Search results for "surface"
showing 10 items of 9345 documents
Novel constant current driver for ISFET/MEMFETs characterization
2001
Abstract In the present work a new constant current driver for ISFETs and MEMFETs sensors has been developed. The proposed circuit maintains the ISFET/MEMFET operation point at constant drain–source current and voltage. The combination of some programmable current sources and an appropriate selection of a simple precision resistor allow a good ISFET/MEMFET polarization. The use of operational amplifiers with low offset and drift are required to provide the buffering function needed by the sensor.
Design, realization, and testing of a SPR biosensing system for wine quality monitoring
2007
A complete innovative and portable, for on-field operation, Surface Plasmon Resonance (SPR) biosensing system for wine quality monitoring was designed, realized and tested; the system takes advantage of the innovative module Spreeta™, an integrated transducer designed by Texas Instruments able to recognize the Surface Resonance Phenomena and to represent it through electrical signals. The system, based on an 8 bit microprocessor board, acquires through a 12 bit A/D converter, elaborates and sends to a PC data from the Spreeta™ sensor. A proprietary high-level software calculates the refractive index related to biological solution flowing on the surface sensor and lets to detect suitable sub…
Tear <sup>1</sup>H Nuclear Magnetic Resonance-Based Metabolomics Application to the Molecular Diagnosis of Aqueous Tear Deficiency and Me…
2020
<b><i>Purpose:</i></b> Meibomian gland dysfunction (MGD) is a major cause of signs and symptoms related to dry eyes (DE) and eyelid inflammation. We investigated the composition of human tears by metabolomic approaches in patients with aqueous tear deficiency and MGD. <b><i>Methods:</i></b> Participants in this prospective, case-control pilot study were split into patients with aqueous tear deficiency and MGD (DE-MGD [<i>n</i> = 15]) and healthy controls (CG; <i>n</i> = 20). Personal interviews, ocular surface disease index (OSDI), and ophthalmic examinations were performed. Reflex tears collected by capillarity were pr…
The history of human-induced soil erosion: Geomorphic legacies, early descriptions and research, and the development of soil conservation—A global sy…
2013
Abstract This paper presents a global synopsis about the geomorphic evidence of soil erosion in humid and semihumid areas since the beginning of agriculture. Historical documents, starting from ancient records to data from the mid-twentieth century and numerous literature reviews form an extensive assortment of examples that show how soil erosion has been perceived previously by scholars, land surveyors, farmers, land owners, researchers, and policy makers. Examples have been selected from ancient Greek and Roman Times and from central Europe, southern Africa, North America, the Chinese Loess Plateau, Australia, New Zealand, and Easter Island. Furthermore, a comprehensive collection on the …
Theory of mercury intrusion in a distribution of unconnected wedge-shaped slits
2004
Effective mercury intrusion in a wedge-shaped slit is gradual, the intruded depth increasing with applied pressure. The Washburn equation must be modified accordingly. It relates the distance, e, separating the three-phase contact lines on the wedge faces to the hydrostatic pressure, P, wedge half-opening angle alpha, mercury surface tension gamma, and contact angle theta: e=(-2gamma/P)cos(theta-alpha) if theta-alpha>pi2. The equations relating the volume of mercury in a single slit to hydrostatic pressure are established. The total volume of mercury V(Hg)(tot)(E(0),e) intruded in a set of unconnected isomorphous slits (same alpha value) with opening width, E, distributed over interval [E(0…
Pattern image enhancement by extended depth of field
2014
Abstract Most optical defect localization techniques such as dynamic laser stimulation or photon emission microscopy require a pattern image of the device to be taken. The main purpose is for device navigation, but it also enables the analyst to identify the location of the monitored activity by superimposing it onto the pattern image. The defect localization workflow usually starts at low or medium magnification. At these scales, several factors can lead to a lack of orthogonality of the sample with the optical axis of the system. Therefore, images can be locally out of focus and poorly resolved. In this paper, a method based on Depth of Field Extension is suggested to correct the pattern …
Comparison of the effect of different medicaments on surface reproduction of two commercially available Polyvinyl Siloxane impression materials - An …
2013
Objective:To determine the effect of different retraction cord medicaments on surface detail reproduction of polyvinyl siloxane impression materials and compare this effect on any two brands of commercially available polyvinyl siloxane impression materials. Material and methods: Four stainless steel dies were made according to ADA specification no.19. Three dies were treated with aluminium chloride (5%), ferric sulphate (13.3%) and epinephrine (0.1%) while the fourth one was left untreated to serve as control. Two impression materials (Dentsply and 3M ESPE) were used. Results: All the three medicaments adversely affected the surface detail reproduction of both the brands of the polyvinyl si…
3D-CT von Frakturen: Vergleich von Volumen- und Oberflächen-Rekonstruktionen
1998
Purpose The comparison of volume rendering (VR) and surface rendering (SSD) for demonstrating fractures from spiral-CT data. Materials and methods Standardized VR and SSD projections were produced from 50 spiral CT scans of 50 consecutive patients with fractures. Appropriate multiplanar reformattings (MPR) were used as the standard. Results SSD provided sufficient information in 31/50 cases. Results of VR were not significantly different (33/50). VR was superior in demonstrating 6/7 craniofacial fractures and 3/3 calcaneal fractures. SSD was superior for visualizing 2/3 shoulder fractures and 2/2 elbow fractures. Conclusion VR is a flexible technique for the depiction of fractures and the a…
Optimization of the straightness measurements on rough surfaces by Monte Carlo simulation
2013
Summary The straightness error of a coordinate measuring machine (CMM) is determined by measuring a rule standard. Thanks to a reversal technique, the straightness uncertainty of the CMM is theoretically dissociated from the straightness uncertainty of the rule. However, stochastic variations of the whole measurement system involve uncertainties of the CMM straightness error. To quantify these uncertainties, different sources of stochastic variations are listed with their associated probability density functions. Then Monte Carlo methods are performed first to quantify error and secondly to optimize measurement protocol. It is shown that a 5-measurement distance from 0.1 mm to each measurem…
Three-dimensional ultrasonography in prenatal diagnosis
1995
Within the past five years, 3D ultrasonography has developed to the degree that it offers both the patient and the examiner an entirely new visual experience in prenatal diagnosis. With the system described here (Kretz-technik, Austria), any desired plane can be displayed within the stored volume, and within seconds a high-quality 3D surface or transparent image can be calculated and displayed on the ultrasound monitor without need for an external workstation. All of this can be performed routinely in the clinical setting. Since 1989 we have routinely examined a total of 458 fetuses (242 normal and 216 with anomalies) between 16 and 38 weeks of gestation, supplementing our conventional 2D u…