Electrodeposition of Fe-Sn from the chloride-based electrolyte

The conditions for electrodeposition of Fe-Sn alloys from a novel, environmentally friendly, ferrous chloride-based electrolyte were studied. The influence of the pH on the electrolyte stability and deposit stoichiometry was studied and discussed. Anodic stripping voltammetry (ASV), XRD and SEM/EDX were used to characterise the electrodeposited phases. The results from ASVs indicated the possibility to deposit at least two different phases at high overpotentials. Hull cell depositions in an electrolyte with a Sn to Fe ratio 1:1 and a pH value of 2.8 showed regular deposition of Fe-Sn. Fe-rich deposits (54.84 at.-%) were obtained from an electrolyte with Sn to Fe ratio 1:10. The XRD results were compatible with the electrochemical investigations. In all studied samples β-Sn, FeSn2 and Fe5Sn3 were detected. The presence of ferromagnetic Fe5Sn3 was not influenced by the Sn to Fe ions ratio in the electrolyte

Pulsed laser ablation and incubation of nickel, iron and tungsten in liquids and air

Incubation effects in the nanosecond laser ablation of metals exhibit a strong dependence on the thermal and mechanical properties of both the target material and the background gas or liquid. The incubation in air is controlled mainly by thermal properties such as the heat of vaporization. In liquid, the correlation of the incubation and the ultimate tensile stress of the metals suggests that incubation may be related to the mechanical impact on the solid material by the cavitation bubble collapse, causing accumulation of voids and cracks in the subsurface region of the ablation craters. At high ultimate tensile stress, however, the low sensitivity to the environment suggests that the mechanical impact is likely to play a negligible role in the incubation. Finally, the correlation between the incubation and the carbon content of alcoholic liquids may be explained by an absorptivity increase of the cavity surfaces due to carbonaceous deposits generated by laser-induced pyrolysis, or by the mechanical impact of long-living bubbles at higher dynamic viscosity of liquids

Advances in multispectral and hyperspectral imaging for archaeology and art conservation

Multispectral imaging has been applied to the field of art conservation and art history since the early 1990s. It is attractive as a noninvasive imaging technique because it is fast and hence capable of imaging large areas of an object giving both spatial and spectral information. This paper gives an overview of the different instrumental designs, image processing techniques and various applications of multispectral and hyperspectral imaging to art conservation, art history and archaeology. Recent advances in the development of remote and versatile multispectral and hyperspectral imaging as well as techniques in pigment identification will be presented. Future prospects including combination of spectral imaging with other noninvasive imaging and analytical techniques will be discussed

ОЦЕНКА ЭФФЕКТИВНОГО КОЭФФИЦИЕНТА ПОГЛОЩЕНИЯ РОГОВИЦЫ ГЛАЗА НА ДЛИНЕ ВОЛНЫ 213 НМ ИЗ АБЛЯЦИОННЫХ ИЗМЕРЕНИЙ

It is shown experimentally that a cornea represents a 213 nm UV inhomogeneous material both at depth and around a surface in relation to UV effective absorption coefficient and local laser depth ablation rate, which should be taken into account for a more exact planning of a profile of removed cornea collagen material during eye vision correction. Экспериментально показано, что роговица глаза для УФ-излучения (213 нм) представляет собой неоднородный материал как по глубине, так и вдоль поверхности, в отношении эффективного коэффициента поглощения и локальной скорости абляционного удаления материала роговицы, что необходимо учитывать для более точного планирования профиля удаляемого коллагена роговицы при операциях коррекции зрения.

ЛАЗЕРНАЯ АБЛЯЦИОННАЯ ОБРАБОТКА РОГОВИЦЫ ГЛАЗА КОМБИНИРОВАННЫМ ИЗЛУЧЕНИЕМ 213+1440 нм

The laser ablation efficiency of eye cornea for UV (213 nm) and combined IR+UV (213 nm + 1444 nm) ablation treatment in safe conditions, preventing laser coagulation at 1444 nm, was investigated. It is shown that the IR+UV combination, when, at the first stage of cornea treatment, an IR laser pulse at 1444 nm, falling into a water absorption band with an absorption coefficient of about 31 cm–1, dehydrates a superficial corneal layer and at the second stage, in about 100 ms, a UV laser pulse at 213 nm ablates a thin (about 1–3 mm) collagen layer, gives promising results. Due to the controlled dehydration of the corneal surface, the process of 213 nm + 1444 nm laser ablation ensures a better reproducibility and a higher productivity. Исследована эффективность лазерной абляции роговицы глаза УФ-излучением (213 нм) и комбинированным УФ+ИК-излучением (213 нм + 1444 нм) в условиях обработки, когда лазерная коагуляция на длине волны 1444 нм не происходит. Показано, что комбинированное УФ+ИК-воздействие, когда сначала ИК-лазерный импульс (1440 нм), попадающий в полосу поглощения воды с коэффициентом поглощения около 31 см–1, обезвоживает поверхностный слой роговицы и следующий через ~100 мкс УФ-лазерный импульс (213 нм) удаляет тонкий поверхностный слой (1–3 мкм) коллагена, дает многообещающие результаты. Благодаря контролируемому обезвоживанию поверхности роговицы процесс лазерной абляции комбинированным (213 нм + 1444 нм) излучением обеспечивает лучшую воспроизводимость и более высокую производительность.

САМОПОГЛОЩЕНИЕ ИЗЛУЧЕНИЯ НА ДЛИНЕ ВОЛНЫ 213 нм ПРИ ЛАЗЕРНОМ ВОЗДЕЙСТВИИ НА РОГОВИЦУ ГЛАЗА

The laser ablation efficiency of cornea at 213 nm radiation was investigated and optimized. It is shown that self-absorption of radiation at 213 nm in a thin cloud of ablated material takes place and strongly influences the ablation efficiency. Ablation products are being blown out in the lateral direction along the cornea surface, as a result of which the pulse fluence at the pit boundary Fbnd is more than the threshold fluence Fth. As a consequence, a pit radius rbnd is less than a laser beam radius rth corresponding to the threshold fluence Fth that should be taken into account in planning ablation surgery at 213 nm radiation. Исследована и оптимизирована эффективность лазерной абляции роговицы глаза УФ-излучением с длиной волны 213 нм. Показано, что самопоглощение лазерного излучения 213 нм в тонком облаке испаренного материала сильно влияет на эффективность абляции. Продукты абляции выбрасываются в боковом направлении вдоль поверхности роговицы, в результате чего плотность энергии импульса на границе абляционной лунки Fbnd выше, чем пороговая плотность энергии Fth. Как следствие, радиус лунки rbnd меньше радиуса rth  лазерного луча, соответствующего пороговой плотности энергии импульса Fth, что необходимо учитывать при планировании абляционной хирургии глаза излучением 213 нм.