数学问题解答

20 0 2年 8月号问题解答(解答由问题提供人给出 )1 3 86　试证明 :有两边及一个角的角平分线对应相等的两个三角形全等 .(湖北宜昌市十一中学　是海松　443 0 0 3 )证明　设△ＡＢＣ和△Ａ′Ｂ′Ｃ′的三边分别记为ａ、ｂ、ｃ和ａ′、ｂ′、ｃ′,三条角平分线分别记为ｔａ、ｔｂ、ｔｃ和ｔａ′、ｔｂ′、ｔｃ′,半周长分别记为ｐ和ｐ′.当有两边及它们的夹角的平分线对应相等时 ,不妨设ｂ=ｂ′,ｃ =ｃ′,ｔａ =ｔａ′.由ｔａ =2ｂ+ｃ ｂｃｐ(ｐ -ａ) ,ｔａ′ =2ｂ′+ｃ′ ｂ′ｃ′ｐ′(ｐ′ -ａ′)得 :2ｂ+ｃ ｂｃｐ(ｐ -ａ) =2ｂ+ｃ ｂｃｐ…     

不同羧酯化的聚马来酸十八醇酯齐聚物的镉盐LB膜成膜特…

由聚马来酸酐和十八醇合成了一系列不同羧酯比的聚马来酸十八醇酯，并以其为成膜材料，ＣｄＣｌ２水溶液为亚相制备了一系列聚马来酸十八醇酯镉盐ＬＢ膜，借助小角Ｘ射线衍射和红外吸收光谱表征了成膜条件及羧酯比对ＣｄＰＭＡ膜有序结构的影响。在较高膜压和快速提拉条件下，低羧酯比的ＣｄＰＭＡ可得到有序性很高的Ｙ－型ＬＢ多层膜；高羧酯比的ＣｄＰＭＡ得不到高有序性的ＬＢ多层膜。     

Multiband Terahertz Photonic Band Gaps of Subwavelength Planar Fractals

Optical transmission properties of subwavelength planar fractals in terahertz （THz） frequency regime are studied by means of time-domain spectroscopy. The transmission spectra with multiple pass bands and stop bands are observed. The tunable photonic band gaps are realized by changing the angle between the principle axis of planar fractal and the polarization of THz wave. The possible application of the subwavelength optical component is discussed. We attribute the detected transmittance from subwavelength fractals to localized resonances.     

低电阻测量设计实验中电位差计指针不稳的解决方法

本文分析了J33Q型电位差计在实验中指针不稳的原因,并提出了解决的办法。     

CONVERGENCE OF AN ITERATION METHOD WITHOUT DERIVATIVE

In this paper, we give a convergence theorem and error estimates for an iteration method under new Kantorovitch-Ostrowski type condition using the information of higher derivatives at initial points. Compared with the corresponding study in [3],the convergence determination is established under one global condition, instead of two , on the function.     

Design and Fabrication of 1.06 μm Resonant-Cavity Enhanced Reflective Modulator with GaInAs/GaAs Quantum Wells

A resonant-cavity enhanced reflective optical modulator is designed and fabricated, with three groups of three highly strained InGaAs/GaAs quantum wells in the cavity, for low voltage and high contrast ratio operation. The quantum wells are positioned in antinodes of the optical standing wave. The modulator is grown in a single growth step in an molecular beam epitaxy system, using GaAs/AlAs distributed Bragg reflectors as both the top and bottom mirrors. Results show that the reflection device has a modulation extinction of 3 dB at -4.5 V bias.     

N-(取代)对三氟甲基苯基-1,3,5-三取代吡唑-4-酰胺衍生物的合成与生物活性

设计合成10个未见文献报道的N-对三氟甲基苯基-1,3,5-三取代吡唑-4-酰胺类化合物, 其结构经元素分析, ¹H NMR, IR 确证. 初步生物活性测试结果表明, 部分化合物对水稻纹枯病、小麦赤霉病、辣椒枯萎病和马铃薯晚疫病有一定的杀菌活性.