Dynamics of Alfvén waves in the night-side ionospheric Alfvén resonator at mid-latitudes

International audienceA numerical solution of the problem on dynamics of shear-mode Alfvén waves in the ionospheric Alfvén resonator (IAR) region at middle latitudes at nighttime is presented for a case when a source emits a single pulse of duration ? into the resonator region. It is obtained that a part of the pulse energy is trapped by the IAR. As a result, there occur Alfvén waves trapped by the resonator which are being damped. It is established that the amplitude of the trapped waves depends essentially on the emitted pulse duration ? and it is maximum at ?=(3/4)T, where T is the IAR fundamental period. The maximum amplitude of these waves does not exceed 30% of the initial pulse even under optimum conditions. Relatively low efficiency of trapping the shear-mode Alfvén waves is caused by a difference between the optimum duration of the pulse and the fundamental period of the resonator. The period of oscillations of the trapped waves is approximately equal to T, irrespective of the pulse duration ?. The characteristic time of damping of the trapped waves ?dec is proportional to T, therefore the resonator Q-factor for such waves is independent of T. For a periodic source the amplitude-frequency characteristic of the IAR has a local minimum at the frequency ?/?=(3/4)T, and the waves of such frequency do not accumulate energy in the resonator region. At the fundamental frequency ?=2?/T the amplitude of the waves coming from the periodic source can be amplified in the resonator region by more than 50%. This alone is a basic difference between efficiencies of pulse and periodic sources of Alfvén waves. Explicit dependences of the IAR characteristics (T, ?dec, Q-factor and eigenfrequencies) on the altitudinal distribution of Alfvén velocity are presented which are analytical approximations of numerical results

The Journal “Higher Education in Russia”: 30 Years of Research and Reflection

The round-table discussion dedicated to the 30th anniversary of the journal Vysshee obrazovanie v Rossii (Higher Education in Russia) took place on October 26, 2022 within the framework of XIII International conference of higher education (ICHE). Since its founding, the journal acts as a platform to discuss the urgent issues of higher education. In different periods, the researchers discussed competence-based approach, Bologna process, online education, quality of higher education, educational policy, educational management, assessment of learning outcomes, training of highly skilled researchers and teaching personnel, digitalization of education and many others. Today higher education in Russia is at a turning point of its history. We should impartially evaluate the path traveled, what has been achieved and what are the consequences. A look at the past became the subject of the round-table discussion

Термолиз аммиакатов рутения(II) и (III) в водных растворах при повышенных температурах и в твердой фазе.

In this work reactions of the hexaammine ruthenium(II) - [Ru(NH3)6]Cl2 and “ruthenium red” -[Ru3O2(NH3)14]Cl6 • 4Н2О chlorides in the water alkaline solution at 190˚С (autoclave) and in the solid phase are investigated. The mechanism of restoration of the ruthenium ion by inside sphere ammonia up to the metal condition is offered.зучены реакции термического разложения хлоридов гексамминрутения(II) [Ru(NH3)6]Cl2 и «рутениевой красной» - [Ru3O2(NH3)14]Cl6•4Н2О в водном щелочном растворе при 190 ˚С (автоклав) и в твердой фазе. Предложен механизм восстановлени

Твердофазное взаимодействие тетраамминов платины(II) и палладия(II) с перренатом аммония в воздушной и инертной атмосфере

Тhe solid phase interaction in systems [Pt(NH3)4]Cl2 - NH4ReO4 and [Pd(NH3)4]Cl2 - NH4ReO4 in argon and on air was studied. The final products of the solid phase interaction of the specified mixtures are systems containing platinum or palladium and rhenium dioxide.Изучено твердофазное взаимодействие в смесях [Pt(NH3)4]Cl2 и NH4ReO4 и [Pd(NH3)4]Cl2 и NH4ReO4 на воздухе и в токе аргона. Установлено, что конечными продуктами термолиза указанных смесей являются двухфазные системы, содержащие платину или палладий и диоксид рения

Тhe solid phase interaction between platinum(II) and palladium(II) tetraammines with ammonium perrhenate in the air and inert atmosphere

Тhe solid phase interaction in systems [Pt(NH3)4]Cl2 - NH4ReO4 and [Pd(NH3)4]Cl2 - NH4ReO4 in argon and on air was studied. The final products of the solid phase interaction of the specified mixtures are systems containing platinum or palladium and rhenium dioxide

Морской врач Пётр Фёдорович Фёдоров

The article presents the scientific, pedagogical and medical activities of the graduate of the Gatchina Nikolaevsky Orphan Institute and the Imperial Military Medical Academy (IMMA), surgeon privat-docent dentist Peter Fedorovich Fedorov, who worked in the IMMA for 22 years. It should be noted that the name of privat-docent P F. Fedorov was undeservedly forgotten. Only in the early 2000s, at the initiative of the staff of the Department of Maxillofacial Surgery, P F. Prokvatilov, D. Yu. Madaya, V F. Chernysha, G. S. Chepik, the articles about privat-docent P F. Fedorov began to publish in the collections of scientific conferences. P. F. Fedorov was a strong and consistent supporter of creating odontology department and clinic in IMMA for training of specialists with higher medical education who can treat dental diseases, diseases of oral organs and maxillofacial area. Long-term scientific, pedagogical and medical work of privatdocent P. F. Fedorov within the IMMA, his efforts and persistance in creating the department and clinic, make it possible to consider him the truly founder of domestic military odontology, and 1891 was defined the date of official recognition of military dentistry as an independent clinical discipline,, when, by the decision of the Conference, a private health center on dental diseases was opened in IMMA and a competition for a vacant position was announced. November 28, 1892, when the Conference of the IMMA approved the «Program of training in dental diseases», compiled by the assistant professor P. F. Fedorov, he began to give his lectures to students of the academy and military doctors. In 2007, a group of authors (G. A. Prokhvkilov, V. F. Chernysh, G. S. Chepik) published the monograph «P. F. Fedorov — the founder of domestic military dentistry « that was reissued in 2009 with the assistance of the Head of the Medical Service of the Russian Navy, Doctor of Medical Sciences, Colonel of the Medical Service, Professor V.K. Sementsov under the name «Privat-docent P. F. Fedorov» (Strokes to the portrait). February 5, 2008, by the decision of the Head of the Department of Maxillofacial Surgery and Dentistry, Colonel of Medical Service, Doctor of Medical Sciences, Honored Doctor of Russia, Professor G. I. Prkhvilov, a portrait of privat-docent for dental diseases IVMA P. F. Fedorov, written by a member of the Union of Artists of Russia A. A. Odeynikom was placed in the conference hall of the department.В статье представлена научная, педагогическая и врачебная деятельность выпускника Гатчинского Николаевского сиротского института и Императорской Военно-медицинской академии (ИВМА) морского врача приват-доцента одонтологии Петра Фёдоровича Фёдорова, проработавшего в стенах ИВМА 22 года. Следует отметить, что имя приват-доцента П. Ф. Фёдорова было незаслуженно забыто. Только в начале 2000-х годов по инициативе сотрудников кафедры челюстно-лицевой хирургии П. Ф. Прохватилова, Д. Ю. Мадая, В. Ф. Черныша, Г. С. Чепика в сборниках научно-практических конференций стали публиковаться статьи о приват-доценте П. Ф. Фёдорове. П. Ф. Фёдоров был убеждённым и последовательным сторонником создания в ИВМА кафедры и клиники одонтологии, а также подготовки специалистов с высшим медицинским образованием, умеющих лечить болезни зубов, органов полости рта и челюстно-лицевой области. Многолетний научный, педагогический и врачебный труд приват-доцента П. Ф. Фёдорова в стенах ИВМА, радение и настойчивость в создании кафедры и клиники одонтологии, позволяют с полным правом считать его основоположником отечественной военной стоматологии, а датой официального признания военной стоматологии самостоятельной клинической дисциплиной — 1891 год, когда решением Конференции в ИВМА была открыта приват-доцентура по зубным болезням и объявлен конкурс на занятие вакантной должности. 28 ноября 1892 г. Конференция ИВМА утвердила «Программу обучешя по зубнымъ бо-лезнямъ», составленную приват-доцентом П. Ф. Фёдоровым, и он начал читать свои лекции слушателям академии и военным врачам. В 2007 г. коллективом авторов (Г. А. Прохватилов, В. Ф. Черныш, Г. С. Чепик) была опубликована монография «П. Ф. Фёдоров — основоположник отечественной военной стоматологии». Монография переиздана в 2008 г. при содействии начальника медицинской службы ВМФ РФ, доктора медицинских наук, полковника медицинской службы, профессора В. К. Семенцова под названием «Приватъ-доцентъ П. Ф. Фёдоровъ» (Штрихи к портрету). 5 февраля 2008 г. по решению начальника кафедры челюстно-лицевой хирургии и стоматологии полковником медицинской службы, доктором медицинских наук, заслуженным врачом России, профессором Г. И. Прохватиловым в конференц-зале кафедры был помещен портрет приват-доцента по зубным болезням ИВМА П. Ф. Фёдорова, написанный членом Союза художников России А. А. Одейником.</p

Leptogorgins A–C, Humulane Sesquiterpenoids from the Vietnamese Gorgonian Leptogorgia sp.

Leptogorgins A&ndash;C (1&ndash;3), new humulane sesquiterpenoids, and leptogorgoid A (4), a new dihydroxyketosteroid, were isolated from the gorgonian Leptogorgia sp. collected from the South China Sea. The structures were established using MS and NMR data. The absolute configuration of 1 was confirmed by a modification of Mosher&rsquo;s method. Configurations of double bonds followed from NMR data, including NOE correlations. This is the first report of humulane-type sesquiterpenoids from marine invertebrates. Sesquiterpenoids leptogorgins A (1) and B (2) exhibited a moderate cytotoxicity and some selectivity against human drug-resistant prostate cancer cells 22Rv1