Study of the electrochemical hydrogen storage properties of the proton-conductive perovskite-type oxide LaCrO3 as negative electrode for Ni/MH batteries

LaCrO₃ was prepared by glycine combustion method and investigated as negative electrode for Ni/MH batteries. The structures of the as-calcined powder and the 20th charge-discharge cycle sample were characterized by XRD. The electrochemical experimental results demonstrated that the LaCrO₃ electrode showed excellent electrochemical reversibility and considerably high charge-discharge capacity at various temperatures. Except for the charge-discharge cycle at 298 K, the discharge capacities of LaCrO₃ electrode keep steady at 107.1 mA h g⁻¹and 285 mA h g⁻¹ at 313 K and 333 K after 5 cycles, respectively.     

Electrochemical properties and hydrogen storage mechanism of perovskite-type oxide LaFeO3 as a negative electrode for Ni/MH batteries

Perovskite-type oxide LaFeO₃ powder was prepared using a stearic acid combustion method. Its phase structure, electrochemical properties and hydrogen storage mechanism as negative electrodes for nickel/metal hydride (Ni/MH) batteries have been investigated systematically. The results of X-ray diffraction (XRD) analysis show that both the calcined powder and the charged/discharged samples after 10 cycles have orthorhombic structures. The discharge capacity, whose maximum value appeared at the first cycle, is 530.3 mA h g⁻¹ at 333 K and increases with an increase in temperature. The discharge capacity decreases distinctly during the first three cycles and then stays steady at about 80 mA h g⁻¹, 160 mA h g⁻¹ and 350 mA h g⁻¹ at 298 K, 313 K and 333 K, respectively. The hydrogen storage mechanism is studied by XRD, X-ray photoelectron spectroscopy (XPS) and mass spectrometry (MS), coupled with pressure-composition-temperature (PCT) methods. Hydrogen atoms may be intercalating into the oxide lattice and forming a homogeneous solid solution during the charging process.     

The microstructure and magnetic properties of Ca2+ ion doped GdCrO3

In this paper, the crystal structure, vacancy defect, local electron density and magnetic properties of Gd_1-xCa_xCrO₃ (0 ≤ x ≤ 0.3) polycrystalline samples were investigated systematically. The crystal structural analyses show that all the samples are orthorhombic phase and a structural distortion happens around x = 0.3. Due to the formation of Cr⁴⁺ ions, both the lattice constant and the Cr–O bond length decrease. The results of positron annihilation spectrum reveals that the vacancy defect concentration increases and the local electron structure changes with the introduction of Ca²⁺ ions. The field-cooled (FC) and zero-field cooled (ZFC) curves of Gd_1-xCa_xCrO₃ samples measured under H = 100 Oe exhibits negative magnetization characteristics due to the interaction between Gd³⁺ and Cr³⁺ ions, and the magnetism can be affected by the structural distortion.     

灌区闸门量水试验研究

为了解决灌区闸门量水公式适用环境苛刻,量水精度偏差大的问题,在量水试验研究中引入自动控制技术,经过负反馈系统调节闸门开度。本文通过大量的数据统计,进行人工智能流态分析,将平均淹没深度与误差建立联系,寻找不同系数下的误差修正方法,同时也依据当前环境状态进行调整,最终将测量误差控制在5%以内。与传统人工调节方法相比,人工智能的引入增强了量水试验的工程应用性,同时提高了水工建筑物量水的灵活性和适用范围。     

南天山库车褶皱冲断带的伸展构造

为利于库车地区天然气的勘探与开发,对该区构造提出了一些不同的认识。通常认为,自渐新世晚期至今,南天山库车地区一直处于南北向挤压构造环境。但实地考察发现,新生界地层不仅被推覆构造卷入,而且亦有受到南北向拉张构造的改造,发育有5种伸展构造:挤缩地质体后部的块断伸展构造(块断构造)、挤缩地质体的反向伸展构造(反向正断层)、挤缩地质体的横向伸展构造(横向正断层)、挤缩地质体的反转伸展构造(负反转构造)、挤缩地质体隆起部的裂陷伸展构造(正地堑)。收缩与拉伸构造的关系表现为,在同一地段,早时挤缩褶冲,后时伸展块断,先后复合;在同一时段,前缘挤缩冲断,后缘伸展正断,前后并列。南天山构造地貌景观表明,通常被否定的我国西北地区含油气盆地的伸展构造是实在的,且与推覆构造相随相伴,这对于该区推覆构造控气与伸展构造调气的分析评价具有实际意义     

Synthesis of nano-Fe3O4-loaded tubular carbon nanofibers and their application as negative electrodes for Fe/air batteries

Nano-Fe₃O₄-loaded tubular carbon nanofibers (nano-Fe₃O₄/TCNFs) were synthesized by adding TCNFs into the high-temperature solution-phase reactions of iron(III) acetylacetonate with 1,2-hexadecanediol in the presence of oleic acid and oleylamine. The morphology and structure of this material were investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements. TEM observation clarified that nano-sized Fe₃O₄ particles with a uniform diameter of several nanometers were distributed and loaded tightly on the TCNF surfaces (inside and outside). After being annealed at 500 °C in Ar gas flow, nano-Fe₃O₄/TCNFs were used as the active material of negative electrodes for Fe/air batteries. Using an alkaline aqueous electrolyte with K₂S additive, a high specific capacity of 786 mAh g⁻¹ and cycling efficiency of 76% at the 30th cycle were obtained. The downsizing of the conductive Fe₃O₄ nano-particles was considered to have contributed to the good electrochemical properties of the material.     

深-石长输管线无线数据监测及泄漏定位技术的研究与应用

主要讲述了负压波理论在输油管道泄漏监测系统的具体应用情况。针对深—石长输管线分析了采用负压波理论进行汇漏定位过程中的时间差求解问题，通过负压波理论的定位公式及时间差对泄漏点进行定位，对异常情况及时报警，并对长输管线泄漏地点进行准确测量。该技术的应用进一步提高了长输管线的整体管理水平，提高了发现问题、解决问题的能力，有效地保证了深—石长输管线的正常运行。     

负离子化学电离GC－MS在单端孢霉烯族毒素分析中的应用

建立了准确、超灵敏的多种单端孢霉烯族毒素的分析方法。方法采用负离子化学电离ＧＣ－ＭＳ技术对十六种单端孢霉烯族毒素的七氟丁酰化衍生物进行气相色谱分离和质谱电离。对每种单端孢霉烯族毒素选择４－５特征碎片离子进行检测，并根据其碎片离子的相对强度和气相色谱保留时间进行鉴定，其检测限可达５×１０（－１１）～０．４×１０（－１２）ｇ。以单离子进行检测，检测限可达１×１０（－１１）～６×１０（－１５）ｇ。该法应用于粮食样品及培养物的测定，检出了以前所建各种方法未曾检出的多种单端抱霉烯族毒素。     

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混相压力是确定油藏能否实现混相驱的重要依据，确定混相压力的方法很多，但每种方法由于具有各自鲜明的特点和适用条件，使用都有一定的局限性，为此提出了一种能广泛适用并准确计算混相压力的新方法——系线解析法，它具有计算方法简单、用时少、结果准确可靠等优点。文章首先介绍了负向闪蒸的基本概念和原理，在此基础上，详细介绍了系线解析法的基本理论、计算方法以及应用系线解析法求解混相压力的原理，然后应用系线解析法求解了四组分系统的混相压力。计算结果表明，与其它方法相比，系线解析法确定的混相压力更准确，更可靠。     

An optimized pretreatment method in the analysis of negative plate of lead acid battery

The composition of the plate in lead acid battery plays a vital role on battery performance. Therefore, controlling and monitoring of plate composition is utmost important in order to attain required battery performance. While monitoring negative plate, it has to be ensured that they are not exposed to air, which would otherwise result in Pb oxidation; thereby affecting the accuracy of the test data. Nevertheless, published information is scarce on the “pretreatment and preservation of the negative plates”. The objective of this study is to develop a suitable procedure to “preserve and pretreat the negative plate” prior to chemical composition analysis. A host of experimental parameters like immersion time in water, effect of drying reagent and air drying time were studied. Two drying solvents; namely, methanol and acetone were studied to evaluate their suitability.