两段加压气化制造合成原料气

一、緒言工业上加压气化的缺点是水蒸汽分解率过低,因而气化过程的热效率不高,如果将加压煤气应用作为合成原料气則甲烷含量太高,須經分离或裂化。如果采用干餾和气化分开的两段加压气化,选擇最有利的干餾条件和适当提高气化溫度,     

可移动激光质谱仪及在机动车尾气监测中的应用

激光质谱法是探测环境污染的新方法,它具有高灵敏度、高选择性、多组分和快速实时的特点.文中介绍了可移动激光质谱仪的系统结构、各部分功能以及主要技术指标,报道了该仪器研制设计过程中的某些关键技术问题,并给出了该仪器在机动车尾气监测中的一些实时在线探测结果.     

Quantum interference effects on the probe amplification without and with inversion in a four-level system

A four-level system driven by two coherent fields is considered. It is shown that in the presence of an incoherent pump, the probe gain at a short wavelength can be achieved due to the quantum interference. Our density matrix calculation provides the conditions for probe amplification from different origins, including gain without population inversion on any state basis, gain with population inversion on the dressed-state basis, and gain with population inversion on the bare-state basis. Also, by controlling the Rabi frequency of the coupling field a total change from non-inversion to inversion can be achieved which does not depend on the intensity of the incoherent pump.     

Mechanical design and analysis of a low beta squeezed half-wave resonator

A superconducting squeezed type half-wave resonator （HWR） of β=0.09 has been developed at the Institute of Modern Physics, Lanzhou. In this paper, a basic design is presented for the stiffening structure for the detuning effect caused by helium pressure and Lorentz force. The mechanical modal analysis has been investigated the with finite element method （FEM）. Based on these considerations, a new stiffening structure is proposed for the HWR cavity. The computation results concerning the frequency shift show that the low beta HWR cavity with new stiffening structure has low frequency sensitivity coefficient df/dp and Lorentz force detuning coefficient KL, and stable mechanical properties.     

A quantum efficiency analytical model for complementary metal–oxide–semiconductor image pixels with a pinned photodiode structure

A quantum efficiency analytical model for complementary metal–oxide–semiconductor（CMOS） image pixels with a pinned photodiode structure is developed. The proposed model takes account of the non-uniform doping distribution in the N-type region due to the impurity compensation formed by the actual fabricating process. The characteristics of two boundary PN junctions located in the N-type region for the particular spectral response of a pinned photodiode, are quantitatively analyzed. By solving the minority carrier steady-state diffusion equations and the barrier region photocurrent density equations successively, the analytical relationship between the quantum efficiency and the corresponding parameters such as incident wavelength, N-type width, peak doping concentration, and impurity density gradient of the N-type region is established. The validity of the model is verified by the measurement results with a test chip of 160×160 pixels array,which provides the accurate process with a theoretical guidance for quantum efficiency design in pinned photodiode pixels.     

微波增压分解人发,原子吸收光谱法测定其中的锌、铁、铜、钙、镁和镉

本文使用国产家用微波炉及自制聚四氟乙烯密闭容器分解人发,其最佳条件是:样品为0.2000克时,加0.5毫升HNO_3及1.5毫升H_2O_2,以500瓦功率作用6分钟,分解后定容至10毫升。Fe、Cu、Ca、Mg、用火焰AAS法测定,塞曼校正背景,Zn用参考光束(σ分量)火焰AAS进行测定,Cd用恒温平台石墨炉(STPF)AAS法测定,镧盐作改进剂。与常规分解法的结果相比,该方法不仅简便、快速,且具有良好的准确度和测定精密度。     

Effect of concentration of Er3+ ions on ultra-large index of refraction via atomic coherence in Er3+: YAG crystal

A four-level system is proposed to produce large index of refraction accompanied by vanishing absorption in the Er^{3+}-doped yttrium aluminium garnet (YAG) crystal. It is found that the high index of refraction with zero absorption can be provided by adjusting the incoherent pumping, the coherent field, as well as the concentration of Er^{3+} ions in the crystal. Furthermore, the value of the incoherent pump to achieve the high index of refraction with zero absorption is greatly changed with increasing the concentration of Er^{3+} ions in the crystal. This indicates that the effect of concentration on the high index of refraction with zero absorption cannot be neglected.