826 resultados para Lasers Industrial applications
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Wavelength tunable electro-absorption modulated distributed Bragg reflector lasers (TEMLs) are promising light source in dense wavelength division multiplexing (DWDM) optical fiber communication system due to high modulation speed, small chirp, low drive voltage, compactness and fast wavelength tuning ability. Thus, increased the transmission capacity, the functionality and the flexibility are provided. Materials with bandgap difference as large as 250nm have been integrated on the same wafer by a combined technique of selective area growth (SAG) and quantum well intermixing (QWI), which supplies a flexible and controllable platform for the need of photonic integrated circuits (PIC). A TEML has been fabricated by this technique for the first time. The component has superior characteristics as following: threshold current of 37mA, output power of 3.5mW at 100mA injection and 0V modulator bias voltage, extinction ratio of more than 20 dB with modulator reverse voltage from 0V to 2V when coupled into a single mode fiber, and wavelength tuning range of 4.4nm covering 6 100-GHz WDM channels. A clearly open eye diagram is observed when the integrated EAM is driven with a 10-Gb/s electrical NRZ signal. A good transmission characteristic is exhibited with power penalties less than 2.2 dB at a bit error ratio (BER) of 10(-10) after 44.4 km standard fiber transmission.
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青稞(Hordeum vulgare L.var.nudum Hook.f.),即裸大麦,是兼食用、饲用和酿造于一体的作物,有着重要的利用价值。淀粉是青稞籽粒中含量最多、最重要的碳水化合物,淀粉含量、直支淀粉比将会直接影响淀粉的功能特性,进而影响淀粉的应用领域。我国青藏高原青稞的栽培和食用历史悠久,特色青稞资源极其丰富。目前关于青藏高原青稞淀粉特性的报道还不多见,筛选和培育特色淀粉青稞利于拓展青稞的应用领域, 从而提高其经济价值。 本研究以114份青藏高原青稞品种(系)为实验材料,通过SDS-PAGE对材料的胚乳淀粉颗粒结合蛋白(SGAPs)进行分离,确定各蛋白的分子量大小、组合类型和多态性等。然后按照国标法测试材料的籽粒总淀粉含量和直链淀粉含量,通过微型糊化粘度仪分析相应的淀粉糊化特性,最后使用显微镜观察比较了青稞的淀粉颗粒形态特征。主要结果如下: 1、114种青稞中共分离出20种不同的SGAP条带,条带分子量为35.00~112.39 KDa,分布频率为12.28~97.37%。材料含有的SGAPs条带数从10到14不等,超过一半的材料含11种SGAP条带。20种条带形成16种组合类型,其中西藏地区青稞包含所有16个组合类型,四川地区青稞包含其中12个组合类型。青藏高原青稞籽粒淀粉颗粒结合蛋白的差异很大,遗传多样性丰富。 2、114份青稞的总淀粉含量、直链淀粉含量、直支淀粉比、峰值粘度、糊化温度和峰值温度的变幅分别为51.26~66.70%、14.64~29.74%、0.17~0.42、194~1135BU、58.8~65.2℃和81.4~92.4℃,相应的平均值分别为59.82%、23.60%、0.31、722.30BU、62.1℃和88.8℃。群体在总淀粉含量、直链淀粉含量、直支淀粉比、峰值粘度、糊化温度和峰值温度上的分布具有明显的正态性;所有胚乳淀粉体的淀粉粒都呈复粒结构。对西藏和四川的材料进行了分组比较, 两地区的青稞在直链淀粉含量和直支淀粉比上的差异达到显著水平。 3、筛选出18份具有特殊淀粉特性的青稞品种,其中5份材料的总淀粉含量超过65%,包括NB63-1、NB67、甘孜白六棱、98221-1和NB63;3份材料的直链淀粉含量大于29%,包括藏青85、藏青3号和喜马拉6号;8份材料的直支淀粉比小于0.25,包括99033-6、春青稞、阿坝330、Jan-03、米麦114、396、NB63-1和92013;7份材料的糊化温度低于60℃,同时材料的峰值粘度大于1000BU,并且峰值温度低于90℃,包括足捉春、Jan-03、阿坝330、米麦114、春青稞、20003和阿青5号。 4、各淀粉特性间存在高度相关性。直链淀粉含量和直支淀粉比与糊化温度成极显著正相关,与峰值粘度成极显著负相关,与A型淀粉粒数量和大小呈负相关。不同SGAPs组合的品种之间,淀粉含量和淀粉糊化特性间差异均达显著水平。SGAP2、SGAP5、SGAP6和SGAP7可能对籽粒直链淀粉含量、直支淀粉比和糊化温度有正向效应;SGAP3、SGAP9∼SGAP20可能对峰值粘度有正向效应。 本研究对青藏高原青稞淀粉资源进行了较为全面的评价,对该区青稞淀粉特性有了系统的认识。研究筛选出的特殊青稞品种可作为青稞育种和青稞淀粉工业应用的潜在资源,淀粉特性差异巨大的众多青稞品种也为拓宽青稞应用领域提供了丰富的资源保障。本研究对部分SGAPs在性质上的鉴定和功能上的初步推断为青稞材料的筛选提供了指导,也为品质育种提供了理论参考。 Hulless barley (naked barley, Hordeum vulgare L.) is a short- season, early maturing crop with a wide range of adaptation. It has been attracting more and more attention due to its superior nutrition and extensive industrial applications. Starch is the main ingredient in hulless barley seeds which makes up 65 percent of hulless barley’s dry weight. The ratio of the amylose/amylopectin and the size, shape, distribution of starch granules can affect the physico-chemical and functional properties of starch, which may turn affect its utilizations. The Qinghai-Tibet Plateau, which is located in southwestern China, is a typical area of vertical agricultural ecosystem and one of the barley origin centers with abundant hulless barley resources. There are little reports about hulless barley in Qinghai-Tibet Plateau at present. To screen and cultivate some characteristic hulless barley can improve its value. An improved SDS-PAGE was used to identify SGAPs combination of 114 hulless barley varieties. Starch content (total starch and amylose starch) was determined according to the standard methods GB5006-85 and GB/T 15683 using PerkinElmer M341 Precision Automatic Polarimeter and UV spectrophotometer 755B respectively. The pasting properties were measured by BRABENDER Micrio Visco-Amylo- Graph 803201. The morphology of starch granules were observed and compared with Axioplan 2 Imaging light microscopy. The following were the results obtained: 1. There were 20 major SGAPs presented in 114 varieties, with the molecular weight ranged from 35.00 to 112.39 KDa, and the frequencies ranged from 12.28% to 97.37%. The number of SGAP bands in each accession varied from 10 to 14, more than half of the population had 11 bands. There were 16 distinct SGAP patterns in the 114 varieties, the Tibet hulless barley had all of the 16 types and the Sichuan hulless barley had 12 types. The results indicated the Qinghai-Tibet Plateau hulless barley had a polymorphism of the SGAPs. 2. The ranges of the total starch content, amylose content, Am/Ap, peak viscosity, pasting temperature and peak temperature of the 114 hulless barley were 51.26~66.70%,14.64~29.74%,0.17~0.42,194~1135BU,58.8~65.2 and 81.4℃~92.4, with an average of ℃59.82%, 23.60%, 0.31, 722.30BU, 62.1 and 88.8,℃℃ respectively. The distributions of the total starch content, amylose content, Am/Ap, peak viscosity, pasting temperature and peak temperature were visibly normal school. All of the amyloplasts in endosperm of varieties showed bimodal size distributions.The main starch properties of hulless barley from Tibet and Sichuan were separated and compared, the differences on amylose content and Am/Ap were obvious. 3. Eighteen accessions which had special starch properties were screened out. Five accessions with total starch content beyond 65%, including NB63-1, NB67, Ganzibailiuleng, 98221-1 and NB63; three accessions, Zangqing85, Zangqing3 and Ximala6, with the highest amylose content (>29%); five accessions with Am/Ap less than 0.25, including 99033-6, Chun Qingke, A Ba 330, Jan-03, Mi Mai114, 396, NB63-1 and 92013; seven accessions had a pasting temperature under 60, ℃meanwhile their peak viscosity beyond 1000BU and their peak temperature under 90℃,including Zu Cuochun, Jan-03, A Ba 330, Mi Mai 114, Chun Qingke, 20003 and A Qing 5. 4. There were high correlations between starch properties. Amylose content and Am/Ap were positively correlated to pasting temperature, negatively correlated to peak viscosity, negatively correlated to the number and granule size of A-type granule. Different SGAP combinations caused significant diversities in starch content and pasting properties. SGAP2, SGAP5, SGAP6 and SGAP7 may have positive effect on amylose content, Am/Ap and pasting temperature; SGAP3, SGAP9∼SGAP20 may have positive effect on peak viscosity. Our research made a comprehensive evaluation on the hulless barley starch from the Qinghai-Tibet Plateau, we can get a systemic understanding. Some special accessions were screened out can be used on the hulless barley breeding lines and industries utilization.The combination of the SGAPs may become a criterion to evaluate the hulless barley endosperm starch quality. Consequently, the results will be good information for further studies on the hulless barley.
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Direct conversion of methane into hydrogen and valuable chemicals under nonoxidative conditions is a process severely limited thermodynamically. However, the movement from the present era of fossil fuels into the coming hydrogen energy age makes it an interesting and important approach compared with the direct conversion of methane under the aid of oxidants. This paper gives a brief overview of the direct conversion of CH4 under nonoxidative conditions. At the same time, our understanding of methane dehydroaromatization over Mo/HZSM-5 catalysts for the simultaneous formation of hydrogen and light aromatics is discussed in general, while the bifunctionality of Mo/HZSM-5 catalysts and the role of carbonaceous deposits formed during the reaction are reviewed in more detail. A perspective of the topic from both academic points of view and potential industrial applications is also presented. (C) 2003 Elsevier Science (USA). All rights reserved.
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A 2-kW-class chemical oxygen-iodine laser (COIL) using nitrogen buffer gas has been developed and tested since industrial applications of COIL devices will require the use of nitrogen as the buffer gas. The laser, with a gain length of 11.7 cm, is energized by a square pipe-array jet-type singlet oxygen generator (SPJSOG) and employs a nozzle bank with a designed Mach number of 2.5. The SPJSOG has advantages over the traditional plate-type JSOG in that it has less requirements on basic hydrogen peroxide (BHP) pump, and more important, it has much better operational stability. The SPJSOG without a cold trap and a gas-liquid separator could provide reliable operations for a total gas flow rate up to 450 mmol/s and with a low liquid driving pressure of around 0.7 atm or even lower. The nozzle bank was specially designed for a COIL using nitrogen as the buffer gas. The cavity was designed for a Mach number of 2.5, in order to provide a gas speed and static temperature in the cavity similar to that for a traditional COIL with helium buffer gas and a Mach 2 nozzle. An output power of 2.6 kW was obtained for a chlorine flow rate of 140 mmol/s, corresponding to a chemical efficiency of 20.4%. When the chlorine flow rate was reduced to 115 mmol/s, a higher chemical efficiency of 22.7% was attained. Measurements showed that the SPJSOG during normal operation could provide a singlet oxygen yield Y greater than or equal to 55%, a chlorine utilization U greater than or equal to 85%, and a relative water vapor concentration w = [H2O]/([O-2] + [Cl-2]) less than or equal to 0.1.
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Gelatin is widely used in food, pharmaceutical, and photographic industries due to the coil-helix transition, whereas the structural inhomogeneity considerably affects its essential properties closely connecting with the industrial applications. The spatially structural inhomogeneity of the gelatin caused by the uneven and unstable temperature field is analyzed by the finite element method during the cooling-induced coil-helix transition process. The helix conversion and the crosslinking density as functions of time and spatial grid are calculated by the incremental method. A length distribution density function is introduced to describe the continuous length distributions of two kinds of triple helices.
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随着自动化程度的不断提高,对设备的种类要求越来越广泛,由此带来的设备配置工作越来越繁琐。设备描述技术和FDT/DTM技术的出现解决了这个问题。本文在对这两种技术研究的基础上,从技术实现的角度上对这两种技术做了分析,并提出了一种多技术结合的方法,以适用于复杂多样的工业应用环境。
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Nowadays, classical (bio)remediation processes are affected by some economical and environmental drawbacks. These approaches often seem to be inadequate, particularly in the perspective of sustainable green processes. Since immobilized metalloporphines can emulate the active site of peroxidases and peroxygenases, their use in several bioremediation processes has been analyzed in this work. The described catalytic reactions use bioinspired, homogenized or heterogenized, commercial porphines and showed a remarkable ability to catalyze substrates oxidation at the expenses of different oxidants such as Oxone and hydrogen peroxide. The biomimetic catalysts have been also investigated about their peroxidase- and peroxygenase-like catalysis and ability to emulate lignolytic peroxidases action and substrate specificity. The adducts showed a remarkable ability to catalyze veratryl alcohol (widely recognized as a simple model compound of lignin) oxidation at the expenses of H2O2. In the perspective of broadening industrial applications of the described catalysts, the oxidation of several pollutants such as durable textile dyes and inorganic sulfides, has been attempted with quite promising results, and some findings open the way toward industrial scaling-up. Accordingly, the inexpensiveness of the synthesis and the mild operational conditions allow these adducts to be proposed as applicable catalysts also for industrial large-scale processes. Besides, these synthetic models are helpful also to understand the behavior of pharmaceuticals, antifungal drugs in this case, in the environment, and to predict the drug metabolism by cytochromes P450. The biomimetic catalysts, for the studied cases, also proved to be much more efficient than the corresponding enzymes.
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C.H. Orgill, N.W. Hardy, M.H. Lee, and K.A.I. Sharpe. An application of a multiple agent system for flexible assemble tasks. In Knowledge based envirnments for industrial applications including cooperating expert systems in control. IEE London, 1989.
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Lee, M.H., Intelligent Robotics, 224pp, Chapman and Hall, 1990.
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This PhD thesis investigates the application of hollow core photonic crystal fibre for use as an optical fibre nano litre liquid sensor. The use of hollow core photonic crystal fibre for optical fibre sensing is influenced by the vast wealth of knowledge, and years of research that has been conducted for optical waveguides. Hollow core photonic crystal fibres have the potential for use as a simple, rapid and continuous sensor for a wide range of applications. In this thesis, the velocity of a liquid flowing through the core of the fibre (driven by capillary forces) is used for the determination of the viscosity of a liquid. The structure of the hollow core photonic crystal fibre is harnessed to collect Raman scatter from the sample liquid. These two methods are integrated to investigate the range of applications the hollow core photonic crystal fibre can be utilised for as an optical liquid sensor. Understanding the guidance properties of hollow core photonic crystal fibre is forefront in dynamically monitoring the liquid filling. When liquid is inserted fully or selectively to the capillaries, the propagation properties change from photonic bandgap guidance when empty, to index guidance when the core only is filled and finally to a shifted photonic bandgap effect, when the capillaries are fully filled. The alterations to the guidance are exploited for all viscosity and Raman scattering measurements. The concept of the optical fibre viscosity sensor was tested for a wide range of samples, from aqueous solutions of propan-1-ol to solutions of mono-saccharides in phosphate buffer saline. The samples chosen to test the concept were selected after careful consideration of the importance of the liquid in medical and industrial applications. The Raman scattering of a wide range of biological important fluids, such as creatinine, glucose and lactate were investigated, some for the first time with hollow core photonic crystal fibre.
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Herein is presented a novel chemical vapour deposition (CVD) route for the fabrication of oxide ferroelectrics. A versatile layer-by-layer growth mode was developed to prepare naturally super-latticed bismuth based materials belonging to the Aurivillius phase family, with which good control over composition and crystal structure was achieved. In chapter 3, the effect of epitaxial strain on one of the very simple oxide materials TiO2 was studied. It has been found that the ultra-thin TiO2 films demonstrate ferroelectric behaviour when grown on NdGaO3 substrates. TiO2 exists in various crystal phases, but none of them show ferroelectric behaviour. The epitaxial strain due to the substrate, changes the crystal structure from tetragonal to orthorhombic which in turn leads to ferroelectric behaviour. In chapter 4, a unique growth method for multiferroic BiFeO3 (BFO) thin films is shown, where a phase pure BFO thin films can be prepared even in the presence of excess bismuth precursor during the growth process. This type of growth is usually called adsorption controlled growth and can be used for growing various bismuth containing compounds, where the volatility of bismuth can create various types of defects. Chapter 5 describes the growth of Bi4Ti3O12 thin films in a layer-by-layer growth mode. In this section, the effect of Bi and Ti precursor flows on the growth of thin films is discussed and it is shown that how change in precursor flows leads to out-ofphase boundary defects during the layer-by-layer growth mode. In chapter 6, the growth of a compound Bi5Ti3FeO15, which is a 1:1 mixture of BiFeO3 and Bi4Ti3O12, is presented. The growth mechanism of Bi5Ti3FeO15 thin films is presented, where the Fe precursor flow was controlled from zero to the insertion of one full BiFeO3 perovskite unit cell into the Bi4Ti3O12 structure in addition, the effect of iron precursor flow on crystalline properties is demonstrated. The methods presented in this thesis can be adopted to grow ferroelectric and multiferroic films for industrial applications.
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The thesis is focused on the magnetic materials comparison and selection for high-power non-isolated dc-dc converters for industrial applications or electric, hybrid and fuel cell vehicles. The application of high-frequency bi-directional soft-switched dc-dc converters is also investigated. The thesis initially outlines the motivation for an energy-efficient transportation system with minimum environmental impact and reduced dependence on exhaustible resources. This is followed by a general overview of the power system architectures for electric, hybrid and fuel cell vehicles. The vehicle power sources and general dc-dc converter topologies are discussed. The dc-dc converter components are discussed with emphasis on recent semiconductor advances. A novel bi-directional soft-switched dc-dc converter with an auxiliary cell is introduced in this thesis. The soft-switching cell allows for the MOSFET's intrinsic body diode to operate in a half-bridge without reduced efficiency. The converter's mode-by-mode operation is analysed and closed-form expressions are presented for the average current gain of the converter. The design issues are presented and circuit limitations are discussed. Magnetic materials for the main dc-dc converter inductor are compared and contrasted. Novel magnetic material comparisons are introduced, which include the material dc bias capability and thermal conductivity. An inductor design algorithm is developed and used to compare the various magnetic materials for the application. The area-product analysis is presented for the minimum inductor size and highlights the optimum magnetic materials. Finally, the high-flux magnetic materials are experimentally compared. The practical effects of frequency, dc-bias, and converters duty-cycle effect for arbitrary shapes of flux density, air gap effects on core and winding, the winding shielding effect, and thermal configuration are investigated. The thesis results have been documented at IEEE EPE conference in 2007 and 2008, IEEE APEC in 2009 and 2010, and IEEE VPPC in 2010. A 2011 journal has been approved by IEEE Transactions on Power Electronics.
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The rapid development of nanotechnology has led to a rise in the large-scale production and commercial use of engineered nano-ZnO. Engineered/manufactured nano-ZnO are applied in a broad range of products such as drugs, paints, cosmetics, abrasive agents and insulators. This can result in the unintended exposure of human beings to nano-ZnO and will inevitably result in the release of nano-ZnO in to the environment. Thus, it is necessary to assess the risk of nano-ZnO to the environment. In this thesis the toxicity of nano-ZnO was analysed using the aquatic, primary producer lesser duckweed (Lemna minor), and the mechanism of toxicity was analysed. Both short-term (one week) and long-term (six weeks) toxicity of nano-ZnO (uncoated) were determined. Results show that the toxicity of nano-ZnO added to the aquatic growth medium increases with increasing concentration and that toxicity accumulates with exposure time. A study of nano-ZnO dissolution reveals that the main reason for nano-ZnO toxicity on Lemna minor is the release of Zn ions. Nano-ZnO dissolution is pH dependent, and toxicity matches the release of Zn2+. Functional coating materials are commonly added to nano-ZnO particles to improve specific industrial applications. To test if coating materials contribute to nano-ZnO toxicity on lesser duckweed, the effect of silane coupling agent (KH550) coated nano-ZnO on Lemma minor was investigated. Results show that coating can decrease the release of Zn ions, which reduces toxicity to Lemna minor, in contrast to uncoated particles. Another commonly hypothesized reason for nano-ZnO toxicity is the formation of Reactive Oxygen Species (ROS) on the particles surface. As part of this thesis, the ROS formation induced by nano-ZnO was studied. Results show that nano-ZnO catalyse ROS formation and this can negatively affect duckweed growth. In conclusion, this work has detailed potentially toxic effects of nano-ZnO on Lemna minor. This study has also provides references for future research, and informs regulatory testing for nanoparticle toxicity. Specifically, the outcomes of this study emphasize the importance of exposure time, environmental parameters and coating material when analysing NPs toxicity. Firstly, impacts of longer exposure time should be studied. Secondly, environmental parameters such as pH and medium-composition need to be considered when investigating NPs toxicity. Lastly, coating of NPs should always be considered in the context of NPs toxicity, and similar NPs with different coatings require separate toxicity tests.
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The development of a new bioprocess requires several steps from initial concept to a practical and feasible application. Industrial applications of fungal pigments will depend on: (i) safety of consumption, (ii) stability of the pigments to the food processing conditions required by the products where they will be incorporated and (iii) high production yields so that production costs are reasonable. Of these requirements the first involves the highest research costs and the practical application of this type of processes may face several hurdles until final regulatory approval as a new food ingredient. Therefore, before going through expensive research to have them accepted as new products, the process potential should be assessed early on, and this brings forward pigment stability studies and process optimisation goals. Only ingredients that are usable in economically feasible conditions should progress to regulatory approval. This thesis covers these two aspects, stability and process optimisation, for a potential new ingredient; natural red colour, produced by microbial fermentation. The main goal was to design, optimise and scale-up the production process of red pigments by Penicillium purpurogenum GH2. The approach followed to reach this objective was first to establish that pigments produced by Penicillium purpurogenum GH2 are sufficiently stable under different processing conditions (thermal and non-thermal) that can be found in food and textile industries. Once defined that pigments were stable enough, the work progressed towards process optimisation, aiming for the highest productivity using submerged fermentation as production culture. Optimum production conditions defined at flask scale were used to scale up the pigment production process to a pilot reactor scale. Finally, the potential applications of the pigments were assessed. Based on this sequence of specific targets, the thesis was structured in six parts, containing a total of nine chapters. Engineering design of a bioprocess for the production of natural red colourants by submerged fermentation of the thermophilic fungus Penicillium purpurogenum GH2.