Magnetotransport properties of bismuth wires below 25 K

Only Abstract.In this paper we report on magnetotransport measurements of single crystalline bismuth wires at high magnetic fields and low temperatures. These investigations are motivated in part by the unusual electronic properties of the semimetal bismuth that reflect its unique location in an intermediate position between good metals and semiconductors and present the fundamental and practical interest. Measurements of the magnetoresistance (MR) and magnetothermopower (Seebeck coefficient) in the range of magnetic field up o 20 T reveal a various behavior of quantum oscillations for the different values of temperatures that persist from 4.2 to 25 K. Observed Shubnikov-de Haas oscillations exhibit anomalies in their amplitude up to 15 T which deviates from the conventional Lifshitz-Kosevich behavior below the magnetic ordering temperature and around 20 K. The latter, which has so far not been observed, suggests a field- and temperature-induced electronic structure transition. Thermopower (S) of the 1.1 µm wire with high resistance residual ratio (R(300K)/R(4.2K) = 30) exhibits a non-linear temperature dependence with ∂S/∂T 0 suggests that increasing the magnetic field enhances the relative contribution of the diffusion TEP and decreases the phonon drag contribution. We provide a thorough analysis of the different samples, highlighting the importance of sample quality for elucidating details in the transport behavior

Transport properties of Bi wires in high magnetic field

The effect of high magnetic field on the transport properties of semi-metallic bismuth has been a subject of increasing interest in the last years because a lot of unexpected findings detected far beyond the quantum limit of electrons.The presented investigations of the magnetotransport measurements of Bi wires complement the series of recently published experimental results on bulk Bi in high magnetic field. The design of measurements in magnetic field was diversified by using uniaxial strain directed along the wire axis. By combining high magnetic field and strain, the electronic structure of the bismuth wires was modified; as a result, the quantum limit for light and heavy electrons could be changed in different ways

Hazard analysis and assessment – key process in food safety management. Case study: meat industry

Food safety is related to the presence of hazards of food origin in food products in the moment of consumption. As these hazards may occur in any stage of food chain, adequate control throughout this one is essential. Due to the fact that most laboratory analyses made on food require some time to be interpreted (it is usually equal or longer than foods’ shelf–life) is practically impossible to make these analyses and afterwards to deliver them to consumers. Three types of dangers and hazards respectively are associated with food products: biological, chemical and physical ones. Hazard assessment is made depending on their seriousness and probability of manifestation. To get very good results it is recommended to consider HACCP implementation as a working instrument and not as an objective, especially not as an objective imposed by the control authorities of the state

Spontaneous intracerebral supratentorial hemorrhage: general aspects and updates in surgical treatment

Laboratory of Neurosurgery Anesthesia and Reanimation, Institute of Neurology and Neurosurgery, Department of Neurology, Institute of Emergency Medicine, Department of Radiology and Medical Imaging, Nicolae Testemitsanu State University of Medicine and Pharmacy, Chisinau, the Republic of MoldovaBackground: Spontaneous intracerebral hemorrhage (SIH) accounts for 9 to 25% of all strokes and is associated with a high morbidity and mortality, with less than 40% of affected persons surviving 1 year. The condition commonly presents a sudden onset of focal neurological deficits with accompanying headache, nausea, vomiting, elevated blood pressure and altered consciousness. Medical treatment commonly includes airway support, blood pressure control, management of cerebral edema, symptomatic therapy such as anticonvulsive medication, anticoagulation reversal etc. Different surgical options such as open craniotomy, stereotactic aspiration, endoscopic evacuations with or without thrombolysis have also been considered. Most of these techniques have already been implemented successfully in the Republic of Moldova. According to the data of the Institute of Neurology and Neurosurgery and the Institute of Emergency Medicine for the period 2011-2014, just within these two institutions were performed 137 neurosurgical interventions, including 67 interventions involving minimally invasive techniques with local fibrilolysis and 70 interventions involving other minimally invasive surgery or conventional craniotomy. The obtained results are in concordance with those reported by other European institutions. Conclusions: The continuous efforts to improve the outcome of SIH during the recent years have led to the development of a variety of minimally invasive techniques, most of which have already been adopted by the autochthonous surgeons. New randomized controlled trials are required to establish the suitability of these techniques for different clinical situations and SIH localizations

Acid Corrosion Inhibitor from Tobacco Waste for Steel of Oil Pipes

AbstractA technology of an acid corrosion inhibitor production for steel of oil pipes has been developed. The inhibitor is obtained by extracting nicotine and related substances with an aqueous solution of benzoic acid from tobacco waste. Extraction, chromato-mass spectrometry, weight and electrochemical methods were applied as research methods for determining inhibitor effectiveness

Manifestare neaşteptată concomitentă a supraconductibilităţii şi feromagnetismului slab la interfeţele bicristalelor de Bi şi a izolatorilor topologici tridimensionali BiSb

Two/one superconducting phases with the onset of transition ≤ 36K are observed at CIs of bicrystals, while the rhombohedral Bi and 3D topological insulator (3DTI) BiSb are diamagnetic and do not exhibit superconductivity. In large crystallite disorientation angle Bi-Sb interfaces both superconductivity and weak ferromagnetism were revealed simultaneously

Thermomagnetic transport due to the superconducting interfaces in inclination bicrystals of Bi

Only AbstractThe group- V semimetals are of major interest for solid state physics, because of easy access to the quantum limit in high magnetic fields and possibility of studying the unusual behaviour of Dirac electrons under extremal conditions of a strong phonon drag effect, electronic topological phase transitions, and proximity-induced superconducting order. Some of these materials like Bi, exhibit remarkable electron transport properties and unique thermoelectric and thermomagnetic characteristics, defining new directions in this field of science. In this report we show the high - field thermomagnetic power Sii(B) and Nernst–Ettingshausen effect Sij(B) in Bi inclination bicrystals with superconducting nano-width interfaces (~ 100 nm). We found that the thermomagnetic effects in small disorientation angle bicrystals (SDA) are considerably higher than in single crystalline Bi and large disorientation angle (LDA) samples. A weak increase of the monotonic Sii(B) in SDA bicrystals and completely saturated thermomagnetic power in LDA specimens were detected, indicating a varying contribution of thermally excited carriers and a different degrees of interface disorder. It was also revealed that the maximum of temperature dependences of Sii(B) quantum oscillation amplitude in SDA bicrystals is shifted ~ 1 K at low temperatures, compared to Bi single crystals. Two new quantum oscillation harmonics we have found in quantizing magnetic fields, characterizing different densities of electronic states and different levels of disorder both in LDA and in SDA interfaces. It should be assumed that the obtained results are important for future applications in thermoelectricity and spintronic devices

The structure phase transition in quantum wires of bismuth under elastic tension

Access full text – https://doi.org/10.1007/BF02571200It was established that at 4.2 K for thin (d<1μm)Bi wires there existed a complicated λ-form dependence of the resistanceR¯ on the strong elastic deformation ξ. The drastic fall in the oscillation amplitude of the flux-quantification type together with theR (ξ) behavior in dependence on the values of temperatureT, impurity concentrationC, wire diameterd and current densityJ indicate the presence of the structure phase transition within the subsurface region due to the shear deformation in the investigated layered structure. The intensive carrier scattering at the fluctuation oscillations of the atoms within the subsurface region brings about sharp resistance rise. Formation of a new long range order in the said region excludes the following rise inR¯(ξ) and ensures the maximum of the said quantity

Variation and evolution of toxin gene expression patterns of six closely related venomous marine snails

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75661/1/j.1365-294X.2008.03804.x.pd