西堠门大桥结构监测系统的设计与实现(Ⅱ):系统实现

采用"西堠门大桥结构监测系统的设计与实现(I):系统设计"中的设计方法,为西堠门大桥设计并实现桥梁结构监测系统。研究西堠门大桥结构监测系统的总体设计方案、子系统的设计方案及其软硬件的实现。分析西堠门大桥结构监测系统在运营中监测的桥梁荷载和结构响应。研究结果表明,西堠门大桥结构监测系统正常运行,实现了预期设计功能,基于工业以太网分布式数据采集与传输系统在桥梁结构监测系统中得以成功应用,可在其他工程中加以推广。     

Evaluation of different screening methods to understand the dissolution behaviors of amorphous solid dispersions

Objective: The objectives of the current study were to understand the dissolution behaviors of amorphous solid dispersions (ASD) using different screening methods and their correlation to the dissolution of formulated products.

Materials and methods: A poorly soluble compound, compound E, was used as a model compound. ASDs were prepared with HPMC, Kollidon VA64 and Eudragit EPO using hot-melt extrusion. Different techniques including precipitation, powder, capsule and compact dissolution and the dissolution of formulated products were conducted in USP simulated gastric fluid using a USP II dissolution apparatus.

Results and discussions: It was found that a precipitation study could generally predict powder, capsule and compact dissolution. Yet, it was recommended to run the dissolution at a higher paddle speed or for a longer duration to improve the predictability. It was also recommended to run powder, capsule and compact dissolution at both slow and high speeds to gain insights into wetting, dispersion and the dissolution of a system. Sometimes, capsule or compact dissolution could not be predicted by precipitation or powder dissolution due to plug formation. In this case, properly designed dosage forms were needed to break up this plug to optimize the dissolution profiles. On the contrary, formulations and dissolution conditions would have minimal effects on the dissolution profiles of a fast-dissolving solid dispersion.

Conclusions: Different techniques are available to select the right polymers to optimize dissolution behaviors. However, it is important to understand the merits and limitations of each technique in order to optimize the formulations for amorphous solid dispersions.     

Dendrite‐Free Lithium Deposition via a Superfilling Mechanism for High‐Performance Li‐Metal Batteries

Uncontrollable Li dendrite growth and low Coulombic efficiency severely hinder the application of lithium metal batteries. Although a lot of approaches have been developed to control Li deposition, most of them are based on inhibiting lithium deposition on protrusions, which can suppress Li dendrite growth at low current density, but is inefficient for practical battery applications, with high current density and large area capacity. Here, a novel leveling mechanism based on accelerating Li growth in concave fashion is proposed, which enables uniform and dendrite‐free Li plating by simply adding thiourea into the electrolyte. The small thiourea molecules can be absorbed on the Li metal surface and promote Li growth with a superfilling effect. With 0.02 m thiourea added in the electrolyte, Li | Li symmetrical cells can be cycled over 1000 cycles at 5.0 mA cm^?2, and a full cell with LiFePO₄ | Li configuration can even maintain 90% capacity after 650 cycles at 5.0 C. The superfilling effect is also verified by computational chemistry and numerical simulation, and can be expanded to a series of small chemicals using as electrolyte additives. It offers a new avenue to dendrite‐free lithium deposition and may also be expanded to other battery chemistries.     

复合材料蒙皮-加筋大开口结构优化设计

采用有限元法对复合材料蒙皮-加筋大开口结构进行了优化设计,研究孔边补强和加筋补强对大开口结构屈曲特 性的影响.结果表明:孔边翻边补强可使应力集中远离孔的自由边,增加翻边深度和宽度皆能提高屈曲载荷;采用共固化加筋要比整体加筋效果明显,同等条件下,优先考虑低而密的筋条布置,同时增加横向筋的数量.     

蓝莓新鲜度指示剂研究

目的研究一种以蓝莓花青素为原料制作的蓝莓新鲜度指示剂,并应用于蓝莓包装,用以指示蓝莓果实在运输贮藏过程中新鲜度的变化情况。方法以新鲜度指示剂在蓝莓贮藏期间的色差值作为考查指标,对影响色差值的因素进行研究。首先通过单因素试验研究果皮浓度、滤液pH值和滤纸浸泡时间对指示剂色差值的影响,然后利用正交试验法优化最佳工艺条件。结果由正交试验分析结果得出蓝莓新鲜度指示剂最佳工艺条件,果皮质量浓度为4 g/(100 m L)、滤液pH值为12、滤纸浸泡时间为1.5 min,该条件下新鲜度指示剂的色差值为54.69。结论通过正交试验法获取最优制作工艺的蓝莓新鲜度指示剂,该指示剂具有明显的颜色界限,是一种实用的蓝莓包装标签。     

Structure and magnetic properties of Ni0.11ZnxCo0.03Fe2.86-xO4 ferrite films deposited on Ag-coated glass substrates by wet chemical method

Ni_0.11Zn_xCo_0.03Fe_2.86-xO₄ spinel ferrite films with x = 0.00, 0.23, 0.34, 0.43 and 0.51 were prepared on Ag-coated glass substrates from nitrate and dimethylamine borane solution at 80 °C. The Ni_0.11Zn_xCo_0.03Fe_2.86-xO₄ ferrite films are singe-phased spinel ferrite. With the Zn content x increasing from 0 to 0.51, the lattice constant of the ferrite films increases from 0.8383 to 0.8425 nm. The Ni_0.11Zn_0.51Co_0.03Fe_2.35O₄ film is about 500 nm thick and composed of uniform equiaxed granules of about 40–50 nm. The Raman spectrum analysis indicates that the Zn²⁺ ions occupy the A sites. Saturation magnetization increases with x increasing from 0 to 0.35, reaches a maximum value of 460 kA/m at x = 0.35, and then decreases with further increase of x. Coercivity decreases monotonically from 12.3 to 1.7 kA/m with x increasing from 0 to 0.51. The change in magnetic properties may be explained by the decrease of A–B interactions and the anisotropy constant due to the incorporation of non-magnetic Zn²⁺ ions.     

Highly Electrochemically‐Reversible Mesoporous Na2FePO4F/C as Cathode Material for High‐Performance Sodium‐Ion Batteries

As promising cathode materials, iron‐based phosphate compounds have attracted wide attention for sodium‐ion batteries due to their low cost and safety. Among them, sodium iron fluorophosphate (Na₂FePO₄F) is widely noted due to its layered structure and high operating voltage compared with NaFePO₄. Here, a mesoporous Na₂FePO₄F@C (M‐NFPF@C) composite derived from mesoporous FePO₄ is synthesized through a facile ball‐milling combined calcination method. Benefiting from the mesoporous structure and highly conductive carbon, the M‐NFPF@C material exhibits a high reversible capacity of 114 mAh g^?1 at 0.1 C, excellent rate capability (42 mAh g^?1 at 10 C), and good cycling performance (55% retention after 600 cycles at 5 C). The high plateau capacity obtained (>90% of total capacity) not only shows high electrochemical reversibility of the as‐prepared M‐NFPF@C but also provides high energy density, which mainly originates from its mesoporous structure derived from the mesoporous FePO₄ precursor. The M‐NFPF@C serves as a promising cathode material with high performance and low cost for sodium‐ion batteries.     

Highly efficient white organic light-emitting devices based on a multiple-emissive-layer structure

Characteristics of white organic light-emitting devices based on phosphor sensitized fluorescence are improved by using a multiple-emissive-layer structure, in which a phosphorescent blue emissive layer is sandwiched between red and green&yellow ones. In this device, bis[(4,6–difluorophenyl)–pyridinato–N,C²] (picolinato), bis(2,4–diphenyl–quinoline) iridium (III) acetylanetonate, fac tris (2-phenylpyridine) iridium, and 5,6,11,12–tetraphenylnaphthacene are used as blue, red, green, and yellow emitters, respectively. The device has a maximum luminance of more than 30,000 cd/m², a maximum luminous efficiency of 27 cd/A, a maximum external quantum efficiency of 12.4%, and a color rendering index of 81 at 100 cd/m².     

应用灰色关联度分析检测结构损伤的位置和程度

开发结构健康监测系统是结构损伤识别的一个重要课题。由于建筑结构具有很多不确定因素,通过模 态分析识别结构损伤的精度很难保证。提出一种灰色关联度分析应用于结构损伤检测的数值方法。通过测量结构的频 率,建立可能损伤频率和实际损伤频率的关联度的关联序,并找出最优序列,逐次迭代逼近来确定结构的损伤位置和损 伤程度。对多种工况进行了框架结构模型的数值模拟。结果表明:对于层间剪切结构,通过测量结构频率变化运用本方 法可以准确地确定结构的损伤位置和损伤程度。     

High-performance flat-panel solar thermoelectric generators with high thermal concentration

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.