排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
2.
3.
G. M. Braga Marcazzan B. Balossi S. Pasello N. Petriccioli F. Apadula 《Il Nuovo Cimento C》1994,17(4):393-406
Summary Results of two measurement campaigns on particulate-matter concentration and composition aimed at studying dispersion and
transport of aerosol particles in areas of different typology are reported. Local and regional aerosol transport affects particulate-matter
concentration in a rural prealpine area, in particular the regional background is a main component of sulphur compounds. A
long-range transport episodic event has been also detected. In the urban area of Milan, under good mixing conditions, the
concentration of particulate matter has been found to be nearly constant up to 100 metres. The measurements of elemental-concentration
values for a time series of particulate-matter samples collected simultaneously at different sites or altitudes proved to
be an effective method for the investigation of transport phenomena.
Paper presented at the IX Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 8–10, 1992, Rome. 相似文献
4.
Summary The characteristics of the air quality monitoring station of Brera Tower are described. The station is focused on the study
of air pollution in the urban area and on the aerosol chemistry and reactivity in the atmosphere. The influence of meteorological
parameters is also taken into account. Results about the concentration, the chemical composition and the size distribution
of suspended particulate matter and about the ionic composition and acidity of rain are also presented.
Paper presented at the IV Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 22–24, 1987, Rome. 相似文献
5.
The room temperature reaction of the complex cis,trans,cis-[Ir(H)2(PPh3)2(Solv)2]PF6 (Solv is a solvent) with the imine PhCH2N=CHPh in acetone generates (with loss of H2) the orthometallated complex [Ir(H){PhCH2N=CH(o-C6H4)}(PPh3)2(Me2CO)]PF6 (3) containing a five-membered cyclometallated imine moiety. In MeOH, the reaction at an imine : Ir ratio = 1 leads to the corresponding MeOH analog of 3, while with excess imine, the mixed orthometallated imine/bezylamine complex [Ir(H){PhCH2N=CH(o-C6H4)}(PPh3)2(PhCH2NH2)]PF2 (4) is formed; the source of the coordinated amine is an Ir-promoted hydrolysis of the imine, the water likely coming from imine. Complexes 3 and 4 are fully characterized by elemental analysis, 1H and 31P{1H} NMR spectroscopy, and X-ray crystal structure analysis. 相似文献
6.
A Rh-catalyzed, homogeneous hydrogenation of the imine, PhCH(2)N=CHPh, is shown to involve a Rh-imine-amine species that subsequently activates H(2), the amine (benzylamine) being formed via a Rh-catalyzed hydrolysis of the imine by adventitious water. The imine-amine complex, cis-(Rh[P(p-tolyl)(3)](2)(PhCH(2)N=CHPh)(NH(2)CH(2)Ph))PF(6) (2b), is structurally characterized, and the solution (1)H NMR data reveal inequivalent NH(2) protons. 相似文献
7.
8.
A Gurtu P K Malhotra I S Mittra P M Sood SC Gupta VK Gupta GL Kaul LK Mangotra Y Prakash NK Rao ML Sharma 《Pramana》1974,3(5):311-322
This is a continuation of our earlier investigation (Gurtuet al 1974Phys. Lett. 50 B 391) on multiparticle production in proton-nucleus collisions based on an exposure of emulsion stack to 200 GeV/c beam at the NAL. It is found that the ratioR em = 〈n s〉/〈n ch〉, where 〈n ch〉 is the charged particle multiplicity in pp-collisions, increases slowly from about 1 at 10 GeV/c to 1·6 at 68 GeV/c and attains a constant value of 1·71 ± 0·04 in the region 200 to 8000 GeV/c. Furthermore,R em = 1·71 implies an effectiveA-dependence ofR A =A 0.18,i.e., a very weak dependence. Predictions ofR em on various models are discussed and compared with the emulsion data. Data seem to favour models of hadron-nucleon collisions in which production of particles takes place through adouble step mechanism,e.g., diffractive excitation, hydrodynamical and energy flux cascade as opposed to models which envisage instantaneous production. 相似文献
9.
Reactions of cis,trans,cis-[Ir(H)2(PPh3)2(MeOH)2]PF6 in MeOH with the imines Ph(R′)C=NR under 1 atm H2 precipitate the neutral, Ir(III)-dihydrido complexes [Ir(H)2{RN=C(R′)(o-C
6H4)}(PPh3)2], where R = alkyl or benzyl, and R′ = Ph, H, or Me; the dihydrides are well characterized through elemental analysis, NMR and IR data
and, in one case, with the imine Ph2C=NCH2Ph, an X-ray structure. These products are formed via intermediate ortho-metallated species, exemplified by [Ir(H){PhCH2N=CPh(o-C
6H4)}(PPh3)2(MeOH)]PF6 in the case of the Ph2C=NCH2Ph reaction; the intermediate then reacts with H2 (via net heterolytic cleavage: H2 → H− + H+) to give the neutral dihydride and HPF6 as co-product. The ‘unique’ imine PhCH=NPh, under the same conditions, does not form a dihydride and instead is readily catalytically
hydrogenated to PhCH2N(H)Ph; remarkably, we have shown previously that this imine is ‘unique’ within the corresponding Rh system in that no catalytic
hydrogenation occurs because the amine product ‘poisons’ the Rh centre by coordination through the N-phenyl ring. 相似文献
10.
The complexes cis,trans,cis-[Rh(H)(2)(PPh(3))(2)(NH(2)CH(2)Ph)(2)]PF(6) (1) and cis-[Rh(PPh(3))(2)(NH(2)CH(2)Ph)(2)]PF(6) (2) are characterized by X-ray crystallography; the structures are maintained in CH(2)Cl(2) where the species are in equilibrium under H(2). In MeOH and in acetone, loss of amine and/or H(2) can occur. Traces of 1 and 2 are present after a Rh-catalyzed H(2)-hydrogenation of PhCH=NCH(2)Ph in MeOH, where the amine is generated by hydrolysis of the imine substrate through adventitious water. The findings are relevant to catalyst poisoning in the catalytic process. 相似文献