Methods for realizing high sensitivity for a frequency-change-type single-crystal silicon two-axis acceleration sensor are proposed. The volume of the prototype sensor is about 4.0 x 4.2 x 0.5 mm(3) and the resonance frequency is approximately 80kHz. The sensor characteristics are analyzed using the finite-element method. Selecting the axis to apply the acceleration and using bent support bars are both effective methods to increase sensor sensitivity. The sensitivity increases 42% when the sensor is rotated and used under the condition of theta(z) = -45 degrees. Using the bent support bars and rotating the sensor around the z-axis, a 100% increase in sensitivity was finally obtained in a sensor which has the mass equal to that of the prototype sensor. On the other hand, a 56% increase was finally realized in the sensor which has the outside-dimension equal to that of the prototype sensor.

We report a case in which bilateral occipital brain metastases and neoplastic cerebral aneurysms developed from primary cardiac malignant fibrous histiocytoma. The origin of metastases was confirmed at autopsy. The clinical presentation, radiographic features, and autopsy findings are presented along with a histopathologic analysis of the tumor.