Abstract: The present invention provides a method and apparatus to identify at least one component from a plurality of components in a fluid mixture, the apparatus including a first input channel into which a first flow containing a plurality of components is introduced; a plurality of buffer input channels, into which additional flows of buffer solution are introduced, disposed on either side of the first input channel; wherein the first flow and the additional flows have a flow direction along a length of the apparatus; a detector apparatus which detects and identifies selected components of the plurality of components; a laser which emits a laser beam which damages or kills selected components of the plurality of components; and at least one channel disposed at the another end of the apparatus which is adapted to receive the first flow and the additional flows after operation of the laser on the selected components.

Abstract: Embodiments described herein generally relate to methods and apparatuses for ensuring the integrity of probe card assemblies and verifying that probe cards are ready for testing. In one embodiment, an apparatus includes a stage that allows stable and precise movement of a sensor. The stage includes a first support, a second support, and a sensor carrier. A plurality of lifting devices is coupled to the second support and the sensor carrier, providing a more stable and precise movement for the sensor carrier. Methods for identifying objects other than the probes disposed on a surface of a probe card and to determine whether the probe card is ready for use are disclosed.

Abstract: The invention makes it possible to measure binding of a biochemical substance with a high throughput and with high sensitivity using a small cell capable of being filled with a small amount of chemical solution. A space between a first substrate and a second substrate such that probes are immobilized on their mutually facing planes is used as a cell that houses a specimen solution. Light is irradiated from a first substrate side, and reflected light is subjected to spectroscopy. Binding of the target with the probe is detected by a wavelength shift in the refection spectrum.

Abstract: An optical device, such as a microscope, is disclosed that can be assembled from flat materials. The optical device can be assembled via a series of folds of a flat material. The optical microscope can include a stage for supporting a sample, an optic stage, and a light source. The optic stage can include one or more lenses. The optical microscope can be capable of obtaining simultaneous images from different forms of microscopy. The optical microscope may have bright field and filter field viewing capabilities wherein a user shifts from bright field to filter field by lateral movement of the stage containing a lens and a light source that cooperate to provide either the bright field or the filter field.

Abstract: The disclosure provides a surface-enhanced Raman scattering substrate, including: a surface-enhanced Raman scattering (SERS)-active substrate; a patterned hydrophilic region and a patterned hydrophobic region formed on the SERS-active substrate, wherein a water contact angle difference between the patterned hydrophilic region and the patterned hydrophobic region is in a range from about 29 degrees to about 90 degrees.

Abstract: A supporting device includes a stage, a level-meter assembly, a supporting pole, a first and second adjusting members. The stage includes a supporting plate having an upper surface and a lower surface, a first side plate, and a second side plate opposite to the first side plate. The two side plates extend from the lower surface. The first side plate includes a first surface facing away from the lower surface. The second side plate includes a second surface facing away from the lower surface. The second surface defines a first receiving hole and a second receiving hole. The level-meter assembly is mounted on the upper surface. The supporting pole is mounted on the first surface. A first extendable pole of the first adjusting member is received in the first receiving hole. A second extendable pole of the second adjusting member is received in the second receiving hole.

Abstract: Techniques, apparatus, material and systems are described for implementing a three-dimensional composite mushroom-like metallodielectric nanostructure. In one aspect, a surface plasmon based sensing device includes a substrate and a layer of an anti-reflective coating over the substrate. The surface Plasmon based sensing device includes a dielectric material on the anti-reflective coating shaped to form a 2-dimensional array of nanoholes spaced from one another. Also, the surface Plasmon based sensing device includes a layer of a metallic film formed on the 2-dimensional array of nanoholes to include openings over the nanoholes, respectively, wherein the sensing device is structured to support both propagating surface plasmon polariton (SPP) waves and localized surface plasmon resonant (LSPR) modes.

Abstract: The present disclosure relates to microfluidic devices adapted for facilitating cytometry analysis of particles flowing therethrough. In certain embodiments, the microfluidic devices allow light collection from multiple directions. In certain other embodiments, the microfluidic devices use spatial intensity modulation. In certain other embodiments, the microfluidic devices have magnetic field separators. In certain other embodiments, the microfluidic devices have the ability to stack. In certain other embodiments, the microfluidic devices have 3-D hydrodynamic focusing to align sperm cells. In certain other embodiments, the microfluidic devices have acoustic energy couplers. In certain other embodiments, the microfluidic devices have phase variation producing lenses. In certain other embodiments, the microfluidic devices have transmissive and reflective lenses. In certain other embodiments, the microfluidic devices have integrally-formed optics.

Abstract: Methods for fabricating nanoscale array structures suitable for surface enhanced Raman scattering, structures thus obtained, and methods to characterize the nanoscale array structures suitable for surface enhanced Raman scattering. Nanoscale array structures may comprise nanotrees, nanorecesses and tapered nanopillars.

Abstract: According to an embodiment of the invention there is provided a system that may include a pivot chuck that may include : a lower chuck portion; an upper chuck portion; a first distance changing module that may include a pivot mechanism and an angle changing element; wherein the pivot mechanism pivotally couples the lower chuck portion to the upper chuck portion; wherein the angle changing element is coupled between the upper and lower chuck portions; wherein the upper chuck portion may be arranged to support a substrate; wherein the angle changing element may be arranged to induce a rotation of the upper chuck portion in relation to the pivot mechanism in response to first focus correction signals.

Abstract: Polymeric fibers may be tested for optical properties; such as transparency in a manner that provides reproducible test results. A holder be used that is configured to hold polymeric fibers in a stacked, single file manner in which the polymeric fibers are held closely together. The fibers may be tested using an optical apparatus employing an integrating sphere.

Abstract: To provide a jig for flexible optical measurement that enables at all times a measurement position to be measured from the normal direction when performing any measurement of a flexible optical display panel with any given curvature. A jig for flexible optical measurement comprises a holding member which has a prescribed curvature that allows it to hold a flexible optical display panel with any given curvature, and a base member which has the same curvature as the holding member in order to shift the holding member and is used to shift the holding member. The holding member can be shifted using the base member, and when performing any measurement by shifting the flexible optical display panel and measuring, it is possible to measure the measurement position from the normal direction.

Abstract: The present invention relates to a chip for optical analysis. In particular, the present invention relates to an optical sensor handling a liquid sample, which is a chip for analysis that can be used for selectively measuring a biologically-relevant substance or a chemical substance such as an environmental pollutant or a health affecting substance in a liquid to be measured. The chip for optical analysis of the present invention is characterized in that (1) an adsorption region (filter region) is provided between a sample introduction section and the observation section in a passage of the chip for analysis, (2) a bypass passage is provided in the passage (main passage) of the chip for analysis, and a time lag is generated between samples passed through the main passage and passed through a bypass passage, and (3) a measurement region and a reference region are provided in the observation section of the chip for analysis.

Abstract: Provided herein are substrates useful for surface-enhanced Raman spectroscopy (SERS), as well as methods of making substrates. The substrates comprise a support element; a nanoparticulate layer; a SERS-active layer in contact with said nanoparticulate layer; and optionally, an immobilizing layer disposed between said nanoparticulate layer and said support element; wherein if the optional immobilizing layer is not present, the nanoparticulate layer is thermally bonded to the support element; and if said optional immobilizing layer is present, said nanoparticulate layer thermally bonded to said immobilizing layer, and optionally, further thermally bonded to said support element. In addition, methods of making the substrates, along with methods of detecting and increasing a Raman signal using the substrates, are described herein.

Abstract: An environmental cell assembly for use in microscopy and spectroscopy applications, including: an environmentally sealed body assembly configured to selectively hold and contain a sample; a plurality of ports manufactured into one or more surfaces of the body assembly for one or more of evacuating the body assembly and injecting a gas into or removing a gas from the body assembly; a port manufactured into a surface of the body assembly for receiving a translating stage configured to move the sample within the body assembly; and a port manufactured into a surface of the body assembly for receiving one or more lenses utilized in a microscopy or spectroscopy application; wherein the one or more lenses are disposed adjacent the sample without intervening structures disposed there between. The cell assembly also includes a port manufactured into a surface of the body assembly for retaining a window and providing visualization of the sample.

Abstract: A sample holder for optical microscopy that incorporates sample holders typically used in electron microscopy to maximize the correlation between optical and electron microscopy images and data.

Abstract: A test apparatus is configured for testing a notebook including a liquid crystal display section and a body section. The positioning structure includes an optical testing module, an adjustable OTM mount, a fine-tuning module, a clamping module and a adjustable LCD mount. The optical testing module tests the liquid crystal display section, and is mounted to the adjustable OTM mount for moving the optical testing module. The optical testing module is attached to the fine-tuning module. The clamping module is for clamping the notebook. The adjustable LCD mount is mounted to the clamping module, and rotates the notebook relative to the optical testing module.

Abstract: A vacuum chamber B which stores a length meter is provided separately from a vacuum chamber A in which an object to be measured is installed, an installation base 5 which is integrally mounted to a surface plate 10 that supports the chamber A and/or an object to be measured is installed on a side portion of the vacuum chamber A, and the vacuum chamber B is disposed and installed on the installation base 5 so that a side wall thereof overlaps a side wall A1 of the vacuum chamber A with a side plate member 13 interposed therebetween

Abstract: A plate-shaped periodic structure is provided that includes at least two aperture portions extending through the periodic structure in a direction perpendicular to a main surface of the periodic structure and periodically arranged in at least one direction along the main surface. Each of the aperture portions has a shape that is not mirror-symmetric with respect to an imaginary plane that is a plane perpendicular to the main surface. Each of the aperture portions includes a constricted portion at which a gap distance of the aperture portion is partially small, the gap distance being a width in a direction parallel to a line of intersection of the main surface and the imaginary plane.

Abstract: A sample support apparatus is provided in which a XY-table and a Z-table moving along a height direction are disposed in a Z-reference surface as a height reference, and in which a sample is disposed at a predetermined height position while supported by the Z-table, the sample support apparatus comprising, a height correction unit that controls movement of the Z-table, and a Z-sensor that is provided on the Z-reference surface to measure the height from the Z-reference surface, wherein a measuring surface is aligned along the same axis with respect to a measuring position of the sample, the height of the measuring surface from the Z-reference surface is measured by the Z-sensor, the height correction unit moves the Z-table according to the measured value of the height so that the sample is disposed at the predetermined height position.

Abstract: The present invention provides an optical detection system in which a first mirror of the control unit is used to receive light beam and redirect it into a first one-dimensional off-axis parabolic mirror. The first one-dimensional off-axis parabolic mirror then directs the light beam to a cylindrical lens. Through the mechanism of reflection, the cylindrical lens further directs the light beam to a second one-dimensional off-axis parabolic mirror. The second one-dimensional off-axis parabolic mirror then directs the light beam into a second mirror. The detection unit of the system is used to detect the light beam coming from the control unit, so as to convert the light signals into electric signals for the analysis in the process unit afterwards.

Abstract: An optical device includes a transparent substrate and a conductive layer disposed over an upper surface of the transparent substrate. The conductive layer defines at least one groove inwardly extending from an upper surface and includes an aperture that is spaced apart from the at least one groove. An interface between the upper surface of the conductive layer and an ambient medium defines an optical branch along which surface plasmon polariton modes are excited in response to at least partially coherent light being received by the optical device.

Abstract: Sampling device geometry reduces specular reflectance, using lenses to focus electromagnetic energy to predominately return scattered rather than reflected electromagnetic energy to detector(s), reducing effect of non-matte surfaces and/or window. Sampling device includes inherent automatic optical calibration, and optionally thermal calibration. Calibration detectors are optically isolated with respective emitters.

Abstract: According to an example, an apparatus for performing spectroscopy includes a substrate on which a plurality of surface-enhanced spectroscopy (SES) elements are positioned substantially along a first plane. The apparatus also includes a first electrode positioned adjacent to the plurality of SES elements substantially along the first plane and a second electrode positioned adjacent to the plurality of SES elements substantially along the first plane and on a side of the plurality of SES elements that is opposite the first electrode. The first electrode and the second electrode are to generate an electric field around the plurality of SES elements when voltages are applied through the first electrode and the second electrode.

Abstract: The present invention provides compositions for making and methods of using a hand-held nucleic acid amplification device, comprising a disposable biochip with a series of sample wells, each sample well having a novel optical arrangement that includes a light-emitting diode (LED) and a single light capturing element (e.g. a photodiode) for quickly measuring light emissions from biological samples such as nucleic acid amplification reactions. Such a device can utilize isothermal amplification for obtaining detectable yields of amplified nucleic acid product in short time periods, for example, within seconds.

Abstract: Systems, devices and techniques are disclosed for optically detecting single molecules using nanoscale chip configurations. In one aspect, a sensing device includes a composite membrane having an array of nanochannels that form openings at opposing sides of the membrane, a first and second substrate each including channels to carry a fluid containing particles, a fluidic module that is fluidically coupled to the channels to supply the fluid, a plurality of electrodes located along the channels, and an electrical module to generate an electric field via the electrodes to effectuate an electrokinetic force within the channels to steer the particles toward the openings of the nanochannels to immobilize the particles, in which the nanochannels operate as resonant structures to amplify localized fields produced in an optical interrogation of the immobilized particles.

Abstract: Apparatus and methods are disclosed that are configured to permit nanoplasmonic spectroscopy sensing in the form of colorimetric sensing. An example apparatus involves: (a) an array layer having a top surface and a bottom surface, wherein a plurality of nanoholes are defined in the top surface of the array layer, wherein the plurality of nanoholes each have at least one sidewall surface and a bottom surface, (b) a thin metal film disposed on the top surface of the array layer and on the bottom surface of each of the plurality of nanoholes, and (c) a plurality of nanoparticles disposed on the at least one sidewall surface of the plurality of nanoholes.

Abstract: A method of preparation of a 2-D array of particles comprising: mixing the particles and a first liquid, the first liquid having the properties of being soluble in water and reducing surface tension of a water surface; adding the mixture to the water surface; and transferring the 2-D array onto a solid surface. A composition comprising: a 2-D array of particles; and a polymer substantially enveloping the 2-D array of particles.

Abstract: An eyeglass support is adapted for pinch-holding the eyeglass (5) between three first contact portions (41-43) and three second contact portions (61-63). The first contact portions form a height reference for positioning the eyeglass whereas the second contact portions ensure application of the eyeglass against the first contact portions while conforming to any possible shape for the eyeglass. The support suits for being incorporated in a reflection measurement apparatus. In particular, it is useful for measuring reflection of eyeglasses provided with antireflecting coatings or for rating a protection against UV hazards which is provided by an eyeglass to a wearer of the eyeglass.

Abstract: A soil analysis device and a method are disclosed for measuring characteristics of a soil sample. A mixing chamber combines a soil sample and an extractant into a liquid mixture. A filtration system receives and filters the liquid mixture. The filtered liquid mixture is transmitted to a measurement cell. The measurement cell is coupled to a light source so that light propagating from the light source is attenuated and/or reflected by the liquid mixture and is measured by one or more optical detectors that are also coupled to the measurement cell. The optical detector generates an attenuation spectrum and/or a reflection spectrum indicating light received by the one or more detectors at different wavelengths. The attenuation and/or reflection spectrum is used to determine the characteristics of the soil sample.

Abstract: A microscope measurement system including: an optical microscope including a microscope body and an objective connected to the microscope body; a chamber including a support mechanism holding an object to be examined therein, the chamber including an opening inserting the objective into the chamber such that the objective is located essentially within the chamber and the microscope body is located essentially outside of the chamber; a sealing mechanism that provides an essentially gas-tight connection between the optical microscope and the chamber such that the chamber is sealed.

Abstract: A surface enhanced Raman spectroscopy (SERS) apparatus employs a nanorod in an indentation in a surface of a substrate. The SERS apparatus includes the nanorod having a tip at a free end opposite to an end of the nanorod that is supported by the substrate indentation. The indentation has a tapered profile and supports the nanorod at a bottom of the indentation. The free end of the nanorod extends away from the indentation bottom. The SERS apparatus further includes a Raman-active material at a surface of one or both of the nanorod and the indentation. The indentation and the nanorod facilitate one or both of production and detection of a Raman scattering signal emitted by an analyte in a vicinity of the nanorod and indentation.

Abstract: Disclosed are systems and methods for cleaning optical windows used in an inline optical fluid analyzer. One system includes a sampling module having an inlet and an outlet and a flow path extending therebetween, the flow path being fluidly coupled to a pipeline containing a fluid, at least one optical computing device arranged within the sampling module in optical communication with the flow path and configured to monitor a sample flow of the fluid for one or more characteristics of the fluid, the at least one optical computing device having one or more optical sampling windows in contact with the sample flow of the fluid, and a solvent dispenser fluidly coupled to the flow path and configured to provide a solvent to the flow path to remove a residue built up on the one or more sampling windows.

Abstract: An optical smoke detector designed for the mining industry that includes an active sampling component and a unique air flow system to reduce the environmental impact of underground mining. The active sampling smoke detector may include an intake fan, an optical sensing unit, an air path between the intake fan and the optical sensing unit, and a controller operatively connected to the intake fan and the optical sensing unit, the controller being configured to regulate fan speed and output at least one signal indicative of air quality passing through the optical sensing unit.

Abstract: A vertical support rigidly mounted to a planar base positions and supports a cryocooler expander unit off axis and away from a sample to be examined. The sample support is likewise rigidly mounted to the planar base with a rigidly mounted sample housing therein. The cryocooler expander unit is suspended in the vertical support by spring dampening bearings. A pair of opposing flexible vacuum bellows connects the cryocooler expander unit to the sample housing and vertical support. This configuration isolates the sample from vibration. Flexible thermal links associated with an predictive electronic closed loop control sequence maintains sample temperature.

Abstract: There are provided an inspection device for substrate deformation at high temperatures and an inspection method for substrate deformation at high temperatures, the inspection device for substrate deformation at high temperatures, including a crucible including an internal space, an inspection hole disposed in an upper portion thereof so as to inspect the internal space, and a heating unit heating the internal space, an indenter tip disposed in the crucible such that a substrate fixed to the internal space is warped, and an inspection unit disposed above the crucible so as to inspect a cross-section of the substrate.

Abstract: An optical device is provided that includes a converging lens device, a transmitting optical fiber, a sample holder, and a receiving optical fiber. The converging lens device focuses light onto the transmitting optical fiber, which receives the focused light through an entrance face and transmits the light from an exit face, through a sample, and onto the receiving optical fiber. The sample holder holds the sample for analysis. The receiving optical fiber receives the light through an entrance face of the receiving optical fiber after transmission through the sample. The converging lens device is positioned to focus the light onto the entrance face of the transmitting optical fiber such that a half-angle of the angular distribution of the focused light that reaches the entrance face of the transmitting optical fiber is selected to underfill an entrance aperture of the entrance face of the receiving optical fiber in both a spatial dimension and an angular dimension.

Abstract: A spectroscopic instrument (1) comprising at least one load bearing anti-vibration foot portion (3) for supporting the instrument on a surface. Each foot portion (3) comprises a load bearing elastomeric portion (5) and an internal stub portion (4) which is provided within the elastomeric portion and which is rigid compared to the elastomeric portion. An internal wall of the elastomeric portion (5) is spaced from an external wall of the stub portion (4) such that the elastomeric portion (5) is moveable relative to the stub portion (4) to absorb vibration. Liquid is provided in the spacing between the internal wall of the elastomeric portion (5) and the external wall of the stub portion (4) to damp such movement.

Abstract: The present invention relates to systems and methods for minimizing or eliminating diffusion effects. Diffused regions of a segmented flow of multiple, miscible fluid species may be vented off to a waste channel, and non-diffused regions of fluid may be preferentially pulled off the channel that contains the segmented flow. Multiple fluid samples that are not contaminated via diffusion may be collected for analysis and measurement in a single channel. The systems and methods for minimizing or eliminating diffusion effects may be used to minimize or eliminate diffusion effects in a microfluidic system for monitoring the amplification of DNA molecules and the dissociation behavior of the DNA molecules.

Abstract: A liquid component concentration meter measures the concentration of a liquid in a liquid supply tube from outside the liquid supply tube. The concentration meter includes a liquid supply tube; a light transmission unit; a light emission unit for irradiating light to the light transmission unit; a light reception unit for receiving light passed through the light transmission unit; a support member that movably supports the light emission unit and the light reception unit such that a measurement position is moved along the light transmission unit; a measurement-position moving mechanism for moving the support member such that the measurement position is moved within a predetermined area in the light transmission unit; and a data processing unit for calculating the concentration of the liquid in the liquid supply tube based on intensities of light received by the light reception unit at different measurement positions.

Abstract: An apparatus for electrical inspection is disclosed. The apparatus comprises an inert gas delivery system that delivers inert gas near a microscope imaging element and electrical test probes. A gas supply provides an inert gas such as argon or nitrogen. The inert gas displaces oxygen to prevent premature oxidation of the test probes. In one embodiment, one or more delivery tubes deliver inert gas to the measurement area.

Abstract: Containerized systems are provided. In one embodiment, a containerized system includes a moveable three-dimensional container, a first generator, a second generator, and a scanner. The first generator is located within the container, and the second generator is located outside of the container. The scanner is mechanically supported by the container and transmits waves received from the first and the second generators. The containerized system optionally includes one or more rails connected to the outside of the container, and the scanner moves along the one or more rails. The containerized system may also include a multi-axes arm that positions the scanner and that is mechanically supported by the container. Furthermore, the containerized system may include an interferometer, an electronics rack, and/or an air conditioning unit.

Abstract: A method and device for periodically perturbing the flow field within a microfluidic device to provide regular droplet formation at high speed.

Abstract: It is an object of the present invention to test a device under test including an optical interface. Provided is a device interface apparatus on which is loaded a device under test including an optical interface. The device interface apparatus comprises a device loading section on which the device under test is loaded; an optical connector that is to be connected to the optical interface of the device under test; and an optical connector moving section that moves the optical connector toward the optical interface of the device under test loaded on the device loading section, to optically connect the optical connector and the optical interface.

Abstract: An apparatus used to calibrate microtiter plate readers. The apparatus includes one or more structures having two exterior surfaces wherein one of the exterior surfaces is coated with a coating selected to establish on that surface a reflection loss that mimics reflection loss at an air-liquid interface, and the other of the two exterior surfaces is coated with a coating selected to establish a reflection loss on that surface that mimics the reflection loss at a bottom surface of a microtiter plate. The apparatus may be a single layer, a multi-layered composition or a container. The apparatus is an artifact that may be used to calibrate a plate reader by mimicking a solution-filled microtiter plate. The artifact may be used for a plurality of liquids, including water. The artifact produces reflection losses more closely mirroring reflection losses expected for a liquid-filled microtiter plate well.

Abstract: A specimen transporter transports a specimen plate to a specimen imaging apparatus. The specimen transporter comprises a plate container configured to contain the specimen plate therein, and a transport mechanism which transports the plate container to the specimen imaging apparatus with the specimen plate contained in the plate container.

Abstract: A device and a method for optical parallel analysis of a sample arrangement. The device includes a system of sample areas provided on and/or in a front face of the carrier substrate for receiving a sample substance; a system of detector areas provided on and/or in a back face of the carrier substrate, each detector area being assigned to a corresponding sample area; and a system of optical devices, each optical system being assigned to a corresponding sample area and being designed in such a way that it deflects light beams, which the corresponding sample area in response to an optical excitation does not emit in the direction of a detector area assigned to it, in the direction of the detector area assigned to it and/or in the direction of a detector-free area on the back face of the carrier substrate.

Abstract: Reference cell (8) for use with a fiber optic probe (1) comprising a base wall (11), upstanding walls (12) each having an optical window (13, 15), and a top wall (14) having a further optical window (16) adapted to allow light to pass to and from a fiber optic probe. The base wall (11) comprises a reflector (19) which reflects incident light from the fiber optic probe back to said probe (1). The top wall (14) has an attachment for receiving an emitting and a receiving end of a fiber optic probe (1). The cell (8) allows use of standard fiber optic probe (1) with other optical equipment when the path length and the probe optical characteristics require validation to international standards. The calibration of the probe (1) is analogous to calibration of laboratory spectrophotometers and can therefore be validated. The device (8) enables probes (1) to be used for applications where precision and accuracy are essential.

Abstract: Systems and methods for opto electric properties are provided. A light source illuminates a sample. A reference detector senses light from the light source. A sample detector receives light from the sample. A positioning fixture allows for relative positioning of the sample or the light source with respect to each other. An electrical signal device measures the electrical properties of the sample. The reference detector, sample detector and electrical signal device provide information that may be processed to determine opto-electric properties of the same.

Abstract: An array chip design is provided where the chip includes a field region arranged with sites according to a first pitch and at least one track region having a one-dimensional site pattern arranged according to a second pitch that is less dense and is an integer multiple of the first pitch so that observation through pixel-based sensors using one-dimensional quad-cell averaging can be applied in the track region, thereby to attain alignment of the chip to pixel-based optical instrumentation with a higher density of sites.