Energy efficient HARQ scheme for wireless communication over block fading channel

Energy efficiency(EE) can be enhanced by retransmissions and combining in hybrid automatic repeat request(HARQ) system. However, it is difficult to optimize the transmit power of each retransmission when the accurate retransmission number and future channel state information(CSI) cannot be obtained. This paper proposes a simple energy efficient HARQ scheme for point-to-point wireless communication. In the proposed scheme, the conditional word error rate(WER) of each retransmission is fixed and the transmit power is adapted correspondingly. Three performance metrics are analyzed including average transmission number, throughput and EE. Compared with the conventional equal power HARQ scheme, the proposed scheme can significantly improve the EE and other two metrics under the same constraint of average transmit power or average energy consumption. Furthermore, it is found that, selecting a conditional WER which is slightly smaller than the optimal one is sufficient for practical implementation.     

基于TIN的露天矿区地形精细模型构建研究

准确构建露天矿区三维地形模型，客观反映露天矿在开采过程中的地形动态变化特征，对于提高露天矿生产管理效率和信息化水平具有重要意义。根据露天矿地形特点，提出了以凸壳算法为基础的建模方法。该方法中，以空间特征为约束条件构建三维地形精细模型。以三维地形精细模型为基准，针对地理信息软件ArcGIS中三维体积计算的局限性，提出了一种土方量计算的改进算法。以宝日希勒露天矿为例，结合矿区地形碎部点测绘数据，进行了三维地形精细模型构建。研究表明：该建模方法提升了三维地形模型的构建效率，同时以边为着眼点对三维地形模型进行优化，提高了模型的几何精度。通过对比分析不同时期露天矿三维地形模型的体积变化和形状变化情况，可为露天矿开采动态量化评估提供可靠依据。     

Insights into the cross-amyloid aggregation of Aβ40 and its N-terminal truncated peptide Aβ11-40 affected by epigallocatechin gallate

Inhibition of protein misfolding and aggregation is a great challenge in the field of biochemical and biopharmaceutical engineering. Alzheimer's disease (AD) is a protein-misfolding disease, and the interactions between 40-amino-acid-residue β-amyloid peptide (Aβ₄₀) and its N-terminal truncated peptide Aβ_11-40 demonstrate that Aβ_11-40 may play an important role in the pathological process of AD. However, the effect of inhibitors on Aβ_11-40 aggregation and on the cross-amyloid aggregation (co-assembly) between Aβ₄₀ and Aβ_11-40 has never been studied. Herein, coaggregation and seeding interactions between Aβ₄₀ and Aβ_11-40 as well as the effect of epigallocatechin gallate (EGCG), a small molecule inhibitor, on the cross-amyloid aggregation have been investigated by extensive analyses. It is found that Aβ_11-40 participates in the aggregation of Aβ₄₀ and leads to the formation of coaggregates that contain less β-sheet structures than pure Aβ₄₀ aggregates. The aggregation kinetics along with morphologies and secondary structures of the coaggregates are also significantly affected by the Aβ₄₀/Aβ_11-40 ratio. EGCG accelerates the nucleation of Aβ₄₀ but retards that of Aβ_11-40 by affecting their elongation and secondary nucleation processes in solution and on solid surfaces. Meanwhile, EGCG makes the conformations of the seeding-induced Aβ aggregates more compact, especially for the homologous seedings. Isothermal titration calorimetry measurement indicates that hydrophobic interactions mainly contribute to the inhibition of the two Aβ isoforms by EGCG. The findings of this research have provided new insights into Aβ aggregation and the effect of an important inhibitor and the results would benefit in the development of potent inhibitors against co-assembly of different amyloid proteins.     

An asymmetrically substituted dithieno[3,2-b:2',3'-d]pyrrole organic small-molecule hole-transporting material for high-performance perovskite solar cells

Hole-transporting materials play a vital role in terms of the performance of perovskite solar cells (PSCs). The dithieno[3,2-b:2',3'-d]pyrrole (DTP), an S,N-heterocyclic building block, has been proved to be desirable for molecular design of hole-transporting materials in PSCs. We developed an asymmetrically substituted DTP small-molecule (JW12) and a reference compound (JW11). The asymmetrical structure of JW12 leads to different absorption properties and electron distribution. The device in a planar n-i-p architecture using JW12 shows a much higher PCE (18.07%) than that based on JW11 (15.46%), which is also better than the device based on spiro-OMeTAD (17.47%). We hope our research can provide a new perspective in molecular design of organic HTMs for perovskite solar cells.     

N-Positive ion activated rapid addition and mitochondrial targeting ratiometric fluorescent probes for in vivo cell H2S imaging

Heterocyclic compound quinoline and its derivatives exist in natural compounds and have a broad spectrum of biological activity.They play an important role in the design of new structural entities for medical applications.Similarly,indoles and their derivatives are found widely in nature.Amino acids,alkaloids and auxin are all derivatives of indoles,as are dyes,and their condensation with aldehydes makes it easy to construct reaction sites for nucleophilic addition agents.In this work,we combine these two groups organically to construct a rapid response site(within 30 s)for H₂S,and at the same time,a ratiometric fluorescence response is presented throughout the process of H₂S detection.As such,the lower detection limit can reach 55.7 nmol/L for H₂S.In addition,cell imaging shows that this probe can be used for the mitochondrial targeted detection of endogenous and exogenous H₂S.Finally,this probe application was verified by imaging H₂S in nude mice.     

Genomic and metabolomic analysis of Bacillus licheniformis with enhanced poly-γ-glutamic acid production through atmospheric and room temperature plasma mutagenesis

Poly-γ-glutamic acid is an extracellular polymeric substance with various applications owing to its valuable properties of biodegradability, flocculating activity, water solubility, and nontoxicity. However, the ability of natural strains to produce poly-γ-glutamic acid is low. Atmospheric and room temperature plasma was applied in this study to conduct mutation breeding of Bacillus licheniformis CGMCC 2876, and a mutant strain M32 with an 11% increase in poly-γ-glutamic acid was obtained. Genome resequencing analysis identified 7 nonsynonymous mutations of ppsC encoding lipopeptide synthetase associated with poly-γ-glutamic acid metabolic pathways. From molecular docking, more binding sites and higher binding energy were speculated between the mutated plipastatin synthase subunit C and glutamate, which might contribute to the higher poly-γ-glutamic acid production. Moreover, the metabolic mechanism analysis revealed that the upregulated amino acids of M32 provided substrates for glutamate and promoted the conversion between L- and D-glutamate acids. In addition, the glycolytic pathway is enhanced, leading to a better capacity for using glucose. The maximum poly-γ-glutamic acid yield of 14.08 g·L^–1 was finally reached with 30 g·L^–1 glutamate.     

Ultrathin Zincophilic Interphase Regulated Electric Double Layer Enabling Highly Stable Aqueous Zinc-Ion Batteries

The practical application of aqueous zinc-ion batteries for large-grid scale systems is still hindered by uncontrolled zinc dendrite and side reactions. Regulating the electrical double layer via the electrode/electrolyte interface layer is an effective strategy to improve the stability of Zn anodes. Herein, we report an ultrathin zincophilic ZnS layer as a model regulator. At a given cycling current, the cell with Zn@ZnS electrode displays a lower potential drop over the Helmholtz layer(stern l...     

电流互感器的饱和对其暂态影响的仿真研究

在分析电流互感器原理基础上,利用MATLAB仿真软件中的PSB模块库建立了系统仿真模型并进行仿真.从仿真结果中,分析了电流互感器饱和机理以及对电流互感器暂态特性的影响.     

The application research of video server system for video on demand

A comprehensive research on key issues of the large-scale video server system for Video On Demand （VOD） client/server system is conducted based mainly on real time （rt）/non-real time （nrt） Variable Bit Rate or Constant Bit Rate （VBR/CBR） MPEG-2 MP@ML Signal Program Transport Stream （SPTS） for movies, and general architecture for storage, control, caching subsystems from Loosely Coupled Computer （LCC）, Symmetric Multiple Processing （SMP）, and Massively Parallel Processing （MPP） video server is conceptualized. Meanwhile, Redundant Array of Inexpensive Disks （RAID） storage system are presented and the centralized FCP/SAN huge storage technology is introduced in terms of its scalability, throughput, and connectivity performances.     

Coordinated restoration optimization of power-gas integrated energy system with mobile emergency sources

In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems.The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable suppl...