We use your earnings and work. history to determine your eligibility. for retirement or disability benefits. or your familyâs eligibility for. survivors benefits when you die. In 2016, you receive one credit for. each $1,260 of earnings, up to the. maximum of four credits per year. Each year the amount of earnings. needed for credits goes up slightly as. average earnings levels increase.
Immersion oil should only be used if you have an immersion oil lens. The lens will actually have oil, immersion or HI (homogeneous immersion) printed on it. Immersion oil is best for viewing samples that are dead or are not moving and no thicker than a few micrometers.
Polycarbonate, however, is not without its drawbacks. One of the chief complaints about polycarbonate is its optical quality, or lack thereof. With an Abbe value of 29, polycarbonate's chromatic aberration is the highest of any lens material in use today. Furthermore, with the increase in popularity of drill mount frames, some dispensers are hesitant to use polycarbonate because of its lack of tensile strength and likelihood of cracking around drill holes.