The nighttime ionosphere of Mars from Mars-4 and Mars-5 radio occultation dual-frequency measurements

Dual frequency radio sounding of the Martian nighttime ionosphere was carried out during the exits from behind the planet of the Mars-4 spacecraft on February 2, 1974 and the Mars-5 spacecraft on February 18, 1974. In these experiments, the spacecraft transmitter emitted two coherent monochromatic signals in decimeter and centimeter wavelength ranges. At the Earth receiving station, the reduced phase difference (or frequencies) of these signals was measured. The nighttime ionosphere of Mars measured in both cases had a peak electron density of approximately 5 X 1,000/cu cm at an altitude of 110 to 130 km. At the times of spacecraft exit, the solar zenith angles at the point of occultation were 127 deg and 106 deg, respectively. The height profiles of electron concentration were obtained assuming spherical symmetry of the Martian ionosphere

Agroecological evaluation of interrelationships of soil properties in time and space

This paper assesses the relationship between the physico-chemical and agro-chemical properties of sod-podzolic soils in the Moscow region and ordinary heavy-loamy chernozems in the Krasnodar region within the catenas and down the soil profile. Soil properties changed significantly through seasonal dynamics. From the end of April to the middle of June in the soil solution of sod-podzolic soils, the value of Eh varied from 534 to 759 mv, the ratio of NO3/NH4 – from 0.2 to 15.4; the content of water-soluble manganese – from 4.0 to 10.1. At the same time, there was a delay in change of soil properties, as humidity and temperature varied. It is shown that in different intervals of soil properties between individual indicators of fertility, the effects of synergism and antagonism are manifested. The degree of mutual influence of soil properties depended on both the degree of soil fertilization and the degree of their cultivation. Information relationships were manifested not only between the soil properties, but also between the processes. Temporary excessive moistening of the soil led to acidification of the soil in the washing type of water mode, and to alkalinization in the non-washing type. It is proposed to account for the relationship of soil properties with humidity, temperature, pH, and Eh to adjust the components of farming systems

ВЛИЯНИЕ ФОРМЫ И РАЗМЕРА ЧАСТИЦ НА ОСТЕОИНТЕГРАЦИЮ ПОРИСТЫХ ИМПЛАНТАТОВ ИЗ ПОРОШКА ТИТАНА

The results of studies of the effect of particle size, pore size, shape, metallic-ray powder osteointergatsii quality (germination of bone tissue into the pores of the implant) are given. It is shown that the adhesion strength at the bone tissue implant made from titanium sponge powder 8-11 % higher than that of the implants obtained from spherical powders.Приведены результаты исследований влияния размеров частиц, размеров пор, формы металлических порошков на качество остеоинтергации (прорастания костной ткани в поры имплантата). Показано, что прочность сцепления с костной тканью у имплантатов, полученных из губчатого порошка титана, на 8-11 % выше, чем у имплантатов, полученных из сферических порошков

On charged impurity structures in liquid helium

The thermoluminescence spectra of impurity-helium condensates (IHC) submerged in superfluid helium have been observed for the first time. Thermoluminescence of impurity-helium condensates submerged in superfluid helium is explained by neutralization reactions occurring in impurity nanoclusters. Optical spectra of excited products of neutralization reactions between nitrogen cations and thermoactivated electrons were rather different from the spectra observed at higher temperatures, when the luminescence due to nitrogen atom recombination dominates. New results on current detection during the IHC destruction are presented. Two different mechanisms of nanocluster charging are proposed to describe the phenomena observed during preparation and warmup of IHC samples in bulk superfluid helium, and destruction of IHC samples out of liquid helium

ПОЛУЧЕНИЕ ВЫСОКОПРОЧНЫХ ДЕФОРМИРУЕМЫХ АЛЮМИНИЕВЫХ СПЛАВОВ ТИПА АМг10

Traditional grades of aluminum alloys do not always meet the requirements of modern aerospace engineering. Al–Si foundry alloys possess insufficient mechanical strength characteristics and low plasticity due to their structural features (coarse brittle silicon inclusions and intermetallic phases). Therefore they cannot be exposed to pressure treatment. A technique for producing high-strength aluminum alloys, which consists in obtaining ring blanks by means of direct crystallization of melts with application of non-stationary centrifugal force fields and simultaneous introduction of modifiers, is proposed. The microstructure and plasticity of resulting tube-shaped blanks allow them to be exposed to sheeting for subsequent production of pipe workpieces with mechanical strength commensurate with mechanical strength of structural steel. The technique involves hydrothermal synthesis of nanostructured particles of aluminum oxide, which are overheated above the melt temperature prior to introduction into the molten aluminum alloy. This procedure enhances the processes of intercrystalline hardening with minimal fluctuations of internal stresses within the hardened material. The materials have tensile strength of up to 380 MPa (before modification by nanodispersed aluminum oxide it was 210 MPa). The microstructure has showed changes in the acicular dendrite component, which tends to become more dispersed and equiaxial. Eventually this leads to an increase in the mechanical strength by a factor of 1.25–1.32. Традиционные марки алюминиевых сплавов не всегда могут обеспечить выполнение требований современной ракетно-космической и авиационной техники. Литейные сплавы системы Al–Si из-за структурных особенностей – грубых хрупких включений кремния и интерметаллических фаз, имеют невысокий уровень прочностных свойств и низкую пластичность, не позволяющую проводить их обработку давлением. Предложена технология создания высокопрочных алюминиевых сплавов, заключающаяся в получении кольцевых заготовок методом направленной кристаллизации расплава при наложении нестационарных силовых полей центробежных сил и одновременном введении модификаторов. Полученные заготовки имеют микроструктуру и пластичность, позволяющую подвергать их раскатке, и форму трубных заготовок, механическая прочность которых соизмерима с конструкционной сталью. Технология включает в себя гидротермальный синтез наноструктурированных частиц оксида алюминия, которые перед введением в расплав алюминиевого сплава перегреваются выше температуры расплава, что повышает полноту протекания процессов интеркристаллического упрочнения при минимальных колебаниях по объему упрочненного материала внутренних напряжений. Материалы имеют предел прочности до 380 МПа (до модификации нанодисперсным оксидом алюминия – 210 МПа). В микроструктуре наблюдается изменение игольчатой дендритной составляющей, которая становится более дисперсной и равноосной, что и приводит к повышению механической прочности в 1,25–1,32 раза.

Вариант расчета экономической эффективности освоения новой техники, технологии и оборудования

The paper gives a variant of determination of economic efficiency while using new technique, technology and equipment under conditions of market economy. The calculation has been made for technological processes of machining steel, cast iron and aluminium alloy cases of automobile brake cylinders.Представлен вариант определения экономической эффективности при использовании новой техники, технологии и оборудования в условиях рыночной экономики. Расчет проведен для технологических процессов механической обработки корпусов автомобильных тормозных цилиндров, изготовленных из стали, чугуна и алюминиевого сплава

Mutations in isocitrate dehydrogenase 1 and 2 occur frequently in intrahepatic cholangiocarcinomas and share hypermethylation targets with glioblastomas

Mutations in the genes encoding isocitrate dehydrogenase, IDH1 and IDH2, have been reported in gliomas, myeloid leukemias, chondrosarcomas, and thyroid cancer. We discovered IDH1 and IDH2 mutations in 34 of 326 (10%) intrahepatic cholangiocarcinomas. Tumor with mutations in IDH1 or IDH2 had lower 5-hydroxymethylcytosine (5hmC) and higher 5-methylcytosine (5mC) levels, as well as increased dimethylation of histone H3K79. Mutations in IDH1 or IDH2 were associated with longer overall survival (p = 0.028) and were independently associated with a longer time to tumor recurrence after intrahepatic cholangiocarcinoma resection in multivariate analysis (p = 0.021). IDH1 and IDH2 mutations are significantly associated with increased levels of p53 in intrahepatic cholangiocarcinomas, but no mutations in the p53 gene were found, suggesting that mutations in IDH1 and IDH2 may cause a stress that leads to p53 activation. We identified 2,309 genes that were significantly hypermethylated in 19 cholangiocarcinomas with mutations in IDH1 or IDH2, compared with cholangiocarcinomas without these mutations. Hypermethylated CpG sites were significantly enriched in CpG shores and upstream of transcription start sites, suggesting a global regulation of transcriptional potential. Half of the hypermethylated genes overlapped with DNA hypermethylation in IDH1-mutant gliobastomas, suggesting the existence of a common set of genes whose expression may be affected by mutations in IDH1 or IDH2 in different types of tumors

Cassini Radio Science

Cassini radio science investigations will be conducted both during the cruise (gravitational wave and conjunction experiments) and the Saturnian tour of the mission (atmospheric and ionospheric occultations, ring occultations, determinations of masses and gravity fields). New technologies in the construction of the instrument, which consists of a portion on-board the spacecraft and another portion on the ground, including the use of the Ka-band signal in addition to that of the S- and X-bands, open opportunities for important discoveries in each of the above scientific areas, due to increased accuracy, resolution, sensitivity, and dynamic range.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43765/1/11214_2004_Article_1436.pd