Synthesis and luminescence properties of nitrided lanthanum magnesium hexaluminate LaMgAl11O19 phosphors

Nitrided LaMgAl₁₁O₁₉ phosphors were prepared by a two-step method involving synthesis at 1550 °C for 4 h, trituration, and firing at 1650 °C for 5 h under a nitrogen atmosphere. Nitrogen was doped into LaMgAl₁₁O₁₉ and bonded with aluminium atoms. The nitrided LaMgAl₁₁O₁₉ phosphors showed plate-like morphology with a rough surface and exhibited strong blue emission at 442 nm and 450 nm, which may be attributed to the energy transition between defect levels. A weak emission band at 590 nm was ascribed to the transition between the V_Al acceptor and the valence band, which was excited at 254 nm.     

Dependence of crystal structure on mechanical and thermophysical properties of magnetoplumbite-type LnMgAl11O19 ceramics with substitution of Ln3+ Ions

Lanthanum hexaaluminate is a promising candidate to establish yttria partially stabilized zirconia as a thermal barrier coating material for super alloy due to their remarkable stability and thermophysical performance. In order to understand the relationship between the structure and properties and gain new low thermal conducting materials, the LnMgAl₁₁O₁₉ (LnMA, Ln: La, Pr, Nd, Sm, Eu, Gd) materials were synthesized firstly and further used to produce the LnMA ceramics. With the increasing relative atomic mass of the replaced Ln³⁺ ions from La to Gd, the lattice parameters and grain sizes of the LnMA platelets decrease, while the mechanical properties increase, and the thermal physic properties decrease. The GdMgAl₁₁O₁₉ ceramics obtain the lowest thermal conductivity with the value of 1.91-1.78 W/m K in the range from room temperature to 800°C, which could be considered as a promising candidate for application in thermal barrier coating materials. These results could further provide reference for developing novel materials lower thermal conductivity.     

Characterization of domain configurations in LiTaO3/Al2O3 ceramic composites

Characterization of domain configurations in 15 vol% LiTaO₃/Al₂O₃ ceramic composites hot-pressed sintered at 1300 °C was carried out using transmission electron microscopy and high-resolution transmission electron microscopy. Mainly banded- and wedge-shaped 90° domains, with few 180° domains, were formed in the LiTaO₃ grains within the composite. The formation of 90° domains was attributed to the large stress caused by residual polarization. Many dark dots, distributed along the 90° domain boundaries, were detected and it was confirmed that they were not a deposited second phase but a type of contrast induced by high strain. The 90° domain boundaries presented an α-type fringe contrast and no δ-type fringes were observed, indicating that they were of the non-conventional type.     

智能化温室大棚的工程研究与实施

本文基于WinCe 6.0系统和PID控制算法,设计一套温室大棚的智能化环境监测控制系统,优势在于:可以实现三种不同的操控界面,1每个大棚里的ARM一体机实现实时的监测和手动控制。2工控机可以实现对各个大棚的自主控制。3用手机或者ipad来控制,实现对大棚环境自动监测和控制。一方面是我们的大棚环境控制更加的智能化,方便了农户,可以在有网络的地方时刻了解自己大棚的情况。另一方面,为作物提供最佳的条件,以提高作物产量和效益。     

压水堆核电厂蒸汽发生器传热管的降质问题

核电厂蒸汽发生器传热管的降质将影响到核电厂一回路边界的完整性。通过对蒸汽发生器传热管的降质模式进行分析，并对在役传热管无损检测技术应用以及寿命预测的介绍，从而针对产生的传热管降质的原因，采取相应的防护措施，确保蒸汽发生器传热管的安全运行。     

Selectivity of C- versus O-acylation of diphenols by clay catalysts. I. Acylation of resorcinol with phenylacetyl chloride

Resorcinol was acylated by phenylacetyl chloride with a set of catalysts consisting of the montmorillonite-based K-series and their cation-exchanged forms. The selectivity of C-acylation over O-acylation could be significantly increased by an appropriate ion exchange and by a solvent-free reaction mode, resulting in a 60% preparative yield of 1-(2,4-dihydroxyphenyl)-2-phenyl-ethanone. This revised version was published online in June 2006 with corrections to the Cover Date.     

Crystal structure and luminescence properties of a single‐component white‐light‐emitting phosphor Ca8ZnLa(PO4)7:Eu2+,Mn2+

A series of novel green emission Whitlockite‐type Ca₈ZnLa(PO₄)₇:Eu²⁺ and color tunable Ca₈ZnLa(PO₄)₇:Eu²⁺,Mn²⁺ phosphors were prepared by the solid‐state reaction method in a reducing atmosphere. Its crystal structure and phase composition were identified by high‐resolution transmission electron microscopy, selected area electronic diffraction, X‐ray photoelectron spectroscopy, and X‐ray powder diffraction Rietveld refinement, and it was found to be trigonal, belonging to R‐3c(161) space group. The luminescence properties of Eu²⁺ singly doped and Eu²⁺/Mn²⁺ codoped Ca₈ZnLa(PO₄)₇ phosphors were revealed in detail. Ca₈ZnLa(PO₄)₇:Eu²⁺ is excitable over a broad range from 200 to 450 nm with a prominent green emitting. With varied Eu²⁺/Mn²⁺ ratios, fine‐tune emission under 365 nm excitation can be achieved from green (0.221, 0.468) to magenta (0.391, 0.276), especially the warm white light (0.392, 0.352), and CCT 3500 K can be obtained by the process of energy transfer between Eu²⁺ and Mn²⁺. The ET mechanism in this system is managed via the dipole‐dipole interaction with the maximum energy‐transfer efficiency 82.8% based on the decay lifetime data. These results suggest that as‐prepared phosphors can serve as promising candidates of UV‐pumped w‐LEDs.     

利用菌-藻体系高效快速脱除生活污水中氮、磷的技术研究

利用菌－藻体系中的细菌与藻类生活习性与摄取食物上的差异性，对它们进行有效的组合来处理城市生活污水，结果表明：在一定的条件下该系统可使污水中磷的去除率达94．4％，氮的去除率为48．3％，COD去除率为87．7％。大大减轻了出水中的磷、氮对受纳水体的环境负荷；高效、经济、可操作性强。     

底框砌体剪力墙震损房屋抗震加固拟动力子结构试验

在完成了3层足尺底框配筋砌块短肢砌体剪力墙震损房屋损伤程度的评估、加固的基础上,通过对加固后的3层房屋进行拟动力抗震性能试验,研究了震后受损结构构件所用加固方法的适用性和加固对恢复结构抗震性能的效果,为寻求震损结构加固修复的方法提供理论依据,并为汶川地震受损底框房屋的结构修复提供参考。     

Colorimetry and photoacoustic spectroscopy as a suitable tool for determination of fat-free cocoa solids in dark chocolates

Laser photoacoustic spectroscopy (PAS) and colorimetry have been used to rapidly and accurately determine the content of fat-free cocoa solids in dark chocolates. Both techniques are inexpensive and require only a one-time calibration step versus a method capable of absolute concentration measurement (for example HPLC). Once the response of PAS and/or colorimetry has been obtained, the content of fat-free cocoa solids in dark chocolates can be determined directly (i.e. without any sample preparation including the process of extraction) from the calibration curves and the experimentally measured microphone signal (in PAS studies) and colorimetric indices L* and ΔE* (in colorimetric investigations). Both colorimetric indices and PA signals correlate positively with the content of fat-free cocoa solids. The correlation is highly linear over a wide concentration range (25–50 %).