Even though black holes are dark and invisible , it doesn ' t mean they have no effects , or extremely strong vortices and they pull matter in these swirling winds around them a lot like a tornado 即使黑洞不发光、无法看到，它仍然会留下痕迹：它会产生极强的、将物质卷入其中的、象龙卷风一样的涡流。
After the examination of pcr , one non - fluorescent cell clone had the same result as the plasmid ploxifn - a 1000bp product ; another non - fluorescent cell clone showed a 500bp product , a deletion reaction was thought to happen between the two lox sites in the genome under the reaction of cre recombinase so that the gfp gene and neo gene etc were cut 经pcr检测后，有一个不发光细胞克隆扩增出了与对照质粒ploxifn相同的约1000bp的条带，表明发生了替换反应；另一个不发光细胞克隆认为是在cre重组酶的作用下其内部自行发生了剪切作用，剪切了gfp基因，从而只扩增出了载体序列和一个lox位点的约500bp的条带。
Changed of moon phases are brough about by the non - self - luminosity and the opacity of the moon . as the moon is a spherical body , sunlight can only illuminate half of the moon . viewing from different directions , the moon will appear to take the shapes of a circle , a semi - circle , a crescent , a gibbous or even completely invisible at all when its dark side faces the earth 由于月球本身不发光，只是反射太阳光，所以当月球运转时，月球地球和太阳三者的相对位置便会不断变化，因此，地球上的观测者所见到月球被照亮的部分也在不断变化，从而产生不同的月相
We researched the influences of systhesis temperature , heat preservation time , eu + concentration , reduction surrounding feeling and flux on luminescent properties of sral2o4 : eu2 + phosphors , optimized the experiment conditions and reduced systhesis temperature about 100 c . we found that the systhesized sample ' s luminescent brightness is better with increasing systhesis temperature , but the phase component is more complex . we found that the luminescence brightness of sample appear a increasing process at first , and then a reducing one with the raise of eu2 + concentration , it indicated that the luminescence brightness is not better if the eu2 + concentration is too high or low . we found that the systhesized sample can not bright at too long heat preservation time , and the luminescence brightness is lower at too short heat preservation time . we found that particle diameter is bigger , the wavelength of emission peak is longer 研究发现合成温度高，合成样品的发光效果好，但物相组成也较复杂； eu ~ ( 2 + )离子在一定掺杂浓度范围内，合成样品的发光亮度先是出现一个提高过程，然后是一个降低过程，说明eu ~ ( 2 + )离子浓度高或低都不利于合成样品发光；保温时间较长，合成样品不发光，保温时间较短，合成样品发光效果不好，只有合适的保温时间才能合成发光效果好的样品；合成样品的粒径大小与发射峰的位置具有一定的关系，粒径越大，发射峰越偏向长波方向；助熔剂对样品的合成温度和发光性能都有影响，助熔剂的量较低时，主要表现为助熔作用，对发光影响不大，助熔剂的量较高时，使得样品发光亮度降低和余辉时间缩短；还原方式的不同，合成样品的发光性能也不一样。
After multiple , plasmid ploxifn and pbs185 dna were co - transfected into the green fluorescent cell clones , then filtrated the non - fluorescent cell clones . two non - fluorescent cell clones , the green fluorescent cell clones and the cells which were co - transfected by the plasmid ploxifn and pbsiss dna were checked up by pcr 首先将质粒ploxgfpdna电转染牛胎儿成纤维细胞，并用g418筛选，筛选出绿色荧光细胞克隆，增殖培养之后，将质粒ploxifn和pbs185dna共转染荧光细胞克隆，筛选出不发光的克隆。
The cathodoluminescence ( cl ) analysis shows the quartz reflects an abundance of brown color , blue - purple , dark blue , dull color , and no cl color for quartz overgrowth , while feldspar shows light blue , yellow - green , yellow - brown , green and brown cl colors . the calcite reflects bright orange - yellow for non - ferroan calcite and dull orange - brown cl colors for ferroan calcite 阴极发光分析证实，砂岩中石英颗粒阴极发光颜色较深，主要位棕色、蓝紫色、深蓝色，石英加大变不发光；长石颗粒阴极发光颜色主要位浅蓝色、黄绿色、绿色、棕黄色等；无铁方解石阴极发光颜色为鲜艳桔黄色，铁方解石阴极发光颜色为暗桔黄色。
