Учебный комплекс для изучения русского языка как иностранного (РКИ) "В добрый путь!" и компьютерный тренажер по РКИ

A description of the nationally oriented training complex for learning Russian as a foreign language "V Dobryi Put’!" for German speakers which includes a textbook, an audio-supplement, a video-film and a test system is given. The computer-based training system, designed for this complex ensures effective teaching foreign students Russian phonetics, vocabulary, grammar, speech etiquette, and also facilitates the formation of the necessary communication skills.Приводится описание национально-ориентированного учебного комплекса по РКИ для немецкоговорящих "В добрый путь!", который включает учебник, аудиоприложение, видеофильм и систему тестов. Разработанный для данного комплекса компьютерный тренажер обеспечивает эффективное обучение иностранных учащихся русской фонетике, лексике, грамматике, речевому этикету, а также облегчает формирование необходимых коммуникативных навыков

За кадры. 1940. № 17 (291)

Большевистские кадры решают всеЮбилеи института - праздник для меняПоезжай за моря - океаны / М. В. ИсаковскийКак оценивали знания студентов / А. Я. ТкаченкоКонтролировать и помогать выполнению конкурсных обязательств / ВинокуровНаш пятилетний путь / В. ТатариновНаши ученые за работой. Новое месторождение марганца / К. В. РадугинНаши ученые за работой. Динамика фрезерованияНаши ученые за работой. Крупный вклад в технику высоких напряженийНаши ученые за работой. В поисках точности и чистоты обработки металлических поверхностейНаши ученые за работой. Перспективы Горного Алтая / Ф. Н. ШаховПлан вводных лекций и семинарских занятий по основам марксизма-ленинизмаЖелезнодорожная насыпь в условиях вечной мерзлоты / П. А. ПаровозниковВ низовьи Томи / В. Татарино

In situ observation of the impact of hydrogen bubbles in Al-Cu melt on directional dendritic solidification

Much research has already been focused on the solid-bubble interaction in the interdendritic space for solidifying materials. However, commonly, bubble nucleation is not limited to the mushy zone but also occurs in the liquid melt. In the present research on an Al-10%wt. Cu alloy, the interaction between these bubbles and the approaching solidification front becomes apparent under in situ X-radiography and allows for new insights into the influence of bubbles on the solidifying microstructure. The observed effects comprise bulging of the solidification front toward the bubble, bending of dendrites in front of the bubble, coronal outgrowths surrounding the bubbles, as well as bubble growth, bubble pushing, and bubble eruption. It is found that for the present Al-Cu alloy, the local variation in the solidification speed can be attributed to the bubbles' insulating properties. The range of this effect was observed to be up to 900mum, depending on the bubble diameter, locally increasing solidification speed by up to 350%. The influences of Marangoni vortices and coronal nucleation of misoriented dendrites around bubbles on the homogeneity of the microstructure are discussed. A comparison with experiments on model alloys and simulations from various other studies highlights the similarities and differences to this metallic alloy system

In situ observation of the cryophile migration of hydrogen bubbles in Al-alloys during directional melting and the impact of surface tension

During metallurgical processing, gas bubbles nucleate and interact with the microstructure, which can result in severe defects. The research presented in this article focuses on in situ observation of bubble movement in semi-solid aluminum alloys (Al-Ge and Al-Cu) during a melting cycle. X-radiography is used to monitor the migration of H-bubbles in the semi-solid mush. For both alloys, H-bubbles are observed to burrow through the mushy zone towards the colder side of a horizontal gradient furnace leaving behind solute-enriched channels. This stands in contrast to the commonly observed bubble movement towards the hot side of the material caused by Marangoni flow-fields surrounding the gas pocket induced by gradients in the bubble’s surface tension. Different dependencies of the surface tension on temperature and concentration for the two alloys are presented as explanation for the observed atypical phenomenon. These results suggest different dominant effects acting on the bubbles, temperature for Al-Ge and concentration for Al-Cu, and explain the cryophile behavior observed