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41.
Agarwal Madhu Kuldeep Brijesh John Annie P. Maheshwari Karishma Dohare Rajeev 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7243-7252
Journal of Thermal Analysis and Calorimetry - In this study, beeswax is studied as a phase change material (PCM) to store heat due to its high latent heat. The disadvantages of using beeswax were... 相似文献
42.
43.
Sakram B. Madhu P. Sonyanaik B. Rambabu S. Ravi D. Kurumanna A. 《Russian Journal of General Chemistry》2018,88(6):1224-1227
Russian Journal of General Chemistry - A new methodology has been developed for the synthesis of novel 2-oxo-1,2-dihydro-1,8-naphthyridine-3-carboxylates from 2-aminonicotinaldehyde,... 相似文献
44.
Dr. Madhu Sheri Dr. Umesh Choudhary Dr. Sunitha Grandhee Prof. Todd Emrick 《Angewandte Chemie (International ed. in English)》2018,57(17):4599-4602
We report a fluoride‐catalyzed deblocking of urethanes as “blocked” isocyanates. Organic and inorganic sources of fluoride ion proved effective for deblocking urethanes and for converting polyurethanes to small molecules. Distinct from conventional deblocking chemistry involving organometallic compounds and high temperatures, the method we describe is metal‐free and operates at or slightly above room temperature. The use of fluorescent blocking agents enabled visual and spectroscopic monitoring of blocking/deblocking reactions, and the selected conditions proved applicable to urethanes containing a variety of blocking groups. The method additionally enabled a one pot deblocking and polymerization with α,ω‐diols. Overall, this deblocking/polymerization strategy offers a convenient and efficient solution to problems that have limited the breadth of applications of polyurethane chemistry. 相似文献
45.
Isiaka A. Owolabi U.V. Subba Reddy Madhu Chennapuram Chigusa Seki Yuko Okuyama Eunsang Kwon Koji Uwai Michio Tokiwa Mitsuhiro Takeshita Hiroto Nakano 《Tetrahedron》2018,74(36):4705-4711
A new type of amino amide organocatalysts was designed and synthesized from commercially available amino acids in easy steps. Their catalytic activities were examined in enantioselective crossed aldol reaction of various acyclic and cyclic ketones with aromatic aldehydes to afford the corresponding chiral anti-aldol adducts with good to excellent chemical yields, diastereoselectivities and enantioselectivities (up to 99%, up to syn:anti?=?1:99, up to 97% ee). 相似文献
46.
Recently, a sequence for heteronuclear dipolar decoupling in solid-state NMR, namely SWf-TPPM, was introduced by us. Under magic-angle spinning (MAS), the decoupling efficiency of the sequence was unaffected over a range of values for various experimental parameters such as the pulse length, pulse phase, and 1H resonance offset. We here demonstrate its use in multiple-quantum (MQ) and high-resolution (HR) MAS experiments. This sequence further improves the MQMAS spectra compared to the earlier reported decoupling sequences with improved immunity to any missets of the pulse length, pulse phase and decoupler offset. In contrast, for HRMAS, the simple CW scheme is as efficient as any of the decoupling schemes that were studied. 相似文献
47.
Infinite Polyiodide Chains in the Pyrroloperylene–Iodine Complex: Insights into the Starch–Iodine and Perylene–Iodine Complexes 下载免费PDF全文
Dr. Sheri Madhu Hayden A. Evans Dr. Vicky V. T. Doan‐Nguyen Dr. John G. Labram Dr. Guang Wu Prof. Dr. Michael L. Chabinyc Prof. Dr. Ram Seshadri Prof. Dr. Fred Wudl 《Angewandte Chemie (International ed. in English)》2016,55(28):8032-8035
We report the preparation and X‐ray crystallographic characterization of the first crystalline homoatomic polymer chain, which is part of a semiconducting pyrroloperylene–iodine complex. The crystal structure contains infinite polyiodide I∞δ?. Interestingly, the structure of iodine within the insoluble, blue starch–iodine complex has long remained elusive, but has been speculated as having infinite chains of iodine. Close similarities in the low‐wavenumber Raman spectra of the title compound and starch–iodine point to such infinite polyiodide chains in the latter as well. 相似文献
48.
Gaurav?Madhu Haripada?BhuniaEmail author Pramod?K.?Bajpai Golok?B.?Nando 《Polymer Science Series A》2016,58(1):57-75
Blends of high density polyethylene/poly(lactic acid) with/without compatibilizer and pro-oxidant (cobalt stearate) were prepared by melt blending technique. In ratio 80/20, the blend revealed a good combination of tensile properties and optimum poly(lactic acid) content. The improvement in mechanical properties of this blend was achieved by addition of 4 phr compatibilizer. Cobalt stearate (CoSt) was added to 80/20 blends in 0.1% and 0.2% (w/w) ratios. The obtained blends were characterized by DSC, SEM, FTIR spectroscopy, rheological study, etc. All the prepared blends were able to biodegrade in composting environment and the blend containing pro-oxidant was maximum degraded. 相似文献
49.
P.K. Madhu 《Solid state nuclear magnetic resonance》2009,35(1):2-11
High-resolution NMR spectroscopy of 1H spins in the solid state is normally rendered difficult due to the strong homonuclear 1H–1H dipolar couplings. Even under very high-speed magic-angle spinning (MAS) at ca. 60–70 kHz, these couplings are not completely removed. An appropriate radiofrequency pulse scheme is required to average out the homonuclear dipolar interactions in combination with MAS to get high-resolution 1H NMR spectrum in solid state. Several schemes have been introduced in the recent past with a variety of applications also envisaged. Development of some of these schemes has been made possible with a clear understanding of the underlying spin physics based on bimodal Floquet theory. The utility of these high-resolution pulse schemes in combination with MAS has been demonstrated for spinning speeds of 10–65 kHz in a range of 1H Larmor frequencies from 300 to 800 MHz. 相似文献
50.
Michal Leskes P.K. Madhu Shimon Vega 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2009,199(2):208-213
Schemes such as phase-modulated Lee–Goldburg (PMLG) for homonuclear dipolar decoupling have been shown to yield high-resolution 1H spectra at high magic-angle spinning (MAS) frequencies of 50–70 kHz. This is at variance to the commonly held notion that these methods require MAS frequencies not comparable to the cycle frequencies of the pulse schemes. Here, a theoretical argument, based on bimodal Floquet theory, is presented to explain this aspect together with conditions where PMLG type of schemes may be successful at high MAS frequencies. 相似文献