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Current property tax policies in Michigan severely constrain the ability of the City of Detroit to raise sufficient revenues, particularly in a weak economy. Almost half of the land area of the city does not contribute to the property tax effort and the valuation of the taxable properties has fallen substantially since the Great Recession. This article considers alternative definitions of the city's tax base, including taxes based on land value or land area, as well as special assessments for specific services. These reform options are found to have considerably different impacts on different classes of real property.  相似文献   
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Mixtures of beryllium and boron powders were reacted under argon at elevated temperatures. X-ray single-crystal and powder diffraction analyses, chemical analyses, and Knoop micro-hardness measurements were made. Melting-point ranges were established for compounds of reasonable purity. One compound was identified. Beryllium diboride (BeB2) had a hexagonal unit cell. Its hardness was 3180 ± 100 (Hk100) and its melting point was greater than 1970°C. Beryllium hexaboride ("BeB6") had a tetragonal unit cell, a hardness of 2577 ± 75 (Hk100), and a melting point between 2020°) and 2120°C. An anisotropic unknown phase existed whose Be: B ratio was between 6:1 and 2:1 and whose hardness ranged between 623 and 917 (Hk25), depending on orientation. A eutectic between beryllium and this unknown phase was observed at 972°± 15°C.  相似文献   
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