38 research outputs found
Magnetohydrodynamic Simulation of the Interaction between Interplanetary Strong Shock and Magnetic Cloud and its Consequent Geoeffectiveness 2: Oblique Collision
Numerical studies of the interplanetary "shock overtaking magnetic cloud
(MC)" event are continued by a 2.5 dimensional magnetohydrodynamic (MHD) model
in heliospheric meridional plane. Interplanetary direct collision (DC)/oblique
collision (OC) between an MC and a shock results from their same/different
initial propagation orientations. For radially erupted MC and shock in solar
corona, the orientations are only determined respectively by their heliographic
locations. OC is investigated in contrast with the results in DC
\citep{Xiong2006}. The shock front behaves as a smooth arc. The cannibalized
part of MC is highly compressed by the shock front along its normal. As the
shock propagates gradually into the preceding MC body, the most violent
interaction is transferred sideways with an accompanying significant narrowing
of the MC's angular width. The opposite deflections of MC body and shock
aphelion in OC occur simultaneously through the process of the shock
penetrating the MC. After the shock's passage, the MC is restored to its oblate
morphology. With the decrease of MC-shock commencement interval, the shock
front at 1 AU traverses MC body and is responsible for the same change trend of
the latitude of the greatest geoeffectiveness of MC-shock compound. Regardless
of shock orientation, shock penetration location regarding the maximum
geoeffectiveness is right at MC core on the condition of very strong shock
intensity. An appropriate angular difference between the initial eruption of an
MC and an overtaking shock leads to the maximum deflection of the MC body. The
larger the shock intensity is, the greater is the deflection angle. The
interaction of MCs with other disturbances could be a cause of deflected
propagation of interplanetary coronal mass ejection (ICME).Comment: 38 pages, 8 figure
Magnetohydrodynamic simulation of the interaction between two interplanetary magnetic clouds and its consequent geoeffectiveness: 2. Oblique collision
The numerical studies of the interplanetary coupling between multiple
magnetic clouds (MCs) are continued by a 2.5-dimensional ideal
magnetohydrodynamic (MHD) model in the heliospheric meridional plane. The
interplanetary direct collision (DC) / oblique collision (OC) between both MCs
results from their same/different initial propagation orientations. Here the OC
is explored in contrast to the results of the DC (Xiong et al., 2007). Both the
slow MC1 and fast MC2 are consequently injected from the different heliospheric
latitudes to form a compound stream during the interplanetary propagation. The
MC1 and MC2 undergo contrary deflections during the process of oblique
collision. Their deflection angles of and continuously increase until both MC-driven shock fronts are merged
into a stronger compound one. The , , and
total deflection angle () reach their corresponding maxima when the initial eruptions
of both MCs are at an appropriate angular difference. Moreover, with the
increase of MC2's initial speed, the OC becomes more intense, and the
enhancement of is much more sensitive to .
The is generally far less than the , and
the unusual case of only occurs for an
extremely violent OC. But because of the elasticity of the MC body to buffer
the collision, this deflection would gradually approach an asymptotic degree.
Therefore, the deflection due to the OC should be considered for the evolution
and ensuing geoeffectiveness of interplanetary interaction among successive
coronal mass ejections (CMEs).Comment: 51 pages, 13 figures, JGR - Space Physics, in pres
El patrimonio arqueológico del distrito Tambobamba - Apurímac y sus perspectivas de gestión
Se focaliza en el poblado de Tambobamba, en la cual analiza la situación actual del patrimonio arqueológico, evaluando el estado de protección del patrimonio arqueológico y los lineamientos existentes para implementar la gestión del Patrimonio Arqueológico del poblado de Tambobamba. Se debe indicar, además, que es el punto de partida para futuros trabajos que engloben a todo el distrito. Para el efecto se recurrió a la investigación documental y de campo, mediante el contacto con la realidad estudiada. Los resultados reflejan escasa participación de las autoridades locales en la gestión y manejo de los vestigios arqueológicos ubicados en su territorio; además de una escasa coordinación entre los diversos niveles de gobierno en lo que respecta a la problemática arqueológica. Por lo anterior se considera que es importante realizar un Plan de Gestión con objetivos a corto, mediano y largo plazo para las acciones de implementación, protección y conservación del patrimonio cultural y arqueológico de la zona; asimismo, promover la participación y la coordinación de todos los comprometidos con la protección del patrimonio, autoridades, instituciones del estado, organismos que promueven el turismo (agencias) y la población de la zona.Tesi
Magnetohydrodynamic simulation of the interaction between two interplanetary magnetic clouds and its consequent geoeffectiveness
Numerical studies of the interplanetary "multiple magnetic clouds (Multi-MC)"
are performed by a 2.5-dimensional ideal magnetohydrodynamic (MHD) model in the
heliospheric meridional plane. Both slow MC1 and fast MC2 are initially emerged
along the heliospheric equator, one after another with different time interval.
The coupling of two MCs could be considered as the comprehensive interaction
between two systems, each comprising of an MC body and its driven shock. The
MC2-driven shock and MC2 body are successively involved into interaction with
MC1 body. The momentum is transferred from MC2 to MC1. After the passage of
MC2-driven shock front, magnetic field lines in MC1 medium previously
compressed by MC2-driven shock are prevented from being restored by the MC2
body pushing. MC1 body undergoes the most violent compression from the ambient
solar wind ahead, continuous penetration of MC2-driven shock through MC1 body,
and persistent pushing of MC2 body at MC1 tail boundary. As the evolution
proceeds, the MC1 body suffers from larger and larger compression, and its
original vulnerable magnetic elasticity becomes stiffer and stiffer. So there
exists a maximum compressibility of Multi-MC when the accumulated elasticity
can balance the external compression. With respect to Multi-MC
geoeffectiveness, the evolution stage is a dominant factor, whereas the
collision intensity is a subordinate one. The magnetic elasticity, magnetic
helicity of each MC, and compression between each other are the key physical
factors for the formation, propagation, evolution, and resulting
geoeffectiveness of interplanetary Multi-MC.Comment: 56 pages, 11 figure
Effect of magnetic field on the physical properties of water
In this study, the effect of magnetic field (MF) on the partial physical properties of water are reported, tap water (TW) and 4 types of magnetized water (MW) were measured in the same condition. It was found that the properties of TW were changed following the MF treatment, shown as the increase of evaporation amount, the decrease of specific heat and boiling point after magnetization, the changes depend on the magnetization effect. In addition, magnetic field strength (MFS) has a marked influence on the magnetization effect, the optimal magnetizing condition was determined as the MFS of 300 mT. The findings of this study offered a facile approach to improve cooling and power generation efficiency in industrial. Keywords: Magnetic field, Water, Specific heat, Evaporation, Boiling poin
Breaking interfacial charge transfer barrier by sulfite for efficient pollutants degradation: a case of BiVO4
Abstract Heterogeneous photocatalytic systems generally lack thermodynamic dependence on the degradation of organic pollutants in aqueous solution. Therefore, it is important to reveal the reasons for the inhibited surface kinetics but still be neglected. Herein, we reveal the mechanism that BiVO4 can’t degrade organics although it is thermodynamically feasible. The surface solvation and formation of double layer (compact layer and diffuse layer) makes low-polarity organics far away from the surface of BiVO4. We found that the introduction of sulfite can solve this problem. Theory calculation illustrates that sulfite can enter into the compact layer because of its higher adsorption energy on BiVO4 and lower adiabatic ionization potential (AIP). Then, photogenerated holes initiate the chain transformation of sulfite and produce strong oxidizing species which can diffuse out to degrade organics. This paper provides an insight into the understand the effects of solid-liquid interface on heterogeneously photocatalytic degradation of organic pollutants
Regression Analysis and Comparison of Economic Parameters with Different Light Index Models under Various Constraints
Economic globalization is developing more rapidly than ever before. At the same time, economic growth is accompanied by energy consumption and carbon emissions, so it is particularly important to estimate, analyze and evaluate the economy accurately. We compared different nighttime light (NTL) index models with various constraint conditions and analyzed their relationships with economic parameters by linear correlation. In this study, three indices were selected, including original NTL, improved impervious surface index (IISI) and vegetation highlights nighttime-light index (VHNI). In the meantime, all indices were built in a linear regression relationship with gross domestic product (GDP), employed population and power consumption in southeast China. In addition, the correlation coefficient R2 was used to represent fitting degree. Overall, comparing the regression relationships with GDP of the three indices, VHNI performed best with the value of R2 at 0.8632. For the employed population and power consumption regression with these three indices, the maximum R2 of VHNI are 0.8647 and 0.7824 respectively, which are also the best performances in the three indices. For each individual province, the VHNI perform better than NTL and IISI in GDP regression, too. When taking employment population as the regression object, VHNI performs best in Zhejiang and Anhui provinces, but not all provinces. Finally, for power consumption regression, the value of VHNI R2 is better than NTL and IISI in every province except Hainan. The results show that, among the indices under different constraint conditions, the linear relationships between VHNI and GDP and power consumption are the strongest under vegetation constraint in southeast China. Therefore, VHNI index can be used for fitting analysis and prediction of economy and power consumption in the future
CLDN6 Suppresses c–MYC–Mediated Aerobic Glycolysis to Inhibit Proliferation by TAZ in Breast Cancer
Claudin 6 (CLDN6) was found to be a breast cancer suppressor gene, which is lowly expressed in breast cancer and inhibits breast cancer cell proliferation upon overexpression. However, the mechanism by which CLDN6 inhibits breast cancer proliferation is unclear. Here, we investigated this issue and elucidated the molecular mechanisms by which CLDN6 inhibits breast cancer proliferation. First, we verified that CLDN6 was lowly expressed in breast cancer tissues and that patients with lower CLDN6 expression had a worse prognosis. Next, we confirmed that CLDN6 inhibited breast cancer proliferation through in vitro and in vivo experiments. As for the mechanism, we found that CLDN6 inhibited c–MYC–mediated aerobic glycolysis based on a metabolomic analysis of CLDN6 affecting cellular lactate levels. CLDN6 interacted with a transcriptional co–activator with PDZ-binding motif (TAZ) and reduced the level of TAZ, thereby suppressing c–MYC transcription, which led to a reduction in glucose uptake and lactate production. Considered together, our results suggested that CLDN6 suppressed c–MYC–mediated aerobic glycolysis to inhibit the proliferation of breast cancer by TAZ, which indicated that CLDN6 acted as a novel regulator of aerobic glycolysis and provided a theoretical basis for CLDN6 as a biomarker of progression in breast cancer