框架结构护岸新技术在城市河道中的应用

好溪堰河是贯穿浙江省丽水市主城区的一条千年古河道,在河道整治过程中,受制于河道周边的密集建筑物,传统的河道护岸技术均难以同时满足水利、市政、交通及景观的多元化要求。在分析其他创新河道护岸技术特点及存在问题的基础上,提出了适用于城市河道的桩柱式、框柱式两种框架结构护岸新技术,这两种护岸在维护河道周边建筑物稳定的同时,均具有不加深河床就可拓宽河道过流断面、不减少河岸用地、保持岸路畅通、改善水质及生态效果、提高亲水性等优点,在丽水好溪堰河水系整治工程中应用较为成功。     

Broadband excited Na3Tb(PO4)2:Ce3+/Eu2+ green/yellow-emitting phosphors with high color purity for LED-based application

To enhance the display quality of light-emitting diodes (LEDs), it is of great significance to exploit green/yellow-emitting phosphors with narrow emission band, high quantum yield, and excellent color purity to satisfy the application. Herein, orthophosphate-based green/yellow-emitting Na₃Tb(PO₄)₂:Ce³⁺/Eu²⁺ (NTPO:Ce³⁺/Eu²⁺) phosphors have been successfully synthesized by a facile solid-state reaction method. The absorption band of NTPO samples was extended to the near-ultraviolet region and the absorption efficiency was significantly improved owing to a highly efficient energy transfer from Ce³⁺/Eu²⁺ ion to Tb³⁺ ion in NTPO host certified by time-resolved PL spectra. Upon 300 nm excitation, the NTPO:Ce³⁺ is characterized by ultra-narrow-band green emission of Tb³⁺ with an absolute quantum yield of 94.5%. Unexpectedly, NTPO:Eu²⁺ emits bright yellow light with a color purity of 73% as a result of the blending of green light emission from Tb³⁺ and red light emission from Eu³⁺. The thermal stability has been improved by controlling the stoichiometric ratio of Na⁺. The prototype white LED used yellow-emitting NTPO:Eu²⁺ phosphor has higher color-rendering index (Ra = 83.5), lower correlated color temperature (CCT = 5206 K), and closer CIE color coordinates (0.338, 0.3187) to the standard white point at (0.333, 0.333) than that used green-emitting NTPO:Ce³⁺ phosphor, indicating the addition of the yellow light component improved the Ra of the trichromatic (RGB) materials.     

Effects of redox-active interlayer anions on the oxygen evolution reactivity of NiFe-layered double hydroxide nanosheets

Nickel-iron layered double hydroxide (NiFe-LDH) nanosheets have shown optimal oxygen evolution reaction (OER) performance; however, the role of the intercalated ions in the OER activity remains unclear. In this work, we show that the activity of the NiFe-LDHs can be tailored by the intercalated anions with different redox potentials. The intercalation of anions with low redox potential (high reducing ability), such as hypophosphites, leads to NiFe-LDHs with low OER overpotential of 240 mV and a small Tafel slope of 36.9 mV/dec, whereas NiFe-LDHs intercalated with anions of high redox potential (low reducing ability), such as fluorion, show a high overpotential of 370 mV and a Tafel slope of 80.8 mV/dec. The OER activity shows a surprising linear correlation with the standard redox potential. Density functional theory calculations and X-ray photoelectron spectroscopy analysis indicate that the intercalated anions alter the electronic structure of metal atoms which exposed at the surface. Anions with low standard redox potential and strong reducing ability transfer more electrons to the hydroxide layers. This increases the electron density of the surface metal sites and stabilizes their high-valence states, whose formation is known as the critical step prior to the OER process.

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无填料振冲挤密法在粉砂土地基处理中的应用——以钱江闸站枢纽工程为例

为消除粉砂土地基液化、减小建筑物地基不均匀沉降、提高地基承载力,可采用无填料振冲挤密法对基础范围内的粉砂土进行加密,使振冲后的地基达到中密至密实状态。结合钱江闸站枢纽工程实例,介绍无填料振冲挤密法在粉砂土地基处理中的应用情况,从设计、施工、质量控制和检测4个方面分析了该地基的处理效果。工程实践表明,只要采用正确的施工工艺和技术参数,用此种方法加固粉砂土地基效果明显,能满足工程质量和施工进度控制要求。     

尿素生产旋风分离器腐蚀与对策

论述了尿素生产旋风分离器的结构、工作工艺条件;重点分析了分离器发生腐蚀的原因;针对不同的腐蚀原因提出了具体的优化措施,收到了良好的技改效果。     

乙丙嵌段共聚物相对分子质量及链结构对PP/EPR共混体系结构与性能的影响

设计合成了一系列不同相对分子质量和乙烯平均序列长度的乙丙嵌段共聚物（EP）,并将其作为聚丙烯（PP）/二元乙丙橡胶（EPR）共混体系的增容剂,考察了EP用量、相对分子质量及乙烯平均序列长度对共混体系性能及分散相形态演变的影响。结果表明,EP增容PP/EPR体系时存在最佳添加量,少量EP的加入可有效提高PP/EPR共混体系的抗冲击性能,并对分散相尺寸及形态起到良好的调控作用;同时,EP的相对分子质量越大对共混体系的冲击性能提高越明显,EP的组成与EPR越接近,对共混体系的增容效果越明显。     

Scale effects and scaling-up by geometric-optical model

This is a follow-up paper to our "Scale effect of Planck's law over nonisothermal blackbody surface". More examples are used to describe the scale effect in detail, and the scaling-up of Planck law over blackbody surface is further extended to three-dimension nonisothermal surface. This scaling-up results in a conceptual model for the directionality and spectral signature of thermal radiation at the scale of remote sensing pixels. This new model is also an improvement of Li-Strahler-Friedl conceptual model in a sense that the new model needs only statistic parameters at the pixel scale, without request of sub-pixel scale parameters as the LSF model does.     

Fabrication of Josephson tunnel junction with suspended metal mask

 A small area Josephson tunnel junction is fabricated with the suspended metal mask made of ordinary razor blades.The junction overlap is formed by two successive evaporations of superconductor materials at oblique angles.The advantages of this technique are that the fabrication processes can be performed continuously without opening the evaporation chamber and also it is suitable for making a small area tunnel junctions.The Ⅰ-Ⅴ characteristic of a tunnel junction made by this technique has been taken at 4.2K.     

Facile synthesis of a Bi-modified PtRu catalyst for methanol and ethanol electro-oxidation in alkaline medium

In this work a facile synthesis for a high-performance PtRuBi/C catalyst was presented through a simple mixture of commercial PtRu/C and Bi(NO₃)₃. Most of the Bimodified the PtRu particle surface via irreversible adsorption and deposition processes. X-ray photoelectron spectroscopy analysis indicated that Bi₂O₃ was the main form in the catalyst and that there exists an interaction between Bi₂O₃ and Pt. The current density of PtRuBi/C (1:1:0.2 for Pt:Ru:Bi) in the cyclic voltammograms for methanol or ethanol oxidation is over 2.6 times higher than that of PtRu/C. The anti-poisoning ability of this catalyst was also greatly improved. The Bi-containing catalyst had abundant oxygenated species and facilitated removal of poisonous intermediate species.