重力无阀滤池处理能力降低原因分析及措施

针对气化循环水系统重力无阀滤池在运行过程中处理能力降低的现象,从滤池跑砂、结泥球及进水分配槽溅水严重等方面进行分析,通过清理滤砂,检修设备及仪表等措施,提高重力无阀滤池的处理能力。     

Investigations on hydrogen storage performances and mechanisms of as-cast TiFe0.8-mNi0.2Com (m=0, 0.03, 0.05 and 0.1) alloys

In order to improve the hydrogen storage performances of TiFe-based alloys, a new type of TiFe_0.8-mNi_0.2Co_m (m = 0, 0.03, 0.05 and 0.1) alloys were prepared through vacuum medium-frequency induction melting. XPS results showed that the composition of surface oxide film contains TiO₂, FeO and NiO for the cobalt-free alloy, and it also includes CoO and Co₃O₄ besides the above oxides for the cobalt-containing alloys. The activation temperature is 523, 403, 383 and 373 K for the TiFe_0.8-mNi_0.2Co_m (m = 0, 0.03, 0.05 and 0.1) alloys, respectively. The changes of the composition and microstructure of the surface oxide film are the root causes of the reduction of the activation temperature. XRD and SEM analyses showed that all the alloys are composed of the majority phase of TiFe phase and non-hydrogenated phase of Ti₂Fe phase. Adding appropriate amount of cobalt is beneficial to inhibiting the generation of Ti₂Fe phase and increasing the cell volume of TiFe phase. The hydrogenation capacity is proportional to the content of TiFe phase, which is 1.11, 1.48, 1.54 and 1.29 wt% for the TiFe_0.8-mNi_0.2Co_m (m = 0, 0.03, 0.05 and 0.1) alloys at 313 K, respectively. The hydrogenation plateau performance also is improved correspondingly.     

不同类型电涡流探头对核电站传热管胀管过渡段缺陷的定位准确性研究

为了更有效和可靠地检测出胀管过渡区出现的缺陷,分析了3种不同类型的涡流探头特性,然后通过一系列试验,对不同探头在传热管胀管过渡段上的缺陷识别并进行准确定位能力进行了对比测试,获得了相关的定位准确性数据,掌握了胀管过渡段缺陷定位技术及其精度范围,能够进一步提高对胀管过渡段上的缺陷的准确判别能力。     

Hybrid photocatalytic H2 evolution systems containing xanthene dyes and inorganic nickel based catalysts

The application of nickel based earth abundant inorganic solids as catalysts in xanthene dye sensitized systems was evaluated for photocatalytic H₂ production from water. The introduction of heterogeneous nanoparticles into molecular systems as catalysts is the conceptual begin to broaden the construction of photocatalytic H₂ production systems. A series of Ni based inorganic nanoparticles, including Ni metal, NiO, NiS and NiSe, are capable of producing H₂ from triethanolamine sacrificial aqueous solution when photosensitized by xanthene dyes. NiS catalysts synthesized from different methods were also evaluated for H₂ production performance. The best H₂ production result is obtained with the use of Erythrosin Y as the photosensitizer and NiS synthesized in ethylene glycol as the catalyst. This system is active even under photons with wavelengths longer than 520 nm with a H₂ production of 2.5 mmol within 26 h of irradiation from a 300 W Xenon lamp. Meanwhile, it can generate over 4.2 mmol of H₂ within 16 h of irradiation with a 440 nm long-pass cut-off filter. Within the visible light range we examined, the highest quantum efficiency is around 15% at 520 nm. The high activity of NiS could be contributed by its high electrochemical activity, metallic nature, unsaturated Ni environment and suitable Fermi energy level. These hybrid systems consist of earth abundant elements, and the catalyst is photostable and recyclable compared to homogeneous metal complex catalyst.     

Multi-agent reinforcement learning based maintenance policy for a resource constrained flow line system

This paper investigates the maintenance problem for a flow line system consisting of two series machines with an intermediate finite buffer in between. Both machines independently deteriorate as they operate, resulting in multiple yield levels. Resource constrained imperfect preventive maintenance actions may bring the machine back to a better state. The problem is modeled as a semi-Markov decision process. A distributed multi-agent reinforcement learning algorithm is proposed to solve the problem and to obtain the control-limit maintenance policy for each machine associated with the observed state represented by yield level and buffer level. An asynchronous updating rule is used in the learning process since the state transitions of both machines are not synchronous. Experimental study is conducted to evaluate the efficiency of the proposed algorithm.     

Selective elution of tea catechins and caffeine from polyvinylpolypyrrolidone

Desorption of catechins and caffeine from polyvinylpolypyrrolidone (PVPP) was comprehensively investigated. The result showed that caffeine could easily be desorbed from PVPP by the tested solvents except n‐hexane, while catechins could only be thoroughly done by dimethyl sulphoxide (DMSO) and N, N‐dimethylformamide (DMF). Excellent desorption efficiency of DMSO and DMF might be attributed to their high dipole moments and H‐bond potentials. Addition of ethanol was recommended considering the elution efficiency and fluidity, but ethanol volume should be <40% (v/v) for DMSO or 20% (v/v) for DMF. Desorption would get to equilibrium within 1 h and followed the pseudo‐second‐order model. Caffeine and catechins could be separately desorbed through two‐stage elution procedure, that is, water or 20% aqueous ethanol for desorbing caffeine and part of nongalloylated catechins and DMSO/ethanol (8/2, v/v) for eluting the remaining catechins. Highly purified catechins (~95%) with high level (~70%) galloylated catechins would be achieved when the desorption procedure was applied in column chromatograph.     

可溶性盐复分解法碳酸钙制备影响因素研究

采用可溶性盐复分解法进行碳酸钙合成影响因素及其机理的研究。以正交试验法对合成温度、pH值、反应物浓度在碳酸钙合成中的影响进行探索,验证了温度以及pH值在合成反应中对产物晶型、形貌以及尺度有显著影响;使用周期键链理论(PBC)讨论了碳酸钙晶体方解石/文石共生现象;研究观察Mg2+对碳酸钙合成的影响,Mg2+作为能够稳定无定形碳酸钙前驱体(ACC)的金属离子,大量存在时碳酸钙形貌随nMg/nCa增大而变化,同时颗粒尺度变小。     

智能阴极保护采集监控系统的应用与发展

目前金属材料广泛应用于油气管网的建设中,金属腐蚀问题备受关注,阴极保护技术是抑制金属腐蚀的一种非常有效的电化学保护手段。对阴极保护各项参数进行检测,能够保证阴极保护的有效性,降低金属发生腐蚀的风险。相对传统的人工检测方式,智能阴极保护采集监控系统能对阴极保护进行实时与同步监测,降低了测量误差并节省大量人工成本。随着科学技术的不断发展,现今有更多相关企业注重智能阴极保护采集监控系统的发展和建设,在获得经济效益与社会效益的同时推动了工业技术的不断创新与发展。     

Temperature stable 0.35Ag2MoO4-0.65Ag0.5Bi0.5MoO4 microwave dielectric ceramics with ultra-low sintering temperatures

In this study, the novel temperature-stable (1-x)Ag₂MoO₄-xAg_0.5Bi_0.5MoO₄ microwave dielectric ceramics were prepared by a modified solid-state reaction method. The phase composition, microstructures and microwave dielectric properties of the (1-x)Ag₂MoO₄-xAg_0.5Bi_0.5MoO₄ ceramics were investigated. All the compounds can be sintered well at ultra-low temperatures (<540 °C). The XRD and SEM analysis indicate that the Ag₂MoO₄ and the Ag_0.5Bi_0.5MoO₄ can coexist with each other. When x = 0.65, the ceramics exhibit the best microwave dielectric properties with a relative permittivity of 23.9, a Q × f value of 16,200 GHz (at 7.3 GHz) and a near-zero TCF value of -2.4 ppm/°C at 520 °C. The results indicate that temperature-stable (1-x)Ag₂MoO₄-xAg_0.5Bi_0.5MoO₄ ceramics are promising candidates for low temperature co-fired ceramics (LTCC) applications.     

Na2SO4对低硫水泥及其混凝土性能的影响

本文探讨了单掺Na2SO4对低硫水泥及其混凝土性能的影响。结果表明:少量的Na2SO4缩短了水泥凝结时间,有利于提高混凝土的坍落度、改善混凝土坍落度损失,而且在低温时可以明显改善混凝土的早期强度。