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Search Results: 1 - 10 of 334391 matches for " K. C. Aw "
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A Surface Acoustic Wave Ethanol Sensor with Zinc Oxide Nanorods
Timothy J. Giffney,Y. H. Ng,K. C. Aw
Smart Materials Research , 2012, DOI: 10.1155/2012/210748
Abstract: Surface acoustic wave (SAW) sensors are a class of piezoelectric MEMS sensors which can achieve high sensitivity and excellent robustness. A surface acoustic wave ethanol sensor using ZnO nanorods has been developed and tested. Vertically oriented ZnO nanorods were produced on a ZnO/128° rotated Y-cut LiNbO3 layered SAW device using a solution growth method with zinc nitrate, hexamethylenetriamine, and polyethyleneimine. The nanorods have average diameter of 45?nm and height of 1?μm. The SAW device has a wavelength of 60?um and a center frequency of 66?MHz at room temperature. In testing at an operating temperature of 270 with an ethanol concentration of 2300?ppm, the sensor exhibited a 24?KHz frequency shift. This represents a significant improvement in comparison to an otherwise identical sensor using a ZnO thin film without nanorods, which had a frequency shift of 9?KHz. 1. Introduction Sensing of ethanol vapour has important applications in industry and society. At high temperatures (200°C to 300°C) zinc oxide absorbs ethanol vapour, causing a significant change in conductivity [1, 2] and also leading to a change in mass. This change in properties can be used to create an ethanol sensor. Surface acoustic wave (SAW) sensors are a class of piezoelectric MEMS sensor which can achieve high sensitivity and excellent robustness. Since their discovery by Rayleigh in 1885 [3] surface acoustic waves have been extensively researched. The energy of a surface acoustic wave is concentrated within several wavelengths of the surface [4, 5]. For this reason, the propagation characteristics of surface acoustic waves are highly sensitive to any change in the properties of the surface on which they travel. Due to the sensitivity of SAW devices to small changes in mass loading and surface conductivity, SAW devices have been extensively studied as gas sensors [6–8]. A typical SAW gas sensor uses an interdigital transducer (IDT) to generate a surface acoustic wave in a piezoelectric substrate. The surface acoustic wave propagates along a delay line coated in some material which absorbs the target gas. A second IDT at the end of the delay line is then used to transduce the SAW to an electrical signal. Absorption of gas onto the sensing layer causes a change in the propagation velocity of the surface acoustic wave, resulting in a shift in the resonant frequency of the device. The majority of existing SAW gas sensors have used thin film sensing layers, with limited surface area. The application of nanostructured sensing layers, such as ZnO nanorods can potentially lead to
Clinical significance of serum levels of matrix metalloproteinase 2 (MMP-2) and its tissue inhibitor (TIMP-2) in gastric cancer
Barbara Mroczko,Marta ?ukaszewicz-Zaj?c,Mariusz Gryko,Bogus?aw K?dra
Folia Histochemica et Cytobiologica , 2011, DOI: 10.5603/4153
Abstract: Matrix metalloproteinase 2 (MMP-2) is able to degrade type IV collagen, and thus plays a key role in the migration of tumor cells. MMP-2 activity is inhibited by its tissue inhibitor (TIMP-2). The imbalance between MMPs and TIMPs may facilitate progression of cancer cells. The aim of this study was to compare the clinical importance of MMP-2 and TIMP-2 to that of classical tumor markers, namely carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9) in the diagnosis of gastric cancer (GC) by calculating the diagnostic criteria and estimating the levels of MMP-2, TIMP-2, CEA and CA 19-9 in GC patients in relation to clinicopathological features of cancer. We found that serum levels of MMP-2 and TIMP-2 were significantly lower, whereas serum tumor markers were higher, in GC patients than in healthy subjects. Moreover, concentrations of TIMP-2 and CEA correlated with gastric wall infiltration, while CA 19-9 levels correlated with gastric wall infiltration and the presence of nodal metastasis. None of the proteins tested was found to be an independent prognostic factor for GC patients’ survival. The percentage of true positive results of TIMP-2 (61%) was higher than those of MMP-2 (54%) and the classical tumor markers CEA (21%) and CA 19-9 (31%). The highest diagnostic sensitivity was observed for the combined use of TIMP-2 with MMP-2 (77%). The results suggest the greater importance of serum MMP-2 and TIMP-2 than of the classical tumor markers CEA and CA 19-9 in the diagnosis of GC. But this issue requires further investigation. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 1, pp. 125–131)
Simulation Model of the Bus Stop
Rados aw B k
Archives of Transport , 2010, DOI: 10.2478/v10174-010-0001-6
Abstract: On the basis of the research conducted at the bus stops in Krakow and Warsaw, the movement processes, related with functioning of a bus stop have been identified. As a result, the simulation model imitating its functioning has been formulated and verified. The stop has been analyzed as a system, in which the input flow comprises of municipal bus transport, whereas the service time corresponds the dwell time. The formulas for time losses incurred due to queuing to reach the boarding and alighting zones have been derived, constituting a basis for operative capacity estimation of a bus stop and specifying the selection determinants for the number of boarding and alighting zones in regards to traffic intensity as well as boarding and alighting time.
Temporal and spatial variation of habitat conditions in the zonation of vegetation in the late stages of lake overgrowth
Stanis?aw K?osowski
Acta Societatis Botanicorum Poloniae , 2002, DOI: 10.5586/asbp.2002.039
Abstract: The water and substrate properties in the vegetation zones characteristic of the late stages of lake overgrowth were determined. It was demonstrated that the spatial distribution of plant communities conformed with the spatial gradient of habitat conditions. With regard to water properties the largest differences between the zones were found in Mg2+, Ca2+, electrolytic conductivity and NH4+. In the case of substrate the zones differed significantly in Ca2+, total Fe and organic matter content. The water properties varied greatly during the vegetative season in the successive zones. The temporal changes often proceeded at a different level of a given component or factor in most zones. The differences between the zones were, however, maintained. It appears that the plant communities can alter their habitats to a large extent. In the lake studied, the invasion of raised and transitional bog vegetation was observed. The process of dystrophy proceeded from the terrestrialized peripheral parts of the lake to the centre of the lake.
Parcelling activity of the National Bank for Agriculture in interwar Poland in the years 1924-1929
Miros?aw K?usek
Journal of Agribusiness and Rural Development , 2009,
Abstract: Scientific literature related to the problem in focus is exceptionally poor. The only book publication concerns the National Bank for Agriculture in the twenty-year interwar period is book position of Marek Nowak’s authorship [Nowak 1988]. But, on account of its modest range, bank agrarian activity has been treated too generally. In this publication author’s opinion is that this activity needs deeper analysis. Parcelling is an economic process which took part in Poland and lasted from the moment of grant freehold. It ran with special intensification towards the end of XIX century and at the beginning of XX century. In inter-war period, on account of source of parcelled soil, parcellation was divided into private and governmental. Governmental parcellation, which related to public property, included lands by Regional District Councils and territories included by military settlement. However, lands allocated by the National Bank for Agriculture and by individual people made private parcellation. The beginning of the National Bank for Agriculture’s agrarian activity’ was enabled by Poland President’s directive from 1924. One of the main tasks put against NBA was support: parcellation and settlement, agricul-tural regulations by landed estates purchase for parcelling aims and giving long-term credits for land purchase. However, according to status, the National Bank for Agriculture was able to parcel out landed properties, both purchased for private property and entrusted to commission state. Tasks put against parcellation conducted by the National Bank for Ag-riculture were not carried out in a satisfactory way. The Bank’s activity did not contribute to shopping the process of farms fragmentation at serious level and process of agrarian overpopulation’s growth among fewer ownership. Similarly, it also was not an essential source of establishing new farms capable of competing with vast-land ownership.
The records of the District Land Registry in Cracow Zespó akt Okr gowego Urz du Ziemskiego w Krakowie
Miros?aw K?usek
Journal of Agribusiness and Rural Development , 2008,
Abstract: The complex records of the District Land Registry in Cracow contain 916 j. a. records and books – 14 mb and 595 j. map. The most important part of the complex are documents from the Faculty of Agricultural Devices concerning aspects connected with conducting agricultural reform. Statistical materials that relate to large secular and church land ownership are next part of the complex records. They are gathered mainly to establish land supply which can be used to allotment. The separate group of records are matters concerning aspects of land turnover. These are land registries’ permissions for part and entirely sale the properties for one buyer. Materials concerning aspects of financing agri-cultural reform on the Ma opolska Voivodeship ought to be searched at the Administra-tive Faculty. A very essential supplement for upper mentioned records is the set of 573 maps and the District Land Registry in Cracow’ plans. The news included in mentioned documents of the District Land Registry in Cracow have an invaluable value, not only for people engaged in polish village issues in the XIX and XX centuary, but they are very es-sential saurce of information for judical and economic purposes. It’s worth remembering of reaching for records of the Provincial Office in Cracow while using with land registry documents, too. There are a lot of materials concerning land registries organization and aspects connected with land allotment and join.
The place of agriculture in credit policy after World War II
Miros?aw K?usek
Journal of Agribusiness and Rural Development , 2009,
Abstract: After World War II the Polish state, which had restricted financial resources was forced to select the most important economic aims, which ought to have been driven out by people in select and taking into consideration credit applications. On this stage of state rebuilding, approval had been voiced, in first order for credits for agriculture production, mining production, industrial production, and craft production. Credits for sowing, harvest, rations, tools purchase, fertilizers, seeds and livestock had been the most important in agriculture. Ministry of Treasury and National Bank of Poland had been driven by planning rules and planning in economic life, central rule of establishing financial and credit politics and central way of establishing distributions ways, supervision and control. Unfortunately state credit politic realisation in relation to agriculture had diverged from its main assumptions. Industry had been favored at the expense of village. The effect of shortage of capital in a village had caused the fall of agricultural production, what, in short time had led to increase of agriculture products’ prices.
Use of convolution and filtration to extract information from the DCM graphic files
Miros aw Zaj c
Annales UMCS, Informatica , 2011, DOI: 10.2478/v10065-011-0021-8
Abstract: The paper describes the problem of using digital filters on the DICOM graphic files. An attempt has been made to improve the process of extracting information from graphic files generated by medical measuring instruments.
How really extensive is the original material of Juncus kochii (Juncaceae)? - A taxonomic and nomenclatural revision
Jaros?aw Pro?ków
Acta Societatis Botanicorum Poloniae , 2008, DOI: 10.5586/asbp.2008.041
Abstract: The identity of the original material of Juncus kochii F. W. Schultz (Juncaceae) is discussed. The taxon at present is best regarded as Juncus bulbosus L. subsp. kochii (F. W. Schultz) Reichg. The relevant literature (protologue and references therein) was searched and details of all original elements were compiled. Nomenclatural and taxonomic remarks are given. Juncus welwitschii Hochst. ex Steud. is here excluded as a synonym of Juncus bulbosus subsp. kochii.
Juncus bulbosus (Juncaceae), a species new to South America (Chile)
Jaros?aw Pro?ków
Acta Societatis Botanicorum Poloniae , 2008, DOI: 10.5586/asbp.2008.028
Abstract: The first localities of Juncus bulbosus (Juncaceae) for South America (Chile) and for the whole south-western part of the world (S latitude and E longitude) are described, including precise geographical location and climatic conditions. General remarks on the invasiveness of the species and on the possibility of finding it in other parts of the world are given. The distribution of the species world-wide requires further studies, since the bulbous rush has become an invasive plant in areas where it did not occur before.
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