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71.
72.
We report on the synthesis of zero valent iron nano particles (nZVI) via chemical reduction method. The large peak visible in the XRD pattern reveals the presence of an amorphous phase of iron. SEM and TEM images signify the dendritic morphology and core-shell-like structure of manufactured nZVI particles respectively. Methylene blue dye (MB) was used as model contaminant to assess the reductive degradation proficiency of nZVI. With complete elimination of MB, the fresh synthesized nZVI exhibited the best performance (97%), while the regenerated nZVI had an 85.1% MB removal efficiency after five regenerations. The equilibrium data of adsorption were fitted to eight different kinetic and isothermal models. The effects of critical operating factors such as pH, varied amounts of nZVI and dye concentration, adsorption temperature, and adsorption time were also studied. A presumptive reaction mechanism and function of core-shell construction in contaminant sequestration has also been investigated. 相似文献
73.
74.
Enzyme from Daucus carota root catalyzed Henry reaction of substituted benzaldehydes and nitromethane in phosphate buffer of pH 7 at 28?°C to afford β-nitroalcohols in excellent yields (up to 94%). 相似文献
75.
Electric field gradient q and quadrupole interaction frequency
calculated at 256.7 K in the high pressure phase (orthorhombic) of
Ga metal are reported. The results are: q=+0.251 atomic units (au),
=5.479 MHz. These are compared with results from experiment and previous calculation available for the monoclinic phase of
Ga metal at normal pressure. The results from the previous calculation at 248 K are: q=-0.250 au and
=5.318 MHz. The result from experiment extrapolated to 256.7 K is:
=4.871 MHz. The sign reversal of the calculated q is attributed mainly to the change of point symmetry of the lattice from the orthorhombic to monoclinic. That the interaction frequency in high pressure phase is higher than experiment may be partly due to the increase of pressure and partly to the structural phase change. 相似文献
76.
The picolinoxy group was found to be an extremely powerful leaving group for allylic substitution with aryl nucleophiles derived from ArMgBr and CuBr*Me2S. The substitution proceeds with anti SN2' pathway and with high chirality transfer. The electron-withdrawing effect of the pyridyl group and chelation to MgBr2 are likely the origin of success. Results suggesting these effects were obtained. 相似文献
77.
Dr. Sourav Sarkar Anushree Shil Suman Maity Dr. Yun Lim Jung Dr. Mingchong Dai Prof. Atanu Acharya Prof. Kyo Han Ahn 《Angewandte Chemie (International ed. in English)》2023,62(43):e202311168
Aryl alcohol-type or phenolic fluorophores offer diverse opportunities for developing bioimaging agents and fluorescence probes. Due to the inherently acidic hydroxyl functionality, phenolic fluorophores provide pH-dependent emission signals. Therefore, except for developing pH probes, the pH-dependent nature of phenolic fluorophores should be considered in bioimaging applications but has been neglected. Here we show that a simple structural remedy converts conventional phenolic fluorophores into pH-resistant derivatives, which also offer “medium-resistant” emission properties. The structural modification involves a single-step introduction of a hydrogen-bonding acceptor such as morpholine nearby the phenolic hydroxyl group, which also leads to emission bathochromic shift, increased Stokes shift, enhanced photo-stability and stronger emission for several dyes. The strategy greatly expands the current fluorophores’ repertoire for reliable bioimaging applications, as demonstrated here with ratiometric imaging of cells and tissues. 相似文献
78.
Acharya S Gautam UK Sasaki T Bando Y Golan Y Ariga K 《Journal of the American Chemical Society》2008,130(14):4594-4595
We report on the narrowest "free" quantum rods of PbS with 1.7 nm diameter produced in a single step under bench-top reaction conditions. The nanorods exhibit molecule-like discrete narrow optical behavior with high fluorescence quantum yield. We propose a new macroscopic vortex assembly formation by simple spin casting route. Interestingly, the pattern generates fluorescence along its line from the nanorod domains. The ultra narrow nanorods with strong discrete fluorescence and robust stability could be useful in biological labeling, fluorescence resonance energy transfer, and optoelectronics applications, as well as to verify the theories in the very strong confinement regime. 相似文献
79.
Debabrata Acharya Anne‐Claire Mitaine‐Offer Nutan Kaushik Tomofumi Miyamoto Thomas Paululat Marie‐Aleth Lacaille‐Dubois 《Helvetica chimica acta》2008,91(12):2262-2269
Four new furostanol steroid saponins, borivilianosides A–D ( 1 – 4 , resp.), corresponding to (3β,5α,22R,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐22‐hydroxyfurostan‐3‐yl O‐β‐D ‐xylopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)]‐β‐D ‐galactopyranoside ( 1 ), (3β,5α,22R,25R)‐ 26‐(β‐D ‐glucopyranosyloxy)‐22‐methoxyfurostan‐3‐yl O‐β‐D ‐xylopyranosyl‐(1→3)‐O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)]‐β‐D ‐galactopyranoside ( 2 ), (3β,5α,22R,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐22‐methoxyfurostan‐3‐yl O‐β‐D ‐xylopyranosyl‐(1→3)‐O‐[β‐D ‐glucopyranosyl‐(1→2)]‐O‐β‐D ‐glucopyranosyl‐(1→4)‐β‐D ‐galactopyranoside ( 3 ), and (3β,5α,25R)‐26‐(β‐D ‐glucopyranosyloxy)furost‐20(22)‐en‐3‐yl O‐β‐D ‐xylopyranosyl‐(1→3)‐O‐[β‐D ‐glucopyranosyl‐(1→2)]‐O‐β‐D ‐glucopyranosyl‐(1→4)‐β‐D ‐galactopyranoside ( 4 ), together with the known tribuluside A and (3β,5α,22R,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐22‐methoxyfurostan‐3‐yl O‐β‐D ‐xylopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)]‐β‐D ‐galactopyranoside were isolated from the dried roots of Chlorophytum borivilianum Sant and Fern . Their structures were elucidated by 2D ‐NMR analyses (COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry. 相似文献
80.
This paper is concerned with the rate of convergence of the distribution of the maximum likelihood estimators of the arrival
and the service rates in a GI/G/1 queueing system.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献