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排序方式: 共有114条查询结果,搜索用时 31 毫秒
1.
Rajendran Arunachalam Eswaran Chinnaraja Arto Valkonen Kari Rissanen Palani S. Subramanian 《应用有机金属化学》2019,33(11)
The multidentate ligand H2 L upon complexation with Zn (II) and Cd (II) provide a one‐dimensional polymeric networks. These coordination polymers (CPs) CP‐1 and CP‐2 containing Zn (II) and Cd (II) metals respectively are well characterized. The single crystal structural analysis confirms the formation of one‐dimensional coordination polymer with zigzag fashion in CP‐1 and ladder chain CP‐2 . Both the CPs are applied as catalysts to synthesize various cyclic carbonates from epoxides and carbon dioxide. The catalysts are giving better conversion under solvent‐free and additive‐free condition using 10 bar CO2 and 100 °C as optimized pressure and temperature. The detailed kinetic experiments suggesting the first order kinetics, the energy of activation (Ea) is calculated for this catalytic conversion. 相似文献
2.
P Permi S Heikkinen I Kilpel?inen A Annila 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1999,139(2):273-280
(1)H-detected two-dimensional double-/zero-quantum experiments are described for measurement of homonuclear (2)J(HH)-couplings of NH(2) or CH(2) groups in proteins. These experiments utilize multiple-quantum coherence for determination of the size and the absolute sign of the geminal scalar and dipolar couplings in the presence of broad lines. Spectra are simplified by gradient selection and spin-state selective filters. 相似文献
3.
Paula I. Oja Timo T. Kouri Arto J. Pakarinen 《Accreditation and quality assurance》2010,15(7):415-420
Modern quality standards for laboratories recommend the use of customer feedback in quality improvement. Spontaneous customer
feedback is one method to obtain information from customers. In the present study, we analysed the feedback data from external
customers (health centres and other hospitals) to our university hospital laboratory during 2001–2006. The most common subject
matters of the feedback, covering 87% of a total of 95 reports, were lacking test results, suspicion of the validity of test
results, return of samples in transportation boxes to customers and delays in service. On investigation, errors or defects
were revealed in 78 cases. The most common errors were lacking (45 cases; 58%), erroneous (20 cases; 26%) or delayed test
results (7 cases; 9%). As much as 68% of these errors took place in the pre-analytical phase of the laboratory process, occurring
most commonly during specimen transfer, when entering orders into the laboratory information system at the university hospital
or during sample processing. The most common underlying causes for errors were unintended errors and non-compliance with operating
instructions. Latent errors were identified in 14% of the cases. Corrective actions were performed in 79% of the reported
cases. It is important that the feedback reports are investigated to find out possible errors and their underlying causes
so that appropriate corrective actions can be taken. When processed properly, spontaneous customer feedback is a method that
can be used supplementarily to other methods to detect errors and defects in clinical laboratories and to aid in quality improvement. 相似文献
4.
Perttu Permi Sami Heikkinen Ilkka Kilpelinen Arto Annila 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1999,139(2):273
1H-detected two-dimensional double-/zero-quantum experiments are described for measurement of homonuclear 2JHH-couplings of NH2 or CH2 groups in proteins. These experiments utilize multiple-quantum coherence for determination of the size and the absolute sign of the geminal scalar and dipolar couplings in the presence of broad lines. Spectra are simplified by gradient selection and spin-state selective filters. 相似文献
5.
Nikolaos Pahimanolis Arto Salminen Paavo A. Penttilä Juuso T. Korhonen Leena-Sisko Johansson Janne Ruokolainen Ritva Serimaa Jukka Seppälä 《Cellulose (London, England)》2013,20(3):1459-1468
In this paper, nanofibrillated cellulose/carboxymethyl cellulose (CMC) composite films were prepared using tape casting. The obtained transparent films showed shear induced partial alignment of fibrils along the casting direction, resulting in birefringence in cross polarized light. The carboxyl groups of CMC could be further utilized to create ionic crosslinking by treatment with glycidyl trimethyl ammonium chloride (GTMA). The GTMA treated composite films had improved mechanical properties both in wet and dry state. The chemical composition and morphologies of composites were analyzed with X-ray photoelectron spectroscopy, elemental analysis, scanning electron microscopy and wide-angle X-ray scattering. 相似文献
6.
Kalle Rnkk Mathias Berner Reija Jokela Arto Tolvanen 《Journal of heterocyclic chemistry》2000,37(5):1145-1149
The total syntheses of 11‐methoxydeethyleburnamonines ( 4 ) and ( 13 ) were carried out with use of 6‐methoxytryptophyl bromide ( 5 ) as starting material. Compound 5 was converted in three steps to trans‐ester 8 . Acid‐catalysed epimerization of 8 , lithium aluminum hydride reduction of the ester group, tosylation and substitution with cyanide gave the cis‐nitrile 12 . Acid‐induced cyclization of 12 yielded mainly (±)‐trans‐11‐methoxydeethyleburnamonine ( 13 ), whereas base‐induced cyclization gave (±)‐cis‐11‐methoxydeethyleburnamonine ( 4 ). 相似文献
7.
Tanja Seraidaris Arto Puranen Mikko Karesoja Barbro Lfgren Timo Repo Markku Leskel Jukka Seppl 《Journal of polymer science. Part A, Polymer chemistry》2006,44(16):4743-4751
Elastic polypropene has gained growing industrial and academic interest as a thermoplastic elastomer. In this study, “rac”‐ and “meso”‐dimethylsilyl(3‐benzylindenyl)(2‐methylindenyl)hafnium dichloride complexes (Hfr and Hfm, respectively), activated with [NHMe2Ph][B(C6F5)4]/triisobutyl aluminum, were used in propene polymerization. Using these catalyst systems, we obtained polymers with high molar masses, up to 550 kg/mol, and moderate isotacticities between 34 and 52%. By varying the polymerization conditions, we could modify the polymer microstructure and molar mass. 13C NMR was used to calculate the polymer pentad sequence distributions. The crystalline parts of the polymers were analyzed with the differential scanning calorimetry successive self‐nucleation and annealing (SSA) technique. The SSA thermograms revealed that Hfr produced polypropene with a more uniform lamellar structure than Hfm. The mechanical properties were tested with dynamic mechanical analysis creep‐recovery tests. In the series, the polymers with the lowest isotacticities and therefore lowest crystallinities showed the best elastic properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4743–4751, 2006 相似文献
8.
Patrik Andersson Arto Annila Gottfried Otting 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,133(2):364-367
A generalized version of the TROSY experiment allows the spin-state selective editing of the four multiplet components of15N–1H cross peaks of amide groups in proteins into four different subspectra, with no penalty in sensitivity. An improvement by
in sensitivity results, if only two of the four multiplet components are selected. Use of the experiment for the measurement of1JHNcoupling constants is discussed. A water flip-back version of the experiment is demonstrated with a 45 kDa fragment of15N/2H labeledStaphylococcus aureusgyrase B. 相似文献
9.
Mikko Keränen Marcin Gnyba Paavo Raerinne Terho Kololuoma Arto Maaninen Juha T. Rantala 《Journal of Sol-Gel Science and Technology》2004,31(1-3):369-372
Sol–gel adhesive material for isostatic hotpressing lamination process was synthesized using 3-aminopropyltrimethoxysilane (APTES), 3-glycidyloxypropyltrimethoxysilane (GPTS) and methacryloxypropyltrimethoxysilane (MPTS) as precursors. Reaction dynamics between APTES and GPTS was followed on-line with Raman spectroscopy. The lamination process was optimized by varying hotpressing times and pressures at the constant temperature. Mechanical shear strength properties were found to be excellent for studied composition, 25–30 kg/cm2 at its best. One possible application of laminated polycarbonate (PC) structure is a soldier helmet visor. Therefore, the ballistic protection properties were tested by shooting with 1.1 gram standard fragment, and determining the v50 velocity value, which corresponds to 50% perforation. The laminated structure gave 5.7% better protection compared with the solid polycarbonate. The laminated components were found to have high optical transparency at the visible wavelengths as well as high environmental stability. 相似文献
10.
Cauliflower-like CdS microspheres composed of nanocrystals and their physicochemical properties 总被引:1,自引:0,他引:1
Rengaraj S Venkataraj S Jee SH Kim Y Tai CW Repo E Koistinen A Ferancova A Sillanpää M 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):352-358
Cauliflower-like cadmium sulfide (CdS) microspheres composed of nanocrystals have been successfully synthesized by a hydrothermal method using poly(ethylene glycol) (PEG) as the template coordination agent and characterized by a variety of methods. Our experiments confirmed that the size of the CdS microspheres could be easily modified by controlling the chain length of PEG. Powder X-ray diffraction and Raman spectroscopy measurements revealed the cubic structure of the CdS microspheres; morphological studies performed by HR-SEM and HR-TEM methods showed the cauliflower-like structure of the synthesized CdS microspheres. Each microsphere was identified to be created by the self-assembly of CdS nanocrystals and is attributed to the oriented aggregation of the CdS nanocrystals around a polymer-Cd(2+) complex spherical framework structure. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray (EDX) analysis confirmed the stoichiometries of the CdS microspheres. Diffuse reflectance spectrum (DRS) measurements showed that increasing the PEG chain length increased the band gap value of the CdS microspheres slightly, from 1.99 to 2.06 eV. The cauliflower-like CdS microspheres could be applied to photocatalytic degradation studies. 相似文献