The possibility that a technical error may occur during nerve conduction studies due to ulnar nerve dislocation when the elbow is flexed has recently been suggested. We investigated normal volunteers using ultrasonography to observe the effects of ulnar nerve dislocation during elbow flexion on short-segment nerve conduction studies. We found significant conduction block in all of the subjects with ulnar nerve dislocation, and the finding was defined as a technical error caused by volume conduction. The results of the present study suggest that caution should be exercised when interpreting the results of short-segment nerve conduction studies at the across-elbow segment due to the possibility of technical error induced by ulnar nerve dislocation. GLOSSARY NCS ϭ nerve conduction study; S-NCS ϭ short-segment NCS; UNE ϭ ulnar neuropathy at the elbow. Neurology ® 2008;70:e9-e13
The dielectric properties of BaSm 2 Ti 4 O 12 ͑BST͒ and Sm 2 Ti 2 O 7 ͑ST͒ films were investigated in order to evaluate their potential for use in metal-insulator-metal ͑MIM͒ capacitors. The crystalline BST phase was formed when the film was grown at 700°C and subjected to rapid thermal annealing ͑RTA͒ at 900°C. The ST phase was formed in the film grown at 300°C and subjected to RTA at 900°C. A high capacitance density of 4.84 fF/m 2 and a low leakage current density of 4.28 fA/pF V were obtained from the BST film with a thickness of 138 nm. The BST film has the linear and quadratic coefficients of capacitance of 684 ppm/V and −295 ppm/V 2 , respectively, and a temperature coefficient of capacitance of −136 ppm/°C at 100 kHz. The ST film has a high capacitance density ͑3.47 fF/m 2 ͒ and a very low leakage current density ͑0.26 fA/pF V͒. The ST film also showed small voltage and temperature coefficients of capacitance. Therefore, both the BST and ST films are good candidate materials for MIM capacitors.Metal-insulator-metal ͑MIM͒ capacitors are important passive devices in radio frequency ͑rf͒ circuits or mixed-signal integrated circuits. MIM capacitors commonly use SiO 2 or Si 3 N 4 dielectrics because they have good voltage linearity properties and thermal stability. However, their capacitance density is very small because of their low dielectric constant ͑͒. 1,2 Recently, many investigations have been conducted into high-dielectrics in order to obtain the high capacitance density, which is essential to reduce the size of integrated circuits. An Al 2 O 3 film with a thickness of 12 nm exhibited a high capacitance density of 5.0 fF/m 2 ; however, it had a large voltage coefficient of capacitance ͑VCC͒. 3 An HfO 2 film with a thickness of 56 nm grown by pulse laser deposition showed small voltage and temperature coefficients of capacitance, but its capacitance density was relatively low. 4 An HfO 2 film deposited by magnetron sputtering showed a high capacitance density, but its VCC was not satisfactory. 5 A MIM capacitor was also produced using a film with a composition of ͑1 − x͒HfO 2 -xAl 2 O 3 and it showed a low VCC; however, its capacitance density was relatively low ͑3.5 fF/m 2 ͒. 6 An MIM capacitor made using a film with an Al 2 O 3 and HfO 2 laminate structure was grown by atomic layer deposition ͑ALD͒. Even though it had small voltage and temperature coefficients, its capacitance density was low, being approximately 3.13 fF/m 2 . 7 Pr 2 O 3 film was also reported to have a high capacitance density but exhibited a large VCC. 8 A high capacitance density of 17.0 fF/m 2 and a low leakage current of 10 −7 A/cm 2 were obtained from a MIM capacitor using a ZrO 2 film with a thickness of 12 nm, but variation of the capacitance with bias voltage and temperature has not been reported. 9 According to the International Technology Roadmap for Semiconductors ͑ITRS͒, capacitance densities of 4.0 fF/m 2 and 20-30 fF/m 2 are required for the analog and bypass capacitors that will be needed in the period from 2007 and 20...
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