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Arctic sea-ice extent: No record minimum.i. 2023 or recent years

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Atmospheric and Oceanic Science Letters 2025年第1期18卷 52-55页

作者： Ola m.Johannessen Tor i.Olaussen Nansen Scientific Society BergenNorway Nansen Environmental and Remote Sensing Center BergenNorway

Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(***^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 ***^(2), 0.794 ***^(2) less than the minimum.i. 2023. However, the ice extent had decreased by 0.432 ***^(2) compared with 2022. Nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. in general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the rem.i.der is caused by natural variability.

关键词： Sea ice Arctic minimum.i.e Climate

Fragmentation Cross Sections of 158 AGeV Pb Projectiles

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Chinese Physics Letters 2007年第10期24卷 2800-2803页

作者： G. Sher m.i. Shahzad m. Hussain Physics Division PINSTECH Islamabad Pakistan Department of Physics University of the Punjab Lahore Pakistan

We investigate the fragmentation cross sections of 158 AGeV ^207Pb projectile interacting with different targets using CR39 nuclear track detectors. The exposure is made at SPS beam facility of CERN. The detectors are chemically etched to obtain data in the form of etched cone length. The nuclear and electromagnetic contributions to the measured total charge-changing cross sections are investigated. The estimated results are compared with those found in the literature for similar research work.

关键词： coated conductor buffer layer self-epitaxy CeO2

Thermal Spray Coating of Tungsten for Tokamak Device

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Plasma Science and Technology 2006年第2期8卷 164-167页

作者：蒋显亮 F. GiTZHOFER m.i. BOULOS institute of Surface and Coatings Technology Central South University Changsha 410083 China Plasma Technology Research Center University of Sherbrooke Sherbrooke J1K 2R1Canada

Thermal spray, such as direct current （d.c.） plasma spray or radio frequency induced plasma spray, was used to deposit tungsten coatings on the copper electrodes of a tokamak device. The tungsten coating on the outer surface of one copper electrode was formed directly through d.c. plasma spraying of fine tungsten powder. The tungsten coating/lining on the inner surface of another copper electrode could be formed indirectly through induced plasma spraying of coarse tungsten powder. Scanning electron microscopy （SEm） was used to examine the cross section and the interface of the tungsten coating. Energy Dispersive Analysis of X-ray （EDAX） was used to analyze the metallic elements attached to a separated interface. The influence of the particle size of the tungsten powder on the density, cracking behavior and adhesion of the coating is discussed. it is found that the coarse tungsten powder with the particle size of 45-75μm can be melted and the coating can be formed only by using induced plasma. The coating deposited from the coarse powder has much higher cohesive strength, adhesive strength and crack resistance than the coating made from the fine powder with a particle size of 5μm.

关键词： tokamak device copper electrode thermal spray tungsten coating tungsten/copper interface

Aspect of the specialty metals potentials of pegmatites in western Oban massif,SE Nigeria:A preliminary geochemical approach

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Chinese Journal Of Geochemistry 2012年第4期31卷 355-361页

作者： Oden m.i. igonor E.E. Department of Geology University of CalabarP.M.B.1115 CalabarNigeria Petra Prospectors Limited Nigeria

minerals in general and rare-metals in particular are of invaluable importance in the development and industrialization of any *** is true as they could affect a nation's national income,employment ratio,Gross National Product,and its entire *** study area(western Oban massif-SE Nigeria) was investigated for its specialty metals bearing potentials because of(1) its geology,which is similar to other specialty metals bearing areas of the world;(2) past works,which points to the area as a likely source of economic deposit of such metals;and(3) the soaring cost of these rare metals in the light of recent upsurge in global information/telecommunication *** from the study,show that only cesium(Cs) and beryllium(Be) show minute signs or indications of enrichment if properly *** these metals should be studied in details to ascertain their economic *** rocks are too deficient in the other rare-metals(lithium,zirconium,strontium,tantalite,niobium,tungsten,gallium,and chromium) to warrant further analysis.

关键词：特种金属尼日利亚地球化学方法电位伟晶岩稀有金属矿地块国民生产总值

Direct Numerical Simulation of Convective Heat Transfer in a Zero-Pressure-Gradient Boundary Layer with Supercritical Water

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Journal of Thermal Science 2012年第1期21卷 49-59页

作者： C. Azih J.R. Brinkerhoff m.i. Yaras Department of mechanical and Aerospace Engineering Carleton University

Experimental research has long shown that forced-convective heat transfer in wall-bounded turbulent flows of fluids in the supercritical thermodynamic state is not accurately predicted by correlations that have been developed for single-phase fluids in the subcritical thermodynamic state. in the present computational study, the statistical properties of turbulent flow as well as the development of coherent flow structures in a zero-pressuregradient flat-plate boundary layer are investigated in the absence of body forces, where the working fluid is in the supercritical thermodynamic state. The simulated boundary layers are developed to a friction Reynolds number of 250 for two heat-flux to mass-flux ratios corresponding to cases where normal heat transfer and improved heat transfer are observed. in the case where improved heat transfer is observed, spanwise spacing of the near-wall coherent flow structures is reduced due to a relatively less stable flow environment resulting from the lower magnitudes of the wall-normal viscosity-gradient profile.

关键词： boundary layer turbulence supercritical fluids improved heat transfer DNS

Effect of magnesium and nickel coatings on the wetting behavior of alumina toughened zirconia by molten Al-mg alloy

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international Journal of minerals,metallurgy and materials 2012年第1期19卷 77-82页

作者： H. Sharifi A.R. Khavandi m. Divandari m.i. Hasbullah School of materials and metallurgical Engineering iran University of Science and Technology Department of material Engineering Faculty of mechanical Engineering University Teknologi malaysia

The wettability of alumina toughened zirconia （ZTA） by Al-mg alloy was investigated using the sessile drop technique. The ef fects of nickel coating, magnesium content, nitrogen atmosphere, and processing temperature on the contact angle between the molten alloy and the substrate were determined. Likewise, the effect of these factors on the wetting properties was studied. The results showed that the nickel coating on the ceramic substrate caused a significant reduction in solid/liquid surface energy and the contact angle decreased obvi- ously. The presence of magnesium.i. the molten aluminum alloy in nitrogen atmosphere reduced the contact angle effectively. The presence of magnesium.i. the alloy must be at a minimum amount of 2wt%-3wt% . moreover, it was suggested that some chemical reactions in the Al-mg-N system led to the production of mg3N2 and AlN compositions. These compositions improved the wetting properties of the systems by reducing the surface energy of the molten. it was shown that increasing the temperature is also an effective factor for the enhancement of wetting properties.

关键词： wetting coatings alumina zirconia ceramic materials composite materials

Geochemical characterization of Cretaceous sandstones from the Southern Benue Trough, Nigeria

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Chinese Journal Of Geochemistry 2009年第1期28卷 44-54页

作者： Odigi m.i. Amajor L.C. Department of Geology University of Port Harcourt Port Harcourt Nigeria

Geochemical studies of sandstones from the three lithostratigraphic successions in the southern Benue Trough of Nigeria were undertaken for a geochemical characterization of the sandstones, and to assess their strati-graphic and source evolution. major and trace elements data were obtained from outcrop sandstone samples. The SiO2/Al2O3, Fe2O3/K2O ratios and CaO contents have been used to characterize the Cretaceous sandstones into Al-rich and high and low Fe2O3/K2O ratio sandstones. Results indicate that there are geochemical features that display stratigraphic trends across the succession from the Asu River Group, Eze-Aku Group to the proto-Niger Delta succession which may imply a discontinuous evolution from different source terrains of Precambrian and mesozoic ages that supplied the sediments. The Asu River Group sandstones have lower SiO2, Al2O3, Fe2O3 and higher mgO; the Eze-Aku sandstones have higher TiO2, CaO, alkalis and lower mgO while the proto-Niger Delta sandstones have higher SiO2, Al2O3, Fe2O3 and lower alkalis and CaO. These discontinuities signify the influence of tectonic impulses that af- fected the southern Benue Trough during the Cretaceous time. Changes in ratios of TiO2/Al2O3, Fe2O3, Cr and Zr suggest an increasingly mafic contribution to the depositional basin with time. The chemical index of alteration increases with time, possibly suggesting that a more intense weathering regime in the hinterland developed with time.

关键词：地球化学特征储层沥青烃源岩对比

Brittle deformation in the Afikpo Basin (Southeast Nigeria): Evidence for a terminal Cretaceous extensional regime in the Lower Benue Trough, Nigeria

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Chinese Journal Of Geochemistry 2009年第4期28卷 369-376页

作者： Odigi m.i. Levi C. Amajor Department of Geology University of Port HarcourtPort Harcourt Nigeria

This paper deals with the regional and structural framework of the Cretaceous rocks in the Afikpo Basin located in the southeastern part of the Lower Benue Trough. Results from regional tectonics are presented together with those of the microtectonic analysis of microfaults in the Owutu-Afikpo-Adadama area in the basin. The Owutu-Afikpo-Adadama ridge at the north-central part of the basin marks the boundary between the Late Cenomanian-Turonian-Conianian sediments and the Campanian-maastrichtian sandstones. This ridge trends N45oE on average and is faulted in three m.i. directions, namely: (1) N-S normal faults; (2) NE-SW strike-slip faults; and (3) NW-SE strike-slip faults. The faulted rocks along these brittle discontinuities are m.i.ly cataclastics with internal fracture cleavage and sigm.i.al quartz mosaics that are reminiscent of extensional deformation. The cataclasites often bear slickenside striations. The NE-SW and NW-SE strike-slip faults are the results of the youngest brittle events on the Owutu-Afikpo-Adadama ridge. These faults were reactivated after deposition of the Campanian-maastrichtain sediments (post-depositional faults) and, therefore, are post-maastrichtain. microfault analysis of these fault trends suggests an extensional regime that prevailed in the Lower Benue Trough. These results are of significance because this event is least poorly understood and less documented in contrast to the Cenomanian and Santonian events that affected the older Cretaceous strata in this region.

关键词：白垩纪末期伸展变形尼日利亚盆地海槽脆性变形菲证据

Heavy metal stress induced hyperglycemia in blue swimmer crab, Portunus pelagicus

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Acta Oceanologica Sinica 2018年第5期37卷 47-53页

作者： SARAVANAN R. SUGUmAR V. BEEmA mAHiN m.i. Department of Oceanography and Coastal Area Studies Alagappa UniversityThondi Campus

The study was to find out the effect of cadmium and mercury on levels of hemolymph glucose, crustacean hyperglycemic hormone（CHH） and hepatopancreas glycogen in the blue swimmer crab Portunus pelagicus. The experiments were performed in both intact and eyestalk ablated crabs. Quantification of CHH was done by the indirect ELiSA with the aid of primary anti-Carcinus maenas-CHH antibody. Higher glucose concentration was observed on exposure to 8×10^–6 of cadmium（（825.6±5.42） μg/m L） and 6×10^–6 of mercury（（90.5±6.25） μg/m L）after 48 h and 24 h respectively. Higher level of hemolymph glucose was observed in eyestalk intact crabs on exposure to cadmium and mercury than eyestalk ablated crabs. Decrease in the levels of CHH was observed in both eyestalk intact and ablated crabs on heavy metal exposure. Decline of the hepatopancreas glycogen level was also witnessed with the exposure to heavy metal, which validated its utilization in the production of glucose. Thus this study brings to light, the variations in hemolymph glucose, CHH and hepatopancreas glycogen on heavy metal stress. These carbohydrate metabolites can be used as biomarkers in assessing heavy metal contamination in water bodies.

关键词： crustacean hyperglycemic hormone cadmium mercury decapod crustaceans blue swimmer crab