300万像素手机镜头设计

设计一种300万像素的手机镜头。该镜头由3片塑料非球面透镜和1个红外滤光片组成,采用三星公司的一款300万像素0.635cm(1/4inch)CMOS作为该镜头的图像传感器,像素颗粒大小为1.75μm,其分辨率极限为285lp/mm,即为奈奎斯特频率。镜头的光圈值F为2.85,视场2ω为62°。该镜头有较好的成像质量,在奈奎斯特频率1/2处绝大部分视场的MTF值大于0.5,波前均方差(RMS wavefront error)小于0.14λ(λ为波长),最大畸变为-0.2%。     

Analysis of the influence shifts of the acetylene of various effects on frequency saturated absorption lines

Frequency shifts of the acetylene saturated absorption lines at 1.5μm with temperature, gas pressure and laser power have been investigated in detail. The second-order Doppler effect, the recoil effect, the Zeeman effect, the pressure shift and the power shift are taken into consideration. The magnitudes of those shifts caused by various effects are evaluated. In order to reproduce the stability of 5.7 × 10^-14 obtained by Edwards, all necessary conditions are given. The results show that when there is a larger external magnetic field, the Zeeman shift could not be neglected, so that the shield should be employed. And the design of a long cavity is advantageous to reduce the influence of the second-order Doppler effect. The results also show that at least 4-2.5℃ temperature control for cavity can effectively prevent several effects and improve the frequency stability.     

傅里叶变换光谱仪准直性误差检测技术

克服准直性误差对傅里叶变换光谱仪光谱性能的影响是研制傅里叶变换光谱仪的难点,定镜动态校准技术是解决该问题的好方法,而准直性误差检测是实现动态校准技术的关键.介绍了一种基于相位检测的傅里叶变换光谱仪准直性误差检测装置,该装置采用相位检测法实时检测动镜倾斜角,并用FPGA实现了相位检测算法,具有实时性好、测量精度高的优点,为实现动态校准系统打下了基础.给出了实测的动镜动态倾角曲线.     

π/4-DQPSK调制解调器设计和实现

π/4-DQPSK调制方式由于具有频谱利用率高、抗衰落性能强等突出特点,广泛应用于现代通信系统中.文章介绍一种基于π/4-DQPSK方式的调制解调器,重点讨论了其调制原理、软件设计和工程实现.     

周边硅笼取代的混杂酞菁卟啉三层铽单分子磁体

通过在铽的酞菁卟啉混杂三层的卟啉周边共价连接体积庞大的笼型倍半硅氧烷(POSS),得到了首个包含POSS的混 杂三层Tb₂(Pc)[T(OPOSS)₄PP]₂(1)[H₂Pc=phthalocyanine;H₂T(OPOSS)₄PP=5,10,15,20-tetra{[[N-[heptakis(isobutyl)propoxy]phenyl]octasiloxane]}porphyrin]。为了对比研究,同时合成了类似的三层化合物Tb₂(Pc)(TPP)₂(2)(H₂TPP=5,10,15,20-tetraphenyporphyrin)。尤其值得注意的是,在没有外加磁场的条件下,Tb₂(Pc)[T(OPOSS)₄PP]₂(1)和Tb₂(Pc)(TPP)₂(2)分别表现出单分子磁体和非单分子磁体的性质,这充分说明了共价连接均匀分布的POSS基团有效地分离了磁性核心,从而改善了酞菁卟啉混杂三层的磁性。     

Doping effects of transition metals on the superconductivity of (Li,Fe)OHFeSe films

The doping effects of transition metals(TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide(Li,Fe)OHFe Se. The samples are grown via a matrix-assisted hydrothermal epitaxy method. Among the TMs, the elements of Mn and Co adjacent to Fe are observed to be incorporated into the crystal lattice more easily. It is suggested that the doped TMs mainly occupy the iron sites of the intercalated(Li,Fe)OH layers rather than those of the superconducting Fe Se layers. We find that the critical current density J_c can be enhanced much more strongly by the Mn dopant than the other TMs, while the critical temperature T_c is weakly affected by the TM doping.     

方程x2-Ny2=c的正整数解

利用数学归纳法和初等方法给出方程x2-Ny2=C(N是非平方正数,C是非零整数)正整数解的表达式     

温度对鱼鳞胶原蛋白二级结构的影响

从草鱼鱼鳞中提取酶溶性胶原蛋白(PSC),通过SDS-PAGE电泳分析为典型Ⅰ型胶原蛋白且达到电泳纯。在此基础上利用傅里叶变换红外光谱(FTIR)、拉曼光谱(Raman)和圆二色谱(CD)研究了温度对鱼鳞胶原蛋白二级结构的影响。FTIR分析表明：鱼鳞胶原蛋白具有典型的胶原蛋白特征吸收带,酰胺Ⅰ、酰胺Ⅱ和酰胺Ⅲ带的特征吸收频率分别出现在1658,1552和1238cm-1处。随温度升高,酰胺A和酰胺B峰位向低波数移动,1658cm-1处吸收峰裂解成多个吸收峰;1552cm-1处的吸收峰在35℃微略红移,随后发生明显蓝移;1238cm-1处吸收峰随温度升高向低波数移动。在拉曼光谱中,胶原蛋白的酰胺Ⅰ、酰胺Ⅱ和酰胺Ⅲ带的特征吸收频率分别出现在1669,1557和1245cm-1处,都较红外光谱的波数高;此外,921和855cm-1处脯氨酸的特征谱峰在拉曼光谱中体现出来。圆二色谱分析表明,胶原蛋白溶液在221.6和204.4nm分别有一正、负峰,具有典型胶原蛋白三螺旋结构的特征圆二色谱峰型。胶原蛋白冻干品的FTIR光谱和Raman谱线大都在35～60℃时发生波数和强度改变,而胶原蛋白乙酸溶液的CD谱线在20～35℃之间发生剧烈改变。由此可以判断胶原蛋白在固态和溶液状态下,变性温度存在一定差异,胶原蛋白冻干品比其乙酸溶液更稳定。     

一种螺[4.5]癸烷衍生物的NMR数据分析

应用核磁共振技术（¹H NMR,¹³C NMR,DEPT, ¹H-¹H COSY, HSQC, HMBC）,确定了3,4-双(-4-甲基苯基)-1-羟基-7, 4′-二氧代-1′, 2′, 3′, 4′-四氢苯并[h]双环[3. 4]壬烷-2-螺-2′-萘-1′-酮的结构,准确归属了它的¹H, ¹³C信号,为其结构鉴定提供了重要依据.