关于锐截止型滤光片有效透射比的确定

采用现代紫外分光光度计测量锐截止型有色光学滤光片的光谱透射比和Lowtran7提供的标准大气下地面的太阳光谱辐照度,按定义计算了滤光片的有效透射比。文中讨论了以“主透射带”透射比代替有效透射比的不当之处和所带来的问题。     

Biophotonics for improving algal photobioreactor performance: A review

The use of algae as a feedstock for biofuels production has drawn considerable attention due to their high biomass yield, their ability to be cultivated using degraded water on nonarable land, and their ability to recover nutrients from wastewater. Although algae have the potential to provide biomass for biofuels, some challenges remain and the limitations may be overcome by improving algal growth rates together with lipid synthesis. To achieve this, scientific researchers have focused on isolating and screening algal strains with better growth rates and lipid synthesis capabilities, bioengineering, and optimizing culture systems. The present review focuses on the biophotonic-based manipulations that can be applied to optimize solar-powered photobioreactors (PBRs). Hence, three different types of solar filters are reviewed herein, that is, the colored glass, thin-film, and thermochromic filters. This review provides evidence that bright red-colored glass filters can lower the spectral intensity of solar radiation from 1982.13 to 393.71 μmol m⁻² s⁻¹, which is preferable for improved biomass productivity. Changing filter color, once the desired biomass concentration has been amassed, to medium blue or bright pink further improves lipid yield. A 34% improvement in biomass productivity was observed for Chlorella vulgaris cultured under thin-film filters. Thin-film filters are also effective in regulating PBR temperature within the 24–31°C range, which is tolerable for most algal species. Furthermore, this study highlights that the applicability of thermochromic filters in PBR designs is still yet to be investigated. Thermochromic filters are reflective and absorptive under high and low temperatures, respectively, a technology that can be a solution to the overheating challenge of PBRs. This review recommends the coupling of these light filtration technologies to the horizontal tubular PBR for effective utilization of solar radiation in algaculture.     

Optical filters from SiO2 and TiO2 multi-layers using sol–gel spin coating method

Sol–gel spin coating process is used to produce optical filters from SiO₂ and TiO₂ multi-layers. By coating the films symmetrically on both sides of the glass substrates, we designed two types of three-layer anti-reflective (AR) filters for the near–infrared region, and a nine-layer reflective filter for the near–UV region. We develop a simple theoretical model for these filters, which incorporates sol–gel film densification during the coating process, and fit it to the experimental data to extract properties of the individual layers in the coatings.     

On the spectral composition of global radiation

The global radiation is recorded at several stations on the Earth. The information about its spectral composition is poor. In this paper the spectral composition means the ratio of spectral global radiation measured by coloured glass filter domes to the total global radiation. From the measurements made by Klein and Goldberg it follows that the monthly ratios vary significantly from place to place, while the variations from month to month at one place are significant only at the station which lies near to the North Pole. The Budapest data proved the dominant effect of cloudiness on the spectral composition of global radiation. This effect is in good statistical relationship with the relative global radiation. The regression constant tabulated in this paper do not contain the error of zero point elevation which is due to the overheating of glass filters by the absorbed solar radiation.     

Thermogravimetric analysis of soot emitted by a modern diesel engine run on catalyst-doped fuel

Understanding the mechanisms that affect catalytic activity in porous ceramic diesel particulate filters (DPF) at the temperature range 200 to 400°C is important for the successful modeling of the initiation and evolution of catalytic regeneration by use of fuel additives. This refers not only to the dry carbon particulate, but also to the volatile hydrocarbons adsorbed on it. In this paper, a detailed analysis of the hydrocarbon adsorption-desorption and oxidation behavior of diesel particulate emitted by a modern diesel engine and collected on a SiC diesel filter is performed by use of thermogravimetric and differential scanning calorimetry analysis (TGA-DSC). Non-isothermal tests were performed with samples collected directly from a ceramic filter connected to the exhaust system of the diesel engine running under low and medium speed and load operating conditions with and without fuel additive. Fuel additive concentration was varied to investigate its effect on the soot oxidation behavior. Based on the TGA data, the kinetic parameters of the soot oxidation reaction were calculated. The effect of volatile adsorbed hydrocarbons on the soot oxidation reaction was evaluated by comparing the calculated activation energies for samples collected from the center and the periphery of the filter at various exhaust temperatures prevailing at filter loading phase. In particular it was seen that the catalytic activity of the fuel additive is enhanced by the presence of the volatile organic components.     

Delivering clean and pure power

There are two approaches to the mitigation of power quality problems. The first approach is called load conditioning, which ensures that the equipment is made less sensitive to power disturbances, allowing the operation even under significant voltage distortion. The other solution is to install line-conditioning systems that suppress or counteract the power system disturbances. Among the different new technical options available to improve power quality, active power filters have proved to be an important and flexible alternative to compensate for current and voltage disturbances in power distribution systems. Power filter topologies are discussed including shunt active filter, series active filters, series-shunt active filters, and hybrid active filters. New topologies using multilevel inverters are also discussed.     

电控柴油机微粒袋滤系统的研究与开发

在１９５柴油机试验台架上进行了柴油机微粒袋滤器的模拟试验研究,考察了柴油机微粒袋滤器不同滤速、不同滤料及不同清灰方式对其过滤效率、阻力特性的影响情况。结果表明：适当提高过滤速度对过滤效率影响不大;滤袋变形清灰比空气反吹清灰更为有效。基于此,提出了双单元过滤、轮流清灰的构思,并设计了采用滤袋变形清灰方式的新型袋滤器。还采用单片机电子控制系统,将袋滤器前排气的温度和柴油机的背压作为输入信号,以此实现对两组袋滤器的工作模式转换以及过热保护控制。并进行了软硬件系统的开发,研制了结构较为紧凑的电控柴油机微粒袋滤系统,可自动清灰,不影响车辆的机动性。最后,将电控柴油机微粒袋滤系统装在４９５Ｑ柴油机台架上进行了初步试验,证明该系统有较好的响应性,可实现对系统的控制功能。     

柴油机微粒袋滤器设计改进的研究

为缩小柴油机微粒袋滤器的体积，简化其结构，本进行了扁袋袋滤器的初步设计和试验，证明在柴油机微粒袋滤器设计中采用扁袋是不合适的。为此研制了结构紧凑的双层多袋过滤器，并在４８５Ｑ柴油机台架上进行了试验，结果证明了，该袋滤器运行可靠，结构设计合理，对微粒的捕集效率在不同工况下均高于９０％，且其对经济性影响不大于２％。     

电弧炉的谐波过滤装置

叙述电弧炉电流的谐波成因、低序特性，供电网络谐波限值、谐波分流模式和适用于电弧炉的谐波过滤装置。在电弧炉的谐波特性中说明了随测定取样时间的加长而在取样时间内有效值急剧降低的现象。叙述了电网常用带６％电抗器的ＬＣ谐波过滤装置由于电弧炉产生的３次谐波能导致电网并联谐振、谐波扩大的事例和适合电弧炉谐波特性的宽频带谐波过滤装置。