Gamma radiation exposure of MCT diode arrays

Investigations of electrical properties of long-wavelength infrared (LWIR) mercury cadmium telluride (MCT) arrays exposed to gamma-radiation have been performed. Resistance-area product characteristics of LWIR n{+}-p photodiodes have been investigated using microprobe technique at T=78 K before and after an exposure to various doses of gamma-radiation. The current transport mechanisms for those structures are described within the framework of the balance equation model taking into account the occupation of the trap states in the band gap.Comment: 11 pages, 4 figures, submitted to Semiconductor Science and Technolog

The spectral manifistation of the new luminescent styryl dyes photostability and phototoxic influence on the DNA

У роботі запропоновано методи спектральних досліджень фотостабільності та фото- токсичного впливу люмінесціюючих зондів-барвників на ДНК. Досліджено спектри оптичного поглинання, флюоресценції та фосфоресценції нових стирилових барвників та систем ДНК+барвник. Спектри оптичного поглинання досліджуваних сполук реєструвалися під час опромінювання зразків цих речовин видимим світлом. У роботі аналізуються результати цих експериментів, проведені на низці барвників. Зафіксовано зміни оптичної густини D розчинів систем ДНК+барвник на ділянці спектра 250+300 нм (що відповідає першому електронному переходу в ДНК) та 370+650 нм (що відповідає першому електронному переходу в молекулах барвників). Динаміка D(t) не є монотонною. Показано, що бавники Mn-Styr ma Di-Styr-30 є фотохімічно безпечними для ДНК; ці барвники є більш фотостабільними у зв 'язаному з ДНК стані, ніж: у вільному. Барвники Di-Styr-24 ma Dst-MdO, на відміну від попередніх, проявляють невеликий фототоксичний вплив на ДНК. Пропонуються версії щодо можливих механізмів фотогтокичності (та фотостабільності).The spectral investigation methods of the phenomena of luminescent dye probes photostability and phototoxic influence on the DNA were proposed. The optical absorption, fluorescence and phosphorescence spectra of the samples of the newest investigated styryl dyes and the systems DNA +dye were studied. The optical absorption spectra of the samples of these compounds were measured under the irradiation of these samples by visible light. The results of the investigations carried out on a number of dyes were analyzed and discussed. The changes of optical density D value in wavelength regions 250+300 nm (that corresponds to the DNA first electronic transition) and 370+650 nm (that corresponds to a dye electronic transition) of the DNA+dye solutions were fixed. The dynamics ofD(t) was not monotonous. It was shown the Mn-Styr and Di-Styr-30 dyes are photochemically safe for the DNA; these dyes bound to the DNA are more photostable than in free state. The Di-Styr-24 and Dst-MdO dyes show slight phototoxic effect on the DNA. The versions of possible phototoxicity (and photostability) mechanisms are proposed

Double zigzag spin chain in a strong magnetic field close to saturation

We study the ground state phase diagram of a frustrated spin tube in a strong external magnetic field. This model can be viewed as two coupled zigzag spin chains, or as a two-leg spin ladder with frustrating next-nearest-neighbor couplings along the legs, and its study is motivated by the physics of such materials as sulfolane-Cu2Cl4 and BiCu2PO6. In magnetic fields right below the saturation, the system can be effectively represented as a dilute gas of two species of bosonic quasiparticles that correspond to magnons with inequivalent incommensurate momenta at two degenerate minima of the magnon dispersion. Using the method previously proposed and tested for frustrated spin chains, we calculate effective interactions in this two-component Bose gas. On this basis, we establish the phase diagram of nearly saturated frustrated spin tube, which is shown to include the two-component Luttinger liquid, two types of vector chiral phases, and phases whose physics is determined by the presence of bound magnons. We study the phase diagram of the model numerically by means of the density matrix renormalization group technique, and find a good agreement with our analytical predictions

Oscillatory regularity of charge carrier traps energy spectra in silicon organic polymer poly(di-n-hexylsilane)

Charge carrier traps energy spectra have been investigated in silicon organic polymer poly(di-n-hexylsilane) by fractional thermally stimulated luminescence in the temperature range from 5 to 200 K. The energy spectrum of traps has been found to be discrete in nature, not the quasi-continuous, as it was considered earlier. It has been established that the traps energies form two characteristic series resulting from the vibrational quanta at 373 and 259 cm⁻¹, respectively. It is important that these vibrational quanta coincide with the frequencies of the totally symmetric vibrational modes of silicon chain which are active in Raman spectrum. The regularities mentioned are analyzed using the oscillatory traps model as the basis

Sub-THz nonresonant detection in AlGaN/GaN heterojunction FETs

Abstract. Un-cooled AlGaN/GaN-based heterojunction field-effect transistors (HFET) designed on sapphire (0001) substrates were considered as 140 GHz direct detection detectors without any specially attached antennas. The noise equivalent power (NEP) of these detectors was ~

Oscillatory regularity of charge carrier traps energy spectra in silicon organic polymer poly(di-n-hexylsilane)

Charge carrier traps energy spectra have been investigated in silicon organic polymer poly(di-n-hexylsilane) by fractional thermally stimulated luminescence in the temperature range from 5 to 200 K. The energy spectrum of traps has been found to be discrete in nature, not the quasi-continuous, as it was considered earlier. It has been established that the traps energies form two characteristic series resulting from the vibrational quanta at 373 and 259 cm⁻¹, respectively. It is important that these vibrational quanta coincide with the frequencies of the totally symmetric vibrational modes of silicon chain which are active in Raman spectrum. The regularities mentioned are analyzed using the oscillatory traps model as the basis

Oscillatory regularity of charge carrier trap energy spectra in ZnSe single crystals

This article presents the results of an experimental investigation of the energy spectra of charge carrier traps in undoped high-resistivity ZnSe single crystals. Fourteen peaks were found in the thermostimulated luminescence spectra of the ZnSe samples at temperatures between 8 K and 450 K, and the thermal activation energies of the charge carrier traps were estimated for the most intense peaks. It was found that the energy spectra of the charge carrier traps in ZnSe exhibit oscillatory regularity, and the energy of a vibrational quantum was estimated to be ħω = 206 cm¯¹, which is in good agreement with the vibrational mode in the Raman spectrum. Additionally, a linear relationship was observed between the thermal activation energies of the charge carrier traps and the temperature positions of the maxima in the thermostimulated luminescence of ZnSe

Current of the first trimester of pregnancy at women with the low index of mass of the body and possibility of preventive maintenance of complications

The analysis of reproductive and somatic health, current of I trimester of pregnancy at women with a low index of mass of a body is carried out. Features of the anamnesis, a state of health before the present pregnancy are taped. Authentically significant complications in I trimester are established. Conducting schemes at a stage pregravidal preparations and in I trimester of pregnancy for the purpose of depression of frequency of possible complications are offered

Интраоперационные разрывы артериальных аневризм головного мозга и их прогнозирование

Больные с аневризмами головного мозга представляют важную проблему здравоохранения, что обусловлено, с одной стороны, неблагоприятным естественным течением болезни, с другой – риском развития осложнений, связанных с проведением лечения. Исход операции определяют патогенетические механизмы болезни и возможные хирургические осложнения. Особое место принадлежит интраоперационному разрыву (ИОР) аневризмы, так как возникающее кровотечение опасно невосполнимой кровопотерей, а предпринимаемые действия для его быстрой остановки могут сопровождаться травмой микрососудистых и нервных структур. В исследование включены 332 больных с церебральными аневризмами, которым проводили оперативное вмешательство в остром периоде разрыва артериальных аневризм передней циркуляции, обоего пола, средний возраст которых составил 43,9 лет. ИОР зарегистрированы у 94 из 332 больных (28,3%)