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排序方式: 共有174条查询结果,搜索用时 31 毫秒
1.
Hafiz Muhammad Bilal Ameer Muhammad Faizan Ameer Kaouther Ghachem Muhammad Ali Ahsan Razaq Sami Ullah Khan Muhammad Hamza Lioua Kolsi 《印度化学会志》2022,99(6):100505
The environmental degradation, combined with the continuous depletion of the world's fossil fuel reserves, has forced the search for alternative fuels. This study was performed to investigate the performance of novel biodiesels in the CI engine. The experiments were performed at three different compressions ratios (16:1, 17:1, 18:1) and four loading conditions (25%, 50%, 75%, 100%). Different types of fuels such as jatropha biodiesel (JB), roselle biodiesel (RB), and ternary biodiesel (TB) were prepared and analyzed. The thermal performance of different fuels was analyzed in terms of brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), and exhaust gas temperature (EGT). The emission characteristics such as CO2 emission, NOx emission, and smoke emission were analyzed for all types of fuels. The results of these fuels in the engine were compared with mineral diesel (MD). The BTE was increased with increasing compression ratios and loads for all types of fuels. The BSFC was increased with increasing compression ratios but decreased with increasing loads. The increase in emission of NOx was observed at higher compression ratios and loads. However, the CO2 emission was decreased at higher loads and lower compression ratio. The performance curves achieved with a 20% jatropha biodiesel blend showed results that were approximate to those obtained with pure MD. The comparative analysis between different fuels showed that JB exhibit higher thermal performance as compared to other biodiesels. Therefore, JB can be a better alternative to conventional fuel. 相似文献
2.
One-pot synthesis of pyrano[2,3-c]pyrazole derivatives via two or multicomponent condensation of β-ketoesters, hydrazine monohydrate/phenyl hydrazine, malononitrile, and substituted benzaldehydes is of great interest not only in synthetic chemistry but also in medicinal chemistry because of the tremendous biological activities, such as anticancer, anti-inflammatory, analgesic, antimicrobial, and enzyme inhibitory activities exhibited by pyranopyrazoles. This review provides extensive knowledge on novel synthetic methodologies of biologically active non-spiro/spiro-pyrano[2,3-c]pyrazole derivatives published recently. 相似文献
3.
Khadhar Navaz Umar Basha Shanthi Gnanamani Prakash Shanmugam Sujatha Venugopal Sangeetha Murthy Balagurunathan Ramasamy 《Journal of heterocyclic chemistry》2021,58(10):2000-2008
A simple and convenient method for the one-pot synthesis of 3-(1H-indole-3-carbonyl)-2H-chromen-2-one derivatives from the reaction of 3-cyanoacetyl indole and salicylaldehyde in the presence of Na2CO3 in water: methanol (1:1) is described. Wider substrate scope, high yields, operational simplicity, and simple purification process make the protocol highly applicable in the synthesis of 3-(1H-indole-3-carbonyl)-2H-chromen-2-ones. For the first time, in vitro antioxidant and antimicrobial activity was studied. Compounds 5e , 7a , and 7b exhibits good radical scavenging ability against DPPH free radical. Compounds 7b , 5f , and 5g possess lower EC50 values than the Standards AA and BHA and thus proving their high reducing power. Compounds 5d and 5f show good antibacterial activity against gram-positive bacteria (MRSA) while compounds 5c , 7a , and 7b exhibits good antibacterial activity against Bacillus sp. Compounds 5b and 5e show good antibacterial activity against gram negative bacterial strains (Escherichia coli, Klebsiella pneumoniae) and compounds 5g and 5h exhibits good antifungal activity against Candida albicans. 相似文献
4.
Monomer of 7-methacryloyloxy-4-methylcoumarin(MAOMC) was synthesized and characterized by FTIR, 1H-NMR and 13C-NMR spectroscopy. Copolymers of MAOMC with butoxyethylmethacrylate(BOEMA) at different feed compositions were prepared by free radical solution polymerization at(70 ± 1) °C in ethylmethylketone(EMK) using benzyl peroxide(BPO) as an initiator. The copolymers were characterized by FTIR and 1H-NMR spectroscopy. Thermogravimetric analysis(TGA) and differential scanning calorimetry(DSC) of the copolymers showed moderate thermal stability and higher Tg values. Gel permeation chromatography(GPC) was used to find out the molecular weights of the different copolymers. Antibacterial activities of the copolymers were also investigated against the selected pathogenic bacteria's. The antibacterial activity of the copolymer increases as the MAOMC content increases in the copolymer. This shows that coumarin moiety plays a very important role in the antibacterial activity. 相似文献
5.
Irum Shahzadi Ameer F. Zahoor Azhar Rasul Nasir Rasool Zohaib Raza Shahla Faisal Bushra Parveen Shagufta Kamal Muhammad Zia-ur-Rehman Faisal M. Zahid 《Journal of heterocyclic chemistry》2020,57(7):2782-2794
Theophylline-7-acetic acid (acefylline) ( 3 ) and its derivatives are pharmacologically active compounds and generally recognized as bronchodilators for the treatment of respiratory diseases like acute asthma for over 70 years. In this article, synthesis of 2-((5-((1,3-dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-yl)thio)-N-arylacetamides ( 10a-j ) has been reported. All the synthesized derivatives ( 10a-j) were structurally verified by FT-IR, 1H NMR, 13C NMR and evaluated for their anti-cancer (using MTT assay), hemolytic and thrombolytic potential. N-(4-Chlorophenyl)-2-(5-((1,3-dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-ylthio)acetamide ( 10g ) was found to be the most active against human liver cancer cell lines (Huh7) having cell viability 53.58 ± 1.28 using 100 μg/mL concentration of compound which was further in-silico modelled to describe the possible mechanistic insights for its anti-proliferative activity. The results of hemolytic and thrombolytic activities indicated that these derivatives were less toxic and hold considerable potential as a drug candidate. 2-(5-((1,3-Dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-ylthio)-N-(2-fluorophenyl)acetamide ( 10c ) of the series was found to be least toxic with 0.1% hemolysis relative to ABTS (95.5%) as positive control. 2-(5-((1,3-Dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-1,3,4-oxadiazol-2-ylthio)-N-(tetrahydro-2H-pyran-4-yl)acetamide ( 10j ) exhibited potent clot lysis activity (90%) as compared to negative control DMSO (0.57%). 相似文献
6.
Heck cross-coupling reactions of 2,3-dichloropyrazine provide a convenient approach to 2,3-dialkenyl-, 2-alkenyl-3-alkyl-, and 2,3-dialkylpyrazines depending on the reaction conditions. 相似文献
7.
The internal bremsstrahlung (IB) spectrum accompanying the β-decay from 185W radionuclide has been measured. The obtained spectrum was analyzed into its constituting gamma lines taking into account all the proper corrections. The analyzed spectrum was compared with those theoretically calculated. The experimental results for the IB probability were found to be in good agreement with theoretical calculations especially with the shape corrected modified KUB theory of Nilsson up to 357.7 keV. 相似文献
8.
The notion of an alternatingly hyperexpansive operator on a Hilbert space is generalized to that of an alternatingly hyperexpansive operator tuple, which necessitates exploring the theory of absolutely monotone functions as defined on the m-fold product N
m of the semi-group N of non-negative integers and as defined on semi-open cubes in the m-dimensional real Euclidean space R
m. The multi-variable Laplace transform and the Stieltjes Moment Problem make a natural appearance in the development of the relevant theory, which also highlights the close connections of alternatingly hyperexpansive operator tuples with completely hyperexpansive and subnormal ones. In particular, if T is subnormal and the joint (Taylor) spectrum of its minimal normal extension is contained in a certain subset of the Hermitian space C
m, then T turns out to be alternatingly hyperexpansive. In the context of multi-variable weighted shifts, the last assertion can be related to the notion of a Stieltjes Moment Net. The general characterization of an alternatingly hyperexpansive m-variable weighted shift T, however, requires a certain net of (positive) numbers associated with T to be absolutely monotone on N
m and allows for such a T to be non-subnormal. 相似文献
9.
Ameer Athavale 《Integral Equations and Operator Theory》1989,12(3):305-323
A notion of the dual of a subnormal tuple of operators is discussed. 相似文献
10.
Syed Rasheed Devineni Subba Rao Chennamsettty Subramanyam Shaik Thaslim Basha 《合成通讯》2014,44(20):2988-2998
An expeditious, simple, and green method was developed for the synthesis of privileged aryl/heterocyclicphosphonates, 8(a–c) to 13(a–c) through Michaelis–Arbuzov reaction of aryl/heterocyclic halides (Br), 1–6, and trialkylphosphites, 7(a–c), in room-temperature ionic liquid [bbim]Br using heterogeneous Lewis catalyst, nano-silica-supported boron trifluoride (BF3-SiO2). The advantages of this protocol are simplicity, good yield of the products, less reaction time (20–38 min), mild reaction conditions, easy workup, and reusability of the catalyst and ionic liquid. It is demonstrated that nano-BF3-SiO2 is a recoverable and easy accessible catalyst for the formation of C(sp2)-P bond in an ionic liquid. 相似文献