CN202305673U - Alternating current (AC) impedance testing device suitable for fuel cells - Google Patents

Alternating current (AC) impedance testing device suitable for fuel cells Download PDF

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Publication number
CN202305673U
CN202305673U CN2011204269396U CN201120426939U CN202305673U CN 202305673 U CN202305673 U CN 202305673U CN 2011204269396 U CN2011204269396 U CN 2011204269396U CN 201120426939 U CN201120426939 U CN 201120426939U CN 202305673 U CN202305673 U CN 202305673U
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China
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circuit
signal
input
fuel cell
output signal
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CN2011204269396U
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Chinese (zh)
Inventor
全书海
谢长君
张鸽
江竑旭
陈启宏
黄亮
全睿
肖朋
童亮
刘力
郑丽丽
郭邑城
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武汉理工大学
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Abstract

The utility model relates to an alternating current (AC) impedance testing device suitable for fuel cells. The AC impedance testing device comprises a program control AC source, a stopping capacitor, a preamplifier, a current-to-voltage (I/V) conversion circuit, a low pass filter, two ways of program control filters, a phase difference detection circuit, an amplitude value detection circuit, a keyboard, a liquid crystal display unit and a micro controller unit (MCU), wherein the program control AC source is connected in series with the stopping capacitor and is then connected in parallel with a load and an output end of a fuel cell stack; the MCU controls the program control AC source to output current excitation signals with different frequencies through a controller area network (CAN) bus; AC impedance of at most 16 fuel cells can be simultaneously tested by a single AC impedance testing device; multiple AC impedance testing devices are connected through a CAN; by using multiple AC impedance testing devices, the AC impedance of any number of fuel cells can be simultaneously tested. The testing device has the advantages of concise and clear circuit, high reliability, moderate cost, high measurement accuracy, quick speed, rich interface and easiness in expansion; and the requirement for real-time high-accuracy testing of the AC impedance of the fuel cells is satisfied.

Description

A kind of ac impedance measurement device that is applicable to fuel cell

Technical field

The utility model belongs to a kind of series electrical source monomer ac impedance measurement device, particularly a kind of ac impedance measurement device that is applicable to fuel cell.

Background technology

Fuel cell is a kind ofly will be stored in the device that chemical energy in fuel and the oxygenant converts electric energy to through electrochemical reaction.According in the practical application to the fuel battery power requirement; Usually fuel cell pack is composed in series to hundreds of sheet monocell by several; In the fuel cell operation process, the performance and the safety that can influence whole stack unusually of monolithic battery, therefore; Efficiently move in order to ensure fuel cell, must monitor in real time each monolithic fuel cell.Undoubtedly, the fuel cell AC impedance is the critical data of fuel cell power generation performance, monitoring in real time, and with data presentation, storage makes things convenient for the scientific research personnel to analyze and research.

The testing impedance equipment of current fuel cell comes with some shortcomings, as: equipment can only be measured under laboratory environment is established in experiment, can't online in real time test; Can only test the monolithic fuel cells impedance, can't satisfy the multi-disc fuel cell simultaneously and measure simultaneously; Can only test fuel cell at the resistance value of a certain Frequency point.And these equipment generally comprise high-grade complex instrument such as fuel battery test platform, electronic load, frequency analyzer; Need the technician correctly to dispose their hardware line, software program and interface communications protocol etc., this makes, and such test operation is complicated, cost is very high.

Summary of the invention

The purpose of the utility model is to provide a kind of ac impedance measurement device that is applicable to fuel cell simply, reliably, to overcome the deficiency of existing proving installation.

To achieve these goals, the utility model comprises program control alternating current source, capacitance, prime amplifier, I/V change-over circuit, low-pass filter, two-way programmable filter, phase difference detecting circuit, amplitude detection circuit, keyboard and liquid crystal display and MCU microprocessor; Parallelly connected with load and fuel cell pack output terminal behind the wherein program control alternating current source serial connection capacitance, the MCU microcontroller is through the current excitation signal of the program control alternating current source output of the total line traffic control of CAN different frequency; The prime amplifier input end links to each other with each monocell in the fuel cell pack, gathers each monolithic battery combined-voltage signal, and the I/V change-over circuit links to each other with the output terminal of current sensor and gathers fuel cell ac and dc current signal, the signal V that is gathered i, V vThrough the AC signal V that obtains after the filtering of two-way programmable filter (v), V (i), link to each other with amplitude detection circuit with phase difference detecting circuit simultaneously; The MCU microcontroller through SPI1, SPI2 interface respectively with phase detecting circuit in FPGA and the amplitude detection circuit A/D converter be connected; The MCU microcontroller can obtain fuel cell different frequency AC impedance amplitude and phase data through computing; And pass through the I/O bus transfer to keyboard and liquid crystal display, finally can obtain the fuel cell ac impedance spectroscopy.16 fuel cells can be tested at most simultaneously in single ac impedance measurement unit, and a plurality of ac impedance measurements unit links to each other through the CAN network can realize the test to any sheet fuel cell AC impedance.

Above-mentioned prime amplifier is by 16 two-way relays, and 4-16 code translator and differential amplifier circuit are formed.Fuel cell output voltage signal V 0, V 1With two-way relay L 1Input end connects, V 1, V 2With two-way relay L 2Input end connects, by that analogy V 15, V 16With two-way relay L 16Connect.4-16 code translator output signal is received 16 relay control ends respectively.The MCU microcontroller is through I/O mouth control 4-16 code translator relay gate L successively 1~L 16, each has only a relay to be in opening state constantly, makes the monolithic fuel cell export signal V n, V N-1(n=1,2 ... 16) by gating, and link to each other with the differential amplifier circuit input end.Differential amplifier circuit can be to input signal V n, V N-1(n=1,2 ... 16) carry out the differential type amplification, enlargement factor is 100 times, makes prime amplifier can gather ac voltage signal faint on the every fuel cell.

Above-mentioned two-way programmable filter is made up of 4 second-order bandpass filter A, B, C, D, and wherein second-order bandpass filter A and B, C and D can form two quadravalence Butterworth BPF.s respectively.Second-order bandpass filter A, C input end link to each other with I/V change-over circuit output signal Vi with prime amplifier output signal Vv respectively, and its output signal Vv ', Vi ' link to each other with second-order bandpass filter B, D respectively.(v) link to each other with effective value testing circuit 1 with zero passage comparator circuit 1 simultaneously, second-order bandpass filter D output signal V's second-order bandpass filter B output signal V (i) links to each other with effective value testing circuit 2 with zero passage comparator circuit 2 simultaneously.The MCU microcontroller sends the Fclk signal through the PWM port and links to each other with two-way programmable filter external clock input port.I/V change-over circuit output signal Vi links to each other A/D converter C in low-pass filter output signal Vi (R) and the amplitude detection circuit simultaneously with the low-pass filter input end 3Port connects.

Above-mentioned phase difference detecting circuit is made up of zero passage comparator circuit 1,2 and FPGA, and wherein FPGA can be reduced to the combinational logic circuit that XOR gate, d type flip flop, register, counter module, SPI module and clock module are formed.(v), V (i) is connected 1 output signal Vv (p) while and XOR gate input end I of zero passage comparator circuit to zero passage comparator circuit 1,2 input ends with AC signal V respectively 2Clk is connected with the d type flip flop input end, 2 output signal Vi (p) whiles and XOR gate input end I of zero passage comparator circuit 1D is connected with the d type flip flop input end.XOR gate output signal V (P) links to each other with the counter module input end, and clock module is that counter module provides clock signal Fclk '.D type flip flop output signal V (A) is connected with the register input end.During test; AC signal V (v), changes square-wave signal Vv (p) and Vi (p) into behind V (i) the process zero passage comparator circuit; As signal Vv (p) and Vi (p) when level is inequality; The signal V (P) of XOR gate output is a high level, so the time T of high level is input signal V (v), the time of V (i) phase phasic difference just in signal V (P) one-period.Enabling counting device module picks up counting when V (P) is high level, and V (P) becomes low level hour counter module and stops timing.Wherein when d type flip flop output signal V (A) be that explanation signal V (i) is ahead of V (v), signal V (A) is to explain that signal V (i) lags behind V (v) for high level for low level.After measuring end, counter module and register are given the SPI module counter value and signal V (A) level information through bus transfer respectively, and the SPI module is given the MCU microcontroller data transmission through the SPI1 interface then.

Above-mentioned amplitude detection circuit is by effective value testing circuit 1,2, and low-pass filter circuit 1,2 and A/D converter are formed.(v), Vv's effective value testing circuit 1,2 input ends (i) is connected with signal V respectively.The output signal Vv (M) of effective value testing circuit 1,2 is connected with low-pass filter circuit 1,2 input ends respectively with Vi (M).A/D converter C 1, C 2And C 3Port is connected with low-pass filter output signal Vi (R) with low-pass filter circuit 1,2 output signal Vv (M) ', Vi (M) ' respectively.During measurement, AC signal V (i), V are (v) through changing into and equal-sized direct current signal Vv of its effective value (M) ' and Vi (M) ' after effective value testing circuit 1,2 and the filtering.A/D converter is to signal Vv (M) ' and Vi (M) ' does, and (v) the amplitude data transmission is given the MCU microcontroller, and the MCU microcontroller promptly can obtain fuel cell AC impedance amplitude ratio through the ratio that calculates two-way amplitude data V (i), V through the SPI2 interface after the analog to digital conversion; A/D converter can obtain the DC current size of fuel cell pile output through the direct current signal Vi (R) of sampling low-pass filter output.

Above-mentioned MCU microcontroller links to each other with phase difference detecting circuit, amplitude detection circuit and keyboard and liquid crystal display respectively through SPI1, SPI2, I/O EBI, and passes through the frequency and the current value of the program control alternating current source output current signal of the total line traffic control of CAN.The MCU microcontroller of a plurality of ac impedance measurements unit links to each other through the CAN bus can form the CAN network, can measure any multi-disc fuel cell pack.

The utility model circuit is succinct, clear, and reliability is high, and cost is moderate, and measuring accuracy is high, speed is fast, and the needs that fuel cell AC impedance real-time high-precision is tested are satisfied in rich interface and easy expansion.

Description of drawings

Fig. 1 is the structural principle block diagram of the utility model.

Embodiment

Below in conjunction with accompanying drawing the utility model is done further detailed description.

The utility model is formed (Fig. 1) by program control alternating current source, capacitance, prime amplifier, I/V change-over circuit, low-pass filter, two-way programmable filter, phase difference detecting circuit, amplitude detection circuit, keyboard and liquid crystal display and MCU microprocessor; Parallelly connected with the fuel cell pack output terminal behind the wherein program control alternating current source serial connection capacitance, the MCU microcontroller is through the current signal of the total line traffic control ac current source output of CAN different frequency; The prime amplifier input end links to each other with each monocell in the fuel cell pack and gathers each monolithic battery combined-voltage signal, the I/V change-over circuit collection fuel cell ac and dc current signal that links to each other with the output terminal of current sensor, the AC signal V that is gathered i, V v(v), V's AC signal V that obtains after the filtering of process two-way programmable filter (i) links to each other with amplitude detection circuit with phase difference detecting circuit simultaneously; The MCU microcontroller through SPI1, SPI2 interface respectively with phase detecting circuit in FPGA and the amplitude detection circuit A/D converter communicate by letter; The MCU microcontroller can obtain the AC impedance amplitude and the phase differential of fuel cell different frequency through computing; And pass through the I/O bus transfer to keyboard and liquid crystal display, finally can obtain the fuel cell ac impedance spectroscopy.Single ac impedance measurement unit can be tested 16 fuel cell 1kHz~100kHz AC impedance data at most simultaneously.A plurality of ac impedance measurements unit links to each other through the CAN network can realize that the whole detection device circuit is succinct, clear to the high precision measurement of any sheet fuel cell AC impedance, and reliability is high, and cost is lower, and extensibility is strong.

Fuel cell output signal V in the prime amplifier of the utility model 0, V 1With two-way relay L 1Input end connects, V 1, V 2With two-way relay L 2Input end connects, by that analogy V 15, V 16With two-way relay L 16Connect, decoder output 16 tunnel level signals are received 16 relay control ends respectively.The MCU microcontroller is through 4 road I/O mouths output, 0000 to 1111 level signal control 4-16 code translator 74HC154 relay gate L successively 1-L 16, each has only a relay to be in on-state constantly, makes the monolithic fuel cell export signal V n, V N-1(n=1,2 ... 16) by gating, and link to each other with the differential amplifier circuit input end.The differential amplifier circuit of being made up of differential amplifier INA106 and tight amplifier AD826 is to input signal V n, V N-1(n=1,2 ... 16) carry out the differential type amplification, wherein the AC signal enlargement factor is 100 times, and can detect minimum ac voltage is 0.1mv (RMS), and highest frequency is 100kHz, and wherein two-way relay control forward voltage is 5V.

The two-way programmable filter of the utility model is made up of the LTC1264 of Linear Tech chip and peripheral circuit; Wherein peripheral circuit is designed by the FilterCAD filter-design software; Be to guarantee that it is 0.1% precision resistance that filter effect, the resistance of peripheral circuit are all selected precision for use.When the two-way programmable filter is worked; The MCU microcontroller is that LTC1264 provides a clock signal Fclk through the PWM port; Its frequency is 20 times of filter center frequency, and the highest filter center frequency of wave filter can reach 250kHz, and maximum filtering amplitude can reach power supply supply voltage ± 5v.Through after the filtering, (v), V (i) noise is less, makes things convenient for the detection of late-class circuit, improved measuring accuracy for output signal V.

That FPGA selects for use in the phase difference detecting circuit of the utility model is the EP2C5T144C8N of ALTERA company, and used clock is 50M.The zero passage comparator circuit is made up of the LM3116 of TI company.During test, suppose the counter module counter value be T, when program control alternating current source output current signal frequency is f, the MCU microcontroller can obtain fuel cell AC impedance phase data through calculating:

Δ phase=360*T*f/Fclk ', wherein Fclk ' is the frequency of FPGA crystal oscillator.

When test frequency was 100kHz to the maximum, FPGA Measurement Phase precision did

100kHz/50M*360=0.72 degree.

When the test frequency minimum was 1kHz, FPGA Measurement Phase precision did

1kHz/50M*360=0.0072 degree.

Effective value testing circuit 1,2 is made up of AD637 of ADI company and peripheral circuit in the amplitude detection circuit of the utility model, and it can convert AC signal and the equal-sized d. c. voltage signal of its effective value into.Vary in size according to input signal, AD637 input signal bandwidth can reach 8M, and wherein working as the input signal effective value is 200mV, and frequency input signal reaches as high as 600kHz.Low-pass filter circuit is the second-order low-pass filter that accurate amplifier AD826 and peripheral circuit are formed, and its design is 1kHz by frequency.A/D converter is made up of 16 8 passage ADC chip TLC3548 of TI company and peripheral circuit; TCL3548 through the SPI1 interface the AC signal V that is gathered (v), V (i) amplitude data VMG1; VMG2 is transferred to the MCU microcontroller, and the MCU microcontroller can obtain fuel cell AC impedance amplitude than data through the ratio that calculates two-way amplitude data:

|Z|=VMG1/VMG2。

The MCU microcontroller of the utility model links to each other with phase difference detecting circuit, amplitude detection circuit and keyboard and liquid crystal display respectively through SPI1, SPI2, I/O EBI, and passes through the frequency and the current value of the program control alternating current source output current signal of the total line traffic control of CAN.The MCU microcontroller of a plurality of ac impedance measurements unit links to each other through the CAN bus can form the CAN network, can measure any multi-disc fuel cell pack.After detecting end, the MCU microcontroller finally can obtain the fuel cell AC impedance through calculating:

Z=|VMG1/VMG2|cos(Δphase)+j|VMG1/VMG2|sin(Δphase)。

Can measure the AC impedance of fuel cell different frequency through changing program control alternating current source output frequency in the test, finally can obtain monolithic fuel cell ac impedance spectroscopy.That wherein the MCU microcontroller is selected for use is the PIC18F458 of MICROCHIP company.

Should explain that at last the enforcement of the utility model only is used to technical scheme is described and is unrestricted.All do not break away from the modification and the replacement of the spirit and the scope of the utility model technical scheme, and it all should be encompassed in the middle of the claim scope of the utility model.

The content of not doing in this instructions to describe in detail belongs to this area professional and technical personnel's known prior art.

Claims (5)

1. ac impedance measurement device that is applicable to fuel cell; Comprise program control alternating current source, capacitance, prime amplifier, I/V change-over circuit, low-pass filter, two-way programmable filter, phase difference detecting circuit, amplitude detection circuit, keyboard and liquid crystal display and MCU microprocessor; It is characterized in that: parallelly connected with load and fuel cell pack output terminal behind the program control alternating current source serial connection capacitance, the MCU microcontroller is through the current signal of the program control alternating current source output of the total line traffic control of CAN different frequency; The prime amplifier input end links to each other with each monocell in the fuel cell pack, gathers each monolithic battery combined-voltage signal; The I/V change-over circuit links to each other with the output terminal of current sensor, gathers fuel cell ac and dc current signal; The AC signal that obtains after the signal process two-way programmable filter filtering of being gathered links to each other with amplitude detection circuit with phase difference detecting circuit simultaneously; The MCU microcontroller through SPI1, SPI2 interface respectively with phase detecting circuit in FPGA and the amplitude detection circuit A/D converter be connected; The MCU microcontroller obtains fuel cell different frequency AC impedance amplitude and phase data through computing; And pass through the I/O bus transfer to keyboard and liquid crystal display, finally obtain the fuel cell ac impedance spectroscopy.
2. a kind of ac impedance measurement device that is applicable to fuel cell as claimed in claim 1 is characterized in that: prime amplifier is by 16 two-way relays, and 4-16 code translator and differential amplifier circuit are formed, fuel cell output voltage signal V 0, V 1Be connected V with two-way relay L1 input end 1, V 2With two-way relay L 2Input end connects, by that analogy, and V 15, V 16With two-way relay L 16Connect; 4-16 code translator output signal is received 16 relay control ends respectively; The MCU microcontroller is through I/O mouth control 4-16 code translator relay gate L successively 1~L 16, each has only a relay to be in on-state constantly, makes the monolithic fuel cell export signal V n, V N-1By gating, n=1 wherein, 2 ... 16, and link to each other with the differential amplifier circuit input end.
3. a kind of fuel cell ac impedance measurement device that is applicable to as claimed in claim 1; It is characterized in that: the two-way programmable filter is made up of 4 second-order bandpass filter A, B, C, D, and wherein second-order bandpass filter A and B, C and D can form two quadravalence Butterworth BPF.s respectively; Second-order bandpass filter A, C input end link to each other with I/V change-over circuit output signal Vi with prime amplifier output signal Vv respectively, and its output signal Vv ', Vi ' link to each other with second-order bandpass filter B, D respectively; (v) link to each other with effective value testing circuit 1 with zero passage comparator circuit 1 simultaneously, second-order bandpass filter D output signal V's second-order bandpass filter B output signal V (i) links to each other with effective value testing circuit 2 with zero passage comparator circuit 2 simultaneously; The MCU microcontroller sends the Fclk signal through the PWM port and links to each other with two-way programmable filter external clock input port; I/V change-over circuit output signal Vi links to each other A/D converter C in low-pass filter output signal Vi (R) and the amplitude detection circuit simultaneously with the low-pass filter input end 3Port connects.
4. fuel cell ac impedance measurement device as claimed in claim 1; It is characterized in that: phase difference detecting circuit is made up of zero passage comparator circuit 1,2 and FPGA, and wherein FPGA is reduced to the combinational logic circuit that XOR gate, d type flip flop, register, counter module, SPI module and clock module are formed; (v), V (i) is connected zero passage comparator circuit 1,2 input ends with AC signal V respectively; Zero passage comparator circuit 1 output signal Vv (p) is connected with d type flip flop input end Clk with XOR gate input end I2 simultaneously, 2 output signal Vi (p) whiles and XOR gate input end I of zero passage comparator circuit 1D is connected with the d type flip flop input end; XOR gate output signal V (P) links to each other with the counter module input end, and clock module is that counter module provides clock signal Fclk '; D type flip flop output signal V (A) is connected with the register input end, and register sum counter module is connected with the SPI module through bus.
5. fuel cell ac impedance measurement device as claimed in claim 1; It is characterized in that: amplitude detection circuit is by effective value testing circuit 1, effective value testing circuit 2; Low-pass filter circuit 1, low-pass filter circuit 2 and A/D converter are formed, and (v), V (i) is connected with signal V respectively for effective value testing circuit 1, effective value testing circuit 2 input ends; The output signal Vv (M) of effective value testing circuit 1, effective value testing circuit 2 is connected with low-pass filter circuit 1, low-pass filter circuit 2 input ends respectively with Vi (M); A/D converter C 1, A/D converter C 2With A/D converter C 3Port is connected with low-pass filter output signal Vi (R) with low-pass filter circuit 1 output signal Vv (M) ', low-pass filter circuit 2 output signal Vi (M) ' respectively.
CN2011204269396U 2011-11-01 2011-11-01 Alternating current (AC) impedance testing device suitable for fuel cells CN202305673U (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103018562A (en) * 2012-12-05 2013-04-03 上海电机学院 Synchronous multi-frequency impedance measurement method and device
CN104635050A (en) * 2013-11-08 2015-05-20 瑞昱半导体股份有限公司 Impedance detection device and method
CN105675995A (en) * 2016-02-01 2016-06-15 凯迈(洛阳)电子有限公司 Embedded multi-channel automatic resistance measurement module
CN106483469A (en) * 2016-09-30 2017-03-08 成都英诺科技咨询有限公司 A kind of circuit improving battery testing flux, device and method
CN106526321A (en) * 2015-09-15 2017-03-22 日置电机株式会社 Impedance measuring device and impedance measuring method
CN106597109A (en) * 2016-11-29 2017-04-26 同济大学 Battery AC impedance measurement circuit and method
CN106847202A (en) * 2016-12-06 2017-06-13 昆山龙腾光电有限公司 Signal processing circuit, display device and its control method
CN109799392A (en) * 2019-02-26 2019-05-24 福建星云电子股份有限公司 A kind of lithium battery AC internal Resistance test method
CN109884532A (en) * 2019-03-06 2019-06-14 郑州大学 A kind of power grid energy-storage battery detection device and detection method

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103018562A (en) * 2012-12-05 2013-04-03 上海电机学院 Synchronous multi-frequency impedance measurement method and device
CN103018562B (en) * 2012-12-05 2014-12-17 上海电机学院 Synchronous multi-frequency impedance measurement method and device
CN104635050A (en) * 2013-11-08 2015-05-20 瑞昱半导体股份有限公司 Impedance detection device and method
CN104635050B (en) * 2013-11-08 2017-06-09 瑞昱半导体股份有限公司 Impedance detection apparatus and method
CN106526321A (en) * 2015-09-15 2017-03-22 日置电机株式会社 Impedance measuring device and impedance measuring method
CN105675995A (en) * 2016-02-01 2016-06-15 凯迈(洛阳)电子有限公司 Embedded multi-channel automatic resistance measurement module
CN106483469A (en) * 2016-09-30 2017-03-08 成都英诺科技咨询有限公司 A kind of circuit improving battery testing flux, device and method
CN106597109A (en) * 2016-11-29 2017-04-26 同济大学 Battery AC impedance measurement circuit and method
CN106847202A (en) * 2016-12-06 2017-06-13 昆山龙腾光电有限公司 Signal processing circuit, display device and its control method
CN106847202B (en) * 2016-12-06 2020-04-24 昆山龙腾光电股份有限公司 Signal processing circuit, display device and control method thereof
CN109799392A (en) * 2019-02-26 2019-05-24 福建星云电子股份有限公司 A kind of lithium battery AC internal Resistance test method
CN109884532A (en) * 2019-03-06 2019-06-14 郑州大学 A kind of power grid energy-storage battery detection device and detection method

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Granted publication date: 20120704

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