ERA5-Land青藏高原湖冰特征误差分析及FLake模式改进

青藏高原上湖泊众多,其中大多数被季节性湖冰覆盖。湖冰对气候变化响应敏感,其生消过程会显著改变湖-气交换通量。而现有的高原湖冰长时间观测数据较少,需要利用湖冰再分析资料进行研究。但目前对ERA5-Land湖冰资料在高原的适用性及改进方法还不甚清楚。因此,本文首先利用2010-2022年青海湖和鄂陵湖的湖冰观测数据,评估了ERA5-Land再分析资料对青藏高原典型湖泊湖冰特征的模拟能力。结果表明:ERA5-Land资料对青海湖和鄂陵湖的冰厚平均高估0.54~0.62 m,对封冻期天数高估约68 d·a^(-1)。其次对再分析湖冰数据误差来源进行分析,通过对比ERA5-Land和鄂陵湖观测资料及其各自驱动模式的模拟结果,得出误差主要来源于输出ERA5-Land湖冰数据的FLake一维湖泊模式。最后基于2010-2022年青海湖和鄂陵湖的MCD43A3地表反照率产品,利用其多年平均反照率和动态日均反照率改进了FLake模型,模拟冰厚平均偏差可分别减小85%和90%,封冻期天数的模拟偏差减小了约6d·a^(-1)和8d·a^(-1)。两种方法均可以改进FLake模型对湖冰的模拟效果,特别是对积雪覆盖时间较长的湖泊,动态反照率方法改进效果更明显。本研究揭示了ERA5-Land湖冰特征的主要误差来源为FLake模式中的湖冰反照率,并对该参数进行了改进,提高了模型对湖冰的模拟效果,可为提高ERA5-Land再分析湖冰数据在青藏高原典型湖泊的模拟精度提供参考。

Deformation behaviors and processing maps of CNTs/Al alloy composite fabricated by flake powder metallurgy

Deformation behaviors of CNTs/Al alloy composite fabricated by the method of flake powder metallurgy were investigated by hot compression tests, which were performed in the temperature range of 300?550 °C and strain rate range of 0.001? 10 s?1 with Gleeble?3500 thermal simulator system. Processing maps of the CNTs/Al alloy at different strains were calculated to study the optimum processing domain. Microstructures before and after hot compressions were characterized by electron backscattered diffraction (EBSD) method. Stress?strain curves indicate that the flow stress increases with the increase of strain rate and the decrease of temperature. The processing maps of the CNTs/Al alloy at different strains show that the optimum processing domain is 500?550 °C, 10 s?1 for hot working. EBSD analysis demonstrates that fully dynamic recrystallization occurs in the optimum processing domain (high strainrate 10 s?1), whereas the main soften mechanism is dynamic recovery at low strain rate (0.001 s?1).

A novel wet-chemical method for preparation of silver flakes

A novel wet-chemical method for the preparation of silver flakes was studied. The well-defined particles were prepared by directly adding FeSO4 solution into AgNO3 solution containing citric acid at an agitation speed of 150 r/min at room temperature. The products were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that particles are irregular thin silver flakes. And the sizes of them range from 2 to 10 μm. It is found that citric acid plays an important role in the formation of sliver flakes. There is an optimum amount of citric acid for the preparation of silver flakes by this method. It is also found that high reduction rate is favorable for the formation of silver flakes.

Hot deformation and processing maps of Al_2O_3/Al composites fabricated by flake powder metallurgy

The deformation behaviors of Al2O3/Al composites were investigated by compressive tests conducted at temperature of 300-450 °C and strain rates of 0.001-1.0 s-1 with Gleeble-1500 D thermal simulator system. The results show that the flow stress increases with increasing strain rate and decreasing temperature. The hyperbolic sine constitutive equation can describe the flow stress behavior of Al2O3/Al composites, and the deformation activation energy and constitutive equations were calculated. The processing maps of Al2O3/Al-2 μm and Al2O3/Al-1 μm composites at strain of 0.6 were obtained and the optimum processing domains are in ranges of 300-330 °C, 0.007-0.03 s-1 and 335-360 °C, 0.015-0.06 s-1 for hot working, respectively. The instability zones of flow behavior can also be recognized by the maps.

Flake tantalum powder for manufacturing electrolytic capacitors

The FTP200 flake tantalum powder was introduced.The microstructures of the powder with leaf-like primary particles having an average flakiness of 2 to 20 and porous agglomerated particles were observed.The chemical composition,physical properties,and electrical properties of the FTP200 powder were compared with those of the FTW300 nodular powder.The FTP200 powder is more sinter-resistant,and the surface area of the flake tantalum powder under sintering at high temperature has less loss than that of the nodular tantalum powder.The specific capacitance of the flake tantalum powder is higher than that of the nodular tantalum powder with the same surface area when anodized at high voltage.Thus,the flake tantalum powder is suitable for manufacturing tantalum solid electrolytic capacitors in the range of median and high（20-63 V） voltages.

Mineralogical and petrographic analysis on the flake graphite ore from Saba Boru area in Ethiopia

The mineralogy and petrography of natural graphite in Saba Boru of Ethiopia indicate that there exists flake graphite with a slightly oval structured fine size according to our study on thin and polished sections.Herein,for estimating the carbon content in graphite,the ASTM-C561,the test method for ash in a graphite sample,was used.For characterizing graphite,x-ray diffraction,x-ray fluorescence,inductively coupled plasma mass spectroscopy,and scanning electron microscopy were also used.Chemical analysis of ore samples determined that the average compositions are 63.35%SiO2,15.45%Al2O3,2.36%Fe2O3,2.07%K2O,less than1%others,and loss-on-ignition(LOI)in the range of^4.74%–37.42%.The total carbon content of graphitic ore ranged from 4.11%to 33.14%.Importantly,when graphite is concentrated through floatation,its average purity and recovery are 92.97%and 90.82%,respectively.Furthermore,once the graphite concentrates are treated with hydrofluoric acid,the average value attains a high grade of 96.48%C.Moreover,the average ash content is 81.93%(pre-flotation)and 3.1%(post-flotation),respectively.Finally,after beneficiation,a silica is identified as a major gangue(85.88%),usable as a raw material for other purposes such as cement.Hence,these graphite-bearing rocks seem to be worth exploring for commercialization opportunities.

Detection of heavy metals in water samples by laser-induced breakdown spectroscopy combined with annular groove graphite flakes

The use of laser-induced breakdown spectroscopy(LIBS) for the analysis of heavy metals in water samples is investigated. Some factors such as splashing, surface ripples, extinction of emitted intensity, and a shorter plasma lifetime will influence the results if the water sample is directly measured. In order to avoid these disadvantages and the ‘coffee-ring effect', hydrophilic graphite flakes with annular grooves were used for the first time to enrich and concentrate heavy metals in water samples before being analyzed by LIBS. The proposed method and procedure have been evaluated to concentrate and analyze cadmium, chromium, copper, nickel, lead,and zinc in a water sample. The correlation coefficients were all above 0.99. The detection limits of 0.029, 0.087, 0.012, 0.083, 0.125, and 0.049 mgl^(-1) for Cd, Cr, Cu, Ni, Pb, and Zn,respectively, were obtained in samples prepared in a laboratory. With this structure, the heavy metals homogeneously distribute in the annular groove and the relative standard deviations are all below 6%. This method is very convenient and suitable for online in situ analysis of heavy metals.

Influence of shape anisotropy on microwave complex permeability in carbonyl iron flakes/epoxy resin composites

To explore the mechanism of carbonyl iron flake composites for microwave complex permeability, this paper investigates the feature of the flakes. The shape anisotropy was certified by the results of the magnetization hysteresis loops and the Mossbauer spectra. Furthermore, the shape anisotropy was used to explain the origin of composite microwave performance, and the calculated results agree with the experiment. It is believed that the shape anisotropy dominates microwave complex permeability, and the natural resonance plays main role in flake.

Enhanced Thermal Conductivity and Bending Strength of Graphite Flakes/aluminum Composites Via Graphite Surface Modification

The effect of graphite surface modification on the thermal conductivity(TC) and bending strength of graphite flakes/Al composites(Gf/Al) prepared by gas pressure infiltration were investigated. Al3 Ni and Al4C3 phase may form at the interface in Ni-coated Gf/Al and uncoated Gf/Al composites, respectively, while the Al-Cu compound cannot be observed in Cu-coated Gf/Al composites. The Cu and Ni coatings enhance TC and the bending strength of the composites in the meantime. TC of Cu-coated Gf/Al composites reach 515 Wm^-1·K^-1 with 75 vol% Gf, which are higher than that of Ni-coated Gf/Al. Meanwhile, due to Al3 Ni at the interface, the bending strength of Ni-coated Gf/Al composites are far more than those of the uncoated and Cu-coated Gf/Al with the same content of Gf. The results indicate that metal-coated Gf can effectively improve the interfacial bonding between Gf and Al.

Effect of Nano Carbon Black and Graphite Flake on Properties of Low Carbon Al2O3-C Refractories

Low carbon Al2O3 - C refractories specimens were prepared with tabular alumina （3. 0 - 1.0, 1.0 - 0. 5, 0.6-0.2, ≤0.3, ≤0. 045 and ≤0. 02 mm）, active alumina micropowder （≤2 μm ） and silicon （ 〈≤0. 045 mm ） as main raw materials. Nano carbon black （N220） and natural graphite flake （ 〈≤0. 074 mm ） were adopted as the carbon sources. The specimens were treated at 800, 1 000, 1 200 and 1 400 ℃ under coke embedded atmosphere. The effects of additions of nano carbon black and graphite flake on mechanical properties and thermal shock resistance of the specimens were stud- ied. Their mechanical properties were measured by three- point bending test and thermal shock resistance was de- termined by water quenching method. The phase compo- sition of the specimens was analyzed with X-ray diffrac- tion and microstruetures were observed through FESEM. The results reveal that： （1） the strengths of A1203 - C refractories with these two carbon sources show no big differences when coked at lower than 1 000 ℃ ; when coked at over 1 200 ℃ , the strengths of the specimens with graphite added are much higher than those of the specimens containing carbon black due to much more sil- icon carbide whiskers formed; （2） since the nano carbon black has small particle size, they can be filled into in- terstice of Al2O3 particles to form the nano carbon net- work structure, absorbing and relieving the thermal stressgenerated from expansion and contraction and reducing the thermal expansion coefficient of the specimens, thus their thermal shock resistance is better than that of the specimens containing graphite ; （ 3 ） low carbon Al2 O3 - C refractories with good mechanical properties and excellent thermal shock resistance can be prepared with combi- nation of nano carbon black and graphite flake.

Nanosheet-stacked flake graphite for high-performance Al storage in inorganic molten AlCl_(3)-NaCl salt

Aluminum storage systems with graphite cathode have been greatly promoting the development of state-of-the-art rechargeable aluminum batteries over the last five years;this is due to the ultra-stable cycling,high capacity,and good safety of the systems.This study discussed the change of electrochemical behaviors caused by the structural difference between flake graphite and expandable graphite,the effects of temperature on the electrochemical performance of graphite in low-cost AlCl_(3)-NaCl inorganic molten salt,and the reaction mechanisms of aluminum complex ions in both graphite materials by scanning electron microscopy,X-ray diffraction,Raman spectroscopy,cyclic voltammetry,and galvanostatic charge-discharge measurements.It was found that flake graphite stacked with noticeably small and thin graphene nanosheets exhibited high capacity and fairly good rate capability.The battery could achieve a high capacity of^219 mA·h·g^(-1) over 1200 cycles at a high current density of 5 A·g^(-1),with Coulombic efficiency of 94.1%.Moreover,the reaction mechanisms are clarified:For the flake graphite with small and thin graphene nanosheets and high mesopore structures,the reaction mechanism consisted of not only the intercalation of AlCl4^-anions between graphene layers but also the adsorption of Al Cl4^-anions within mesopores;however,for the well-stacked and highly parallel layered large-size expandable graphite,the reaction mechanism mainly involved the intercalation of AlCl4^-anions.

Sintering behavior and thermal conductivity of nickel-coated graphite flake/copper composites fabricated by spark plasma sintering

Nickel-coated graphite flakes/copper（GN/Cu） composites were fabricated by spark plasma sintering with the surface of graphite flakes（GFs） being modified by Ni–P electroless plating. The effects of the phase transition of the amorphous Ni–P plating and of Ni diffusion into the Cu matrix on the densification behavior, interfacial microstructure, and thermal conductivity（TC） of the GN/Cu composites were systematically investigated. The introduction of Ni–P electroless plating efficiently reduced the densification temperature of uncoated GF/Cu composites from 850 to 650℃ and slightly increased the TC of the X–Y basal plane of the GF/Cu composites with 20 vol%–30 vol% graphite flakes. However, when the graphite flake content was greater than 30 vol%, the TC of the GF/Cu composites decreased with the introduction of Ni–P plating as a result of the combined effect of the improved heat-transfer interface with the transition layer, P generated at the interface, and the diffusion of Ni into the matrix. Given the effect of the Ni content on the TC of the Cu matrix and on the interface thermal resistance, a modified effective medium approximation model was used to predict the TC of the prepared GF/Cu composites.

Synthesis and characterization of MgSO_4·5Mg(OH)_2·2H_2O flake powders

Magnesium oxysulfate （MgSO4·5Mg（OH）2·2H2O） flake powders with an average diameter of 2 ~tm and a thickness of 0.052 μm were prepared using magnesium sulfate and sodium hydroxide as raw materials by hydrothermal synthesis process. The composition, morphology and structural features of the hydrothermal products were examined with X-ray powder diffraction （XRD）, scanning electron microscopy （SEM） and Fourier transform infrared spectroscopy （FTIR）. The experimental results indicate that in the conditions of n（NaOH）/n（MgSO4） of 1.25, the dosage of w（Na3PO4） crystal additives of 1.0% w（MgSO4）, stirring for 5 h at 180 ℃, the morphology of MgSO4·5Mg（OH）2·2H2O products is flaky and laminar, which is a kind of complex magnesium singlecrystal. The recycling of MgSO4 mother liquor was also investigated to make a full use of the materials and reduce disposal. The results prove that there is no adverse effect on the yield and purity of the products.

Extruded Corn Meal as a Partial Replacement for Steam Flaked Corn in Finishing Diets for Feedlot Cattle: Growth Performance and Digestive Function of Feedlot Cattle

Sixty-four Holstein steers (247 ± 4 kg) were used in a 70-d experiment to evaluate the effects of partial replacement of steam flake corn (SFC) with extruded corn meal (EC) on growth performance and dietary net energy. Treatments consisted of a steam flaked corn-based finishing diet containing 0%, 10%, 20%, or 30% EC, where EC replaced 0%, 15%, 30%, or 45% of SFC (DM basis). Replacement of SFC with increasing levels of EC did not affect (P > 0.10) ADG, DMI, and gain efficiency. When EC replaced 15% to 30% of SFC, observed dietary NE was 99% of expected. Whereas, when EC replaced 45% of SFC, observed dietary NE was 94% of expected. Four Holstein steers (210 ± 7 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square experiment to evaluate treatment effects on characteristics of digestion. Partial replacement of SFC with EC did not affect (P > 0.10) flow of undegraded feed N and microbial N and to the small intestine, and ruminal microbial N efficiency (g microbial N/kg OM fermented). Likewise, there were no treatment effects (P > 0.10) on ruminal digestion of OM, NDF, starch and feed N. As expected, total tract digestion of starch for all treatments exceeded 99%. However, partial replacement of SFC with EC decreased total tract digestion of DM and OM (linear effect, P = 0.02), and dietary DE (linear effect, P = 0.03). These effects were more pronounced where EC replaced 45% of SFC. Partial replacement of SFC with EC did not affect (P > 0.10) ruminal pH, total VFA concentration, molar proportions of acetate, propionate, and butyrate, and estimated methane production. It is concluded that partial replacement of SFC with EC does not have a beneficial effect on ruminal microbial efficiency and digestive function. The feeding value of extruded corn for feedlot cattle is comparable to that of steam flaked corn provided the inclusion rate does not exceed 20% of diet dry matter.

Unusual Normal and Superconducting State Properties Observed in Hydrothermal Fe_(1-δ)Se Flakes

The electronic and superconducting properties of Fe_(1-δ)Se single-crystal flakes grown hydrothermally are studied by the transport measurements under zero and high magnetic fields up to 38.5 T.The results contrast sharply with those previously reported for nematically ordered Fe Se by chemical-vapor-transport(CVT)growth.No signature of the electronic nematicity,but an evident metal-to-nonmetal crossover with increasing temperature,is detected in the normal state of the present hydrothermal samples.Interestingly,a higher superconducting critical temperature T_c of 13.2 K is observed compared to a suppressed T_c of 9 K in the presence of the nematicity in the CVT Fe Se.Moreover,the upper critical field in the zero-temperature limit is found to be isotropic with respect to the field direction and to reach a higher value of-42 T,which breaks the Pauli limit by a factor of 1.8.

Vertically aligned NiS nano-flakes derived from hydrothermally prepared Ni(OH)2 for high performance supercapacitor

In present work,the vertically aligned Ni S nano-flakes composed thin film is prepared by anionic exchange process in which hydrothermally prepared Ni（OH）2is used as a parent thin film and Na2S as a sulfide ion source.This synthesis process produced fully transformed and shape-controlled nano-flakes of Ni S from nano-flowers of Ni（OH）2.The electrochemical supercapacitor properties of Ni S electrode are studied with cyclic voltammetry（CV）,galvonostatic charge discharge（GCD）and electrochemical impedance spectroscopy（EIS）techniques.Highly porous surface area（85 m^2/g）of Ni S nano-flakes makes large material contribution in electrochemical reaction stretching specific capacitance（Cs）of 880 F/g at scan rate of 5 m V/s and 90%electrochemical stability up to 4000 CV cycles in 2 M KOH electrolyte.Further,the flexible solid-state symmetric supercapacitor device（Ni S/PVA–Li ClO4/Ni S）has been fabricated using Ni S electrodes with polyvinyl alcohol（PVA）–lithium perchlorate（Li ClO4）gel electrolyte.The Ni S/PVA–Li ClO4/Ni S device exhibits specific capacitance of 56 F/g with specific energy of 14.98 Wh/kg and excellent cycling stability after 2000 cycles.In addition,the Ni S/PVA–Li ClO4/Ni S device demonstrates illumination of red light emitting diode（LED）for 60 s,which confirms the practical applicability of Ni S/PVA–Li ClO4/Ni S device in energy storage.

Undrained dynamical behavior of Nanjing flake-shaped fine sand under cyclic loading

A series of dynamic behavior tests on Nanjing flake-shaped fine sand were performed by using the WFI cyclic triaxial apparatus made in England. The dynamic behaviors of Nanjing flake-shaped fine sand under different static deviator stress levels and cyclic stress ratios were studied. Through comparing the effective stress path under cyclic loading with static loading, the processes of liquefaction of saturated Nanjing flake-shaped fine sand with development of dynamic pore-water pressure, including the initial compact state, compression state and dilative state, were investigated. The variation of the shear stiffness with the number of cycles and cyclic strain was investigated by analyzing the secant shear modulus in each unload-reload loop of dynamic stress-strain relationship. And by means of the exponential function, the empirical equations of the relationship between secant shear modulus Gsec, shear modulus ratio Gsec/Gmax and cyclic strain ε were established based on series of test results. The results show that according to different combinations of static deviator stress and cyclic stress, two kinds of failure patterns with deviator stress reversal or no deviator stress reversal are observed in the samples tested in this series, including cyclic mobility and the failure of accumulation residual strain. In addition, the degradation of dynamic shear modulus is due to the development of vibration pore-water pressure and it is observed that the shear modulus reduces with the progressive number of cycles.

Preparation and study of ultrafine flake-aluminum with high reactivity

To achieve aluminum particles with ultrafine granularity and high reactivity,the mechanical ball-milling method was adopted and three kinds of coatings,including stearic acid(SA),viton and dinitrotoluene(DNT),were added.The effects of milling time and different coatings on granularity and reactivity of ultrafine aluminum particles were studied.The structures of prepared ultrafine aluminum were characterized by scanning electron microscopy,X-ray particle diffraction and the thermal properties were analyzed by TG/DSC.Besides,the reactivity of prepared ultrafine aluminum particles was comprehensively analyzed and judged according to several thermodynamic parameters,the maximal oxidation rate,the oxidation degree of aluminum and the enthalpy change.The results revealed that aluminum particles prepared by the mechanical ball milling method were all flake-like and the particle sizes were below5 mm with nanometer-scale thickness.And the crystal form of aluminum was found to be unchanged.Besides,the ultrafine flake aluminum coated with stearic acid after milling for 5 h showed the highest reactivity with 56.1% of oxidation degree before 660℃,0.945 mg/℃ of maximal oxidation rate and 20491 J/g of enthalpy change.

Morphological Characterization of Graphene Flake Networks Using Minkowski Functionals

Two Minkowski functionals were tested in the capacity of morphological descriptors to quantitatively compare the arrays of vertically-aligned graphene flakes grown on smooth and nanoporous alumina and silica surfaces. Specifically, the Euler-Poincaré characteristic and fractal dimension graphs were used to characterize the degree of connectivity and order in the systems, i.e. in the graphene flake patterns of petal-like and tree-like morphologies on solid substrates, and meshlike patterns (networks) grown on nanoporous alumina treated in low-temperature inductivelycoupled plasma. It was found that the Minkowski functionals return higher connectivity and fractal dimension numbers for the graphene flakepatterns with more complex morphologies, and indeed can be used as morphological descriptors to differentiate among various configurations of vertically-aligned graphene flakes grown on surfaces.

MODIFICATION OF FLAKE REINFORCED FRICTION BRAKE COMPOSITE MATERIAL

According to the recent development trend and need of the frictionbrake material, the flake rein- forced friction brake material hasbeen made out by adjust- ing the recipe and techniques. Thetwo-dimensional flake vermiculite is selected as the reinforcedstuffing of the ma- terial; the modified resin is used as the basalbed of the material. The tests manifest that the properties ofmechan- ics are high, the friction coefficients are suitable andstabel, and especially in high temperatures the wear is low. It is anexcellent friction brake material.