5,441 research outputs found

    Skyrmion-skyrmion and skyrmion-edge repulsions in skyrmion-based racetrack memory

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    Magnetic skyrmions are promising for building next-generation magnetic memories and spintronic devices due to their stability, small size and the extremely low currents needed to move them. In particular, skyrmion-based racetrack memory is attractive for information technology, where skyrmions are used to store information as data bits instead of traditional domain walls. Here we numerically demonstrate the impacts of skyrmion-skyrmion and skyrmion-edge repulsions on the feasibility of skyrmion-based racetrack memory. The reliable and practicable spacing between consecutive skyrmionic bits on the racetrack as well as the ability to adjust it are investigated. Clogging of skyrmionic bits is found at the end of the racetrack, leading to the reduction of skyrmion size. Further, we demonstrate an effective and simple method to avoid the clogging of skyrmionic bits, which ensures the elimination of skyrmionic bits beyond the reading element. Our results give guidance for the design and development of future skyrmion-based racetrack memory.Comment: 15 pages, 6 figure

    Embedded Applications of MS-PSO-BP on Wind/Storage Power Forecasting

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    Higher proportion wind power penetration has great impact on grid operation and dispatching, intelligent hybrid algorithm is proposed to cope with inaccurate schedule forecast. Firstly, hybrid algorithm of MS-PSO-BP (Mathematical Statistics, Particle Swarm Optimization, Back Propagation neural network) is proposed to improve the wind power system prediction accuracy. MS is used to optimize artificial neural network training sample, PSO-BP (particle swarm combined with back propagation neural network) is employed on prediction error dynamic revision. From the angle of root mean square error (RMSE), the mean absolute error (MAE) and convergence rate, analysis and comparison of several intelligent algorithms (BP, RBP, PSO-BP, MS-BP, MS-RBP, MS-PSO-BP) are done to verify the availability of the proposed prediction method. Further, due to the physical function of energy storage in improving accuracy of schedule pre-fabrication, a mathematical statistical method is proposed to determine the optimal capacity of the storage batteries in power forecasting based on the historical statistical data of wind farm. Algorithm feasibility is validated by application of experiment simulation and comparative analysis

    Efficient Query-Based Attack against ML-Based Android Malware Detection under Zero Knowledge Setting

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    The widespread adoption of the Android operating system has made malicious Android applications an appealing target for attackers. Machine learning-based (ML-based) Android malware detection (AMD) methods are crucial in addressing this problem; however, their vulnerability to adversarial examples raises concerns. Current attacks against ML-based AMD methods demonstrate remarkable performance but rely on strong assumptions that may not be realistic in real-world scenarios, e.g., the knowledge requirements about feature space, model parameters, and training dataset. To address this limitation, we introduce AdvDroidZero, an efficient query-based attack framework against ML-based AMD methods that operates under the zero knowledge setting. Our extensive evaluation shows that AdvDroidZero is effective against various mainstream ML-based AMD methods, in particular, state-of-the-art such methods and real-world antivirus solutions.Comment: To Appear in the ACM Conference on Computer and Communications Security, November, 202

    固本益肺汤联合腹针治疗尘肺30例疗效观察

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    Objective: To observe the clinical effect of Guben Yifei decoction combined with acupoint sticking therapy on pneumoconiosis. Methods: 60 cases of pneumoconiosis with syndrome of deficiency of both lung and kidney were randomly divided into two groups. The two groups were treated with oxygen, anti fibrosis, antiasthmatic, expectorant, and so on for 15 days of a course. In addition to the treatment program of control group, the patients in treatment group were also treated with Guben Yifei decoction (1 doses /d, water decoction) combined with abdominal acupuncture therapy, 1 times /d, for two courses. Observation of patients with cough, sputum, asthma, pulmonary rales and other effects was made and paid attention to symptoms and signs, serum immunoglobulin and changes of blood oxygen saturation before and after the treatment. Results: symptoms, signs disappeared time and healing time, oxygen saturation, serum immunoglobulin were better than the control group (P < 0.05), there was significant difference (P < 0.05). Conclusions: The curative effect of Guben Yifei decoction combined with abdominal acupuncture therapy on pneumoconiosis is remarkable.目的  观察固本益肺汤联合穴位贴敷治疗尘肺的临床疗效。方法  将60例辨证为肺肾两虚型尘肺的患者随机分为两组,两组均予以吸氧,抗纤维化,平喘,化痰等治疗。两组均以15天为1个疗程。治疗组在对照组治疗方案基础上加固本益肺汤治疗,1剂/d,水煎服,同时联合腹针疗法,1次/d,连续治疗两个疗程。观察患者咳嗽、咳痰、喘憋、肺部罗音等疗效,同时观察治疗前后症状、体征、血氧饱和度、血清免疫球蛋白等变化情况。结果  治疗组在症状、体征消失时间及治愈时间、血氧饱和度、血清免疫球蛋白等方面均优于对照组(P<0.05),两组疗效比较,有显著性差异(P<0.05)。结果  固本益肺汤联合腹针疗法治疗尘肺疗效显著

    苦碟子联合低分子肝素钙治疗急性脑梗死疗效观察

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    Objective:  to evaluate combinative effect of Kudiezi Injection and low molecular weight heparin calcium in the treatment of acute cerebral infarction. Methods:  72 cases of acute cerebral infarction were randomly divided into two groups, the treatment group of 36 cases were treated with the combination of Kudiezi Injection and low molecular heparin calcium; the other 36 cases in the control group were treated with the combination of Xuesaitong injection and low molecular weight heparin calcium. The degree of neurological deficit score and clinical outcome were respectively evaluated before and after treatment. Results:  There are significant differences between the treatment group and the control group in results efficiency. Conclusion:  It can improve the curative effect and the prognosis of the patients in the acute stage of cerebral infarction in the combinative treatment of Kudiezi Injection and low molecular weight heparin.目的 评价苦碟子注射液联合低分子肝素钙治疗急性脑梗死的临床效果及护理方法。方法 将72例急性脑梗死患者随机分为两组,治疗组36例用苦碟子联合低分子肝素钙治疗;对照组36例用血塞通注射液联合低分子肝素钙治疗。治疗前后分别进行神经功能缺损程度评分以及临床疗效评定[5]。结果 治疗组显效率与对照组比较差异有非常显著性(P=0.009)。结论 对急性期脑梗死患者在常规治疗基础上加用苦碟子及低分子肝素钙可显著提高疗效,改善患者预后。

    A Review of Nontraditional Biomanipulation

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    The aim of this review is to identify problems, find general patterns, and extract recommendations for successful management using nontraditional biomanipulation to improve water quality. There are many obstacles that prevent traditional biomanipulation from achieving expectations: expending largely to remove planktivorous fish, reduction of external and internal phosphorus, and macrophyte re-establishment. Grazing pressure from large zooplankton is decoupled in hypereutrophic waters where cyanobacterial blooms flourish. The original idea of biomanipulation (increased zooplankton grazing rate as a tool for controlling nuisance algae) is not the only means of controlling nuisance algae via biotic manipulations. Stocking phytoplanktivorous fish may be considered to be a nontraditional method; however, it can be an effective management tool to control nuisance algal blooms in tropical lakes that are highly productive and unmanageable to reduce nutrient concentrations to low levels

    Impact of the tissue factor pathway inhibitor gene on apoptosis in human vascular smooth muscle cells

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    Tissue factor pathway inhibitor (TFPI) plays a vitally important role in the blood coagulation pathway. Recent studies indicated that TFPI induces apoptosis in vascular smooth-muscle cells (VSMCs) in animals. The present study investigated whether the TFPI gene could also induce apoptosis in human vascular smooth-muscle cells (hVSMCs). Such cells were isolated from human umbilical arteries and subsequently transfected with pIRES-TFPI plasmid (2 μg/mL). MTT assaying and cell counting were applied to measure cell viability and proliferation, RT-PCR was utilized to analyze TFPI gene expression in the cells. Apoptosis was analyzed by fluorescence activated cell sorting (FACS). Several key proteins involved in apoptosis were examined through Western blotting. It was shown that TFPI gene transfer led to its increased cellular expression, with a subsequent reduction in hVSMC proliferation. Further investigation demonstrated that TFPI gene expression resulted in lesser amounts of procaspase-3, procaspase-8 and procascase-9, and an increased release of mitochondrial cytochrome c (cyt-c) into cytoplasm, thereby implying the involvement of both extrinsic and intrinsic pathways in TFPI gene-induced apoptosis in hVSMCs

    Static Semantics Reconstruction for Enhancing JavaScript-WebAssembly Multilingual Malware Detection

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    The emergence of WebAssembly allows attackers to hide the malicious functionalities of JavaScript malware in cross-language interoperations, termed JavaScript-WebAssembly multilingual malware (JWMM). However, existing anti-virus solutions based on static program analysis are still limited to monolingual code. As a result, their detection effectiveness decreases significantly against JWMM. The detection of JWMM is challenging due to the complex interoperations and semantic diversity between JavaScript and WebAssembly. To bridge this gap, we present JWBinder, the first technique aimed at enhancing the static detection of JWMM. JWBinder performs a language-specific data-flow analysis to capture the cross-language interoperations and then characterizes the functionalities of JWMM through a unified high-level structure called Inter-language Program Dependency Graph. The extensive evaluation on one of the most representative real-world anti-virus platforms, VirusTotal, shows that \system effectively enhances anti-virus systems from various vendors and increases the overall successful detection rate against JWMM from 49.1\% to 86.2\%. Additionally, we assess the side effects and runtime overhead of JWBinder, corroborating its practical viability in real-world applications.Comment: Accepted to ESORICS 202

    Topological triply-degenerate point with double Fermi arcs

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    Unconventional chiral particles have recently been predicted to appear in certain three dimensional (3D) crystal structures containing three- or more-fold linear band degeneracy points (BDPs). These BDPs carry topological charges, but are distinct from the standard twofold Weyl points or fourfold Dirac points, and cannot be described in terms of an emergent relativistic field theory. Here, we report on the experimental observation of a topological threefold BDP in a 3D phononic crystal. Using direct acoustic field mapping, we demonstrate the existence of the threefold BDP in the bulk bandstructure, as well as doubled Fermi arcs of surface states consistent with a topological charge of 2. Another novel BDP, similar to a Dirac point but carrying nonzero topological charge, is connected to the threefold BDP via the doubled Fermi arcs. These findings pave the way to using these unconventional particles for exploring new emergent physical phenomena

    Wide input-voltage range boost three-level DC-DC converter with quasi-Z source for fuel cell vehicles

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    To solve the problem of the mismatched voltage levels between the dynamic lower voltage of the fuel cell stack and the required constant higher voltage (400V) of the DC link bus of the inverter for fuel cell vehicles, a Boost three-level DC-DC converter with a diode rectification quasi-Z source (BTL-DRqZ) is presented in this paper, based on the conventional flying-capacitor Boost three-level DC-DC converter. The operating principle of a wide range voltage-gain for this topology is discussed according to the effective switching states of the converter and the multi-loop energy communication characteristic of the DRqZ source. The relationship between the quasi-Z source net capacitor voltages, the modulation index and the output voltage, is deduced and then the static and dynamic self-balance principle of the flying-capacitor voltage is presented. Furthermore, a Boost three-level DC-DC converter with a synchronous rectification quasi-Z source (BTL-SRqZ) is additionally proposed to improve the conversion efficiency. Finally, a scale-down 1.2 kW BTL-SRqZ prototype has been created, and the maximum efficiency is improved up to 95.66% by using synchronous rectification. The experimental results validate the feasibility of the proposed topology and the correctness of its operating principles. It is suitable for the fuel cell vehicles
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