness of the implemented algorithm will also be justified based on the comparison of the simulation results between these two categories.Bachelor of Engineerin

Spectral Index for Mapping Topsoil Organic Matter Content Based on ZY1-02D Satellite Hyperspectral Data in Jiangsu Province, China

Estimation of soil organic matter content (SOMC) is essential for soil quality evaluation. Compared with traditional multispectral remote sensing for SOMC mapping, the distribution of SOMC in a certain area can be obtained quickly by using hyperspectral remote sensing data. The Advanced Hyper-Spectral Imager (AHSI) onboard the ZY1-02D satellite can simultaneously obtain spectral information in 166 bands from visible (400 nm) to shortwave infrared (2500 nm), providing an important data source for SOMC mapping. In this study, SOMC-related spectral indices (SIs) suitable for this satellite were analyzed and evaluated in Shuyang County, Jiangsu Province. A series of SIs were constructed for the bare soil and vegetation-covered (mainly rice crops and tree seedlings) areas by combining spectral transformations (such as reciprocal and square root) and dual-band index formulas (such as ratio and difference), respectively. The optimal SIs were determined based on Pearson’s correlation coefficient (ρ) and satellite data quality, and applied to SOMC level mapping and estimation. The results show that: (1) The SI with the highest ρ in the bare soil area is the ratio index of original reflectance at 654 and 679 nm (OR-RI(654,679)), whereas the SI in the vegetation area is the square root of the difference between the reciprocal reflectance at 551 and 1998 nm (V-RR-DSI(551,1998)); (2) the spatial distribution trend of regional SOMC results obtained by linear regression models of OR-RI(654,679) and V-RR-DSI(551,1998) is consistent with the samples; (3) based on the optimal SIs, support vector machine and tree ensembles were used to predict the SOMC of bare soil and vegetation-covered areas of Shuyang County, respectively. The determination coefficient of the soil–vegetation combined prediction results is 0.775, the root mean square error is 3.72 g/kg, and the residual prediction deviation is 2.12. The results show that the proposed SIs for ZY1-02D satellite hyperspectral data are of great potential for SOMC mapping

The Influence of Hot Compression on the Surface Characteristics of Poplar Veneer

The surface characteristics of wood veneer are inevitably influenced by hot compression treatment, which is crucial to bonding ability in the production of veneer-based composites such as plywood and laminated veneer lumber (LVL). The objective of this study was to investigate the effect of compression at the temperature of 120 °C on the surface roughness, surface element compositions, and surface free energy (SFE) of poplar veneer. The results showed that the surface roughness of veneer decreased with increasing compression ratio (CR). X-ray photoelectron spectroscopy (XPS) analysis indicated that the oxygen to carbon atoms ratio (O/C ratio) of the veneer surface decreased, while the carbon C1 to C2 atoms ratio (C1/C2 ratio) increased due to hot compression. The SFE of veneer increased by 12% at the CR level of 11%. The improvement in wettability was mainly due to the interfacial contact area increase of the hydrophilic veneer and the decrease in hydrophobic air in the liquid-veneer interface as the CR level increased

Combined Effects of Land Use/Cover Change and Climate Change on Runoff in the Jinghe River Basin, China

In the context of global warming and intensified human activities, the quantitative assessment of the combined effects of land use/cover change (LUCC) and climate change on the hydrological cycle is crucial. This study was based on the simulation results of future climate and LUCC in the Jinghe River Basin (JRB) using the GFDL–ESM2M and CA–Markov combined with the SWAT models to simulate the runoff changes under different scenarios. The results revealed that the future annual precipitation and average temperature in the JRB are on the increase, and the future LUCC changes are mainly reflected in the increase in forest and urban lands and decrease in farmlands. Changes in runoff in the JRB are dominated by precipitation, and the frequency of extreme events increases with the increase in the concentration of CO2 emissions. Under four climate scenarios, the contribution of future climate change to runoff changes in the JRB is −8.06%, −27.30%, −8.12%, and +1.10%, respectively, whereas the influence of future LUCC changes is smaller, ranging from 1.14–1.64%. In response to the future risk of increasing water-resources stress in the JRB, the results of this study can provide a scientific basis for ecological protection and water-resources management and development

Robust Cubic-Based 3-D Localization for Wireless Sensor Networks

Copyright © 2013 Hnin Yu Shwe et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The rapid progress of wireless communication and the availability of many small-sized, light-weighted and low-cost communication and computing devices nowadays have greatly impacted the development of wireless sensor network. Localization using sensor network has attracted much attention for its comparable low-cost and potential use with mon-itoring and targeting purposes in real and hostile application scenarios. Currently, there are many available approaches to locating persons/things based on global positioning system (GPS) and radio-frequency identification (RFID) tech-nologies. However, in some application scenario, e.g., disaster rescue application, such localization devices may be damaged and may not provide the location information of the survivors. The main goal of this paper is to design and de-velop a robust localization technique for human existence detection in case of disasters such as earthquake or fire. In this paper, we propose a 3-D localization technique based on the hop-count data collected from sensor anchors to esti-mate the location of the activated sensor mote in 3-D coordination. Our algorithm incorporates two salient features, cu-bic-based output and event-triggering mechanism, to guarantee both improved accuracy and power efficiency. Both si-mulation and experimental results indicate that the proposed algorithm can improve the localization precision of the human existence and work well in real environment