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Scheeline A 《Analytical and bioanalytical chemistry》2010,398(7-8):2751-2753
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《天然气化学杂志》2004,(1)
About 200 billion yuan (24.3 billion US dollars) of investment was spent in infrastructure projects in west China region in 2003, occupying 55.2 percent of the country's total annual investment to the region. According to a leading group conducting the west development strategy, China plans to invest 363.5 billion yuan (44 billion US dollars) to the west in 2003, including 76 key projects. 相似文献
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利用数学方法解决化学问题是化学及相关专业学生必备的技能之一。作者Daley,H.O.针对这一需要,为大学学习普通化学的学生编写了这本习题集。通过解题学生可以检验自己对化学原理掌握的深浅程度。 相似文献
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Ohne Zusammenfassung 相似文献
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《International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry》1992,39(4):321-327
Solutions of 2,3-dimethylbutane (DMB) and cyclohexane containing a captodative solute, methylmethoxyacetate (MMA), were irradiated (continuous wave). Alkane dimeric products were analysed by capillary gas chromatography. G-yields were estimated as a function of the concentration of the captodative solute. By reaction with alkyl radicals, the captodative solute gives the free radical stabilized by the captodative effect. Combination reaction of this radical with itself or with alkyl radicals gives solute or mixed dimer which were also analysed. A large intensity effect was noticed, as was seen in the solutions of n-hexane-MMA. Dose effect was definitely rejected. 相似文献
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I. Radwan Z. Pietrzak-Flis T. Wardaszko 《Journal of Radioanalytical and Nuclear Chemistry》2001,247(1):71-77
Concentrations of tritium in environmental waters (precipitation, rivers, lakes, tap water) have been determined using electrolytic enrichment and liquid scintillation counting. In waters of big rivers (the Vistula and the Odra rivers), lakes and tap water the annual average concentrations were similar to each other being from 1.4 to 1.9 Bq·dm-3. These concentrations were similar to those in the precipitation in which they ranged from 1.7 to 2.2 Bq·dm-3. The lowest tritium concentrations were found in waters of the Seashore Region rivers (average for 1994–1999 was 1.1 Bq·dm-3). The tritium concentrations in surface waters and in precipitation are still higher than that of natural level. The data obtained show that tritium concentration in the water of rivers might depend on the size of drainage area. The observed seasonal variations of tritium concentration in the precipitation collected in Warsaw and at the Mount Sniezka indicate the stratospheric source of tritium. It was found that about 30% of tritium deposited with precipitation is removed to the Baltic Sea with river waters. 相似文献
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Henryk Bem Ewa Maria Bem Joanna Krawczyk Marcin Płotek Sławomira Janiak Daria Mazurek 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):2229-2232
Plastic PicoRad detectors with activated charcoal have been used for radon monitoring in local kindergartens and schools in two cities, Kalisz and Ostrów Wielkopolski, in the region of Greater Poland. Detectors were exposed for a standard time of 48 h during the autumn and winter of 2011 in 103 rooms (Kalisz) and 55 rooms (Ostrów Wlkp), respectively. The detectors were calibrated in the certified radon chamber of the Central Laboratory for Radiological Protection in Warsaw, Poland. The arithmetic and geometric means of indoor radon concentrations in the examined rooms were 46.0 and 30.3 Bq/m3 for Kalisz and 48.9 and 29.8 Bq/m3 for Ostrów Wlkp, respectively. The measured levels of the indoor radon concentrations were relatively low, since the main source of indoor radon for these low storey (max. three storeys) buildings is radon escaping from the underlying soil with a low 226Ra concentration (~15 Bq/m3). Therefore, the calculated annual effective doses from that source for the children in Kalisz and Ostrów Wlkp were also low 0.35 mSv. 相似文献
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This study assessed elemental concentrations in the serum of 154 preschool children in central Taiwan via instrumental neutron activation analysis (INAA). A total of eight elements, Br, C1, Fe, Na, Rb, Sc, Se and Zn of sera for Taiwanese preschool children living at four residential areas: Taichung city, Taichung urban townships and in a remote area inhabited by two groups of aborigines, Atayal and Bunun were determined. Standard reference materials (tomato leaves, NIST-SRM 1570a, and lichen, IAEA-336) were used as quality control standards to crosscheck the accuracy. Residential area, socioeconomic status and gender were shown to significantly influence serum levels of the eight trace elements. Statistical analysis revealed several different gender patterns via the two-tailed student's test. A quantified index of agreement (AT) was used to classify these elements. Small AT indicated a close consistency, while large AT indicated a larger fluctuation, or less agreement, such that the correlation between the elements could be interpreted using a series of quantified indices at the serum levels of preschool children. 相似文献
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The γ-radiation-initiated polymerization of acrylonitrile (AN) at 25[ddot] C has been studied, both in aqueous solution and in emulsion, at dose rates between 70 and 175 krad/hr. The effect of added emulsifier, sodium lauryl sulfate (SLS), on reaction rates, Rp, and on polymer molecular weight, Mn, has been investigated. G (monomer polymerized) values ranged from 7,500 in aqueous solution to 20,000 in bulk to 45,000 in emulsion, all based on the total energy absorbed. In the aqueous solution polymerization, where Rp is approximately first order in initial monomer concentration over the range 0.15 ± [AN]o ± 1.06 moles/liter, addition of SLS increases Rp but does not influence the order of the reaction with respect to [AN]o. In the emulsion system at 70 krad/hr and at a phase volume ratio AN/H2O of 1/2, (PR = 1/2), Rp varies as [SLS]0.1 over the concentration range 0.01 ± [SLS] ± 2.5± wt/vol of aqueous phase. At the same PR value, and at 80 krad/hr, Mn of the polymer (measured by viscometry in dimethylformamide solution) is effectively independent of [SLS] in the range of 0.01 ± [SLS] ± 10± wt/vol of aqueous phase. Initial Rp values are either independent of PR in the range 1/3 ± PR ± 1/1 or exhibit an insensitive and unsystematic dependence thereon. Based on measurements at 70 and at 175 krad/hr, the intensity exponent of Rp at PR = 1/2 is approximately 0.4. 相似文献
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Domain structures in mineral crystals could be categorized into three groups and several subgroups within each group, based on characteristics of domain structures and mechanisms causing domain structures: (ⅰ) domain structures constituted by domains with the same (or identical) crystal structure and chemical composition, including anti-phase domain structures, twinning domain structures, inversion domain structures, and translationtwinning domain structures; (ⅱ) domain structures constituted by two or more than two kinds of domains with the same chemical composition but different crystal structures; and (ⅲ) domain structures constituted by two kinds of compositional and structural different domains, including exsolution-induced and polysomatic reaction-induced domain structures. Different types of domain structures may display different phenomena in their TEM images and SAED patterns, due to different crystallographic characteristics of different domain structures. The domain structures in minerals 相似文献
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