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1.
Current and future measurements for the total cross sections at E-811,PP2PP,CSM,FELIX,and TOTEM have been analyzed using various models.In the light of this study an attempt has been made to focus on the behavior of total cross section at very high energies.  相似文献   

2.
In the past decades the topic of climate change has been subjected to intense scientific scrutiny, and since the mid-1990’s it has become an increasingly political issue. Because of increased temperatures and more frequent and intense extreme weather events, the number of direct injuries and deaths will increase, along with infectious diseases, whether food, water or vector-borne; respiratory and cardiovascular diseases are expected to rise due to worsened air pollution and extreme heat. In a context of on-going environmental degradation, local food-producing systems, both marine and terrestrial, will be affected and the risk of malnutrition, especially in children, will increase. These impacts on health and livelihood are expected to be significant factors in the spread of regional social crises, potentially leading to forced migration, conflicts and increased poverty.  相似文献   

3.
In this paper we will focus on the nucleon-nucleon interaction in relative S-states. The 1S0 interaction is known to be close to that for critical two-body binding. We will discuss two approaches to the NN interaction, which are equivalent on-shell but not off-shell. There is a well-defined transformation between these approaches [1]. One (my preferred approach) is to minimize the tensor forces far off-shell, which leads to more rapid convergence, but at the price of significant non-locality. This approach is used in a model of relativistic tensor quenching of OPEP [2]. With non-local NN interactions it is possible to fit not only NN observables, but also the NNN ground-state energies [3]. The other approach is to maximize the role of the and keep the interaction as local as possible [4]. This approach is also internally consistent, but requires additional NNN interactions to fit nuclear data. Also, we discuss briefly a so-called low momentum interaction [5, 6], which fits S-wave phase shifts quite well. This interaction is strongly non-local, and it can be approximated by a schematic separable interaction. Finally, we mention the Nambu–Jona-Lasinio model [7] and a good approximation, the Hulthen potential, which provides some insight into the near critical two-body binding.  相似文献   

4.
An improved HarshawTLD? extremity dosimeter system that is rugged in design and easy to wear is presented. This dosimeter is improved from the earlier version (2008) for personnel beta monitoring while still having full range photon performance. The dosimeter style, referred to as DXTRAD, is small in size and has identification by means of a circular barcode. It consists of a detector composed of a thin 7 mg cm?2 monolayer of HarshawTLD-700H (7LiF:Mg,Cu,P) powder and a ring cap with a 3.3 mg cm?2 entrance window. The use of the TLD-700H TLD material provides a good beta energy response as well as a flat energy response from low energy x-rays to high energy gamma rays. A new assembly tool that improves the consistency of dosimeter geometry and ruggedness for warm and cold sterilization is also developed. With the optimized design, this dosimeter is capable of meeting the stringent energy and angular response requirements of the Physikalisch Technische Bundesanstalt (PTB) for both betas and photons. Presented in this paper are the ISO-12974 and PTB type tests as well as additional operational tests, such as residue, reuse, warm and cold sterilization, and environmental leakage.  相似文献   

5.
The acoustics of an authentically reconstructed ancient Greek tortoise-shell lyre, known as Chelys, is investigated for the first time. Modern experimental methods are employed, such as electronic speckle pattern laser interferometry and impulse response, to extract the vibrational behavior of the instrument and its main parts. Additionally, the emitted sound from the instrument was recorded, under controlled conditions, and spectrally analyzed. Major findings include the concentration of the emitted sound between 400 Hz and 800 Hz, with an amplitude modified in a manner consistent with the experimentally measured vibrational characteristics of the instrument’s sound box and bridge. The experimental results validate the historical evidence that Chelys was used in Greek antiquity as an accompaniment instrument to the human voice.  相似文献   

6.
Electrochemical, acoustic and imaging techniques are used to characterise surface cleaning with particular emphasis on the understanding of the key phenomena relevant to surface cleaning. A range of novel techniques designed to enhance and monitor the effective cleaning of a solid/liquid interface is presented. Among the techniques presented, mass transfer of material to a sensor embedded in a surface is demonstrated to be useful in the further exploration of ultrasonic cleaning of high aspect ratio micropores. In addition the effect of micropore size on the cleaning efficacy is demonstrated. The design and performance of a new cleaning system reliant on the activation of bubbles within a free flowing stream is presented. This device utilised acoustic activation of bubbles within the stream and at a variety of substrates. Finally, a controlled bubble swarm is generated in the stream using electrolysis, and its effect on both acoustic output and cleaning performance are compared to the case when no bubbles are added. This will demonstrate the active role that the electrochemically generated bubble swarm can have in extending the spatial zone over which cleaning is achieved.  相似文献   

7.

Background  

One major problem for cognitive neuroscience is to describe the interaction between stimulus and task driven neural modulation. We used fMRI to investigate this interaction in the human brain. Ten male subjects performed a passive listening and a semantic categorization task in a factorial design. In both tasks, words were presented auditorily at three different rates.  相似文献   

8.
In metal cutting machining, major factors that affect the cutting tool life are machine tool vibrations, tool tip/chip temperature and surface roughness along with machining parameters like cutting speed, feed rate, depth of cut, tool geometry, etc., so it becomes important for the manufacturing industry to find the suitable levels of process parameters for obtaining maintaining tool life. Heat generation in cutting was always a main topic to be studied in machining. Recent advancement in signal processing and information technology has resulted in the use of multiple sensors for development of the effective monitoring of tool condition monitoring systems with improved accuracy. From a process improvement point of view, it is definitely more advantageous to proactively monitor quality directly in the process instead of the product, so that the consequences of a defective part can be minimized or even eliminated.In the present work, a real time process monitoring method is explored using multiple sensors. It focuses on the development of a test bed for monitoring the tool condition in turning of AISI 316L steel by using both coated and uncoated carbide inserts. Proposed tool condition monitoring (TCM) is evaluated in the high speed turning using multiple sensors such as Laser Doppler vibrometer and infrared thermography technique. The results indicate the feasibility of using the dominant frequency of the vibration signals for the monitoring of high speed turning operations along with temperatures gradient. A possible correlation is identified in both regular and irregular cutting tool wear. While cutting speed and feed rate proved to be influential parameter on the depicted temperatures and depth of cut to be less influential. Generally, it is observed that lower heat and temperatures are generated when coated inserts are employed. It is found that cutting temperatures are gradually increased as edge wear and deformation developed.  相似文献   

9.
The kinetics of the reaction of hydrogen atoms with 2,5-dimethylfuran (25DMF), a promising liquid transport biofuel, was experimentally studied in a shock tube at temperatures between 970 and 1240 K and pressures of 1.6 and 4.8 bar. The hydrogen atoms were produced by pyrolysis of ethyl iodide and monitored by atom resonance absorption spectrometry. From the hydrogen atom concentration–time profiles, overall rate coefficients for the reaction H + 25DMF  products (R1) were inferred. The results can be expressed by the Arrhenius equation k1 = 4.4 × 10?11 exp(?1180 K/T) cm?3 s?1 with an estimated uncertainty of ±30%. A significant pressure dependence was not observed. The results were analyzed in terms of statistical rate theory with molecular and transition state data from quantum chemical calculations. Three different compound methods were used to characterize the potential energy surface: CBS-QB3, CBS-APNO, and G3. It is found that reaction (R1) mainly (>75%) proceeds via an addition–elimination mechanism to yield 2-methylfuran + CH3. Kinetic parameters for the most important competing channels of the net reaction (R1) were calculated.  相似文献   

10.
In this work, we study and characterize the cholesteric sequence of phases (ChDr ? ChB ? ChD), where the first ChDr is the reentrant cholesteric discotic phase, ChB is the cholesteric biaxial phase and the second ChD is the cholesteric discotic phase. This sequence of phases is studied through polarized light microscopy and image processing technique, where, for the first time, the domains and borders of these transitions are established and characterized. They are also investigated and optically characterized throughout their textures.  相似文献   

11.
《Comptes Rendus Physique》2019,20(6):583-592
During the growth of a single-crystal diamond by MPCVD, polycrystalline diamonds are prone to grow in the edge regions. This substantially reduces the usable area of the grown diamond film. In addition, the inhomogeneous distribution of internal stress causes diamond to crack during continuous growth. In recent years, a series of experimental studies have been carried out to solve these problems and some achievements have been obtained. However, in order to understand fundamentally the growth mechanism of diamond, the relationship between growth quality and various influencing factors still needs to be quantitatively studied through integrated simulations and experiments. Electron number density and substrate temperature are important factors affecting diamond crystallization quality. In this paper, the growth conditions of the diamond were simulated and analyzed. Simulation results were compared with the experimental results. This evidences that the surface temperature distribution is relatively homogeneous, and that the significant electron number density gradient in the axial direction is the main reason for the formation of polycrystals in the edge regions. Therefore, substrate holders with different cavity depths were designed and the substrates grew in the same temperature range. The surface morphologies, crystalline qualities, and internal stress distributions of the grown diamonds were measured, and it was found that the quality of growth increased first and then decreased with the depth of the cavity, while the growth rate decreased with increasing the latter. These results are in good agreement with the simulation results. Finally, suggestions on the selection of the substrate holder for film growth with different thicknesses are proposed.  相似文献   

12.
13.
We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions (5) 2 to the running of the QED coupling, Δαbad^5)(MZ^2). Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2π channel and from the energy region just below 2 GeV.  相似文献   

14.
We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions to the running of the QED coupling,αh(5a)d(MZ2).Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2π channel and from the energy region just below 2 GeV.  相似文献   

15.
The focus of the present work is on the design, synthesis, characterization, DNA-interaction, photo-cleavage, radical scavenging, in-vitro cytotoxicity, antimicrobial, docking and kinetic studies of Cu (II), Cd (II), Ce (IV) and Zr (IV) metal complexes of an imine derivative, 3 – (1 – (6 – methoxybenzo [d] thiazol – 2 – ylimino) ethyl) – 6 – methyl – 3H – pyran – 2, 4 – dione. The investigation of metal ligand interactions for the determination of composition of metal complexes, corresponding kinetic studies and antioxidant activity in solution was carried out by spectrophotometric methods. The synthesized metal complexes were characterized by EDX analysis, Mass, IR, 1H-NMR, 13C-NMR and UV–Visible spectra. DNA binding studies of metal complexes with Calf thymus (CT) DNA were carried out at room temperature by employing UV-Vis electron absorption, fluorescence emission and viscosity measurement techniques. The results revealed that these complexes interact with DNA through intercalation. The results of in vitro antibacterial studies showed the enhanced activity of chelating agent in metal chelated form and thus inferring scope for further development of new therapeutic drugs. Cell viability experiments indicated that all complexes showed significant dose dependent cytotoxicity in selected cell lines. The molecular modeling and docking studies were carried out with energy minimized structures of metal complexes to identify the receptor to metal interactions.  相似文献   

16.
17.
Using a standing wave sonochemical reactor (SWSR), the influences of parameters of ultrasonic power input, sonication time, sonication temperature and the amount of propanol (which generates the reducing radicals) were systemically investigated to ascertain and optimize the best conditions for the sonochemical reduction of Pt from its precursor hexachloroplatinic acid and then its deposition on rutile TiO2 (platinization of rutile titania) catalysts. Catalytic activity of the prepared platinized catalysts was tested in the reaction of methyl orange degradation. The results of photocatalytic activity study in the degradation of methyl orange further demonstrate that sonochemically as-prepared Pt/TiO2 catalysts show a pronounced increase (~2 times) in photodegradation, even with a deposition of small amounts of platinum (1.4 wt.%), as compared to the unsupported or naked rutile titania. Although there are various parameters that influence the sonochemical platinization of rutile titania, the present optimization results clearly indicate that the best photocatalytic degradation of methyl orange can be obtained when the experimental conditions of the preparation were with an input power of 50 W, an initial hexachloroplatinic acid volume of 70 ml (which results into 1.4 wt.% Pt on TiO2), sonication time of 90 min, 0.18 g of propanol and a temperature of 10 °C were adopted. The method of ultrasound application to prepare metal supported semiconductors has many advantages such as convenience, safety and high efficiency. Furthermore, it is hopeful that this optimization study can also be extended to the generation of similar metal supported semiconductors.  相似文献   

18.
The research on the potential of cavitation exploitation is currently an extremely interesting topic. To reduce the costs and time of the cavitation reactor optimization, nowadays, experimental optimization is supplemented and even replaced using computational fluid dynamics (CFD). This is a very inviting opportunity for many developers, yet we find that all too often researchers with non-engineering background treat this “new” tool too simplistic, what leads to many misinterpretations and consequent poor engineering.The present paper serves as an example of how complex the flow features, even in the very simplest geometry, can be, and how much effort needs to be put into details of numerical simulation to set a good starting point for further optimization of cavitation reactors. Finally, it provides guidelines for the researchers, who are not experts in computational fluid dynamics, to obtain reliable and repeatable results of cavitation simulations.  相似文献   

19.
This review of dosimetry for second cancer risk estimation introduces work carried out by Working Group 9 (WG9: Radiation Protection Dosimetry in Medicine) of the European Radiation Dosimetry Group (EURADOS). The work concentrates on the measurement of out-of-field doses in water phantoms using a variety of dosimeters to measure photon and neutron doses. These include optically stimulated luminescence (OSL), radiophotoluminescence (RPL) and thermoluminescence (TLD) dosimeters for photon dosimetry (together with ion chambers for reference measurements) and track etch and superheated emulsion detectors for neutron measurements. The motivation of WG 9 was to assess undue, non-target patient doses in radiotherapy and the related risks of second malignancy. Improvements in cancer treatment have increased survival times and thus increased incidence of second cancer may be expected in the future. In addition, increased whole body exposure may result from some developments in radiotherapy. This means that radiotherapy clinics will need to simulate their treatments in order to estimate and minimise doses to healthy tissues and organs. The proposed work is designed to generate a robust dataset of out-of-field dose measurements which can be used for the development and validation of dose algorithms.  相似文献   

20.
A review of The Symbiotic Universe: Lfe ∧ Mind in the Cosmos, by G. Greenstein. (New York: William Morrow ∧ Co., 1988.) [Pp. 271.] $18.95. ISBN 0 688 07604 1.  相似文献   

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