4,473 research outputs found
Guide to the Linfield College Photograph Collection
This collection contains photographs, glass lantern and plastic slides, and film negatives depicting the many-layered facets of life at Linfield College on its McMinnville and Portland campuses. The photography features (without limit to): students, faculty and staff, commencements, guest speakers and performers, buildings, activities and clubs, athletics, the arts (studio and performance), residence life, social, and study scenes
Measuring the Impossible: an EU New and Emerging Science and Technologies Initiative Symposium
Comparative study of Clâ‚‚, Clâ‚‚/Oâ‚‚, and Clâ‚‚/Nâ‚‚ inductively coupled plasma processes for etching of high-aspect-ratio photonic-crystal holes in InP
An extensive investigation has been performed on inductively coupled plasmaetching of InP. An important motivation for this work is the fabrication of high-aspect-ratio holes for photonic crystals. The essential chemistry is based on Clâ‚‚ with the addition of Nâ‚‚ or Oâ‚‚ for sidewall passivation. The influence of different process parameters such as gas flows, temperature,pressure, ion energy, and inductively coupled plasma power on the hole geometry is presented. It is concluded that photonic crystals can be etched with Clâ‚‚ only; however, temperature and pressure control is critical. Adding passivation gases largely broadens the window in the parameter space for hole etching. Most importantly, etching of narrow holes can be carried out at higher temperatures where the etching is mass limited and spontaneous etching of InP by Clâ‚‚ occurs.Part of this research is supported by NanoNed, a technology program of the Dutch
Ministry of Economic Affairs
Study of intermixing in a GaAs/AlGaAs quantum-well structure using doped spin-on silica layers
The effect of two different dopants, P and Ga, in spin-on glass (SOG) films on impurity-free vacancy disordering (IFVD) in GaAs/AlGaAs quantum-well structures has been investigated. It is observed that by varying the annealing and baking temperatures, P-doped SOG films created a similar amount of intermixing as the undoped SOG films. This is different from the results of other studies of P-doped SiOâ‚‚ and is ascribed to the low doping concentration of P, indicating that the doping concentration of P in the SiOâ‚‚ layer is one of the key parameters that may control intermixing. On the other hand, for all the samples encapsulated with Ga-doped SOG layers, significant suppression of the intermixing was observed, making them very promising candidates with which to achieve the selective-area defect engineering that is required for any successful application of IFVD.One of the authors (H.H.T.) acknowledges a fellowship
awarded to him by the Australian Research Council
Buckling and lift-off of a heavy rod compressed into a cylinder
We develop a comprehensive, geometrically-exact theory for an end-loaded heavy rod constrained to deform on a cylindrical surface. The cylinder can have arbitrary orientation relative to the direction of gravity. By viewing the rod-cylinder system as a special case of an elastic braid, we are able to obtain all forces and moments imparted by the deforming rod to the cylinder as well as all contact reactions. This framework allows for the monitoring of stresses to ascertain whether the cylinder, along with its end supports, is able to sustain the rod deformations. As an application of the theory we study buckling of the constrained rod under compressive and torsional loads, as well as the tendency of the rod to lift off the cylinder under further loading. The cases of a horizontal and vertical cylinder, with gravity having only a lateral or axial component, are amenable to exact analysis, while numerical results map out the transition in buckling mechanism between the two extremes. Weight has a stabilising effect for near-horizontal cylinders, while for near-vertical cylinders it introduces the possibility of buckling purely due to self-weight. Our results are relevant for many engineering and medical applications in which a slender structure is inserted into a cylindrical cavity
Detection of the tulip breaking virus (TBV) in tulips using optical sensors
The tulip breaking virus (TBV) causes severe economic losses for countries that export tulips such as the Netherlands. Infected plants have to be removed from the field as soon as possible. There is an urgent need for a rapid and objective method of screening. In this study, four proximal optical sensing techniques for the detection of TBV in tulip plants were evaluated and compared with a visual assessment by crop experts as well as with an ELISA (enzyme immunoassay) analysis of the same plants. The optical sensor techniques used were an RGB color camera, a spectrophotometer measuring from 350 to 2500 nm, a spectral imaging camera covering a spectral range from 400 to 900 nm and a chlorophyll fluorescence imaging system that measures the photosynthetic activity. Linear discriminant classification was used to compare the results of these optical techniques and the visual assessment with the ELISA score. The spectral imaging system was the best optical technique and its error was only slightly larger than the visual assessment error. The experimental results appear to be promising, and they have led to further research to develop an autonomous robot for the detection and removal of diseased tulip plants in the open field. The application of this robot system will reduce the amount of insecticides and the considerable pressure on labor for selecting diseased plants by the crop expert. © 2010 The Author(s
How Fast Tobacco Can Be: the Logistical Process at Rothmans of Pall Mall Indonesia in the 1997 Indonesian Economic Crisis
Every year Rothmans International Group publishes a geographical business report. In this report the different Asian geographical regions are compared with one another concerning profit, costs, sales etc. Before 1996, Rothmans of Pall Mall Indonesia was always at the 1st place concerning profit. This is because of the low costs spent in Indonesia. In 1996 profits were declining and their place at the hit list was taken by Malaysia. This wakened the management in Jakarta and Malang. The Profit numbers were still declining due the higher costs than expected (sales maintain constant). The costs increased in the year of 1996 with 10% (usually between 4% and 6%). Those 10% total for a RP 2,6 billion: 1996
The influence of thermo-chemotherapy on bladder tumours: an immunohistochemical analysis
To study the influence of microwave induced thermo-chemotherapy on high-grade urothelial cell carcinomas. Five groups of each three patients were formed of whom initial biopsies and cystectomy samples were collected. Patients were treated 2Â days prior to cystectomy with mitomycin-C (group 1), hyperthermia (group 2) or thermo-chemotherapy (group 3). Group 4 patients had been treated with a cycle of six thermo-chemotherapy treatments prior to cystectomy and group 5 patients served as control (no treatment). Tumour samples were stained with Haematoxylin and Eosin, monoclonal antibody Ki-67 and the monoclonal antibody p53. In six out of the nine patients treated with hyperthermia a decrease in proliferation activity in the tumour was found. Seven out of nine patients treated with hyperthermia showed a decrease in p53 activity. A decrease in proliferation activity and p53 activity illustrate the potential role of thermo-chemotherapy as a promising intravesical treatment
The influence of thermo-chemotherapy on bladder tumours: an immunohistochemical analysis
To study the influence of microwave induced thermo-chemotherapy on high-grade urothelial cell carcinomas. Five groups of each three patients were formed of whom initial biopsies and cystectomy samples were collected. Patients were treated 2Â days prior to cystectomy with mitomycin-C (group 1), hyperthermia (group 2) or thermo-chemotherapy (group 3). Group 4 patients had been treated with a cycle of six thermo-chemotherapy treatments prior to cystectomy and group 5 patients served as control (no treatment). Tumour samples were stained with Haematoxylin and Eosin, monoclonal antibody Ki-67 and the monoclonal antibody p53. In six out of the nine patients treated with hyperthermia a decrease in proliferation activity in the tumour was found. Seven out of nine patients treated with hyperthermia showed a decrease in p53 activity. A decrease in proliferation activity and p53 activity illustrate the potential role of thermo-chemotherapy as a promising intravesical treatment
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