Silicene transistors——A review

Free standing silicene is a two-dimensional silicon monolayer with a buckled honeycomb lattice and a Dirac band structure. Ever since its first successful synthesis in the laboratory, silicene has been considered as an option for post-silicon electronics, as an alternative to graphene and other two-dimensional materials. Despite its theoretical high carrier mobility,the zero band gap characteristic makes pure silicene impossible to use directly as a field effect transistor(FET) operating at room temperature. Here, we first review the theoretical approaches to open a band gap in silicene without diminishing its excellent electronic properties and the corresponding simulations of silicene transistors based on an opened band gap.An all-metallic silicene FET without an opened band gap is also introduced. The two chief obstacles for realization of a silicene transistor are silicene's strong interaction with a metal template and its instability in air. In the final part, we briefly describe a recent experimental advance in fabrication of a proof-of-concept silicene device with Dirac ambipolar charge transport resembling a graphene FET, fabricated via a growth-transfer technique.     

Silicene spintronics——A concise review

Spintronics involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. The fascinating spin-resolved properties of graphene motivate numerous researchers to study spintronics in graphene and other two-dimensional(2D) materials. Silicene, the silicon analog of graphene, is considered to be a promising material for spintronics. Here, we present a review of theoretical advances with regard to spin-dependent properties, including the electric field- and exchange field-tunable topological properties of silicene and the corresponding spintronic device simulations.     

Using stable isotopes in mangrove fisheries research — A review and outlook

Mangrove forests are important coastal wetlands in most of the tropics, but their importance to fisheries is poorly understood. Rationales for conserving these ecosystems are partly based on ideas that mangroves are important to food webs that support fisheries. Here we review use of stable isotopes to test the strength of the mangrove forest-fish connection, suggesting that a dual focus on both food web ecology and habitat use may be most profitable in future studies of this type.     

EPR——标准样品

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Graphene's photonic and optoelectronic properties——A review

Due to its remarkable electrical and optical properties,graphene continues to receive more and more attention from researchers around the world.An excellent advantage of graphene is the possibility of controlling its charge density,and consequently,the management of its conductivity and dielectric constant,among other parameters.It is noteworthy that the control of these properties enables the obtaining of new optical/electronic devices,which would not exist based on conventional materials.However,to work in this area of science,it is necessary to have a thorough knowledge regarding the electrical/optical properties of graphene.In this review paper,we show these graphene properties very well detailed.     

Book review A History of Acoustics in China

ThisisthefirstmonographonacousticalcontributionsinChina,mostlyancient,andsomemodernuptol95o.AcousticsisoneofthebranchesofsciencewhichattractedChinesepeopleearly,startingwiththedevelopmentofmusicalinstruments.AtloooBCca,thetimeofJiahu,Wuyangdistrict,theboneflutalreadypossessed6-toneor7-tonescale.Musicalinstrumentsandmusicalscalearethemainattractions.EversincethebeginningoftheZhoudynasty,llOoBC,etiquetteandmusicmakingswereconsideredhighpoliticsinrulingthecountry,andmusicwasamongthesixartSof…     

MIMO-OFDM underwater acoustic communication systems—A review

The ever increasing demand for bandwidth, efficiency, spatial diversity and performance of underwater acoustic (UWA) communication has opened doors for the use of Multi-Input Multi-Output (MIMO). A combination of MIMO and Orthogonal Frequency Division Multiplexing (OFDM) has proved to be a promising solution for many scenarios in UWA communication; on the contrary, it also amplifies the design challenges for implementing such schemes to acquire the required bandwidth efficiency. The goal of this study is to provide a comprehensive survey of the latest researches in the field of UWA MIMO-OFDM communication. The previous works are summarized, reviewed and compared according to their years of publication while problems faced by UWA MIMO-OFDM communication are highlighted. The articles are classified according to the focused techniques like channel estimation, equalization, coding and detection. Furthermore the works are compared based on the complexity and performance of the algorithms while some future research issues are identified.     

Silicene:from monolayer to multilayer——A concise review

Silicene, a newly isolated silicon allotrope with a two-dimensional(2D) honeycomb lattice structure, is predicted to have electronic properties similar to those of graphene, including the existence of signature Dirac fermions. Furthermore,the strong spin–orbit interaction of Si atoms potentially makes silicene an experimentally accessible 2D topological insulator. Since 2012, silicene films have been experimentally synthesized on Ag(111) and other substrates, motivating a burst of research on silicene. We and collaborators have employed STM investigations and first principles calculations to intensively study the structure and electronic properties of silicene films on Ag(111), including monolayer, bilayer, and multilayer silicenes, as well as hydrogenation of silicene.     

A review of: “Advances in phase transitions”

From specific heat, thermal expansion, and dielectric constant measurements between 150 and 300 K we have confirmed the low temperature phase transition in barium chloride dihydrate (BaCl₂.2H₂O) at 195 ± 1 K. This transition appears to be associated with the local ordering (or displacements) of the two water molecules in the crystal. A “pseudospin” type model is proposed to explain the transition mechanism.     

Models of optical absorption in amorphous semiconductors at the absorption edge — A review and re-evaluation

Davis-Mott and Tauc models of optical absorption at the absorption edge in the high absorption coefficient region (10⁴cm^–1) are carefully reviewed with regard to their theoretical foundations, assumptions, mathematical derivations, and results. The full implications of these models are exploited, and it is found that the Davis-Mott model for negligible matrix elements between localised states could account for the cubic power law behaviour of with photon energy of some amorphous semiconductors such as a-Si. A fractional power law to find the optical band gapE _opt, of the form [ (–E _opt)^r; 2r3] based on Davis-Mott model is proposed in which the indexr can be a function of disorder. The Tauc model has further been extended to the case of negligible matrix elements between localised states, in which the same square power law for vs. with the same meaning of the optical gap as in the original Tauc model has resulted. A consideration of the case of unequal matrix elements for those transitions between localised states and those between extended states is also included. The meaning ofE _opt has been re-assessed and it is emphasized that it is an extrapolation of delocalised states to the zero of the density of states rather than a threshold energy for the onset of some kind of optical transitions.This paper is cordially dedicated to Professor C. A. Hogarth who taught us the Physics of amorphous materials.     

Theory of neutrinoless double beta decay—A brief review

Neutrinoless double decay (0νββ-decay) is a unique probe for lepton number conservation and neutrino properties. This is a process with long and interesting history with important implications for particle physics and cosmology, but its observation is still elusive. The search for the 0νββ-decay represents the new frontiers of neutrino physics, allowing to determine the Majorana nature of neutrinos and to fix the neutrino mass scale and possible CP violation effects, which could explain the matter-antimatter asymmetry in the Universe. At present a complete theory is missing and, thus, to motivate and guide the experiments the mechanism mediated by light neutrinos is mostly considered. The subject of interest is an effective mass of Majorana neutrinos, which can be deduced from the measured half-life, once this process is definitely observed. The accuracy of the determination of this quantity is mainly determined by our knowledge of the nuclear matrix elements. There is a request to evaluate them with high precision, accuracy and reliability. Recently, there is an increased interest to the resonant neutrinoless double electron capture, which may also establish the Majorana nature of neutrinos. This possibility is considered as alternative and complementary to searches for the 0νββ-decay.     

Self-assembled superparamagnetic nanoparticles as MRI contrast agents — A review

Recent progress of the preparation and applications of superparamagnetic iron oxide(SPIO) clusters as magnetic resonance imaging(MRI) probes is reviewed with regard to their applications in labeling and tracking cells in vivo, in diagnosis of cardiovascular diseases and tumors, and in drug delivery systems. Magnetic nanoparticles(NPs), especially SPIO nanoparticles, have long been used as MRI contrast agents and as an advantageous nanoplatform for drug delivery,taking advantage of their unique magnetic properties and ability to function at the molecular and cellular levels. Due to advances in nanotechnology, various means to control SPIO NPs' size, composition, magnetization and relaxivity have been developed, as well as ways to usefully modify their surface. Recently, self-assembly of SPIO NP clusters in particulate carriers — such as polymeric micelles, vesicles, liposomes, and layer-by-layer(Lb L) capsules — have been widely studied for application as ultrasensitive MRI probes, owing to their remarkably high spin–spin(T2) relaxivity and convenience for further functionalization.     

Energy recovery from municipal solid waste incineration—A review

Heat recovery from the incineration of municipal solid waste (MSW) can make a useful contribution to the nation's energy needs. This paper reviews the literature on the field of energy recovery from MSW incineration. This review includes (1) An historical background on the MSW methods of disposal and the recent trends. (2) The potential role of waste as a fuel from the knowledge of its analysis, heating value and quantity. (3) The alternative methods of waste disposal including the thermal (mass incineration, refuse-derived fuel and pyrolysis), the mechanical and the biochemical processes. (4) Some economic considerations regarding MSW disposal costs. (5) The combustion characteristics of MSW and waste combustion plants. (6) Heat recovery from waste burning including the main types of waste heat boilers; the heat recovery rates; heat exchange boundary conditions; fouling, erosion and corrosion of waste heat boilers; control of waste incineration particulate emissions and finally the control of nitrogen oxides emissions. The intensive data given here is essential to the proper design and operation of any MSW-to-energy plant. The design needs to be undertaken with careful consideration of the experience that already exists in order to achieve success.     

Hearing protection and warning sounds in industry—a review

Member States of the European Economic Community are required to introduce Regulations which, in part, make the wearing of hearing protection mandatory under certain noise exposure conditions. Provisions are also to be introduced which can take into account possible difficulties that the wearer may have in the perception of warning sounds. This paper reviews the evidence that is relevant to any expert appraisal which formed part of a scheme of exemptions from the otherwise mandatory requirement.The evidence indicates that, when worn by people with normal hearing, the protectors will not in general impair the perception of appropriately selected alarm sounds. However, specific conditions are identified where the hearing protectors may reduce the effectiveness of some warning sounds, in particular for those machinery sounds which are associated with potential danger and for those people with an existing noise-induced hearing loss. It is recommended that the design of warning systems and the development of work practices should take account of possible failures in the perception of auditory warnings.     

A review of: “Isotopes in Water Resources Management”

Abstract

Proceedings of the International Symposium, organized by the IAEA, in co-operation with UNESCO, Vienna, 20–24 March 1995. Vol. 1 (ISBN 92-0-105595-1) and Vol. 2 (ISBN 92-0-100796-5), edited by IAEA, Vienna, Austria, March 1996.     

Ultrasonic encapsulation – A review

Encapsulation of materials in particles dispersed in water has many applications in nutritional foods, imaging, energy production and therapeutic/diagnostic medicine. Ultrasonic technology has been proven effective at creating encapsulating particles and droplets with specific physical and functional properties. Examples include highly stable emulsions, functional polymeric particles with environmental sensitivity, and microspheres for encapsulating drugs for targeted delivery. This article provides an overview of the primary mechanisms arising from ultrasonics responsible for the formation of these materials, highlighting examples that show promise particularly in the development of foods and bioproducts.     

Comparisons of electrical and optical properties between graphene and silicene——A review

Two-dimensional(2D) metamaterials are considered to be of enormous relevance to the progress of all exact sciences.Since the discovery of graphene, researchers have increasingly investigated in depth the details of electrical/optical properties pertinent to other 2D metamaterials, including those relating to the silicene. In this review are included the details and comparisons of the atomic structures, energy diagram bands, substrates, charge densities, charge mobilities, conductivities,absorptions, electrical permittivities, dispersion relations of the wave vectors, and supported electromagnetic modes related to graphene and silicene. Hence, this review can help readers to acquire, recover or increase the necessary technological basis for the development of more specific studies on graphene and silicene.     

Relaxation mechanism in γ-ray-irradiated L-alanine studied by transfer saturation EPR and pulse EPR

Stable paramagnetic centers in γ-ray-irradiated L-alanine dosimeters exhibit a maximum in relaxation rate in the vicinity of 190 K. The mechanism of this relaxation rate has been investigated on the first stable alanine radical center, SARI, by employing continuous-wave transfer saturation electron paramagnetic resonance and pulse electron paramagnetic resonance techniques. The detected in-phase and out-of-phase spectra as well as phase memory times,T _M, indicate that besides the well-known τ_p of the CH₃ group of SAR1 an additional correlation time, τ_l (ΔElk=2689±50 K and 0 τ₁₀ = 0.15 ± 0.03 ps), is involved in the transverse relaxation process and effects the SAR1 center. For the SAR1 center this mechanism originates from the hindered motion of undamaged CH₃ and NH ₃ ⁺ groups in the lattice. The motion of these groups additionally effects the spectrum of the SAR1 center through averaging out of the anisotropic splitting.     

A review of: “Surface effects in controlled fusion devices”

Proceedings of the second conference on surface effects in controlled fusion devices, San Francisco, USA, February 1976. (Eds. W. Bauer, C. R. Finfgeld and M. Kaminsky). North Holland (Amsterdam), 534 pages. US $120.50.