司机的难题

一天,一个出租车司机在一个偏僻的小村庄遇到了1名老师带着7名七年级学生到考场参加数学竞赛,此地距离考场15km,而离截止进考场的时刻只剩下40min,大家非常着急,已知这辆车的平均速度是60km/h,人步行     

科研与教学相结合的初步尝试与体会——乙酸乙酯制备实验的改革

高校教师在完成教学工作的同时,积极投身科研,对提高教师的业务素质,改善教学过程的软环境有着极为重要的作用。     

准备是成功的保证

有一个年轻的猎人带着充足的弹药、擦得锃亮的猎枪去寻找猎物.虽然老猎手们都劝他在出门之前先把弹药装在枪筒里,然而他还是带着空枪出发了.他嚷道:“我到达那里需要一个小时,哪怕装一百同子弹,也有的是时间.” 仿佛命运之神在嘲笑他的想法似的,他还没有走到目的地,就发现一大群野鸭密密地浮在水面上.     

Optimal Schemes of Teleportation One-Particle State by a Three-Particle General W State

Recently, Xiu et al. [Commun. Theor. Phys. 49 （2008） 905] proposed two schemes of teleporting an N particle arbitrary and unknown state when N groups of three particle general W states are utilized a.s quantum channels. They gave the maximal probability of successful teleportation. Here we find that their operation is not the optimal and the successful probability of the teleportation is not maximum. Moreover, we give the optimal schemes operation and obtain maximal successful probability for teleportation.     

Characteristics and New Measurement Method of NCSFs of Individual Color Mechanisms of Human Vision

We propose a new method for determining neural contrast sensitivity functions （NCSFs） of isolated color mechanisms based on the measurements of wave-front aberrations and isoluminant color contrast sensitivity functions （CSFs）. Compared with the traditional method, this technique avoids the coherent noise and speckle noise, which are brought by the interference of laser beams, and has great flexibility for the measurements of NCSF of different color mechanisms. Our experiments indicate that the mean NCSF and CSF of the red mechanism are higher than those of the green mechanism, respectively, while those of the blue mechanism are the lowest. However the relative heights of the peak of NCSF and CSF between red and green mechanisms vary in subjects. There are some individuals whose peak values of NCSF and/or CSF of green mechanism are higher than that of the red mechanism. The NCSFs and CSFs of isolated color mechanisms all exhibit the similar characteristics and variation tendency. With the statistical average, the NCSFs of the red, green and blue mechanisms are higher than the corresponding CSFs in the whole spatial frequency. Compared with the corresponding CSFs curves, the peaks of the NCSFs of isolated color mechanisms shift toward higher spatial frequencies, especially for that of blue mechanism which has a largest shift of 3.9 c/deg.     

日钠离子电池研发初见成效

据《日本经济新闻》2012年4月30日报道,东京理科大学薮内直明讲师、驹场慎一副教授组织的研究小组与电池专业制造商GS.YUASA公司合作,成功开发出新型钠离子蓄电池电极材料。实验表明,钠离子氧化物含有同量的铁、锰,在层结构中,钠离子作为电储存在层间,其存储量     

在四能级系统中实现单粒子及两粒子量子态的远程制备

本文提出两种协议来实现远程态制备.第一个方案描述基于两体最大纠缠信道,如何远程制备四能级系统中的任意单粒子量子态.然后由第一个方案概括出第二个方案,即在四能级系统中实现两粒子纠缠态的远程制备方案.在两种制备的过程中, 需要分别实施一个单粒子投影测量和一个两粒子投影测量.结果表明,两个方案都能以大于25%的几率忠信地实现.此外,对于两类特殊态,即赤道态和实数态,其成功概率大大提高至100%,此时我们几率的协议转变为决定性的协议.