Abstract: The present invention relates to an electromechanical transducer capable of arbitrarily varying the amount of deflection of a vibrating membrane for every element. The electromechanical transducer includes a plurality of elements including at least one cell that includes a first electrode and a second electrode opposed to the first electrode with a gap sandwiched therebetween and a direct-current voltage applying unit configured to be provided for each element and to separately apply a direct-current voltage to the first electrodes in each element. The first electrodes and the second electrodes are electrically separated for every element.

Abstract: Disclosed herein is a piezoelectric vibration module including a vibration plate that is surrounded by an upper case and a lower case, and includes a first stopper capable of preventing direct collision between a piezoelectric element and an internal constituent member, for example, an upper plate while vibrating linearly therein. In particular, the piezoelectric vibration module may further include a second stopper in the lower case.

Abstract: An actuator, which can include piezoelectric material, is provided in the form of a single-layer or multi-layer flat plate. At least one layer has two electrodes spaced from each other by means of a separating area and arranged opposite each other both on the upper face of the at least one layer and on the lower face of the at least one layer. The electrodes of the upper face are arranged at an offset from the electrodes of the lower face. A motor is also provided to include the actuator and a movable element to be driven by means of the actuator.

Abstract: The invention relates to a method for obtaining electrical energy from the kinetic energy waves. According to said method, a device is provided in the water, comprising an electroactive polymer that can expand with the action of the waves. When the electroactive polymer expands, an electrical charge is applied at a specific time for a specific time interval. Said electrical charge is removed during the relaxation of the polymer, except for a residual charge. According to said method, the variables of the electrical target charge required for the operation of the method, and the time intervals for the beginning and end of the charging and discharging of the electroactive polymer are determined. The invention also relates to a system for obtaining electrical energy and to a computer program product comprising commands that can be implemented by a microprocessor for carrying out the calculations in the method according to the invention.

Abstract: Tuning-fork type quartz-crystal vibrating pieces are disclosed, of which the vibration frequency can be adjusted without increasing CI. An exemplary piezoelectric device has a pair of vibrating arms extending in a predetermined direction from a first edge of a base. Respective first grooves are defined in a first principal surface of the vibrating arms. The first grooves extend in the predetermined direction, and have first excitation electrodes extending from a back-edge surface but not completely to a front-edge surface of the grooves. Respective second grooves are defined in a second principal surface, opposite the first principal surface, of the vibrating arms. The second grooves extend in the predetermined direction, and have second excitation electrodes extending from a back-edge surface completely to a front-edge surface of the second grooves.

Abstract: A tuning fork-type piezoelectric resonator plate has a resonator blank comprising a pair of vibrating leg portions and a base portion from which the leg portions protrude. The pair of leg portions are arranged in parallel protrudingly from one end face of the base portion, and a pronged portion is formed between the pair of leg portions in an intermediate position in a width direction of the one end face of the base portion. The base portion has a pair of through holes along the one end face of the base portion, and on another end face side opposite to the one end face of the base portion, a joining region that joins to an external portion. The pair of through holes are specially positioned and have special wall surface configurations.

Abstract: Disclosed are a spindle motor and a method of manufacturing the same. A base plate is integrated with a bearing housing using an insert molding or insert injection method at the same time when the bearing housing is made of resin, thereby being capable of securing the verticality of a bearing and a pivot assembled with the bearing housing and the base plate, reducing the manufacturing cost, and improving the efficiency of a manufacturing process. The motor includes a rotor, a pivot configured to have one end connected to the rotor, a bearing configured to rotatably support the outer circumferential face of the pivot, and a bearing housing made of resin and configured to comprise a first concave groove for receiving the bearing and a second concave groove for supporting the other end of the pivot.

Abstract: An inductively coupled plasma charged particle source for focused ion beam systems includes a plasma reaction chamber with a removably attached source electrode. A fastening mechanism connects the source electrode with the plasma reaction chamber and allows for a heat-conductive, vacuum seal to form. With a removable source electrode, improved serviceability and reuse of the plasma source tube are now possible.

Abstract: A 360-degree projection LED bulb includes a bulb holder, a transparent bulb seat, a transparent bulb shell, an upper luminosity module, a heat dissipating seat, and a plurality of sidelight luminosity modules. The upper luminosity module includes upper LEDs supported within an upper end of the transparent bulb seat and can be driven to project light beams towards the transparent bulb shell. The heat dissipating seat is engaged on a lower end face of an upper LED substrate of the upper luminosity module and includes side walls formed as an annular polygon. Each sidelight luminosity module is mounted on an associated side wall and includes a lateral LED substrate and at least one lateral LED disposed on the lateral LED substrate. Each lateral LED can be driven to radiate horizontally and downward via the transparent bulb seat. As such, the LED bulb realizes wide-angle radiation effect and superior cooling effect.

Abstract: A ground electrode includes a main body portion and a projecting portion having a width smaller than a width of the main body portion. A spark discharge gap is formed between a discharging surface of the projecting portion and a front end surface of a center electrode. When the front end surface and the ground electrode are projected on a first plane, at least a part of the projection region of the projecting portion overlaps the projection region of the front end surface. A width Le (mm), a width Lc (mm), a cross-sectional area Sg (mm2), a cross-sectional area Sc (mm2), an angle ?1 (°), an angle ?2 (°), an angle ?3 (°), and an angle ?4 (°) satisfy expressions Le<Lc, 2.9?Sc+Sg?4.25, and 0.30?(?1/?2)×(?3/?4)?0.67.

Abstract: A spark plug for an internal-combustion engine. The spark plug includes a central electrode, an insulator that holds the central electrode inside, a housing that holds the insulator inside, a ground electrode that forms a spark gap with the central electrode. The ground electrode includes a ground base member connected to the housing, and a ground protrusion protruding from a confronting face of the ground base member confronting the central electrode. The ground protrusion has a diameter of 0.9 to 1.4 mm. The spark plug is configured to satisfy ???53R+49, where R [mm] is a curvature radius of a base member corner and ?[degrees] is an angle formed by a shortest connecting line between the base member corner and a protrusion corner and a plane perpendicular to an axial direction of the ground protrusion.

Abstract: An ignition plug, wherein, when a relative density of a portion of an insulator, which is positioned between a radial virtual plane including a front end of the insulator and a radial virtual plane including a front end of a portion of the insulator which is in contact with a metal shell or the plate packing, is referred to as A (%), and a relative density of a portion of the insulator, which is positioned between the radial virtual plane including the front end of the portion of the insulator which is in contact with the metal shell or the plate packing and a radial virtual plane including a center of a resistor in an axial direction, is referred to as B (%), the following equations are satisfied: 93.90?A, and 0.10?A?B?0.90.

Abstract: An electron emission device and a method of manufacturing the same are provided. The electron emission device includes i) a hydrophilic resin substrate and ii) carbon nano tubes that are positioned on the resin substrate. Surface roughness Ra of the resin substrate is 7.3 ?m to 9.75 ?m.

Abstract: A method of production of a radio frequency accelerator which has a tubular part 1 which forms an acceleration cavity, including a temporary assembly step of making a plurality of component members 11 to 14 which have shapes obtained by splitting the tubular part 1 mate with each other to temporarily assemble them into the shape of the tubular part 10 and a welding step of welding the plurality of component members 11 to 14 together. The temporary assembly step includes a step of placing, inside of the tubular part 1, support members 21 for contacting the inside surface of the tubular part 1 and supporting the tubular part 1 from the inside, and the welding step includes a step of welding the plurality of component members 11 to 14 along the butt lines 51 by friction stir welding.

Abstract: Disclosed is an organic light emitting display device improving light efficiency by forming a metal layer having a nanometer thickness on a protective layer formed in order to protect the organic light emitting diode.

Abstract: A dielectric barrier discharge lamp includes a lamp tube, a discharge gas, a support member, a first electrode, and a second electrode. The lamp tube has a first and a second sealed end. The discharge gas is filled in the lamp tube. The support member is disposed at the first sealed end and extended toward the inside of the lamp tube. The support member has an accommodating space with its opening facing the inside of the lamp tube. The first electrode is disposed in the lamp tube. A first terminal of the first electrode passes through the opening of the accommodating space. A gap exists between an end of the first terminal of the first electrode and a closed end of the accommodating space. A second terminal of the first electrode penetrates and is closely fitted with the second sealed end. The second electrode is disposed outside the lamp tube.

Abstract: In one embodiment, a light-emitting device having a body, a reflector, a light source die, and a spectral converter is disclosed. The spectral converter may be formed adjacent to, but distanced away from, the light source die. The spectral converter may be configured to spectrally adjust a portion of the light output having a predetermined spectral content. In another embodiment, a system for illumination having a plurality of lighting assemblies is disclosed. Each of the lighting assemblies comprises a spectral converter configured to spectrally adjust a portion of the light output so that the plurality of lighting assemblies are configured to emit substantially similar spectral output. In yet another embodiment, a lighting apparatus having the spectral converter is disclosed.

Abstract: A white light emitting device includes: a blue light emitting diode (LED) which emits blue light; and a resin packing unit which encapsulates the blue LED, wherein the resin packing unit includes a first wavelength conversion material which, in response to being excited by the blue light, emits green light, a second wavelength conversion material which, in response to being excited by the blue light, emits red light, and a complex compound which absorbs light of a region in which the green light and the red light are mixed, the light of the region being included in white light implemented through a mixture of the green light and the red light excited together with the blue light.

Abstract: A display device having a plurality of light-emitting elements that construct picture elements aligned on a TFT substrate in a formation of a matrix. The display device includes the plurality of light-emitting elements each having a flat surface portion and including a light-emitting layer, an anode, and a cathode; a plurality of driver elements each coupled to the light-emitting element; a plurality of capacitor elements each of which is coupled to the light emitting element and receives an image signal; a plurality of switching elements each of which is coupled to the capacitor element and the light emitting element and control input of the image signal to the capacitor; and an insulation layer having a contact hole formed over the driver element. The anode is formed on the insulation layer and coupled to the driver element via the contact hole.

Abstract: A an organic electroluminescent display device includes an array substrate including a driving thin film transistor in a pixel region on a first substrate; an opposing substrate including an organic electroluminescent diode in the pixel region on a second substrate; an adhesive layer filling a space between the array substrate and the opposing substrate; and a connection spacer to electrically connect the organic electroluminescent diode with the driving thin film transistor.

Abstract: A magnetron has an anode cylinder, ten vanes, three strap rings. The ten vanes are fixed to an inner surface of the anode cylinder and arranged in a radial pattern of which center is at an axis of the anode cylinder. Each of the three strap rings connects vanes that are alternatively arranged. A first strap ring and a third strap ring are arranged on a first end of the vanes in a direction of axis, and a second strap ring is arranged on a second end that is opposite to the first end. Outer diameter of the second strap ring is equal to inner diameter of the first strap ring and outer diameter of the third strap ring is equal to inner diameter of the second strap ring.

Abstract: There is provided a lamp capable of informing a user that the LED lamp is at the end of its productive life and urging the user to replace the lamp reliably with a simple configuration. The lamp includes: a light emitting diode (1) as a light source; and a driving circuit (3) that turns on the light emitting diode (1) by an alternating-current or direct-current power source. The lamp further includes a life detecting element (2) that turns off the light emitting diode (1) following the occurrence of insulation deterioration in a resin material when the light emitting diode (1) has been operated for a predetermined time.

Abstract: Provided is a display device in which design properties have been improved by eliminating the flickering when the display level changes. A microcomputer (5) causes light emission of first LEDs (23 and 24) which are the first and second ones counting from the right end among the emitting first LEDs (21 to 24), with decreasing brightness towards the right end. Furthermore, the microcomputer (5) causes light emission of second LEDs from a second LED (77) which is disposed at the right end of the second LEDs (71 to 77), to a second LED (73) which is disposed at a position overlapped with the first LEDs (23 and 24) that emit light with decreasing brightness towards the right end, and also causes light emission of second LEDs (73 and 74), which are the first and second ones counting from the left end among the emitting second LEDs (73 to 77), with decreasing brightness towards the left end.

Abstract: A combination lamp for use in a vehicle includes a number of reflector modules, with each reflector module including a reflector, a first light emitting diode (“LED”) positioned at a focus of the reflector, and a second LED offset from the focus of the reflector. The lamp may also include another reflector module having a reflector and a single, common LED positioned at a focus of the reflector. When the first LEDs and the common LED are energized, the combination lamp produces a first light pattern. When the second LEDs and the common LED are energized, the combination lamp produces a second light pattern. The first light pattern may be a fog lamp light pattern, and the second light pattern may be a daytime running lamp light pattern. The combination lamp may include four, five, or more reflector modules, including the one reflector module having the single, common LED.

Abstract: A system and method are provided for mimicking a bioluminescent signal from an animal or an insect, such as a firefly. A first version includes a controller, an electrical energy battery, a solar energy collector and a light emitting device. The solar energy collector receives sunlight and converts the sunlight to electrical energy that is stored in the battery. The electrical energy battery provides electrical energy to the light emitting device under management by the controller, and may comprise two or more battery cells or circuits. A time sequence for energizing the light emitting device may be applied to cause the light emitting device to mimic a bioluminescent lighting pattern generally exhibited by a selected species of insect or animal. A light emitting diode may be used with a voltage source and a voltmeter to detect the approximate intensity of light of an ambient environment surrounding the device.

Abstract: In one embodiment, the trajectory of one or more electrons is controlled in a field emission device. In another embodiment, the field emission device is configured analogously to a klystron. In another embodiment, the field emission device is configured with electrical circuitry selected to control the input and output of the device.

Abstract: A physical vapor deposition system may include an RF generator configured to supply a pulsing AC process signal to a target in a physical vapor deposition chamber via the RF matching network. A detector circuit may be coupled to the RF generator and configured to sense the pulsing AC process signal and to produce a corresponding pulsing AC voltage magnitude signal and pulsing AC current magnitude signal. An envelope circuit may be electrically coupled to the detector circuit and configured to receive the pulsing AC voltage and current magnitude signals and to produce a DC voltage envelope signal and a DC current envelope signal. A controller may be electrically coupled to the envelope circuit and the RF matching network and configured to receive the DC voltage and current envelope signals and to vary an impedance of the RF matching network in response to the DC voltage and current envelope signals.

Abstract: A cold plasma treatment device for delivery of a cold plasma to patient treatment area. Gas is fed to a gas compartment where it is energized by an electrode coupled to a pulse source to thereby generate a cold plasma. A dielectric barrier is sandwiched between the gas compartment and the electrode to form a dielectric barrier discharge device. The cold plasma exits the gas compartment via a bottom member having a plurality of holes. Gases that can be used include noble gases such as helium or combinations of noble gases.

Abstract: A fault-tolerant controller for a lighting system comprising: a plurality of light emitting diode (LED) circuits and a controllable power source to power the plurality of LED circuits. The controller comprising a minimum voltage selector to determine a minimum voltage from a plurality of feedback voltages, one feedback voltage for each of the plurality of LED circuits. A control logic to regulate the drive voltage for the LEDs; and an overvoltage warning mechanism to determine an overvoltage of the drive voltage. The controller identifies one or more open-circuit conditions, one for each LED circuit, for which the respective feedback voltage is below an open-circuit threshold, and which causes the minimum voltage selector to exclude one or more respective feedback voltages associated with the LED circuits which have an open-circuit condition.

Abstract: Networked intelligent lighting devices and other elements connected to the network of a lighting system are readily adaptable to desirable networking arrangements as well as logical functional groups, for example by each storing communication provisioning data and/or configuration data for logically associating system elements into one or more groupings or sub-networks. The exemplary systems and system elements may also enable such enhanced network arrangement via autonomous discovery and device commissioning.

Abstract: A light emitting diode control circuit with carrier signal control includes a signal coupling unit, an operational amplifier, a demodulation unit, an identification and control logic unit, a counting and shift-registering unit, a data register, an output register, at least a current output unit, an address encoding unit, an address register, a voltage regulator and an oscillator. The efficiency of the present invention is to reduce the transmission lines of the light emitting diode lamp. Therefore, the cost of the light emitting diode lamp is reducing.

Abstract: A lighting apparatus is disclosed. The lighting apparatus is capable of achieving improved aesthetics by irradiating mood lighting into a storage container and also, of functioning to display a variety of status information about the storage container to the outside and to sterilize the interior of the storage container.

Abstract: A power converter includes dimmer circuit, a rectifier circuit, and a thyristor damper circuit. The dimmer circuit provides a dimmer voltage in response to an input voltage. The rectifier circuit provides a rectified voltage in response to the dimmer voltage. The thyristor damper circuit dampens an input current associated with the rectified voltage based on the input current and ceases dampening the rectified voltage based on the rectified voltage.

Abstract: A constant current LED driver circuit includes a unified controller operable to control start up peripheral circuits and control power output of the driver circuit. The unified controller initializes, starts driver circuit components in a predetermined order, and controls operation to prevent runaway operation, failure to start, and nuisance shut downs. Additionally, due to centralized operational condition monitoring, the controller can detect conditions that would cause unnecessary shut downs and prevent such nuisance shutdowns. The unified controller enables fast, finite control over switches of a DC-to-DC converter of the driver circuit to improve output current and voltage control, improving closed loop responsiveness and operation of the DC-to-DC converter.

Abstract: A luminaire according to one embodiment includes a DC power supply circuit, a switching power supply, and a lighting load. The DC power supply circuit converts an AC voltage controlled in phase to a DC voltage. The switching power supply is connected to the DC power supply circuit, and is controlled so that an input current becomes a constant current. The lighting load is connected as a load circuit of the switching power supply.

Abstract: A supplemental dimming circuit for an electronic led driver comprising a universal control section has a VCC3 startup and low conduction period circuit for providing a current during start-up and during low conduction periods; a CC hold current circuit for providing a hold current for the dimmer at low conduction periods; a latch circuit for providing a current draw latch on; and a PWM synchronized dimming circuit for providing a PWM signal dependent on the conduction period of the dimmer in real time. The supplemental dimming circuit also has a socket and a plug. The universal control section is on a daughter board that is pluggable to the socket. The VCC3 startup and low conduction period circuit creates a low AC voltage dummy load, which is a resistive load. The CC hold current circuit creates a low AC current dummy load that is a constant current load.

Abstract: A backlight driver includes current sources that are connected between LED strings and a number of bias voltages. There can be any number of different bias voltages, each at a ground potential or higher voltage. The bias voltage is selected for a particular LED string in order to reduce a current drop across the current source. This reduces the power consumption of the current source and LED string. Heat dissipation is also reduced.

Abstract: A method and system for driving an organic light emitting diode (OLED) with a regular LED driver without pre-charge are provided. In the examples, at least one passive element is included in parallel with the OLED across the output of the power supply. This passive element may be a capacitor. In one example, the effective series resistance (ESR) of the parallel capacitor may be substantially less than an ESR of the OLED at turn-on of the OLED. The turn-on delay of the OLED substantially is determined by the ESR of the parallel capacitor and is not substantially determined by the ESR of the OLED. In another example, the ESR of the parallel capacitor is less than or equal to 10% of an ESR of the OLED at turn-on of the OLED.

Abstract: A circuit for driving a light emitting diode (LED) comprises: an alternating voltage power supply, comprising a triac dimmer having a firing angle and output terminals that provide power to the LED; a zero crossing detector that detects a polarity change of the alternating voltage provided by the alternating voltage power supply and provides a zero crossing output signal indicative of the zero crossing; a timer triggered by the zero crossing output signal that generates a timer output signal during a time period of the timer; and LED power circuitry that reduces current to the light emitting diode based upon timing characteristics of the timer output signal.

Abstract: A dimmer system for a luminaire is provided. The dimmer system has a dimmer that receives a first current and supplies a reduced-magnitude current. The dimmer system also has a boosting system that receives the reduced-magnitude current and supplies a boosted current to a light source or lamp if the reduced-magnitude current is being received in conjunction with the initial turn-on of the dimmer. The boosted current can be provided for a predetermined period of time. The boosted current can also be provided as pulses of boosted current interspersed with pulses of the reduced-magnitude current. The boosted current can have the magnitude of the first current or range from 70% to 100% of the first current.

Abstract: A light driving system is provided that includes a light dimmer that receives an AC input signal and provides a dimmer output signal that includes a fast rising leading edge, a rectifier that receives the dimmer output signal and provide a rectified dimmer output signal and an AC/DC converter that filters the rectified dimmer output signal to provide a DC input signal that is employed to drive a light. The light driving system also comprises a protection circuit that limits current to the AC/DC converter during the fast rising leading edge of the dimmer output signal.

Abstract: A semiconductor light source lighting circuit includes a switching regulator that produces a drive current ILED with a switching element, and a control circuit that controls turning on and off of the switching element so that the magnitude of the drive current ILED approaches a target value. The control circuit includes an error comparator that compares the drive current ILED and the target value, an up/down counter that performs a counting operation, in which the control digital value is incremented or decremented based on the result of the comparison, a D/A converter that converts the control digital value into an analog duty ratio setting signal S4, and a drive circuit that controls the turning on and off of the switching element based on the signal S4. The up/down counter stops the counting operation when the switching regulator is brought into the inactive state.

Abstract: A driving circuit comprising a control unit, a current control unit, a pulse width modulation control unit and a current driving unit is described. The control unit provides a first control signal and a second control signal. The current control unit is connected to the control unit, and converts a reference current into a plurality of current setting signals based on a data signal and the first control signal. The pulse width modulation control unit is connected to the control unit and outputs a pulse signal based on the data signal and the second control signal. The current driving unit is connected to the pulse width modulation control unit and drives the light emitting diode based on a driving current, wherein the control unit generates a continuous conduction time in a predetermined operation period based on the pulse signal and the current setting signals.

Abstract: One embodiment of a display backlight driver integrated circuit can be configured for operation in at least two different ways. A first method transfers data from an EEPROM to hardware registers prior to regular operation. A second method also transfers data from an EEPROM to registers. However, hardware registers can be overwritten with data accepted from a control bus, prior to regular operation. A keyboard driver IC can detect the presence or absence of a cable to an LED. If the cable is absent, the driver IC will not supply power for the LED. One embodiment of a keyboard and display backlight control system can be configured to allow substantially independent operation.

Abstract: A light emitting diode (LED) illumination device having a power compensation function is provided. The illumination device includes a light emitting unit including a plurality of LEDs connected in series, a rectifier for rectifying input AC power to provide a rectified voltage to the light emitting device, and a power compensator for detecting a change in the rectified voltage provided to the light emitting device and compensating a current provided to the light emitting device according to the detected change in the rectified voltage.

Abstract: Provided is a step up/down converter, in which the inductor current can be easily detected by a simple configuration in any connecting mode of the switches.

Abstract: A system provides white light having a selectable spectral characteristic (e.g. a selectable color temperature, delta uv, and intensity) using a combination of sources (e.g. LEDs) emitting light of three, four, five, or six different characteristics, for example, one or more white LEDs, and one or more LEDs of each of three primary colors, plus cyan and royal blue. A controller maintains a desired spectral characteristic, e.g. for white light at a selected point on or within a desired range of the black body curve. In addition, the controller provides selectable adjustments for values of the spectral characteristics, while maintaining substantially constant overall output intensity for the light output of White LEDs, thereby achieving Maximum Utilization.

Abstract: A light fixture includes a driver circuit that fully defines operational characteristics for operation outside of “Nominal Operation” of the driver circuit. The driver circuit increases a target current or set point when the current of the light source (i.e., output current of the driver circuit) or the voltage of the light source (i.e., output voltage of the driver circuit) is below a minimum operating current or minimum operating voltage of the driver circuit regardless of a command current level of the driver circuit. The driver circuit implements a soft start ramp up scheme having a default rate of increase for a set point or target current. After a shutdown, the driver circuit periodically attempts to restart operation by increasing the set point or target current from zero (i.e., shutdown) at a reduced rate as compared to the default rate.

Abstract: A driver circuit for driving light emitting diodes (LEDs). The driver circuit includes a string of LEDs divided into n groups and the n groups of LEDs is electrically connected to each other in series, where a downstream end of group m?1 is electrically connected to the upstream end of group m. The driver circuit also includes a power source coupled to an upstream end of group 1 and provides an input voltage. The driver circuit further includes current regulating circuits, where each of the current regulating circuits is coupled to the downstream end of the corresponding group at one end and coupled to a ground at the other end. Each of the current regulating circuits includes a sensor amplifier and a cascode having first and second transistors. The driver circuit also includes detectors, where each of the detectors detects a source voltage of the first transistor.

Abstract: An embodiment of the disclosure relates to a voltage converter for supplying a semiconductor light source and having at least an input terminal connected to a power supply reference, namely an AC mains voltage reference, and an output terminal providing a current signal to said semiconductor light source, the converter being also connected to a voltage reference and comprising at least a step-down block inserted between a switching node and to the output terminal and connected to the voltage reference and an input block connected to the input terminal, as well as to a first input node and to a first output node of a control circuit, in turn connected to the switching node and to the voltage reference.