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微波技术在有机化学反应中的应用 总被引:4,自引:0,他引:4
本文介绍了微波技术在干法有机反应、加速有机合成速率及合成短寿命放射性药剂中的应用,概述了微波技术中影响反应速率的因素等,说明了微波特有的能量及快速加热能力在化学反应研究中具有广泛的实际意义。 相似文献
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一种新型铂电阻温度计及其性能研究 总被引:1,自引:0,他引:1
中国计量科学研究院同云南仪表厂合作研制一种新型的套管铂电阻温度计,并对其作为较为详细的实验研究,研究结果如下:在水三相点,温度计的稳定性优于±0.3mK,在一周之内,复现性优于±0.1mK,1mA测量电流下自热不超过1mK,温度计在4.2K温度下的电阻比W小于5.9×10^-4,其标准偏差的绝对值不大于3×10^-8;而非一致性在83K以上稍大,而在17K-83K间小于0.4mK,在其余温度范围均 相似文献
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本文用PPP-SCF-CI法对2-(1或2萘基)苯并噁唑及其Z、E同分异构体的电子结构及紫外光谱进行了理论研究,讨论了各分子的光谱特性,解析了对应于实验的不同异构体紫外吸收光谱,找到了该分子体系的主要生色团,理论计算与实验结果的偏差约在1%以内。这为深入研究苯并噁唑类分子的光物理性质、进一步预测具有更好性能的新型材料提供了理论依据。 相似文献
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肟化反应和贝克曼重排反应是高校化学专业重要的基础有机实验,现行的实验教材常采用由环己酮制备己内酰胺,该实验存在反应过程难监测,反应后处理损失大,收率低,实验效果不理想等问题。以二苯甲酮为原料,经肟化、贝克曼重排合成苯甲酰苯胺,产物经1H NMR、13C NMR、IR等确证分子结构。研究结果表明:苯甲酰苯胺合成反应平稳,实验现象明显,后处理简便,收率较高。通过TLC监测反应进程,能使学生对反应过程有清楚的认知和掌控。实验内容和时间适合大学实验要求,实验综合性强,拓展空间大,能够有效训练学生的创新思维和科研意识,提高学生的实验技能。 相似文献
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In this paper,the chaotic behaviors in an erbium-doped fiber(EDF) single-ring laser(EDFSRL) are investigated experimentally by using the loss modulation method.An electro-optic modulator(EOM) made of LiNbO 3 crystal is added to the system.Thus,by changing the modulation voltage and the modulation frequency of the EOM,the freedom of the EDFSRL system is increased.The chaotic characteristics of the system are studied by observing the time series and the power spectra.The experimental results indicate that the erbium-doped fiber single-ring laser system can enter into chaos states through period-doubling bifurcation and intermittency routes. 相似文献
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We present a scheme for the anti-control of chaos in the p--Ge
photoconductor system by using a chaotic laser to irradiate and
disturb this system. The numerical simulations show that this scheme
can be effectively used to control periodic states in this p--Ge
system into chaotic states. Moreover, the different chaos states
with different chaotic orbits can be obtained by appropriately
adjusting the disturbance intensity and disturbance frequency, and
by increasing this intensity or reducing this frequency, this p--Ge
system gradually evolves to fully developed chaotic states. 相似文献
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Hyperchaotic behaviours and controlling hyperchaos in an array of RCL-shunted Josephson junctions 下载免费PDF全文
This paper deals with dynamical behaviours in an array composed of two resistive-capacitive-inductive-shunted (RCL-shunted) Josephson junctions (RCLSJJs) and a shunted resistor. Numerical simulations show that periodic, chaotic and hyperchaotic states can coexist in this array. Moreover, a scheme for controlling hyperchaos in this array is presented by adjusting the external bias current. Numerical results confirm that this scheme can be effectively used to control hyperchaotic states in this array into stable periodic states, and different stable periodic states with different period numbers can be obtained by appropriately choosing the intensity of the external bias current. 相似文献
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文章探讨了经会阴盆底超声在评价压力性尿失禁患者子宫全切术后盆底结构变化.收集既往行子宫全切手术治疗的91例患者为病例组、100例健康女性作为对照组;采用会阴盆底超声分别对两组研究对象在静息状态、Valsalva状态下的盆底结构特征及变化参数进行检测;并根据病例组患者是否发生压力性尿失禁将患者进行分层分析.病例组患者静息... 相似文献
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The chaotic behaviours in the p--Ge photoconductor system
are studied by changing the photo-excitation coefficient and the
routes and parameter conditions are given for chaos generation in
this system. A scheme for controlling chaos in the p--Ge
photoconductor is presented by adding an ac bias current. Numerical
simulations show that this scheme can be effectively used to control
chaotic states into stable period states for this system. Moreover,
the different period states with different period numbers can be
obtained by appropriately adjusting the amplitude, frequency, and
initial phase of the additional ac current. 相似文献