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能够替代钻石、黄金、铂金的最廉价的珠宝有哪些?

钻石:玻璃

黄金:铝青铜、北欧金(不能用于首饰)

铂金:钛钢

瓷器:还是瓷器

丝绸:涤纶

书画:激光照排印刷

还有吗?
我来自火星,一颗美丽的星球!
立方氧化锆,不是最廉价,但是最像
山不走到我这里来,我就到它那里去。
本帖最后由 Manaus 于 2018-5-3 16:57 编辑

最近以358元的价格在某宝上买了一只机械表,每天都快30秒,一直很好奇金色的金属成份是什么?

表圈、按钮是金色。表链(表带)是银色间金色。表圈和表链(表带)肯定是金属,按钮可能是金属也可能是塑料











黄金:铝青铜、北欧金(不能用于首饰)
欧元区 发表于 2018-4-28 22:55
两种都是铜的合金。看来我的手表应该有铜成份。很合理,因为铜有黄铜青铜之分
立方氧化锆,不是最廉价,但是最像
剪径者 发表于 2018-5-3 10:07
最像的应该是莫桑石、HPHT钻和CVD钻
作为人类学领域的重要器物,和田玉有没有非透闪石类的廉价的替代品?先秦不是有不属于透闪石玉的和氏璧吗?
我来自火星,一颗美丽的星球!
关于金(银、铜)缕玉衣、黄金(白银、铜)面具、金(银)缕衣、朱砂等重金属的杀菌防腐作用,还有玉、宝石什么的,有些有夜光效果(假如含放射性元素,就更持久了),常常是因为有辐射,而这也是能杀菌的,古人很早就对此有了认识,所以有制作木乃伊并用金属护身的传统,也可证明古人在金属化学、辐射化学、生物药学方面其实已经积累了很深的经验认识?最早产生冶金和利用贵金属与宝石的地方,有没可能是上一次核大战的遗民的所在。


Archaeologists solve mystery of 150-year-old remains of a baby found with one MUMMIFIED hand: Study reveals child was buried clutching a coin that protected flesh from decay
  • Dried up, flesh-covered forearm was found alongside other skeletal remains
  • Extremely high copper levels indicated it came in contact with the metal
  • But, until recently, researchers had no other evidence of the object in question
  • Researchers say it may be one of the first known cases of copper mummification
By Cheyenne Macdonald For Dailymail.com
Published: 20:05 BST, 22 May 2018 | Updated: 21:18 BST, 22 May 2018


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Roughly 13 years ago, archaeologists examining remains from a dig in southern Hungary stumbled upon something truly bizarre.
Inside a forgotten storage box, the team uncovered a set of human bones so tiny they may have belonged to a rat – and, with the skeleton was a single mummified hand.
The dried up, flesh-covered forearm was stained green down to the bone, as were some of the vertebrae, a hip bone, and the leg bones, according to the NY Times.
Now, more than a decade after the remains were rediscovered, researchers may finally have solved the mystery of the mummified hand; additional artifacts held at a nearby museum indicate the baby was buried holding a copper coin.

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Inside a forgotten storage box, the team uncovered a set of human bones so tiny they may have belonged to a rat – and, alongside the skeleton was a single mummified hand, seen on the left side of the image above

The remains were found with more than 500 graves discovered at a cemetery in Nyárlőrinc, Hungary, all dating back to the 12-16th centuries.
But, the burial containing the mummified hand was unlike all the others.
The child likely measured just 11 to 13 inches and only weighed up to two pounds, indicating it was either a stillbirth or premature baby, according to János Balázs, who analyzed the bones, NY Times reports.
While the discoloration and unusual ‘quasi-natural mummification’ suggested the body came in contact with some sort of metal, no such object was found in the box of bones.
A chemical analysis, however, revealed extremely high copper levels compared to the surrounding environment, and several hundred times higher than average.

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The dried up, flesh-covered forearm was stained green down to the bone, as were some of the vertebrae, a hip bone, and the leg bones. Two angles of the mummified hand are pictured above

In the study, published to the journal Archaeological and Anthropological Sciences, the researchers say the ‘posture of the fingers and very high Cu concentration values around the hip refer to a copper coin having been placed in the right palm.’
‘Nearby soft tissues (right hand and forearm, lower trunk, hips) were possible exposed to the highest level of copper infiltration in the entire study resulting in quasi-natural mummification of the affected body parts,’ the researchers continue.
‘As we move further away from the corroded copper coin, superficial copper concentrations gradually decrease in the remains.’
With no coin present, though, the strange mummification remained a mystery for roughly a decade – until one day, the researcher discovered more storage boxes from the site, contained at a nearby museum, according to NY Times.


The coin dates back to a period from 1858 to 1862, indicating that the child was buried long after the Medieval remains found at the same site

HOW DOES COPPER CAUSE MUMMIFICATION?The unusual remains of a baby buried 150 years ago have shed new light on the bizarre effects of copper on a decomposing body.
While the remains were almost entirely skeletonized, the body contained a single mummified hand.
Further analysis revealed the child was buried clutching a copper coin, which protected some body parts from decay.
‘Copper compounds often cause superficial green coloration on human remains,’ the authors wrote in a study about the discovery.
‘Soluble copper may also penetrate soft tissues and bones.’


While the discoloration and unusual ‘quasi-natural mummification’ suggested the body came in contact with some sort of metal. A later-discovered copper coin finally helped researchers solve the mystery

Flesh and discoloration could be seen in the areas closest to the copper; the dried up, flesh-covered forearm was stained green down to the bone, as were some of the vertebrae, a hip bone, and the leg bones.
The copper levels seen in the remains were several hundred times higher than average, according to the researchers.
‘While copper is essential for the functioning of some human enzymes, it is also known to have antimicrobial character and its compounds have been used as fungicides and bactericides for many years,’ the researchers explain.
Still, the process of ‘copper-driven quasi-natural mummification’ has not been documented, and this may be the first reported case.

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Inside these boxes, Dr. Balázs found a corroded copper coin and a small ceramic pot, in which the tiny body was likely buried.
The analysis suggests the body was ‘surrounded by a moist microenvironment in the pot,’ the authors write, ‘where gradual diffusion of soluble copper originating from the coin was facilitated for a longer period of time, and this relatively isolated setting did not allow complete decay of the little dead body.’
The coin dates back to a period from 1858 to 1862, indicating that the child was buried long after the Medieval remains found at the same site.
While it wasn’t customary for Christians of that era to bury the dead with coins, the child likely died before baptism, according to NY Times, and was given the token to assist the journey to the afterlife.
The remarkable remains are now on display at Hungary’s Móra Ferenc Museum.

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Inside additional boxes found at a nearby museum, Dr. Balázs found a corroded copper coin and a small ceramic pot, in which the tiny body was likely buried


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Read more: http://www.dailymail.co.uk/sciencetech/article-5759063/Archaeologists-solve-mystery-150-year-old-remains-baby-one-mummified-hand.html#ixzz5GIdaEfBm
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本帖最后由 癯鹤 于 2018-5-23 14:20 编辑

天人感应每如此,寒士说多都是累。卖家卖地纳身奴,对此如何不泪垂:
宰相定远拆棚户,司农龙江转基因!据悉化工石鼓繁,诶唉动脑恸吾心!

呜呼,我化学人怎么这么点背命苦哟!咱还没能由化学人转化为文化人呢!不要这么急呀!在哀鸿遍野之前,先天下之忧而忧,在咱们奥陶纪嚎啕一番:


AI将“触手”伸向合成化学 脑力劳动还是人类专长吗?


2018年05月23日 09:46新浪科技综合
缩小字体放大字体收藏微博微信分享2腾讯QQQQ空间



  来源:Nature自然科研
  原文以AI designs organic syntheses为标题
  发布在2018年3月28日的《自然》新闻与观点上
  原文作者:Derek Lowe
  为合成化学设计有效合成路线的软件一直依赖于研究者的规则输入。现在有报道称人工智能程序系统可以自己学习相关规则。
  合成有机化学是一门关于从简单的分子着手构建所需化学结构的科学。研究者的学识和经验一直是构建成功的合成路线的关键。但在《自然》发表的一篇论文中(论文免费阅读链接:https://rdcu.be/OQBL),Segler 等人报道称:一款人工智能程序可以设计化合物合成路线,而且效果至少在理论上与由人类设计的不相上下。
  在设计合成路线时,有机化学家常常需要使用逆向思维。上世纪60年代,E。 J。 Corey提出逆向合成的概念,并因此荣获1990年的诺贝尔化学奖。逆向合成为化学家们提供了特定的思维方式(图1)。在观察目标分子时,他们会问:“这个化合物能从什么原料制得?要形成哪些键?哪些原子或化学基团可以增加或转化?”然后,重复该过程,直到得到前体分子。这样做的目的是反推得到易获取的起始化合物,同时平衡好构成良好合成路线的各种因素,包括反应的步数、预计的产率以及所涉及的化学物质的易用性。有机化学家们经常要处理这些问题,例如在药物发现项目中制备大量化合物用于测试。
  图1|逆合成分析。化学家使用被称为逆向合成的策略来设计有机分子合成的路线。a,首先设计一个理论路线,将目标分子依次转换成易制备或可购买的中间体。在这个例子中,目标分子中的红色键和原子可以从中间体分子中的红色双键得到。接下来,中间体的红色双键和蓝色键可以通过两个可直接购买的原料一步得到(Et是乙基的缩写)。b,然后选择反应将原料转化为目标分子:在上面的例子中,使用狄尔斯-阿尔德反应得到中间体,随后通过金属催化氧化获得目标分子。Segler等人报道的人工智能程序可以通过自行推断设计规则,来为分子设计合理的合成路线。
  自19世纪中叶合成有机化学诞生以来,已有大量的合成有机反应被报道,且其数量每时每刻都还在增长。20世纪80年代之前,许多化学家通过收集记载了文献中有用反应的、交叉引用的手写索引卡片,来指导设计合成路线。随着计算机技术的普及,这些索引卡片自然地移动到数字数据库中。
  近年来,当化学家想了解将官能团X转变为官能团Y的各种方法时,他们会先使用计算机程序来绘制感兴趣的分子结构,然后在线搜索相关反应。这几乎总是会产生一个长长的清单,研究人员需要根据其知识和经验来选择最合适的反应。一直以来,把这些反应串成一种有用的合成方法被认为只有人类才能做到。
  但一定要这样做才行吗?是否有一个程序能够基于一个足够大并精心制作的化学反应数据库,不仅可以找到反应还能将它们编排成合理的合成路径呢?从上世纪60年代Corey提出逆向合成以来,人们就一直在试图找到这样的程序,但几无进展(直到最近)。
  两个根本问题使该梦想受挫。首先,计算机硬件无法处理这一量级的挑战。第二,化学文献很难用软件程序所能理解的术语来定义:对于给定的反应,它们大部分时间都适用于某种化合物类型,但仅在某些特定条件下才真正适用。例如,官能团X将变成官能团Y,除非官能团Z存在于反应物分子的其他地方。当官能团Z存在时,如果官能团Q与其在同一个分子的附近,则反应可能仍然有效,但仅当pH低于某个值或温度足够高或无水时,这些才会成立。
  克服第二个问题的方法多种多样。一是为程序提供一份人为制定的可实现预期化学转化反应的详尽列表,把所有的限制和条件都考虑在内。然后,程序利用一种类似于评估国际象棋招式组合的方式,将这些反应组合起来得到合成路线。这种方法已取得一定成效,市场上已有几个相互竞争的商业软件产品。
  Segler等人研究了另一种方法:可不可以设计一个可以自行学习研究人员所知知识的程序,从而代替研究人员把专业知识加载到机器上的过程呢?这个概念已经产出了惊人的结果,已有程序可以自行学习玩游戏,如围棋,而不是使用人的策略来训练它们。
  作者设计了一个计算程序,它可以自动从一个大型商业数据库中提取化学转化反应,并谨慎地使用那些报道过多次的反应。他们的系统认为这些挑出来的反应是有机合成中“可行的步骤”。当系统被要求设计一个目标分子的合成路线时,它会像人一样从目标分子开始逆向工作,根据所学的设计规则挑选出最有希望的前体分子,然后评估合成这些分子的可行性。作者将三个人工神经网络与随机蒙特卡洛树搜索(计算机在某些决策过程中使用的一种搜索算法)相结合,以缩小最有希望的合成路线范围,且不会在某一特定路径上被很快卡住。
  更重要的是,给出的路线不仅由程序的评分系统评估,还由训练有素的有机化学家对其可行性进行盲评。面对机器生成的目标分子的合成路线以及研究文献中报道的合成路线,这些化学家没有对同仁们研究得出的合成路线表现出任何的偏好。换句话说,他们认为这个程序所建议的化学反应和研究人员提出的一样合理。
  这并不一定意味着所有机器建议的路线都能在实验室中得到预期的结果;但是,正如有机化学家所抱憾的一样,许多人类设计的路线一样会失败。未来进一步的程序开发应该将这些实际结果包括在内,以确定机器提出的路线是否比人类设计的路线更好(或者至少不差)。今年,有一项评估较传统的、人工管理的逆向合成程序的研究值得注意,该研究就包含了一个类似的实验室测试部分。就Segler及其同事所做的程序而言,其设计的合成路线与研究人员做的相比“不差”就是一次重大胜利,因为其用时更少,覆盖的文献更多。
  如果这类程序达到预期——几乎没有理由认为它们做不到,那么合成化学家的一项主要工作就将消失。技术创新在过去也产生了类似的效果,但通常是取代那些没有人会怀念的繁重的体力活。令人不安的是,日益发展的人工智能正在将“触手”伸向脑力劳动。虽说总会有那些软件无法处理的、复杂而又不同寻常、前所未见的结构,但是在解决较为常规的合成问题时,研究员将被人工智能取代。
  说智力活动可以被划为能被自动化代替的繁重体力活,可能冒犯了许多化学家,并让其感觉受到威胁。但是人工智能的应用实际上会释放出更多的时间来让化学家思考更高深的问题,譬如应该合成哪些分子以及为什么,而不是把重点放在如何制备出分子的细节上。并非所有的研究人员都欢迎这种转变。但不管怎样,它似乎不可回避。



关键词 : 有机化学人工智能官能团
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