Tailoring of Bandgap and Spin-Orbit Splitting in ZrSe_(2) with Low Substitution of Ti for Zr

Tuning the bandgap in layered transition metal dichalcogenides(TMDCs) is crucial for their versatile applications in many fields. The ternary formation is a viable method to tune the bandgap as well as other intrinsic properties of TMDCs, because the multi-elemental characteristics provide additional tunability at the atomic level and advantageously alter the physical properties of TMDCs. Herein, ternary Ti_(x)Zr_(1-x)Se_(2) single crystals were synthesized using the chemical-vapor-transport method. The changes in electronic structures of ZrSe_(2) induced by Ti substitution were revealed using angle-resolved photoemission spectroscopy. Our data show that at a low level of Ti substitution, the bandgap of Ti_(x)Zr_(1-x)Se_(2) decreases monotonically, and the electronic system undergoes a transition from a semiconducting to a metallic state without a significant variation of dispersions of valence bands. Meanwhile, the size of spin-orbit splitting dominated by Se 4p orbitals decreases with the increase of Ti doping. Our work shows a convenient way to alter the bandgap and spin-orbit coupling in TMDCs at the low level of substitution of transition metals.

基于双路径网络的端到端肺结节检测模型

为解决肺结节检测方法复杂、耗时且存在检测结果假阳性率高的问题,提出基于双路径网络(daul-path network,DPN)的肺结节自动检测模型。使用DPN自动提取深度特征,结合残差网络和密集连接网络实现特征复用;候选框提取使用三维编码解码网络结构,融合结节空间信息和上下文信息准确定位结节位置,生成多尺度候选框;将网络嵌入基于区域的全卷积网络框架中对结节实现分类。实验结果表明,该算法有效提高了结节检出率和检测速度,灵敏度达到90.5%,一个序列的肺部CT图像的处理时间为5.9 s。

Development of 19-plex Y STR system and polymorphism studies in Pakistani population

For the development of 19-plex Y STR system and polymorphism studies in local ethnic populations sixteen markers of non-recombining regions (NRY) of Y chromosome, which show high power of discrimination among individuals, were selected in this study. Blood samples (600) were collected from the males of three most common castes of Pakistani population (Arain, Awan and Rajput) with different parent lineages. Three markers (DYS385a/b, DYS389I/II and YCAIIa/b) among 16 Y STRs are double-targeted regions of the Y chromosome and thus provide two polymorphic peaks for each respective primer set. These 16 Y-STRs were developed into Megaplex system for simultaneous amplification of all markers within the population. The overall power of discrimination observed in focused populations was 60.5%, 66.5% and 55% in Rajput, Awan and Arain casts respectively. This discrimination power will be helpful in human identification for forensic casework studies including sexual assaults and paternity testing.

Impact of risk management strategies on the credit risk faced by commercial banks of Balochistan

This study aims to identify risk management strategies undertaken by the commercial banks of Balochistan,Pakistan,to mitigate or eliminate credit risk.The findings of the study are significant as commercial banks will understand the effectiveness of various risk management strategies and may apply them for minimizing credit risk.This explanatory study analyses the opinions of the employees of selected commercial banks about which strategies are useful for mitigating credit risk.Quantitative data was collected from 250 employees of commercial banks to perform multiple regression analyses,which were used for the analysis.The results identified four areas of impact on credit risk management(CRM):corporate governance exerts the greatest impact,followed by diversification,which plays a significant role,hedging and,finally,the bank’s Capital Adequacy Ratio.This study highlights these four risk management strategies,which are critical for commercial banks to resolve their credit risk.

In situ trapped high-density single metal atoms within graphene： Iron-containing hybrids as representatives for efficient oxygen reduction

Atomically dispersed catalysts have attracted attention in energy conversion applications because their efficiency and chemoselectivity for special catalysis are superior to those of traditional catalysts. However, they have limitations owing to the extremely low metal-loading content on supports, difficulty in the precise control of the metal location and amount as well as low stability at high temperatures. We prepared a highly doped single metal atom hybrid via a single-step thermal pyrolysis of glucose, dicyandiamide, and inorganic metal salts. High-angle annular dark field-scanning transmission electron microscopy （HAADF-STEM） and X-ray absorption fine structure spectroscopy （XAFS） revealed that nitrogen atoms doped into the graphene matrix were pivotal for metal atom stabilization by generating a metal-Nx coordination structure. Due to the strong anchoring effect of the graphene matrix, the metal loading content was over 4 wt.% in the isolated atomic hybrid （the Pt content was as high as 9.26 wt.% in the Pt-doped hybrid）. Furthermore, the single iron-doped hybrid （Fe@N-doped graphene） showed a remarkable electrocatalytic performance for the oxygen reduction reaction. The peak power density was - 199 mW·cm-2 at a current density of 310 mA·cm-2 and superior to that of a commercial Pt/C catalyst when it was used as a cathode catalyst in assembled zinc-air batteries. This work offered a feasible approach to design and fabricate highly doped single metal atoms （SMAs） catalysts for potential energy applications.

Electron doping induced semiconductor to metal transitions in ZrSe2 layers via copper atomic intercalation

Atomic intercalation in two-dimensional （2D） layered materials can be used to engineer the electronic structure at the atomic scale and generate tuneable physical and chemical properties which are quite distinct in comparison with the pristine material. Among them, electron-doped engineering induced by intercalation is an efficient route to modulate electronic states in 2D layers. Herein, we demonstrate a semiconducting to metallic phase transition in zirconium diselenide （ZrSe2） single crystals via controllable incorporation of copper （Cu） atoms. Our angle resolved photoemission spectroscopy （ARPES） measurements and first-principles density functional theory （DFT） calculations dearly revealed the emergence of conduction band dispersion at the M/L point of the Brillouin zone due to Cu-induced electron doping in ZrSe2 interlayers. Moreover, electrical measurements in ZrSe2 revealed semiconducting behavior, while the Cu-intercalated ZrSe2 exhibited a linear current-voltage curve with metallic character. The atomic intercalation approach may have high potential for realizing transparent electron-doping systems for many specific 2D-based nanoelectronic applications.

Phytochemical composition, biological potential and enzyme inhibition activity of Scandix pecten-veneris L.

Objective： Scandix pecten-veneris L. is a less studied wild edible herb and is considered an extinct plant species in many parts of the world. This study was designed to evaluate its phytochemical composition and biological potential of S. pecten-veneris L. Methods： Phytochemicals including alkaloids, fiavonoids, polyphenols, and tannins were determined in extracts of S. pecten-veneris. Antioxidant activity was determined using 2,2-diphenyl-1- picrylhydrazyl （DPPH）, while reducing power was tested by ferric reducing/antioxidant power （FRAP） assay. Antimi- crobial activity against seven bacterial and four fungal strains was evaluated using agar well diffusion assay. Enzymes inhibition study was performed for urease, phosphodiesterase-I, and catalase-II. Results： S. pecten-veneris showed moderate antiradical activity and reducing potential of hydroxyl radicals to about 20% of the initial value. The antiox- idant activity of various extracts of S. pecten-veneris showed a linear correlation with total phenolic contents in the order of water〉n-butanol〉chloroform〉ethyl acetate〉methanol extracts. S. pecten-veneris leaves showed the highest inhibitory activity against Staphylococcus aureus while the highest antifungal activity was observed against Candida albicans. The plant extract was most potent against urease enzymes but showed moderate activity against phosphodiestrase-I and carbonic anhydrase-II. Conclusions： Our data demonstrate that in addition to its culinary uses, S. pecten-veneris has good medicinal potential and hence could be used for treating some specific health ailments.