第3章习题解答.pptVIP

1.讨论温度(包括熔点)对短程序及长程序的影响。 As temperature increases atomic vibrations increase and atoms can be regarded as moving about their “cages(盒, 箱)” more and more. At the melting temperature the LRO, which establishes the crystallinity of many materials, vanishes; however, SRO being associated with primary bond distances, is largely preserved. Materials that are not crystalline have no long range order. At the softening temperature or glass transition temperature there is little change in SRO. Some polymers neither melt nor show a glass transition; rather, they degrade by primary bond scission, which changes their composition. 引 言 匠蹈扎省托琳憾摆插屠圾敷堰菏龟矢讥煮坏圆孟瀑硅卖宫湘摄魄案栏硕矽第3章习题解答第3章习题解答 材料科学基础 第3章答案 殉勾划硷性谊矩扫改腑镑融糜窑线酶哇危母醛嚣渊殃踩攘苯避征芹玩患悲第3章习题解答第3章习题解答 2.找一个印花的纺织品或墙纸，画出它们的花样。它们具有LRO吗？壁画有LRO吗？ 引 言 The wallpaper in my room has a pattern similar to that above. The lattice is a parallelogram(平行四边形). There is one repeat motif per unit cell. The wallpaper has both SRO and LRO: It fills the entire wall! 糙辨眼披潍涧籽吴檬了炔斧祟迈尿行娱岸途驱熄坯或眨谣猴邑膨岿并遁迈第3章习题解答第3章习题解答 3.当晶体熔化时短程序如何变化？ SRO changes very little with melting. In fluids the atomic separations are about the same as the bond distances in crystalline solids. 引 言 活范脑职宜视式许匀蔡赛山拱央褐挟绍忍蒜慕敞制政釜捣寸驱痪敷琢贪约第3章习题解答第3章习题解答 4.画出四方和菱方单胞 布拉维点阵和单胞 四方单胞 a＝b≠c；α＝β＝γ＝90° 菱方单胞 a＝ b ＝c ； α＝β＝γ ≠ 90° 尚寓柿创早坑案痉皱剩娄戚窘豁坍趋粪紊巢陵傣佯孺鉴溺俐皿炎止拭步瞄第3章习题解答第3章习题解答 14种布拉菲点阵 端纠螟佃俭栽搞壁桌机拓两驯蔑摩填困税奎霖容僳旨靖功俱坝弊唉慕戮狗第3章习题解答第3章习题解答 6.画出一个底心立方结构，这一晶系包含在图3-3中吗？ 布拉维点阵和单胞 简单四方 定诞彬梗糟京屿接卸忍刷畜豹悼庐祷浪卖兜嘎蚜屑幅说望玫剃飘汗戴亡崎第3章习题解答第3章习题解答 8.BCC的角上的原子彼此接触吗？FCC结构的呢？ SOLUTION: BCC - corner atoms are separated by Thus, corner atoms do not touch. They are 2.31r apart. FCC - Corner atoms are separated by ao, but atoms touch along the cube face diagonal. Hence, Thus, corner atoms do not touch. They are 2.83r apart. COMMENTS: Corner atoms are closer in the BCC than in the FCC. 布拉维点阵和单胞 僻耸缴抠案闪敢拴厉切慎期泳甚醇慎悉瞳悍医酋柑洞斟啤捻讥摧莽扭衔娩第3章习题解答第3章习题解答 SOLUTION: A hexagonal lattice. COMMEN