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971.
Bo Wu Huiying Du Ping Hu Zhanyu Gao Ruikai Liu Chonghua Pei 《Journal of Energetic Materials》2021,39(1):10-22
ABSTRACT In recent years, the exploration of a practical strategy for novel energetic molecules with high energy and low sensitivity is very desirable but highly challenging. Novel ionic energetic molecules have attracted much attention in this area due to their prominent advantages including low sensitivities, high thermal stability, and excellent energy performances. Herein, five different ionic energetic molecules based on new monovalent and divalent 4-oxyl-3,5-dinitropyrazolate moieties with enhanced oxygen balance have been synthesized, characterized and evaluated as potential high-energy materials. Thermal stability, sensitivities and energy output test were measured and studied in detail. The heats of formation and energetic parameters were calculated by using Gaussian 09 suite of programs and EXPLO 5 code. The results suggest that all as-prepared new molecules exhibit good thermal stability with high decomposition temperature (3, 231°C; 5, 160°C; 6, 185°C; 7, 180°C; 8, 213°C), and relative low sensitivity (IS > 20 J, FS = 324 N). Inheriting the significant oxygen content of monovalent and divalent 4-oxyl-3,5-dinitropyrazolate moieties, they also possess good energy properties (v D = 8238 ~ 9208 m s?1, P = 26.8 ~ 36.7 GPa, V o = 481.8 ~ 959.4 L kg?1), which make them competitive high-energy materials. 相似文献
972.
高轧机作业率是冷连轧机经济高效运行的关键因素,当某种故障导致1个机架不能正常运行时,势必导致5机架轧机停止生产,影响产能。简述了"甩机架"轧制模式在1 700mm 5机架冷轧机上的应用,介绍了"甩机架"轧制的策略以及实现方式,对"甩机架"后轧机的压下率、张力等轧制规程的变化进行了分析。"甩机架"生产应用的实例表明,该轧制模式切换平稳快速,提高了轧机作业率,降低了故障成本。 相似文献
973.
974.
Junji Fukuda Shintaro Takahashi Tatsuya Osaki Naoto Mochizuki Hiroaki Suzuki 《Science and Technology of Advanced Materials》2012,13(6)
Plugs, i.e. droplets formed in a microchannel, may revolutionize microfluidic cell-based assays. This study describes a microdevice that handles nanolitre-scale liquid plugs for the preparation of various culture setups and subsequent cellular assays. An important feature of this mode of liquid operation is that the recirculation flow generated inside the plug promotes the rapid mixing of different solutions after plugs are merged, and it keeps cell suspensions homogeneous. Thus, serial dilutions of reagents and cell suspensions with different cell densities and cell types were rapidly performed using nanolitres of solution. Cells seeded through the plug processing grew well in the microdevice, and subsequent plug processing was used to detect the glucose consumption of cells and cellular responses to anticancer agents. The plug-based microdevice may provide a useful platform for cell-based assay systems in various fields, including fundamental cell biology and drug screening applications. 相似文献
975.
The duration of freeway traffic accidents duration is an important factor, which affects traffic congestion, environmental pollution, and secondary accidents. Among previous studies, the M5P algorithm has been shown to be an effective tool for predicting incident duration. M5P builds a tree-based model, like the traditional classification and regression tree (CART) method, but with multiple linear regression models as its leaves. The problem with M5P for accident duration prediction, however, is that whereas linear regression assumes that the conditional distribution of accident durations is normally distributed, the distribution for a “time-to-an-event” is almost certainly nonsymmetrical. A hazard-based duration model (HBDM) is a better choice for this kind of a “time-to-event” modeling scenario, and given this, HBDMs have been previously applied to analyze and predict traffic accidents duration. Previous research, however, has not yet applied HBDMs for accident duration prediction, in association with clustering or classification of the dataset to minimize data heterogeneity. The current paper proposes a novel approach for accident duration prediction, which improves on the original M5P tree algorithm through the construction of a M5P-HBDM model, in which the leaves of the M5P tree model are HBDMs instead of linear regression models. Such a model offers the advantage of minimizing data heterogeneity through dataset classification, and avoids the need for the incorrect assumption of normality for traffic accident durations. The proposed model was then tested on two freeway accident datasets. For each dataset, the first 500 records were used to train the following three models: (1) an M5P tree; (2) a HBDM; and (3) the proposed M5P-HBDM, and the remainder of data were used for testing. The results show that the proposed M5P-HBDM managed to identify more significant and meaningful variables than either M5P or HBDMs. Moreover, the M5P-HBDM had the lowest overall mean absolute percentage error (MAPE). 相似文献
976.
《Planning》2018,(4):1-4
应用离子色谱法检测大同辖区水源水、末梢水及出厂水中的F-、Cl-、Cl-、NO_3-、NO_3-、SO_4-、SO_4(2-)4种阴离子,以3.5 mol/L的Na_2CO_3和1.0 mol/L的Na HCO_3溶液为淋洗液,等度洗脱。采用戴安ICS1100离子色谱仪及Ion Pac AS14分离柱,流量为1.2 m L/min。4种离子的质量浓度与其色谱峰面积呈良好的线性关系,相关系数为0.999 14(2-)4种阴离子,以3.5 mol/L的Na_2CO_3和1.0 mol/L的Na HCO_3溶液为淋洗液,等度洗脱。采用戴安ICS1100离子色谱仪及Ion Pac AS14分离柱,流量为1.2 m L/min。4种离子的质量浓度与其色谱峰面积呈良好的线性关系,相关系数为0.999 140.999 99,检出限为0.10.999 99,检出限为0.10.4μg/m L,加标回收率均为98.3%0.4μg/m L,加标回收率均为98.3%103.8%,测定结果的相对标准偏差为0.2088%103.8%,测定结果的相对标准偏差为0.2088%5.0873%。该方法测定结果准确可靠,并且操作简便快捷,一次进样可同时测定多种阴离子,适用于水中F5.0873%。该方法测定结果准确可靠,并且操作简便快捷,一次进样可同时测定多种阴离子,适用于水中F-、Cl-、Cl-、NO_3-、NO_3-、SO_4-、SO_4(2-)的测定。 相似文献
977.
Synthesis of trimethylene carbonate/ϵ‐caprolactone copolymers initiated with zinc alkoxide: influence of copolymer chain microstructure on thermal and mechanical properties 下载免费PDF全文
Malgorzata Pastusiak Piotr Dobrzynski Janusz Kasperczyk Michal Sobota Bozena Kaczmarczyk Henryk Janeczek 《Polymer International》2017,66(9):1259-1268
Ethylzinc(II ) ethoxide is a highly active and efficient initiator for the bulk polymerization of 1,3‐trimethylene carbonate and its copolymerization with ? ‐caprolactone. This initiator allows one to obtain (co)polymers with high molar masses in quite a short time. Significant difference in co‐monomer reactivity and relatively low participation of intermolecular transesterification processes lead to the obtained copolymers being characterized by a gradient chain microstructure. In 13C NMR spectra, in all regions, we observed the presence of triads which were distinctly represented by four peaks for the carbonyl signal. Mechanical tests showed that copolymers containing 70% and more of ? ‐caprolactone presented a relatively high Young's modulus and a very high maximum elongation factor; therefore these materials are promising in many biomedical applications. Due to the high reaction rate, we also made an attempt at copolymerization using reactive extrusion which gave promising results. © 2017 Society of Chemical Industry 相似文献
978.
《International Journal of Hydrogen Energy》2014,39(35):20614-20624
High cost and lack of convenient supply infrastructure for hydrogen is believed to the major hurdle to the commercialization of hydrogen energy. Low cost compact onsite hydrogen generator is developed to produce three purity levels of hydrogen for use with high temperature polymer electrolyte membrane (HTPEM) or low temperature polymer electrolyte membrane (LTPEM) fuel cell. The small modular reformer has process efficient higher or equal to large scale central production plant without the penalty of expensive distribution cost. The cost of hydrogen from primary reformate hydrogen to high purity hydrogen ranges from $3.16/kg to $5.84/kg and the corresponding power cost from FC system is $0.352 to $0.408/KWh. The hydrogen costs are much lower than one can obtain from an industrial gas company with central supply system and expensive cost in distribution. These direct power costs without depreciation cost are comparable or lower than the comparable size of diesel power cost. 相似文献
979.
Christina Kopp Afshin Hosseini Shiva P. Singh Petra Regenhard Hamed Khalilvandi-Behroozyar Helga Sauerwein Manfred Mielenz 《International journal of molecular sciences》2014,15(11):21401-21418
The transition period in dairy cows (3 weeks prepartum until 3 weeks postpartum) is associated with substantial mobilization of energy stores, which is often associated with metabolic diseases. Nicotinic acid (NA) is an antilipolytic and lipid-lowering compound used to treat dyslipidaemia in humans, and it also reduces non-esterified fatty acids in cattle. In mice the G-protein coupled receptor 109A (GPR109A) ligand NA positively affects the secretion of adiponectin, an important modulator of glucose and fat metabolism. In cattle, the corresponding data linking NA to adiponectin are missing. Our objective was to examine the effects of NA on adiponectin and AMPK protein abundance and the expression of mRNAs of related genes such as chemerin, an adipokine that enhances adiponectin secretion in vitro. Differentiated bovine adipocytes were incubated with pertussis toxin (PTX) to verify the involvement of GPR signaling, and treated with 10 or 15 µM NA for 12 or 24 h. NA increased adiponectin concentrations (p ≤ 0.001) and the mRNA abundances of GPR109A (p ≤ 0.05) and chemerin (p ≤ 0.01). Pre-incubation with PTX reduced the adiponectin response to NA (p ≤ 0.001). The NA-stimulated secretion of adiponectin and the mRNA expression of chemerin in the bovine adipocytes were suggestive of GPR signaling-dependent improved insulin sensitivity and/or adipocyte metabolism in dairy cows. 相似文献
980.
《Journal of Materials Processing Technology》2014,214(6):1211-1227
In this article, a constitutive model for quench-hardenable boron steel is presented. Three sets of boron steel blanks are heat treated such that their as-treated microstructures are close to fully martensitic, bainitic and ferritic/pearlitic, respectively. Hardness measurements show that the resulting blanks cover the full scope of possible hardness values, from 165 HV in the ferritic/pearlitic range to 477 HV in the fully hardened state. These three main grades provide the input data for a constitutive model consisting of an extended Swift hardening law and a stress triaxiality and Lode angle dependent fracture criterion. The hardening behavior of each grade is determined using standard tensile tests at quasi-static strain rates. The strain-based fracture criterion is calibrated using four different flat fracture samples. The behavior of intermediate hardness grades is approximated by piecewise linear combination of the three calibrated constitutive models. A newly developed tapered tensile test specimen featuring a hardness transition zone in the gauge section is used to verify the model at hand. A four point bending test of a top hat section of intermediate hardness is used to verify the model for complex loading conditions. 相似文献