ALBERT

Description: In this work, hexagonal solid solutions of (Gd 0.95 Eu 0.05 )(OH) 3 with two distinctive morphologies of nanorods and nanotubes were successfully synthesized via hydrothermal treatment of mixed nitrate solutions in the presence of ammonium hydroxide. The hydroxide samples exhibited characteristic Eu 3+ photoluminescence through the energy transfer from Gd 3+ to Eu 3+ and the self-excitation of Eu 3+ . The hydroxide precursors transformed into cubic (Gd 0.95 Eu 0.05 ) 2 O 3 at ~500 °C via an intermediate monoclinic (Gd 0.95 Eu 0.05 )OOH phase, and the Eu 3+ coordination accordingly experienced symmetry changes from D 3 h to C 2 v , and then to C 2 / S 6 . The cubic (Gd 0.95 Eu 0.05 ) 2 O 3 well retained the original morphologies of their p...

Description: In this paper, the curing kinetics of 4,4′-Methylenebis epoxy resin(TGDDM) and m-Xylylenediamine(m-XDA) was investigated by non-isothermal differential scanning calorimetry(DSC) at various heating rates. Selected non-isothermal methods for analyzing curing kinetics were compared. The activation energy(E) and the correlation coefficient(R) were obtained by different isoconversional methods. The reaction order(n) was obtained by the activation energy in different isoconversional methods for the by Crane equation. The results show that the apparent activation energy are 65.23kJ/mol, 52.20 kJ/mol and 66.10 kJ/mol by using the method of Kissinger, Friedman and F-W-O, the reaction order are 0.911, 0.729 and 0.923 by using the method of Kissinger, Friedman and F-W-O.

Description: The Handan-Xingtai district in the North China craton is one of the most important concentrations of iron skarn deposits in China, with proven reserves of 900 to 1,000 Mt at an average of 40 to 55 wt % Fe. The iron mineralization occurs predominantly along contact zones between Early Cretaceous intermediate-silicic intrusions and Middle Ordovician marine carbonates intercalated with numerous evaporite beds. In this paper, we present textural features and laser ablation ICP-MS U-Pb dating results of hydrothermal zircon from five major iron skarn deposits to place tight constraints on the timing and duration of the district-scale iron mineralization. Zircon grains from the mineralized skarns are anhedral to subhedral crystals and euhedral tetragonal bipyramids. They are closely intergrown or texturally associated with diopside, garnet, epidote, calcite, albite, and phlogopite. Other common minerals in the skarn assemblages include F-rich hornblende, wilkeite-F, F-apatite, and fluorite. Zircon grains typically contain abundant inclusions of skarn minerals and daughter mineral-rich (mostly magnetite, halite, and sylvite) fluid inclusions. Compositionally, these zircon grains have moderately to extremely high Th (518–7,477 ppm) and U (109–25,610 ppm) contents, with highly variable Th/U ratios ranging from 0.01 to 5.23. The morphological, textural, and geochemical features of the zircons confirm their hydrothermal origin and indicate that they most likely precipitated from high-temperature, F-rich, magmatic-derived ore-forming fluids. The hydrothermal zircon grains yield well-defined concordant U-Pb ages for the five studied iron skarn deposits, with weighted mean 206 Pb/ 238 U dates ranging from 133.6 ± 0.9 to 128.5 ± 1.4 Ma (2 ). These ages are remarkably consistent with U-Pb ages (134.1 ± 1.2 to 128.5 ± 0.9 Ma; 2 ) of magmatic zircon grains from the ore-related intrusions in each deposit, demonstrating that iron skarn mineralization was genetically related to the coeval magmatism. Our new geochronological data, when combined with existing isotopic ages, indicate that iron mineralization and associated magmatism in the Handan-Xingtai district took place mainly at the ca. 137–133 and 131–128 Ma intervals. Iron skarn deposits of similar ages also occur widely in other parts of the eastern North China craton, forming the only known giant Mesozoic iron skarn province in a cratonic block on the Earth. The formation of these iron skarn deposits and associated intrusions coincided in time with lithospheric thinning or destruction of the North China craton, strongly suggesting a causal link between the two processes.

Description: This paper mainly researched the hydrothermal synthesis of Natrolite, using amorphous silicon source from the purified attapulgite. The effects of silicon source, silicon aluminum ratio, crystallization time and crystallization temperature on the synthesis of natrolite were investigated. The results showed that the optimal synthesis condition of natrolite was: Hydrothermal activated ATP with NaOH was silicon source, silicon aluminum ratio was 10:1, crystallization time lasted to 72h and crystallization temperature was 150°C, the template was removed by calcining 8 hours at 550°C. The structural formula of obtained natrolite is Na 2 Al 2 Si 3 O 10 •2H 2 O.

Description: Vermifiltration system has been reported to enhance sludge degradation and relieve the potential risks of heavy metals, whereas few studies focus on the seasonal variability of heavy metal content and its chemical speciation in excess sludge by vermi-stabilization. The results of this study showed that total contents of Zn, Pb, Cr and the treatment efficiency of vermifilter were higher in summer and lower in winter due to the temperature effect. While Cu was observed to not be dependent on season. Further investigation using a five-step fractionation procedure to evaluate the main chemical speciations of metals in the sludge showed that there were similar variations in the five fractions (F1-F5) between each season, which indicated that the chemical speciation of heavy metals were most affected by vermifiltration technique than seasonal factor. The transformations among the five fractions suggested that the vermifiltration significantly reduced the mobility and bioavailability o...

Description: The Kangdian iron oxide copper-gold (IOCG) metallogenic province contains a number of economically important Fe-Cu deposits in South China and northern Vietnam. Due to the lack of precise mineralization ages, the metallogenesis of this province has long been a matter of debate. In this study, molybdenite Re-Os, pyrite Re-Os, and Rb-Sr isotope methods are used to date the Yinachang and E’touchang Fe-Cu deposits in the central part of this province. Fine-grained (〈0.1 mm) molybdenite occurs as veinlets along bandings or fractures of magnetite ores and hydrothermal veins in the Yinachang deposit. Molybdenite separates from magnetite ores have highly reproducible Re-Os model ages of 1654 ± 7 Ma, whereas those from hydrothermal veins have a much younger Re-Os model age of 1451 ± 6 Ma. Euhedral pyrite grains occur locally along foliations of hematite ores and their proximal alteration assemblages in the E’touchang deposit. Pyrite separates have an Re-Os isochron age of 1487 ± 110 Ma and a single-grain Rb-Sr isochron age of 1453 ± 28 Ma, both of which are compatible with the molybdenite Re-Os age of hydrothermal veins from the Yinachang deposit. The molybdenite age of magnetite ores is in good agreement with zircon U-Pb ages of dolerite intrusions in the region, and is considered to represent the timing of a major ore formation event at ~1655 Ma. The younger Re-Os and Rb-Sr ages likely record a secondary hydrothermal overprint event at ~1450 Ma, which has not been recognized before. The mineralization potential and implications of this event need to be investigated in future studies. Our new isotopic data set hence demonstrates that the Kangdian IOCG deposits were likely formed at ~1655 Ma, synchronous with the late Paleoproterozoic intracontinental rifting event of the western Yangtze block.

Description: Sleep plays a significant role in human health. Along with the emergency of diseases related to sleep, sleep monitoring is becoming a hotspot. Traditionally, Polysomnography (PSG) is considered as the gold standard for sleep monitoring, but it is expensive, time-consuming, and uncomfortable, especially not ideal for long-term sleep studies. Thus, exploring alternative sleep monitoring method has drawn much attention of researchers. Currently most of the sleep monitoring methods require complicated signals and feature extraction process. However, this paper innovatively proposes a method using simple signal of heart rate and respiration rate, and integrating the prior knowledge of experts to simplify the feature extraction process, which can make the subsequent classifier distinguish wake state and sleep state easily. In this paper, we used multi-layer neural network as a classifier, getting a Cohen’s kappa value of 0.739, and the overall accuracy of classifying sleep and wake st...

Description: In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.