48 research outputs found
Effect of surfactant/water ratio and reagents’ concentration on sizedistribution of manganese carbonate nanoparticles synthesized bymicroemulsion mediated route
No full texttIn this work nanoparticles of manganese carbonate were produced by microemulsion-mediated routeat room temperature, without any post-thermal treatment. All produced samples were characterizedby XRD and by TEM and obtained images were analyzed in order to evaluate particle size distribution,mean size and polydispersity (variance). The influence of water–surfactant molar ratio and concentrationof reagents were investigated in the range 5–7.5 and 0.25–1.0 M, respectively, according to factorialdesign. Significant effects on particle mean size and polydispersity were assessed by statistical analysis.Results showed that by increasing the water–surfactant molar ratio from 5 to 7.5, the average particlesize increased from less than 10 nm to around 100 nm, and the standard deviation increased from lessthan 5 nm to 35 nm. Statistical analysis put in evidence that water–surfactant molar ratio has significantpositive effect on both mean and variance of particle size. Concentration of reactants, in the investigatedrange, did not influence mean size of particles, while significant changes of variance were observed:passing from 0.25 to 1 M concentration, variances of particle size increased for w = 5 and for w = 6.25,while decreased for w = 7.5
Popularization and Education at Gunma Astronomical Observatory
No full textThe largest public observatory in Japan, Gunma Astronomical Observatory (GAO), is now under construction. The purposes of this observatory are popularization, education and research of astronomy and astrophysics. The main telescope is a 150-cm reflector equipped with a public-viewing eyepiece, a highresolution spectroscope, a near-IR camera, and so on. In this article, I will report an outline of the observatory and our plan for education and popularization of astronomy and astrophysics via the internet
THE POSSIBILITIES OF PROMOTING ADAPTATION IN CLASS 1
No full textPētījuma mērķis: pētīt un analizēt adaptācijas sekmēšanas iespējas 1. klasē. Uzsākot skolas gaitas, bērna dzīve krasi izmainās. Sākumskolas pirmajā klasē jāapgūst jauna sociālā loma – skolēns. Skolēnam ir jāpielāgojas jaunam dienas režīmam, jāpakļaujas noteiktai kārtībai, jākomunicē ar vienaudžiem un pieaugušajiem, kurus bērns iepriekš nav pazinis. Lai pielāgotos jaunajiem apstākļiem, nepieciešama gribas piepūle, kas prasa zināmu psihoemocionālu briedumu. Bērnam ir jādod laiks un jārada piemēroti apstākļi, lai mācīšanās nekļūtu par smagu apgrūtinājumu. Šajā laikā, adaptācijas periodā, pedagogi ciešā sadarbībā ar vecākiem nodrošina bērnam individuālu atbalstu, kas atbilst viņa konkrētajām vajadzībām. Bērnu sagatavotības līmenis ir atšķirīgs, tāpēc sākumskolotājiem, kas darbojas ar bērniem adaptācijas periodā jāpārzina vecumposma attīstības īpatnības un jālieto daudzveidīgi metodiskie paņēmieni, lai 1,5 -2 mēnešu laikā bērns adaptētos sākumskolā. Bakalaura darba autore pētījumā apstiprina hipotēzi: bērns labāk adaptējas 1. klasē, ja: •pedagogs pārzina jaunākā skolas vecumposma bērnu attīstības likumsakarības; •tiek ņemtas vērā bērna individuālās vajadzības, intereses un pieredze; •tiek izmantotas daudzveidīgas metodiskas pieejas adaptācijas sekmēšanai. Autore secina, ka skolotāja un vecāku sadarbībai ir būtiska loma, pieaugušo sadarbība adaptācijas periodā ietekmē skolēna turpmāko mācību darbu visā izglītošanās periodā. Darbs ir noderīgs informācijas avots studentiem, pedagogiem, vecākiem, un citām personām, kas iesaistītas sākumskolēnu audzināšanā.The aim of the research: to study and analyze the possibilities of improving adaptation in the 1st grade. At the beginning of school, a child's life changes dramatically. In the first grade of primary school, a new social role must be acquired - a student. The student has to adapt to a new daily routine, follow certain procedures, communicate with peers and adults that the child has not known before. Adapting to new conditions requires a effort of the will, which requires a certain psycho-emotional maturity. The child must be given time and appropriate conditions so that learning does not become a serious burden. During this period of adaptation, educators, in close cooperation with the parents, provide the child with individual support that meets his or her specific needs. The level of preparedness of children is different, so primary teachers who work with children during the adaptation period must know the specifics of the development of the age group and use a variety of methodological techniques in order for the child to adapt to primary school within 1.5 to 2 months. In the research, the author confirms the hypothesis: a child adapts better in the 1st grade if: •the teacher knows the principles and specifics of the development of the youngest children of the school age; •the child's individual needs, interests and experience are taken into account; •diverse methodological approaches are used to facilitate adaptation. The author of the bachelor's thesis concludes that the cooperation of the teacher and parents plays an important role, the cooperation of adults during the adaptation period influences the student's further studies throughout the period of education. The work is a useful source of information for students, teachers, parents, and others involved in teaching primary school students
Production of Rare-Earth-Free Iron Nitride Magnets (α″-Fe<sub>16</sub>N<sub>2</sub>)
No full textTo realize rare-earth-free magnets, we studied iron nitride (α″-Fe16N2) magnets, which contain no rare-earth elements. Fe-N powder with the α″-Fe16N2 phase has a high saturation magnetization comparable to high-performance rare-earth magnets but is not stable at temperatures over 539 K. We consolidated Fe-N powder into bulk material at low temperatures by spark plasma sintering (SPS) and spark plasma sintering with dynamic compression (SPS-DC). Fe-N magnets were successfully obtained at low temperatures of 373–573 K. The magnets produced by the SPS-DC method had a higher density than those produced by the SPS method. The density of the magnets produced by the SPS-DC method increased as the consolidation temperature increased. That produced at 373 K had a saturation magnetization of 1.07 T with a coercivity of 0.20 MA/m
Applying the Hands-On Universe Image Processing Tool to Other Sciences
No full textIn the Science Club of the Technical High School Affiliated with Tokyo Institute of Technology, we tried participating in the Hands-On Universe (HOU) astronomical education program in 1997. The image processing tool, HOU-IP, is an excellent tool that we have applied to measurement of pollen in photos obtained by means of a Scanning Electron Microscope (SEM). Therefore, we recognize that HOU-IP is a good tool not only for astronomy but also other sciences
Encephalitozoon hellem in a patient with CD4+ T-cell prolymphocytic leukemia: case report and genomic identification.
No full textInternational audienceFive cases of microsporidioses among leukemic patients, 4 in myeloid-leukemic patients and 1 in a chronic lymphocytic leukemia, have been described until now. We report a case of microsporidiosis and the genomic identification of Encephalitozoon hellem in a patient with CD4(+) T-cell prolymphocytic leukemia
Stability of the perovskite structure and possibility of the transition to the post-perovskite structure in CaSiO3, FeSiO3, MnSiO3 and CoSiO3
No full textHigh pressure and high temperature experiments on CaSiO3, FeSiO3, MnSiO3 and CoSiO3 using a laser-heated diamond anvil cell combined with synchrotron X-ray diffraction were conducted to explore the perovskite structure of these compounds and the transition to the post-perovskite structure. The experimental results revealed that MnSiO3 has a perovskite structure from relatively low pressure (ca. 20 GPa) similarly to CaSiO3, while the stable forms of FeSiO3 and CoSiO3 are mixtures of mono-oxide (NaCl structure) + high pressure polymorph of SiO2 even at very high pressure and temperature (149 GPa and 1800 K for FeSiO3 and 79 GPa and 2000 K for CoSiO3). This strongly suggests that the crystal field stabilization energy (CFSE) of Fe2+ with six 3d electrons and Co2+ with seven 3d electrons at the octahedral site of mono-oxides favors a mixture of mono-oxide + SiO2 over perovskite where Fe2+ and Co2+ would occupy the distorted dodecahedral sites having a smaller CFSE (Mn2+ has five 3d electrons and has no CFSE). The structural characteristics that the orthorhombic distortion of MnSiO3 perovskite decreases with pressure and the tolerance factor of CaSiO3 perovskite (0.99) is far from the orthorhombic range suggest that both MnSiO3 and CaSiO3 perovskites will not transform to the CaIrO3-type post-perovskite structure even at the Earth's core-mantle boundary conditions, although CaSiO3 perovskite has a potentiality to transform to the CaIrO3-type post-perovskite structure at still higher pressure as long as another type of transformation does not occur
Emerg Infect Dis
No full textWe describe 7 cases of extensive tinea corporis since 2018 in a hospital in Paris, France, after failure to cure with terbinafine. Molecular analysis indicated Trichophyton mentagrophytes internal transcribed spacer type VIII (T. indotineae). This strain, which has mutations in the squalene epoxidase gene, is spreading on the Indian subcontinent
Crystal structure and physical properties of Yb 2 In and Eu 2-x Yb x In alloys
No full textInternational audienceWhile binary RE 2 In, where RE = rare earth, have been reported a few decades ago, recent investigations revealed intriguing new physical insights. For instance, the discovery of a nearly ideal first-order ferromagnetic transition in Eu 2 In calls for further exploration of structures and properties of RE 2 In, in particular for the leastdocumented RE = Eu and Yb cases. Here, we investigate Eu 2-x Yb x In pseudobinaries with nominal values of x = 0.25, 0.5, 0.75, 1, 1.5, 2 by powder x-ray diffraction (including as function of temperature from 100 to 375 K for Yb 2 In), magnetization (5-300 K), as well as electrical resistivity (5-300 K) and calorimetric (2-150 K) measurements for Yb 2 In. Compared to other RE, Yb or Eu always raise challenging questions linked to their valence states. From average atomic volume, Yb is anticipated to be divalent in Yb 2 In, at least between 100 and 375 K, which is in line with the absence of 4 f magnetism. In agreement with x-ray diffraction and magnetization data, the resistivity of Yb 2 In is rather featureless and typical of a metal. Establishing Yb 2 In as a nonmagnetic isostructural reference for Eu 2 In allows one to use its heat capacity to revisit that of the latter, and get experimental insights into the exceptional magnetocaloric effect of the compound with Eu. In particular, we show that a third of the total magnetic entropy (S m ≈ 35.6 J mol −1 K −1 at T = 100 K) is concentrated in a 3 K temperature window around the T C of Eu 2 In. Starting from the ferromagnetic compound Eu 2 In [T C = 55.2(5) K], we show that Yb substitutions in Eu 2-x Yb x In lead to a decrease in both the Curie temperature [T C = 41(2) and 32(2) K for x = 0.25 and 0.5] and magnetic saturation, while weakening the first-order character of the transition as x increases. A significant isothermal entropy change of 5.1(4) J mol −1 K −1 for B = 2 T is found at 44 K in Eu 1.75 Yb 0.25 In, demonstrating that the giant magnetocaloric effect of Eu 2 In can be tuned to lower temperatures by Yb substitutions
