乡亲们
前段时间我写了一篇文章《寻找锡须》，迈克尔在下面做了回应。他提出了一些很好的观点。
罗恩博士，我正在回复您关于锡须的博客。实际上，我有一份几年前做的失效分析报告，其中我们的产品就是因为这个问题而失效的，而且是在 3 个月前才符合 RoHS 标准的部件上发生的。
I'm not sure that your question of identifying whisker issues in product that proper steps have been taken to mitigate the problem is a constructive one. The fact is that many of the component manufacturers from overseas jumped into compliance without any thought or regard to this issue thereby flooding the industry with components such as plagued my company. We have not had this issue since we've specified an alternate finish.
These whiskers are so delicate that most problems disappear when the technician starts to work on the failed unit and the problem never re-appears so it is written off as an anomaly, loose/bad connection and not investigated any further. It was only my own curiosity as to the number of "no problem found" failures of our keypads we had suddenly encountered that caused me to dig deeper and when I looked into the connector I was amazed at the crystal city staring back at me. I couldn't believe what I was seeing after all of these years.
在亲眼目睹了这一问题之后，我深信，过去和现在都会有人因为这种强制履约及其风险没有得到全世界的适当关注而失去生命、肢体和财产。
迈克尔
A popular topic Re my blog is solder density calculations. Rhonda writes……
Hi Dr. Lasky,
I am a precious metals recycler and would very much appreciate your verifying the validity of an equation that approximates the Karat Value of various alloys of gold based on S.G. which I will call density or "D," and the Karat Value is "K." The equation is seems to hold relatively true even when the exact composition of the alloy is unknown, although the percent of error obviously will increase as density decreases. I would also appreciate not only verification but also more specific information on percent of error for densities below about 14 or 15 g/cc. Here is the equation:K = 0.0089D^3 - 0.550D^2 + 12.5299D - 77.06
非常感谢你们能提供任何帮助。
朗达
These types of equations can only work for one alloying metal with the gold. This one is only for copper. It is also calibrated in Rhonda’s favor as it reads the karat level about 10% low. I was able to determine this by using the Excel Solder Density worksheet that I developed. If the alloy was gold and lead, a 50% by weight gold (12 karat) would show as 15.7 karat with this equation and Rhonda would lose her shirt.
In response to my blog post on copperas the precursor to civilization, Harvey writes about pollution from early mining operations…..
Also interesting, early copper mining and processing led to the first examples of human induced environmental damage. There are documented sites in the Alps where copper processing by prehistoric peoples has left areas treeless to this day, due to heavy metal contamination.
哈维
在古代，采矿和冶炼是非常艰难的行业。除了污染，许多工人还死于有毒烟雾。
罗恩博士
