Calculation of extinction cross-section of single vegetation elements placed in open resonator

The results of calculation of extinction cross — section for bodies of various shapes and electrical constants placed in open resonator are presented. Theoretical model for such structure was developed. It allowed to calculate transfer ratio, Q-factor and another characteristics of the resonator with sample. The results presented can be used for investigation of extinction cross — section for vegetation elements in millimeter wave band using open resonator.     

Phosphorus recovery from digested sewage sludge as MAP by the help of metal ion separation

This study was designed to solve metal ion influence problem on phosphorus recovery from digested sewage sludge as MAP. The experimental steps were proceeded to maximize MAP production and its quality. Used experimental steps were:

(a)

Acidic dissolution of phosphorus,

(b)

Removal of metal ions from phosphorus rich water phase,

(c)

Recovery of phosphorus as MAP,

(d)

Separation of MAP.

All digested sewage sludge samples were taken from Stuttgart University sewage treatment plant for research and education (LFKW). Four different forms of LFKW digested sewage sludge were used as feeding sample. These were: original digested sludge, diluted digested sludge, centrifuged digested sludge and incinerated digested sludge.A Donnan membrane unit having a Nafion 117 (DuPont) cation exchange membrane was used to remove metal ions from the samples used. Highest metal ion removal efficiencies, which were 98%, 97%, and 80% for Al, Ca and Fe ions, respectively, were obtained from incinerated digested sludge run.Incinerated digested sludge run was used as preliminary step for MAP production and high quality MAP was produced. Produced MAP fulfils all requirements related with Düngemittelverordnung 2003 and it could be used as a fertilizer in Germany.     

Increased Exciton Delocalization of Polymer upon Blending with Fullerene

Interfaces between donor and acceptor in a polymer solar cell play a crucial role in exciton dissociation and charge photogeneration. While the importance of charge transfer (CT) excitons for free carrier generation is intensively studied, the effect of blending on the nature of the polymer excitons in relation to the blend nanomorphology remains largely unexplored. In this work, electroabsorption (EA) spectroscopy is used to study the excited‐state polarizability of polymer excitons in several polymer:fullerene blend systems, and it is found that excited‐state polarizability of polymer excitons in the blends is a strong function of blend nanomorphology. The increase in excited‐state polarizability with decreased domain size indicates that intermixing of states at the interface between the donor polymers and fullerene increases the exciton delocalization, resulting in an increase in exciton dissociation efficiency. This conclusion is further supported by transient absorption spectroscopy and time‐resolved photoluminescence measurements, along with the results from time‐dependent density functional theory calculations. These findings indicate that polymer excited‐state polarizability is a key parameter for efficient free carrier generation and should be considered in the design and development of high‐performance polymer solar cells.     

政府开放数据的国家安全风险评估模型研究

政府开放数据作为国家和社会发展重要战略资源,蕴含着巨大价值,但我国在政府开放数据的安全风险评估方面缺乏标准,国家数据安全面临风险。借鉴信息安全风险评估理论,以国家安全资产、开放数据脆弱性和安全威胁作为主要安全风险要素,构建政府开放数据的安全风险评估模型,利用层次分析法和模糊综合评价法对政府开放数据的安全风险进行量化评估,并通过实例验证模型的有效性。     

Metal Halide Perovskites for Laser Applications

Metal halide perovskites have drawn tremendous attention in optoelectronic applications owing to the rapid development in photovoltaic and light-emitting diode devices. More recently, these materials are demonstrated as excellent gain media for laser applications due to their large absorption coefficient, low defect density, high charge carrier mobility, long carrier diffusion length, high photoluminescence quantum yield, and low Auger recombination rate. Despite the great progress in laser applications, the development of perovskite lasers is still in its infancy and the realization of electrically pumped lasers has not yet been demonstrated. To accelerate the development of perovskite-based lasers, it is important to understand the fundamental photophysical characteristics of perovskite gain materials. Here, the structure and gain behavior in various perovskite materials are discussed. Then, the effects of charge carrier dynamics and electron–phonon interaction on population inversion in different types of perovskite materials are analyzed. Further, recent advances in perovskite-based lasers are also highlighted. Finally, a perspective on perovskite material design is presented and the remaining challenges of perovskite lasers are discussed.     

Fracture strength of composite resins for endodontically treated molars

Objectives: The purpose of this study was to evaluate the effect of different fabrication techniques on the fracture strength of the composite resin-based inlay restorations of endodontically treated molars. Methods: Sixty mandibular molars were divided into six groups (n = 10) designated according to the treatment as: Group-1: Control group, intact teeth; Group-2: Filtek Ultimate Universal restorative with incremental technique; Group-3: Filtek Bulk Fill Posterior restorative; Group-4: Biodentine with Filtek Ultimate Universal restorative; Group 5: everX Posterior with Filtek Ultimate Universal restorative; and Group-6: Lava Ultimate CAD/CAM restorative. The standard mesio-occluso-distal cavities were prepared and the roots filled for all the teeth, except those of the control group. Following the placement of the restorations, the fracture resistance of the specimens was measured. The data were analyzed by the one-way analysis of variance and Tukey’s post hoc test. Results: While Group-1 (2815.80 N) exhibited significantly higher fracture strength than the other groups (p < 0.05), Groups-2 (2062.20 N), 3 (2166.00 N), 5 (2355.60 N), and 6 (2340.70 N) exhibited statistically similar results (p > 0.05). The Biodentine group (1480.50 N) exhibited significantly lower fracture strength than the rest of the groups (p < 0.05). Conclusions: The CAD/CAM and manual build-up techniques exhibited statistically similar results with the exception of Biodentine, which exhibited a significantly lower in vitro performance compared to the other composites used in the study. The fiber-supported composite everX Posterior increased the fracture strength of the endodontically treated teeth.     

使用光纤传输信号波形的技术

光纤是传输信号波形的一种介质纤维波导,在传输过程中它具有下列的优点传输损耗小,比同轴电缆的损耗小三个数量级;通频带宽,可以10Ghz以上;光纤是绝缘体,因而不受电磁感应干扰,耐高压300kV;采用光纤传输容易实现被测信号波形与终端测量仪器的隔离与接地问题.     

An experimental study on composite adhesives reinforced with different types of organo-clays

In this study, the mechanical properties of single lap joints prepared by adding nanoclays with different properties into adhesives with different characteristics (toughened, flexible, paste-type, and rigid) were experimentally investigated. Single lap joints and bulk specimens were produced using DP460, DP125, Araldite 2015, and AV138 as adhesives. High-concentration hydrocarbon-doped organo-clay (HDOC-1) obtained from Çank?r?, low-concentration hydrocarbon-doped organo-clay (HDOC-2) obtained from Erzurum, and organo-clay (OC) were incorporated into the adhesives as reinforcements at two different concentrations (1% and 2% wt.). The aluminum alloy AA2024-T3 was used as the adherend material. Evaluation of experiment results showed that both the characteristics of the adhesive (toughened, flexible, paste-type, and rigid) and the different forms of clays significantly influenced failure loads of the joints. Moreover, increasing or decreasing the amount of clay added into the adhesive also affected failure loads of the joints; 1% wt. reinforcement provided the best results.     

磁场辅助法制备钴纳米线

为扩展废旧硬质合金中钴的回收再利用价值,采用"磁场辅助法"从纯化后的废旧硬质合金回收液中液相还原制备钴纳米线,并考察其在空气中的热稳定性。研究结果表明:有无外加磁场的作用是决定产物形貌的关键因素。磁场作用下,可以得到平均直径在500 nm左右,长度能达到40μm的钴纳米线;而无磁场作用时,只能得到球状的无明显排列取向的钴颗粒。当温度低于225.0℃时,制备的钴纳米线在空气中有较好的热稳定性,具有较好的催化应用潜力。既能提高废旧硬质合金的回收再利用价值、发展钴资源循环利用经济,又对指导1维磁性金属纳米线特别是钴纳米线的制备与应用具有重要的基础理论和实际意义。