Author Keywords: Track formation; Heavy ion; Bubble detector; Track detector; Threshold detector; Identification of heavy ions 相似文献
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901.
S. -L. Guo L. Li T. Doke J. Kikuchi A. Kyan E. Yoshihira T. Kato T. Murakami 《Radiation measurements》2001,34(1-6):269-272
Characteristics of tracks created by heavy ions in bubble detectors have been studied in detail by using four types of super long (23 cm), self-made bubble detectors and six species of high energy heavy ions: 12C, 28Si, 40Ar, 56Fe, 84Kr and 132Xe. The following characteristics of heavy ion tracks in bubble detectors have been recognized:
902.
To find a model that describes the gas diffusion on irradiated polymers (Makrofol KG polycarbonate) the diffusion constants have been measured with argon as diffusion gas. The polymers were irradiated with uranium, gold and lead ions of about 10 MeV/u and ion fluences between 1×1010 and 4×1011 ions/cm2. The ion irradiated probes show two quite different dependencies of the diffusion constant on the ion energy loss. These effects are strongly related to the fluence of the irradiation. In case of low ion fluences, the diffusion constant is up to 8 times higher than that of pristine material. In the probes with high ion fluences we observe a decrease of diffusion constant to half the value of the pristine material. To understand the dependence of the diffusion constant on ion fluences we apply a model of compacting. This model describes the compacting ability of shockwaves arising from latent tracks. A track formation model is suggested. When an ion penetrates the foil it creates shockwaves around its path. These shockwaves put compacting forces on earlier created latent tracks in the same foil. 相似文献
903.
Halina D. Inerowicz 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(3-4):211-214
Novel chromogenic crown ethers having an intraannular azo and phenolic hydroxy subunits have been used as complexing reagents for alkali metal cations. The complex formation was studied by visible spectroscopy and formation constants were calculated. The most pronounced spectral changes were observed for lithium ion. 相似文献
904.
H.-J. Buschmann E. Cleve K. Jansen A. Wego E. Schollmeyer 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(1-2):117-120
The complex formation between cucurbit[5]uril, decamethylcucurbit[5]uril and cucurbit[6]uril and alkali, alkaline earth and ammonium cations is examined. The solubility of these ligands is rather small in aqueous solution. In the presence of salts the solubility normally increases due to the formation of complexes. The total concentration of the ligands can be easily measured from the total organic carbon content of the salt solutions saturated with the ligand. From these results it is possible to calculate the stability constants of the complexes formed even without the knowledge of the exact solubility of the ligand. 相似文献
905.
Five solid complexes of zinc with L‐α‐methionine, L‐α‐phenylalanine and L‐α‐histidine were prepared. The constant‐volume combustion energies of the complexes, ΔEc (coordination), were determined by a precise rotating bomb calorimeter at 298.15 K. They were ‐ 2969.03 ± 0.34, ‐2929.46 ± 1.59, ‐9597.13 ± 6.12, ‐4378.98 ± 3.27 and ‐14047 ± 6.75 kJ/mol, respectively. Their standard enthalpies of combustion, ΔHθm,c(coordination, s, 298.15 K), and standard enthalpies of formation, ΔHθm,f (coordination, s, 298.15 K), were calculated. They were ‐2959.73 ± 0.34, ‐2923.88 ± 1.59, ‐9649.18 ± 6.12, ‐4373.40 ± 3.27, ‐14048.53 ± 6.75 kj/mol and ‐1180.94 ± 0.92, ‐1401.26 ± 1.77, ‐2501.69 ± 6.50, ‐1381.47 ± 3.49, ‐1950.19 ± 7.65 kJ/mol, respectively. 相似文献
906.
907.
钾芒硝是一种成因复杂的复盐[1~ 3 ] ,并且由于钾芒硝K3 Na(SO4 ) 2 与硫酸钾石 [K3 Na(SO4 ) 2 或Na2 SO4 ·3K2 SO4 ]的化学组成相同 ,未能确定二者是否属于同一种复盐[4 ,5] 。我们合成了复盐K3 Na(SO4 )2[3 ] ,用溶解量热法测定了K3 Na(SO4 )2 和反应物 [Na2 SO4 (s) +K2 SO4 (s) ]的溶解焓 ,通过设计热化学循环计算出复盐的标准生成焓 ,为我们了解钾芒硝和硫酸钾石是否为同一复盐 ,并为进一步研究其成因和组成提供参考。1 实验部分1 1 试剂与仪器K2 SO4 (s)和Na2 SO4 (s)为A .R .… 相似文献
908.
The review is devoted to the photochromism of pericyclic reactions of crown-containing photochromic systems. The complex formation of photochromic crown ethers with metal cations has a substantial effect on both the spectral characteristics of molecules and occurrence of photochromic reactions. A possibility to create systems with photocontrolled complex-forming properties is an attractive feature of the novel systems. 相似文献
909.
Rahim Hekmatshoar Issa Yavari Yahya S. Beheshtiha Majid M. Heravi 《Monatshefte für Chemie / Chemical Monthly》2001,132(6):689-691
Summary. In the presence of metallic zinc, aldehydes and ketones experience reductive coupling in tetrahydrofuran-saturated aqueous
ammonium chloride (5:3) to afford the corresponding pinacols in moderate to high yields.
Received October 23, 2000. Accepted (revised) December 12, 2000 相似文献
910.
Charles H. Langley Jenn‐Huei Lii Norman L. Allinger 《Journal of computational chemistry》2001,22(13):1476-1483
Molecular mechanics (MM4) calculations on the heats of formation of aldehydes and ketones were carried out for a total of 59 compounds (10 aldehydes and 49 ketones). Optimization of the heat of formation parameters was obtained by a least squares fit to the experimentally known heats of formation. With the optimized MM4 heat of formation parameters, the MM4 calculated heats of formation showed significant improvement over those of MM3. The standard and weighted root mean square deviations for the MM4 values were 0.35 and 0.31 kcal mol?1, respectively, whereas for the MM3 values they were 0.42 and 0.39 kcal mol?1, respectively. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1476–1483, 2001 相似文献