Disclosed herein are optical stacks that are stable to light exposure by incorporating one or more UV-blocking layers.

Hundreds of thousands of concrete bridges and hundreds of billions of tons of concrete require characterization with time for corrosion. Accordingly, protocols for rapid testing and improved field characterization systems that automatically triangulate electrical resistivity and half-cell corrosion potential measurements would be beneficial allowing discrete/periodic mapping of a structure to be performed as well as addressing testing for asphalt covered concrete. Further, it is the low frequency impedance of rebar in concrete that correlates to corrosion state but these are normally time consuming vulnerable to noise. Hence, it would be beneficial to provide a means of making low frequency electrical resistivity measurements rapidly. Further, prior art techniques for electrical rebar measurements require electrical connection be made to the rebar which increases measurement complexity/disruption/repair/cost even when no corrosion is identified. Beneficially a method of determining the state of a rebar without electrical contact is taught.

A circuit arrangement for resistance measurement comprises a capacitor coupled between a first potential node and a second potential node, a pair of terminals that comprises a first terminal and a second terminal, the first and second terminals being coupleable to one of the at least one resistor. The circuit arrangement further comprises a set of circuit branches comprising a first circuit branch, a second circuit branch, a third circuit branch and a fourth circuit branch, each comprising a switch switchable between a conductive state and an insulating state. The circuit arrangement further comprises the first terminal being coupled to the first potential node via the first circuit branch and the second circuit branch being connected in parallel. The circuit arrangement further comprises the second terminal being coupled to the second potential node via the third circuit branch and the fourth circuit branch being connected in parallel.

In a driver circuit having a signal generator, end stage and amplitude control, the signal outputs an analog signal to a signal input of the end stage, with an amplitude predetermined by an amplitude control value. A load output of the end stage is connected with a voltage measurement input of the amplitude control providing a load current having an electrical current level dependent on an electrical input signal applied on signal input and a load voltage having a voltage level dependent on the electrical current level of the load current. The amplitude control ascertains an amplitude deviation between actual and desired amplitude values for ascertaining an indicator value, which signals that a magnitude of a measurement voltage input is too high, if a threshold value has been exceeded and, if so, to ascertain an amplitude control value lessening further amplitude control values outputted to the amplitude control input.

In a driver circuit having a signal generator, end stage and amplitude control, the signal outputs an analog signal to a signal input of the end stage, with an amplitude predetermined by an amplitude control value. A load output of the end stage is connected with a voltage measurement input of the amplitude control providing a load current having an electrical current level dependent on an electrical input signal applied on signal input and a load voltage having a voltage level dependent on the electrical current level of the load current. The amplitude control ascertains an amplitude deviation between actual and desired amplitude values for ascertaining an indicator value, which signals that a magnitude of a measurement voltage input is too high, if a threshold value has been exceeded and, if so, to ascertain an amplitude control value lessening further amplitude control values outputted to the amplitude control input.

Various aspects of the disclosure relate to evaluating the electromagnetic impedance characteristics of a material under test (MUT) over a range of frequencies. In particular aspects, a system includes: an electrically non-conducting container sized to hold the MUT, the electrically non-conducting container having a first opening at a first end thereof and a second opening at a second, opposite end thereof; a transmitting electrode assembly at the first end of the electrically non-conducting container, the transmitting electrode assembly having a transmitting electrode with a transmitting surface; and a receiving electrode assembly at the second end of the electrically non-conducting container, the receiving electrode assembly having a receiving electrode with a receiving surface, wherein the receiving electrode is approximately parallel with the transmitting electrode, and wherein the transmitting surface of the transmitting electrode is larger than the receiving surface of the receiving electrode.

Various aspects of the disclosure relate to evaluating the electromagnetic impedance characteristics of a material under test (MUT) over a range of frequencies. In particular aspects, a system includes: an electrically non-conducting container sized to hold the MUT, the electrically non-conducting container having a first opening at a first end thereof and a second opening at a second, opposite end thereof; a transmitting electrode assembly at the first end of the electrically non-conducting container, the transmitting electrode assembly having a transmitting electrode with a transmitting surface; and a receiving electrode assembly at the second end of the electrically non-conducting container, the receiving electrode assembly having a receiving electrode with a receiving surface, wherein the receiving electrode is approximately parallel with the transmitting electrode, and wherein the transmitting surface of the transmitting electrode is larger than the receiving surface of the receiving electrode.

Disclosed herein are a test wiring structure, a test apparatus and a test system. The test wiring structure includes sequentially cascaded signal wirings. Each signal wiring includes a first interface and a second interface respectively located at the two ends of the signal wiring, and a cascade interface disposed on the signal wiring. In the sequentially cascaded signal wirings, the first interface and the second interface of a previous-stage signal wiring are respectively connected to the cascade interfaces of corresponding signal wirings in next-stage signal wirings. Moreover, the cascade interface of a first-stage signal wiring is used to connect to a test pad, and the first interfaces and the second interfaces of last-stage signal wirings are respectively used to connect to corresponding display panels.

Hundreds of thousands of concrete bridges and hundreds of billions of tons of concrete require characterization with time for corrosion. Accordingly, protocols for rapid testing and improved field characterization systems that automatically triangulate electrical resistivity and half-cell corrosion potential measurements would be beneficial allowing discrete/periodic mapping of a structure to be performed as well as addressing testing for asphalt covered concrete. Further, it is the low frequency impedance of rebar in concrete that correlates to corrosion state but these are normally time consuming vulnerable to noise. Hence, it would be beneficial to provide a means of making low frequency electrical resistivity measurements rapidly. Further, prior art techniques for electrical rebar measurements require electrical connection be made to the rebar which increases measurement complexity/disruption/repair/cost even when no corrosion is identified. Beneficially a method of determining the state of a rebar without electrical contact is taught.

Various aspects of the disclosure relate to evaluating the electromagnetic impedance characteristics of a material under test (MUT) over a range of frequencies. In particular aspects, a system includes: an electrically non-conducting container sized to hold the MUT, the electrically non-conducting container having a first opening at a first end thereof and a second opening at a second, opposite end thereof; a transmitting electrode assembly at the first end of the electrically non-conducting container, the transmitting electrode assembly having a transmitting electrode with a transmitting surface; and a receiving electrode assembly at the second end of the electrically non-conducting container, the receiving electrode assembly having a receiving electrode with a receiving surface, wherein the receiving electrode is approximately parallel with the transmitting electrode, and wherein the transmitting surface of the transmitting electrode is larger than the receiving surface of the receiving electrode.