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61.
Integer overflow vulnerability will cause buffer overflow. The research on the relationship between them will help us to detect integer overflow vulnerability. We present a dynamic analysis methods RICB (Run-time Integer Checking via Buffer overflow). Our approach includes decompile execute file to assembly language; debug the execute file step into and step out; locate the overflow points and checking buffer overflow caused by integer overflow. We have implemented our approach in three buffer overflow types: format string overflow, stack overflow and heap overflow. Experiments results show that our approach is effective and efficient. We have detected more than 5 known integer overflow vulnerabilities via buffer overflow.  相似文献   
62.
63.
对In(0.2)Ga(0.8)As/GaAs应变多量子阱在77K下的光调制反射谱(PR)和热调制反射谱(TR)进行了实验研究.对PR结果的线形拟合指认了应变多量子阱中子能级的跃迁,并与理论计算结果作了比较.实验对比确认PR中11H、13H等跃迁结构为非耦合态、具有电场调制机构的一阶微商性质.而11L、31H、22H等跃迁结构为阶间耦合态,对这些隧穿耦合的低场调制产生三阶微商特性.  相似文献   
64.
将表面增强激光拉曼技术(SERS)作为探针引入光敏损伤的研究。利用这种新的光谱方法研究了新光敏剂铝酞菁对几种核酸碱基分子的光敏损伤过程,发现G(乌嘌呤)对光敏化的敏感性最强,A(腺嘌呤)其次,C(胞嘧啶)和U(尿嘧啶)则不敏感。实验证实,是铝酞菁的光动力反应产物单线态氧,在核酸碱基的光敏损伤中起主要作用。  相似文献   
65.
The proposal herein is based on an efficient sulfur host, namely hierarchical microporous–mesoporous carbonaceous nanotubes (denoted as HMMCNT) that feature a thick microporous wall and inner hollow channel. The electrochemical performance of the composite (HMMCNT‐S) is studied systematically at different discharge cut‐off voltages and at varying sulfur content. The cycling behavior in different voltage windows is compared and the highest specific capacity is shown for HMMCNT‐S‐50 in the range of 1.4–2.8 V. These results imply that better energy densities can be achieved by controlling the discharge cut‐off voltage. Moreover, we show that when the sulfur loading is 50% (HMMCNT‐S‐50), the cycling and rate performance is better than that of the composite loaded with 40% sulfur (HMMCNT‐S–40). Benefiting from the attractive hierarchical micro/mesoporous configuration, the obtained hybrid structure not only promotes electron and ion transfer during the charge/discharge process, but also efficiently impedes polysulfide dissolution. More specifically, the electrode can deliver a specific capacity of 558 mA h g‐1 even after 150 cycles at a high rate of 1600 mA g‐1 with a decay rate of only 0.13% per cycle. Considering the beneficial structure of these carbon nanotubes, it is very feasible that these structures may also be used in other research fields, including in catalysis, as supercapacitors, in drug‐delivery applications, for absorption, and so on.  相似文献   
66.
An ideal craniofacial bone repair graft shall not only focus on the repair ability but also the regeneration of natural architecture with occlusal loads-related function restoration. However, such functional bone tissue engineering scaffold has rarely been reported. Herein, a hierarchical 3D graft is proposed for rebuilding craniofacial bone with both natural structure and healthy biofunction reconstruction. Inspired by the bone healing process, an organic–inorganic nanoink with ultrasmall calcium phosphate oligomers and bone morphogenetic protein-2 incorporated is developed for spatiotemporal guidance of new bone. Based on such homogeneous nanoink, a biomimetic graft, including a cortical layer containing Haversian system, and a cancellous layer featured with triply periodic minimum surface macrostructures, is fabricated via projection-based 3D printing method, and the layers are loaded with distinct concentrations of bioactive factors for regenerating new bone with gradient density. The graft exhibits excellent osteogenic and angiogenic potential in vitro, and accelerates revascularization and reconstructs neo-bone with original morphology in vivo. Benefiting from such natural architecture, loading force is widely transferred with reduced stress concentration around the inserted dental implant. Taken from native physiochemical and structural cues, this wstudy provides a novel strategy for functional tissue engineering through designing function-oriented biomaterials.  相似文献   
67.
A novel Bacterial Foraging Algorithm (BFA) based neural network is presented for image compression. To improve the quality of the decompressed images, the concepts of reproduction, elimination and dispersal in BFA are firstly introduced into neural network in the proposed algorithm. Extensive experiments are conducted on standard testing images and the results show that the proposed method can improve the quality of the reconstructed images significantly.  相似文献   
68.
Cancer remains an intractable medical problem. Rapid diagnosis and identification of cancer are critical to differentiate it from nonmalignant diseases. High-throughput biofluid metabolic analysis has potential for cancer diagnosis. Nevertheless, the present metabolite analysis method does not meet the demand for high-throughput screening of diseases. Herein, a high-throughput, cost-effective, and noninvasive urine metabolic profiling method based on TiO2/MXene-assisted laser desorption/ionization mass spectrometry (LDI-MS) is presented for the efficient screening of bladder cancer (BC) and nonmalignant urinary disease. Combined with machine learning, TiO2/MXene-assisted LDI-MS enables high diagnostic accuracy (96.8%) for the classification of patient groups (including 47 BC and 46 ureteral calculus (UC) patients) from healthy controls (113 cases). In addition, BC patients can also be identified from noncancerous UC individuals with an accuracy of 88.3% in the independent test cohort. Furthermore, metabolite variations between BC and UC individuals are investigated based on relative quantification, and related pathways are also discussed. These results suggest that this method, based on urine metabolic patterns, provides a potential tool for rapidly distinguishing urinary diseases and it may pave the way for precision medicine.  相似文献   
69.
Lead‐free dielectric ceramics have been the spotlight in the search for environmentally benign materials for electrostatic energy storage because of the ever‐increasing environmental concerns. However, the inverse correlation between the polarization and dielectric breakdown strength is the major barrier hindering the provision of sufficient energy densities in lead‐free dielectric ceramics and practical applications thereof. Herein, a rational structure design inspired by nature is demonstrated as an effective strategy to overcome these challenges. Bioinspired raspberry‐like hierarchically structured all‐inorganic nanocomposites have been prepared by enclosing microsized BaTiO3‐Bi(Mg0.5Zr0.5)O3 (BT‐BMZ) relaxor ferroelectrics using core‐shell BT‐BMZ@SiO2 nanoparticles. The synergistic effects of the bioinspired hierarchical structure and insulating SiO2 nano‐coating result in significantly improved dielectric breakdown strength and sustained large polarization in the nanocomposites, as corroborated by experimental characterizations and theoretical simulations. As a result, an ultrahigh energy density of 3.41 J cm?3 and a high efficiency of 85.1%, together with outstanding thermal stability within a broad temperature range, have been simultaneously achieved in the hierarchically structured nanocomposites. This contribution provides a feasible and paradigmatic approach to develop high‐performance dielectrics for electrostatic energy storage applications using bioinspired structure design.  相似文献   
70.
为了减轻辐射环境中静态随机存储器(SRAM)受单粒子翻转(SEU)的影响以及解决低功耗和稳定性的问题,采用TSMC 90nm工艺,设计了一款可应用于辐射环境中的超低功耗容错静态随机存储器。该SRAM基于双互锁存储单元(DICE)结构,以同步逻辑实现并具有1KB(1K×8b)的容量,每根位线上有128个标准存储单元,同时具有抗SEU特性,提高并保持了SRAM在亚阈值状态下的低功耗以及工作的稳定性。介绍了这种SRAM存储单元的电路设计及其功能仿真,当电源电压VDD为0.3V时,该SRAM工作频率最大可达到2.7MHz,此时功耗仅为0.35μW;而当VDD为1V时,最大工作频率为58.2MHz,功耗为83.22μW。  相似文献   
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