Off-axis MgB2 films using an in situ annealing pulsed laser deposition method

Highly smooth and c-axis oriented superconducting MgB2 thin films were prepared by pulsed laser deposition (PLD) with off-axis geometry. The films were deposited on Al2O3-C substrates perpendicularly aligned to a stoichiometric MgB2 target in a 120 mTorr high purity Ar background gas. An in situ annealing was carried out at 650C for 1 min in a 760 Torr Ar atmosphere. Despite the short annealing time, an x-ray theta-2 theta scan shows fairly good crystallization, according to the clear c-axis oriented peaks for the films. Both atomic force microscopy and the x-ray diffraction results indicate that the crystallite size is less than 50nm. The root mean square roughness of our off-axis film is ~4 nm in a 5x5 square micron area. The Tc onset value of the best off-axis film reaches 33.1 K with a narrow transition width of 0.9 K. The films showed no anisotropy in Hc2-T curves when parallel and perpendicular fields were applied. The slope of Hc2-T curves in low field regime is 1 T/K, which is among the highest reported values.Comment: 7 pages 7 figure

Les relations franco-roumaines de 1938 à 1944

L’effondrement du système politique international tel qu’il fut conçu par les traités de Paris (1918-1920) signifiait à la fois pour la Roumanie et la France, la fin d’une ère et le début d’une autre. En plus des conséquences intérieures et extérieures pour l’État français, la défaite de 1940 marqua également la fin de l’État national roumain et la perte du plus sûr allié de la Roumanie. Mais cependant, l’installation dans les deux pays de régimes politiques autoritaires permit la continuité des relations bilatérales. S’appuyant sur les intérêts économiques et politiques, les similitudes du discours idéologique contribuèrent à une telle continuité lors de la Deuxième Guerre mondiale. À l’été 1944, l’effondrement des deux régimes autoritaires presque simultané, semblait offrir des raisons supplémentaires à une continuité des relations bilatérales. Malheureusement, le contexte de sécurité de l’après-guerre, et la position de la France et de la Roumanie dans des blocs politiques et militaires opposés l’emportèrent. Bien qu’elles aient été maintenues, les relations bilatérales traversaient une période de déclin considérable lors de la première décennie d’après-guerre.The French-Romanian relations from 1938 till 1944. A breaking moment in the international political system, the years 1938-1944 represent for the history of Romanian-French relations a still unveiled period. In the general circumstances before and during the Second World War, those relations passed through many stages: 1938-1939 (from the Anschluss to the beginning of the war); September 1, 1939 – May 1940; 1940-1944. The collapse of the international political system as it was designed by the Peace Treaties of Paris (1918-1920) meant for both Romania and France the end of an era and the beginning of a new one. Along with its internal and external significances for the French state, the French defeat of 1940 also marked the end of the Romanian national state and the losing of Romania’s most staunch ally. Even so, the setting up in the two countries of authoritarian political regimes allowed rather then hindered the continuity of bilateral relations. Along with political and economical interests, the similarities in the ideological discourse contributed to such continuity during the Second World War. In the summer 1944, the break down of the two authoritarian regimes almost in the same time seemed to offer supplementary reasons for a continuity of the Romanian-French relations. Unfortunately, the post-war security environment and the positioning of France and Romania in opposite political and military blocks prevailed. Although they have been maintained, the bilateral relations passed through a considerable decline during the first post-war decade

Les relations franco-roumaines de 1938 à 1944

L’effondrement du système politique international tel qu’il fut conçu par les traités de Paris (1918-1920) signifiait à la fois pour la Roumanie et la France, la fin d’une ère et le début d’une autre. En plus des conséquences intérieures et extérieures pour l’État français, la défaite de 1940 marqua également la fin de l’État national roumain et la perte du plus sûr allié de la Roumanie. Mais cependant, l’installation dans les deux pays de régimes politiques autoritaires permit la continuité des relations bilatérales. S’appuyant sur les intérêts économiques et politiques, les similitudes du discours idéologique contribuèrent à une telle continuité lors de la Deuxième Guerre mondiale. À l’été 1944, l’effondrement des deux régimes autoritaires presque simultané, semblait offrir des raisons supplémentaires à une continuité des relations bilatérales. Malheureusement, le contexte de sécurité de l’après-guerre, et la position de la France et de la Roumanie dans des blocs politiques et militaires opposés l’emportèrent. Bien qu’elles aient été maintenues, les relations bilatérales traversaient une période de déclin considérable lors de la première décennie d’après-guerre.The French-Romanian relations from 1938 till 1944. A breaking moment in the international political system, the years 1938-1944 represent for the history of Romanian-French relations a still unveiled period. In the general circumstances before and during the Second World War, those relations passed through many stages: 1938-1939 (from the Anschluss to the beginning of the war); September 1, 1939 – May 1940; 1940-1944. The collapse of the international political system as it was designed by the Peace Treaties of Paris (1918-1920) meant for both Romania and France the end of an era and the beginning of a new one. Along with its internal and external significances for the French state, the French defeat of 1940 also marked the end of the Romanian national state and the losing of Romania’s most staunch ally. Even so, the setting up in the two countries of authoritarian political regimes allowed rather then hindered the continuity of bilateral relations. Along with political and economical interests, the similarities in the ideological discourse contributed to such continuity during the Second World War. In the summer 1944, the break down of the two authoritarian regimes almost in the same time seemed to offer supplementary reasons for a continuity of the Romanian-French relations. Unfortunately, the post-war security environment and the positioning of France and Romania in opposite political and military blocks prevailed. Although they have been maintained, the bilateral relations passed through a considerable decline during the first post-war decade

High-quality Polyurethane Foams and Sheets from Sustainable Natural Resources

Bio-polymers from sustainable natural resources serve mankind keeping environmental factors under consideration. Resources such as soybean, castor and orange oil are among highly cultivable agro-resources. Polyols formulated from these oils shows clean-environmental pathway for synthesizing polyurethane foams and sheets. Facile single-step synthesis, with negligible waste as well as byproducts produces 100% qualitative yield for polyurethane foams. Present work displays use of synthesized polyols in developing polyurethane foams and casts. Viscometry, FTIR spectroscopy, GPC and other chemical analysis were done to ensure the quality of the raw materials. Cast Sheets and foams were produced by chemical polymerization with di-phenyl methane diisocyanate using different formulations of polyols. Foams and sheets were stable until 200oC. Mercaptenized polyol sheets displayed ultimate tensile stress around 25 MPa. Hence, overall study suggests that these bio-polyols from sustainable resources serves to be very good source for polyurethane foams and sheets

Ion implantation of calcium and zinc in magnesium for biodegradable implant applications

In this study, magnesium was implanted with calcium-ion and zinc-ion at fluences of 10(15), 10(16), and 10(17) ion.cm(-2), and its in vitro degradation behaviour was evaluated using electrochemical techniques in simulated body fluid (SBF). Rutherford backscattering spectrometry (RBS) revealed that the implanted ions formed layers within the passive magnesium-oxide/hydroxide layers. Electrochemical impedance spectroscopy (EIS) results demonstrated that calcium-ion implantation at a fluence of 10(15) ions.cm(-2) increased the polarisation resistance by 24%, but higher fluences showed no appreciable improvement. In the case of zinc-ion implantation, increase in the fluence decreased the polarisation resistance. A fluence of 10(17) ion.cm(-2) decreased the polarisation resistance by 65%, and fluences of 10(15) and 10(16) showed only marginal effect. Similarly, potentiodynamic polarisation results also suggested that low fluence of calcium-ion decreased the degradation rate by 38% and high fluence of zinc-ion increased the degradation rate by 61%. All the post-polarized ion-implanted samples and the bare metal revealed phosphate and carbonate formation. However, the improved degradative behaviour in calcium-ion implanted samples can be due to a relatively better passivation, whereas the reduction in degradation resistance in zinc-ion implanted samples can be attributed to the micro-galvanic effect

Comparative study of in situ and ex situ MgB2 films deposited by pulsed laser deposition

Two types of MgB2 films were prepared by pulsed laser deposition (PLD) with in situ and ex situ annealing processes respectively. Significant differences in properties between the two types of films were found. The ex situ MgB2 film has a Tc of 38.1K, while the in situ film has a depressed Tc of 34.5K. The resistivity at 40K for the in situ film is larger than that of the ex situ film by a factor of 6. The residual resistivity ratios (RRR) are 1.1 and 2.1 for the in situ and ex situ films respectively. The Jc-H curves of the in situ film show a much weaker field dependence than those of the ex situ film, attributable to stronger flux pinning in the in situ film. The small-grain feature and high oxygen level may be critical for the significant improvement of Jc in the in situ annealed MgB2 film.Comment: 6 pages, 6 figure

Lifestyle Changes and Weight Loss: Effects in PCOS

Even though controversies surrounding the polycystic ovary syndrome are not yet close to be solved, its clinical manifestations are well known—insulin resistance and obesity, hirsutism, irregular and anovulatory menstrual cycles. The treatment of polycystic ovarian syndrome (PCOS) is mainly symptomatic as its etiology is not yet clear. Lifestyle changes are the primary therapy in overweight and obese women with PCOS. According to majority of the studies, lifestyle changes are the most effective form of treatment not only for weight loss but also for the improvement of insulin sensitivity, decreasing incidence of metabolic syndrome and type 2 diabetes. Studies also show that weight loss has fertility benefits by restoring ovulatory cycles. Although initial studies researching pharmacologic treatment were showing excellent results concerning the weight loss, maintenance of weight loss and reduction of cardiovascular risks, some of these drugs were in the end, has proven to actually increase the risk for cardiovascular events and were removed from the market. Bariatric surgery has been demonstrated to improve or even cure type 2 diabetes, hypertension, hyperlipidemia, and obstructive sleep apnea. More so, there are studies that reported complete resolution of all features of PCOS, even hirsutism, hyperandrogenism, anovulation, and menstrual irregularity