排序方式: 共有129条查询结果,搜索用时 483 毫秒
31.
Astha Srivastava Shashank Gupta Megha Quamara Pooja Chaudhary Vidyadhar Jinnappa Aski 《International Journal of Communication Systems》2020,33(12)
In the recent era, the security issues affecting the future Internet‐of‐Things (IoT) standards has fascinated noteworthy consideration from numerous research communities. In this view, numerous assessments in the form of surveys were proposed highlighting several future IoT‐centric subjects together with threat modeling, intrusion detection systems (IDS), and various emergent technologies. In contrast, in this article, we have focused exclusively on the emerging IoT‐related vulnerabilities. This article is a multi‐fold survey that emphasizes on understanding the crucial causes of novel vulnerabilities in IoT paradigms and issues in existing research. Initially, we have emphasized on different layers of IoT architecture and highlight various emerging security challenges associated with each layer along with the key issues of different IoT systems. Secondly, we discuss the exploitation, detection, and defense methodologies of IoT malware‐enabled distributed denial of service (DDoS), Sybil, and collusion attack capabilities. We have also discussed numerous state‐of‐the‐art strategies for intrusion detection and methods for IDS setup in future IoT systems. Third, we have presented a brief classification of existing IoT authentication protocols and a comparative analysis of such protocols based on different IoT‐enabled cyber attacks. For conducting a real‐time future IoT research, we have presented some emerging blockchain solutions. We have also discussed a comparative examination of some of the recently developed simulation tools and IoT test beds that are characterized based on different layers of IoT infrastructure. We have also outlined some of the open issues and future research directions and also facilitate the readers with broad classification of existing surveys in this domain that addresses several scopes related to the IoT paradigm. This survey article focuses in enabling IoT‐related research activities by comparing and merging scattered surveys in this domain. 相似文献
32.
Min Gyu Kang Seul‐Yi Lee Deepam Maurya Christopher Winkler Hyun‐Cheol Song Robert B. Moore Mohan Sanghadasa Shashank Priya 《Advanced functional materials》2017,27(29)
1D ferroelectric nanostructures are promising for enhanced ferroelectric and piezoelectric performance on the nanoscale, however, their synthesis at the wafer scale using industrially compatible processes is challenging. In order to advance the nanostructure‐based electronics, it is imperative to develop a silicon‐compatible growth technique yielding high volumetric density and an ordered arrangement. Here, a major breakthrough is provided in addressing this need and ordered and close‐packed single crystalline ferroelectric nanorod arrays, of composition PbZr0.52Ti0.48O3 (PZT), grown on commercial grade 3 in. silicon wafer are demonstrated. PZT nanorods exhibit enhanced piezoelectric and ferroelectric performance compared to thin films of similar dimensions. Sandwich structured architecture utilizing 1D PZT nanorod arrays and 2D reduced graphene oxide thin film electrodes is fabricated to provide electrical connection. Combined, these results offer a clear pathway toward integration of ferroelectric nanodevices with commercial silicon electronics. 相似文献
33.
Homo- and heteroleptic aryloxides of the type MX4–x(OAr)x [M = TiIV, ZrIV; X = OPri, Cl; x = 1,2,3,4; OAr = OC6H4Pri-4(OAr1), OC6H3Me-2-Pri-5(OAr2), OC6H3Me-5-Pri-2(OAr3), OC6H2Me3-2,4,6(OAr4), OC6H3But2-2,4(OAr5), OC6H3But2-2,6(OAr6)] have been prepared either by alkoxo–aryloxo or chloro-aryloxo exchange reactions in benzene or tetrahydrofuran. All these new derivatives have been characterized by elemental analyses, spectroscopic (i.r., 1H-, 13C-n.m.r.) studies and molecular weight measurements. The FAB mass spectral studies of four representative derivatives Support a dimeric nature for [Ti(OC6H3Me-5-Pri-2)4], [TiCl2(OC6H3Me-5-Pri-2)2], and [Zr(OC6H3But2-2,4)4(thf)], whereas the derivative [ZrCl(OC6H3But2-2,4)3(thf)] is monomeric. 相似文献
34.
The aim of preclarification is to minimize sludge going to yeast separators. This purpose is partially fulfilled. However,
it has been measured during the plant trial runs that preclarification does not noticeably improve fermentation.
The aim of postclarification is to minimize sludge going to distillation. This purpose is well served as noted from the fact
that cycle run of distillation columns using postclarification is three times longer (9–12 mo) as compared to the normal one
(3–4 mo). 相似文献
35.
36.
Dr. Esther Frederick Dr. Quinn Campbell Dr. Igor V. Kolesnichenko Dr. Luis F. Peña Dr. Angelica Benavidez Dr. Evan M. Anderson Dr. David R. Wheeler Dr. Shashank Misra 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(53):13337-13341
Ultradoping introduces unprecedented dopant levels into Si, which transforms its electronic behavior and enables its use as a next-generation electronic material. Commercialization of ultradoping is currently limited by gas-phase ultra-high vacuum requirements. Solvothermal chemistry is amenable to scale-up. However, an integral part of ultradoping is a direct chemical bond between dopants and Si, and solvothermal dopant-Si surface reactions are not well-developed. This work provides the first quantified demonstration of achieving ultradoping concentrations of boron (∼1e14 cm2) by using a solvothermal process. Surface characterizations indicate the catalyst cross-reacted, which led to multiple surface products and caused ambiguity in experimental confirmation of direct surface attachment. Density functional theory computations elucidate that the reaction results in direct B−Si surface bonds. This proof-of-principle work lays groundwork for emerging solvothermal ultradoping processes. 相似文献
37.
The coordination chemistry of copper, gallium and indium halides with the simplest possible selenoether i.e. Me2Se was investigated with the aim to use the resulting complexes as precursors for selenium-containing chalcopyrite semiconducting materials. An optimized general procedure for the high yield synthesis is described and the influence of a halide ion on the structure and solubility of these metal halide dimethyl selenide complexes are discussed. These complexes were characterized by the elemental analysis, FT-IR and 1H NMR spectroscopy as well as single crystal X-ray structures, the later study showing them to be monomeric for gallium halides, mono- or dimeric for indium halides and either an ion-pairs or 2-D extended structure in the case of copper halides. 相似文献
38.
Mudigonda K Jukanti R Apte SS Ajjala DR Shrivastava W Kandikere VN Nirogi RV 《Biomedical chromatography : BMC》2006,20(10):1028-1032
A rapid, reliable HPLC method with UV detection (240 nm) was developed and validated for quantitation of saquinavir in mice brain and testis. Saquinavir and the internal standard were isolated from homogenized tissue matrices using liquid-liquid extraction procedure and were then analyzed using an isocratic mobile phase by reversed-phase liquid chromatography. The lower limit of quantification was 50 ng/g for both brain and testis. A linear dynamic range of 50-5000 ng/g for both brain and testis was established. This HPLC method was validated with between-batch precision of 0.5-4.4 and 1.5-5.5% for brain and testis, respectively. The between-batch accuracy was 94.7-105.9% and 97.5-105.0% for brain and testis, respectively. The present method was applied for tissue distribution studies of the novel drug delivery systems of saquinavir in mice. 相似文献
39.
The existence of incoherently coupled two-component steady state photovoltaic solitons in biased two-photon photorefractive materials due to two-photon photorefractive effect has been investigated. In the steady state regime, these incoherently coupled solitons can propagate in bright–bright, dark–dark and bright–dark configurations. The most important finding is that, with the application of electric field, it is possible to generate solitons and control them in those media where soliton formation was hitherto prohibited. Dynamic evolution of these solitons has been examined using numerical simulations, which show that these solitons are stable. 相似文献
40.
Homo- and heteroleptic N-arylsalicylaldiminate derivatives of TiIV and ZrIV of the type, MX4–x
(OC6H4CH=NAr)
x
(X = OPri, x = 2,3; X = Cl, x = 1,2,3,4; Ar = C6H3Me2-2,6, C6H3Et2-2,6) have been prepared by reactions in the desired molar ratios of: (i) Ti(OPri)4/Zr(OPri)4·PriOH with N-arylsalicylaldimines in benzene, and (ii) MCl4 (M = Ti, Zr) with Me3SiOC6H4CH=NAr or HOC6H4CH=NAr in the presence of Et3N as a base or the potassium salt of N-arylsalicylaldimines in benzene. The three homoleptic derivatives of CrIII, Cr(OC6H4CH=NAr)3 (Ar = C6H2Me3-2,4,6, C6H3Et2-2,6, C6H3Pri
2-2,6) have also been prepared by salt-elimination. All of these new derivatives have been characterized by elemental analyses, spectroscopic [i.r., 1H and 13C-n.m.r. (Ti and Zr complexes), and electronic (for Cr complexes)] studies, as well as molecular weight measurements. 相似文献