晶体Sr_2Cu（HCOO）_6·8H_2O作为先驱物制备Sr_2CuO_2（C

应用ＳｒＣＯ３和ＣＵ（ＮＯ３）·３Ｈ２Ｏ从甲酸溶液中制备出晶体Ｓｒ２Ｃｕ（ＨＣＯＯ）６·８Ｈ２Ｏ，用这一晶体作为先驱物，石英管式炉中，８２５℃烧结六小时，得到单相的Ｓｒ２ＣｕＯ２（ＣＯ３）．通Ｎ２气体，８５０℃烧结十小时，得到Ｓｒ２ＣｕＯ３．Ｓｒ２ＣｕＯ２（ＣＯ３）是形成Ｓｒ２ＣｕＯ３的一种中间相．     

Bi2222相单晶生长的相关问题研究

从名义组份Ｂｉ２．４Ｓｒ２ＰｒＣｕ２Ｏｙ生长出一种新的Ｂｉ２２２２相单晶，其实际组份测定为Ｂｉ２Ｓｒ１．５Ｐｒ２．５Ｃｕ２Ｏｙ．用Ｘ射线衍射对单晶的结构进行了表征，并且研究了该单晶生长中Ｂｉ２２０１和Ｂｉ２２１２相的交生等相关问题．另外，如果从名义组份为Ｂｉ２．４Ｓｒ１．５Ｐｒ２．５Ｃｕ２Ｏｙ出发，得到的却是Ｐｒ２ＣｕＯ４单晶．     

Bi系高Tc超导材料的核四极共振（NQR）研究

用标准固相反应法，我们制备了Ｂｉ１．６Ｐｂ０．４Ｓｒ２Ｃａ２Ｃｕ３Ｏｙ和Ｂｉ２ＣａＣｕ２Ｏｙ纯相样品，在液氮温度下测量了Ｃｕ－ＮＱＲ和Ｂ－ＮＱＲ静态谱，发现ＮＱＲ谱都为大宽包，Ｃｕ－ＮＱＲ谱线位置反映铜原子所处的氧环境，Ｂｉ２Ｓｒ２Ｃｕ２Ｏｙ的ＮＱＲ谱宽反映其调制结构，Ｂｉ１．６Ｐｂ０．４Ｓｒ２Ｃａ２Ｃｕ３ＯｙＮＱＲ谱宽取决于其掺杂浓度。由于电场梯度弥散很大，Ｂｉ－ＮＱＲ谱很难观察。     

Si（Li）谱仪测定X射线荧光谱中CrKβ谱线化学位移的探索

采用放射源＾２４１Ａｍ５９．６ｋｅＶγ射线分别激发金属Ｃｒ、Ｃｒ２Ｏ３和Ｋ２ＣｒＯ４，用Ｓｉ（Ｌｉ）谱仪比较测量其Ｋｘ射线的能量。实验表明Ｋ２ＣｒＯ４和ＣｒＫβ能峰相对于金属Ｃｒ有２．１２±０．２７ｅＶ的位移。     

Si(Li)谱仪测量X射线荧光谱中CrK_β谱线化学位移的探索

采用放射源２４１Ａｍ５９．６ｋｅＶγ射线分别激发金属Ｃｒ、Ｃｒ２Ｏ３和Ｋ２ＣｒＯ４，用Ｓｉ（Ｌｉ）谱仪比较测量其Ｋｘ射线的能量。实验表明Ｋ２ＣｒＯ４中ＣｒＫβ能峰相对于金属Ｃｒ有２．１２±０．２７ｅＶ的位移。     

Bi系银衬底厚膜的制备及其传输电流性质

采用物理沉积法制了名义组分为Ｂｉ１．８Ｐｂ０．４Ｓｒ２Ｃａ２Ｃｕ３Ｏｙ的银夹板厚膜成相的影响表现为热处理过程中银夹板阻止了厚膜中的物质尤其是Ｐｂ的挥发，使厚膜处于低氧压状态，加速了８０Ｋ相向１１０Ｋ相的转化，测量了银衬底厚膜在外加磁场平行和垂直于厚膜表面的传输临界电流密度Ｊｃ与磁场Ｈ的关系。典型数据为Ｊｃ＝２．３１×１０＾４Ａ／ｃｍ＾２（７７Ｋ，０Ｔ），３．６×１０＾２Ａ／ｃｍ＾２（７７Ｋ，１Ｔ）     

不同气氛退火对Tl2Ba2CaCu2Ox超导电性的影响

本研究了Ａｒ气和Ｈ２／Ａｒ混合气体退火对Ｔｌ２Ｂａ２ＣａＣｕ２Ｏｘ（２２１２）超导体超导电性的影响。实验表明，在Ａｒ气中４００℃退火１至１２小时后Ｔｌ２Ｂａ２ＣａＣｕ２Ｏｘ的Ｔｃ（Ｒ＝０）随退火时间的增长明显降低。Ｘ－光衍射分析证实，在Ａｒ气或Ｈ２／Ａｒ混合气体中退火前后，Ｔｌ２Ｂａ２ＣａＣｕ２Ｏｘ超导体的结构没有发生变化。     

高温下H_2─Ar、H_2O─CO_2混合气体中H_2O分子谱线的半宽度

本文用ＩＯＳ方法和我们改进的Ｂｕｃｋｉｎｇｈａｍ势计算了Ｈ２Ｏ—Ａｒ、Ｈ２Ｏ—ＣＯ２混合气体中Ｈ２Ｏ分子谱线在高温下（６００Ｋ、９００Ｋ、１２００Ｋ、１５００Ｋ）的压力展宽半宽度。分析了谱线半宽度随温度变化的规律，同时也讨论了半宽度和被加宽分子大小的关系。     

高温下H2O—Ar,H2O—CO2混合气体中H2O分子谱线的半宽度

本文用ＩＯＳ方法和我们改进的Ｂｕｃｋｉｎｇｈａｍ势计算了Ｈ２Ｏ－Ａｒ、Ｈ２Ｏ－ＣＯ２混合气体中Ｈ２Ｏ分子谱线在高温下（６００Ｋ、９００Ｋ、１２００Ｋ、１５００Ｋ）的压力展宽半宽度。分析了谱线半宽度随温度变化的规律，同时也讨论了半宽度和被加宽分子大小的关系。     

ICP－AES法直接测定高纯Eu_2O_3中14种稀土元素

建立了ＩＣＰ－ＡＥＳ测定高纯Ｅｕ２Ｏ３中１４种稀土元素的方法。用正交设计法优化仪器测量条件，实验了基体Ｅｕ２Ｏ３对被测元素的干扰和对方法测定下限的影响。１４个稀土元素的测定下限为：Ｙｂ２Ｏ３０．５μｇ·ｇ－１，Ｙ２Ｏ３１μｇ·ｇ－１，Ｄｙ２Ｏ３、Ｈｏ２Ｏ３、Ｔｍ２Ｏ３和Ｎｄ２Ｏ３５μｇ·ｇ－１，Ｇｄ２Ｏ３、Ｓｍ２Ｏ３、Ｅｒ２Ｏ３、Ｃｅ２Ｏ３、Ｐｒ６Ｏ１１和Ｌａ２Ｏ３１０μｇ·ｇ－１，Ｌｕ２Ｏ３２０μｇ·ｇ－１以及Ｔｂ４Ｏ７３０μｇ·ｇ－１。加入回收率为８８－１１２％，六次取样分析的相对标准偏差小于１１％。方法简便不经化学分离，可用于９９．９－９９．９９％Ｅｕ２Ｏ３中稀土杂质的测定或生产控制分析。     

Multiphoton conductivity in KBr

Multiphoton conductivity measurements at room temperature on KBr monocrystals are reported. The experimental results show evidence of two- and four-photon processes and confirm the assignment of the optical gap obtained by means of two-photon spectroscopy.     

V centers in KBr

One of the major products of radiation damage in the range 120 K < T < 200 K is the D₃ center. Many effects previously associated with the V₄ center are more properly due to the D₃ center in conjunction with a center peaking at 280 nm. All results observed are consistent with the model of the D₃ center proposed by Itoh and Ikeya[7], an X₃⁻² trihalide molecule ion oriented in a 〈100〉 direction.     

The A-emission of KBr : Tl

The line shapes and relative efficiencies of A_T and A_X emission bands of KBr : Tl have been studied over a wide temperature range (10–500 K). The behavior of A_T and A_X emissions has been described phenomenologically in terms of the coexistence of two different kinds of minima on the adiabatic potential energy surface of the ³T_1u relaxed excited state. The line shape parameters and the A-emission temperature dependence show that T and X minima belong to distortions of different symmetry. A model considering the emission processes from T and X minima separately, in spaces of different distortions, is shown to account well for the experimental results. The emission at very low temperatures (below 50 K) was found to be sensitive to trace impurities.     

CdTe aggregates in KBr crystalline matrix

In this work, we report the experimental results on the fabrication and optical characterization of Czochralski (Cz) grown KBr single crystals doped with CdTe crystallites. The results of the optical absorption have shown two bands, the first one located at 250 nm demonstrates the incorporation of cadmium atoms in the KBr host followed by a partial chemical decomposition of CdTe, the second band located at 585 nm shows an optical response of CdTe aggregates. Photoluminescence spectra at room temperature before annealing showed a band located at 520 nm (2.38 eV), with a blue shift from the bulk gap of 0.82 eV (E_g (CdTe)=1.56 eV). While the photoluminescence spectra after annealing at 600 °C showed a band situated at 640 nm (1.93 eV), these bands are due to band-to-band transitions of CdTe nanocrystals with a blue shift from the bulk gap at 0.38 eV. Blue shift in optical absorption and photoluminescence spectra confirm nanometric size of dopant. X-ray diffraction (XRD) spectra have shown the incorporation of CdTe aggregates in KBr.     

Hyperfine spectra of KBr and KI

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectra of ³⁹K⁷⁹Br, ³⁹K⁸¹Br and ³⁹K¹²⁷I. Coupling constants for the nuclear electric quadrupole interactions, the spin–rotation interactions, the tensor and scalar spin–spin interactions, as well as the electric dipole moment of KI, and their dependence on vibrational and rotational state have been determined. A few transitions observed for ⁴¹K¹²⁷I show a small shift in the iodine nuclear electric quadrupole interaction, and the fit improves somewhat with the inclusion of an iodine nuclear electric hexadecapole interaction term.     

Paraelectric pairs in lithium doped KBr

The low lying paraelectric modes observed in Li doped KBr have been identified with Li pairs by a systematic far infrared study of isotopic mixtures of the Li dopant. We conclude that isolated Li⁺ ions do not tunnel in KBr but Li⁺ ion pairs do.     

Interstitial-exciton interaction in KBr:Na

The intensity of luminescence of the alkali halides submitted to an ionizing radiation decreases when color centers are created. The action of the interstitial as a quenching center is directly shown in KBr:Na. At LNT, the crystal has an emission band (430 nm), due to the exciton localized close to a sodium, which disappears according to a kinetics anticorrelated with that of the formation of the H_A (interstitials stabilized by Na) unde ionizing radiation.     

A new paraelectric center in lithium-doped KBr

We report paraelectric resonance measurements for KBr:Li⁺⁷ and KBr:Li⁺⁶. The observed zero-field splittings are large - 62, 65, and 141.5 GHz ± 1 GHz in KBr:Li⁺⁷, and 88 and 118 GHz ± in KBr:Li⁺⁶ — giving an isotope shift of 40% for the lower lines. The uncorrected dipole moment is p = 0.98 ± 0.05 eA. The presence of OH^- seems to suppress the Li⁺ signal.     

Luminescence of KBr crystals doped with copper

Radiation produced in copper-doped KBr crystals with a maximum near 2.49 eV was investigated. Luminescence with a maximum at 2.49 eV is caused by excitation processes at luminescence centers, the structure of which includes interstitial positively charged univalent copper ions bound to divacancies and bromine ions. The copper-doped solid solution (K,Na)Br was used for observation of the transformation of luminescence centers and for increasing their concentration.S. M. Kirova State Pedagogical Institute, Pskov. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 79–82, September, 1993.