JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
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2014
·Vol. 25
·期 9
·1704-1711
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IF 1.253
Tan Zhongqin,Fang Miaoli,Du Huan,Song Lelian,Ren Dahai,Tang Xiujuan,Han Xiaoxiang,Liang Xinle
The synthesis between palmitic acid and methanol was carried out in a w/o reverse microemulsion prepared from the mixture of dodecylbenzenesulfonic acid (DBSA)/isooctane/water. Box-Behnken design was adopted to evaluate the effect of significant factors on the methyl palmitate yield and response surface methodology (RSM), which was employed to optimize the process parameters in the esterification. The conditions that showed optimal results for methyl palmitate preparation were: 3.33 w0 ([H2O]/[surfactant]), 4.2 h reaction time, 5:1 methanol/acid molar ratio, and 130 mg g-1 lipase ([lipase]/[acid]) concentration. The following verification experiment obtained a result of 97% in almost total agreement with the expected value (98%). The kinetic constants of the model were determined by experiments at 40 °C with initial concentrations of 0.025-0.25 mol L-1 palmitic acid and 0.025-0.3 mol L-1 methanol in the microemulsion system. The kinetic studies showed that the reaction obeyed the Ping-Pong bi-bi mechanism with inhibition by methanol.
研究领域:
生物化学
·
生物工程
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International Journal of Minerals Metallurgy and Materials
·
2025
·Vol. 32
·期 3
·645-656
·
IF 7.2
Wang Long,Liu Jiurong,Xie Shenghui,Deng Yanli,Wang Zhou,Hou Shanyue,Yue Shengying,Wang Gang,Wu Na,Zeng Zhihui
W-type barium–nickel ferrite (BaNi 2 Fe 16 O 27 ) is a highly promising material for electromagnetic wave (EMW) absorption because of its magnetic loss capability for EMW, low cost, large-scale production potential, high-temperature resistance, and excellent chemical stability. However, the poor dielectric loss of magnetic ferrites hampers their utilization, hindering enhancement in their EMW-absorption performance. Developing efficient strategies that improve the EMW-absorption performance of ferrite is highly desired but remains challenging. Here, an efficient strategy substituting Ba 2+ with rare earth La 3+ in W-type ferrite was proposed for the preparation of novel La-substituted ferrites (Ba 1− x La x Ni 2 Fe 15.4 O 27 ). The influences of La 3+ substitution on ferrites’ EMW-absorption performance and the dissipative mechanism toward EMW were systematically explored and discussed. La 3+ efficiently induced lattice defects, enhanced defect-induced polarization, and slightly reduced the ferrites’ bandgap, enhancing the dielectric properties of the ferrites. La 3+ also enhanced the ferromagnetic resonance loss and strengthened magnetic properties. These effects considerably improved the EMW-absorption performance of Ba 1− x La x Ni 2 Fe 15.4 O 27 compared with pure W-type ferrites. When x = 0.2, the best EMW-absorption performance was achieved with a minimum reflection loss of −55.6 dB and effective absorption bandwidth (EAB) of 3.44 GHz.
研究领域:
材料科学
·
电磁学
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MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2023
·
IF 6.4
He Zhang,Guo-Hua Zhang
In this paper, using the ultrafine W-27.5 wt%Cu-2wt.%Mo-1.75 wt%Ni-0.75 wt%Fe-(0–1)wt.%CeO 2 alloy powders as raw materials, W–Cu–Mo–Ni–Fe–CeO 2 alloys with excellent performances were prepared by low temperature sintering . Two-step reduction method consisting of carbothermic pre-reduction and hydrogen deep deoxidation was used to produce ultrafine W–Cu–Mo–Ni–Fe–CeO 2 alloy powders with uniform distributed composition. All sintered blocks obtained relatively high densification degree (97.1 %∼99.2 %) to ensure the excellent comprehensive properties. Moreover, the existences of γ-(Cu, Ni, Fe) and W–Mo solid solutions ensured the alloy possessed a high mechanical strength . More importantly, the introduction of CeO 2 inhibited the growth of W–Mo grains. With increasing CeO 2 content from 0 wt% to 1 wt%, the W–Mo grain size decreased from 1.76 μm to 1.44 μm. Especially, alloy sample with the highest tensile and compressive strengths was obtained by adding 0.5 wt% CeO 2 , which were 602 MPa and 3187 MPa, respectively. Furthermore, owing to finer W–Mo grain size, this sample also possessed the maximum micro-hardness and bending strength of 482 H V and 1685 MPa, respectively. Nevertheless, the existences of Ni, Fe and CeO 2 also destroyed the electrical conductivities of the samples to some extent. Specifically, with increasing CeO 2 content from 0 wt% to 1 wt%, the electrical conductivity of the sample decreases from 32.56 %IACS to 30.16 %IACS.
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ACS Biomaterials Science & Engineering
·
2023
·
IF 5.8
Kaibo Xu,Liqin Cao,Zhouyu Wang,Liu-ping Chen
Hemoperfusion (HP) is one of the most prominent therapies for treating uremia, hyperbilirubinemia, and acute drug toxicity. The comprehensive performance of currently used porous HP adsorbents needs to be improved due to the impediment to their synthesis strategy. Herein, green carbon dioxide-in-water high internal phase emulsions (C/W HIPEs) were utilized and emulsified with poly(vinyl alcohol) (PVA) for the formation of a heparin-mimetic chitosan oligosaccharides/poly(acrylamide-co-sodium 4-styrenesulfonate) [COS/P(AM-co-SSS)] monolith, which exhibited good mechanical properties, stable swelling performance, hydrophilic properties, anticoagulant effect, and low hemolysis. It showed a strong toxin adsorption capacity (415.2 mg/g for creatinine, 199.3 mg/g for urea, 279.5 mg/g for bilirubin, and 160 mg/g for tetracycline). The adsorption process of porous COS/P(AM-co-SSS) followed the pseudo-second-order kinetic and Langmuir isotherm models. Moreover, the porous materials had a strong electrostatic force on creatinine. The removal of creatinine by simulated in vitro blood perfusion was 80.2% within 30 min. This work provides a green preparation strategy for developing novel HP materials, highlighting their potential application value in blood and environmental purification.
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PubMed
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METALS AND MATERIALS INTERNATIONAL
·
2021
·Vol. 27
·期 12
·5389-5398
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IF 3.642
Hong S. F.,Lu Z. C.,Liu Y. H.,He Q. M.,Jiang W.,Zeng M. Q.
Abstract Supersaturated solid–solutions in a W–Cr alloy system were fabricated by conventional milling and plasma milling. The different extension mechanisms of the solid solubility that were created by ball milling with and without discharge plasma were studied. The solid–solubility of Cr in W for the P-milling W–Cr alloy system was higher, which indicates that plasma milling promotes the formation of W(Cr) solid–solution more easily than conventional milling. According to Miedema’s model, in the W–Cr alloy system, the free-energy change to form a W(Cr) solid solution by plasma milling is reduced compared with conventional milling because of the heating effect of the discharge plasma. Therefore, a higher stored energy in the grain boundaries and dislocations of the W–Cr nanograins during plasma milling makes it easier to overcome the thermodynamic barrier in the formation of a solid–solution, when compared with conventional milling. Graphic Abstract
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CELLULOSE
·
2020
·Vol. 27
·期 13
·7591-7605
·
IF 4.21
Wang Haiyong,Hu Xiaohong,Liu Siwei,Cai Chiliu,Zhu Changhui,Xin Haosheng,Xiu Zhongxun,Wang Chenguang,Liu Qiying,Zhang Qi,Zhang Xinghua,Ma Longlong
The bi-functional Ni–W@C catalysts were prepared by one-pot reduction–carbonization method and used in hydrogenolysis of cellulose as well as raw lignocellulosic biomass to chemicals. The catalytic performance for cellulose conversion showed that it was more favorable for ethylene glycol (EG) production, obtaining the highest EG yield 60.1% over the Ni–W@C 700 catalyst. The Ni–W@C bimetallic catalysts are systematically characterized with BET, XRD, Raman, XPS, TEM techniques and experiments to probe the active catalytic sites of the catalysts. The effects of calcination temperature of Ni–W catalysts, reaction time, temperature and H 2 pressure on cellulose hydrogenolysis were investigated in detail. The Ni particles could lead to produce more W 5+ active sites, which promotes the glucose retro-aldol condensation to break the target C–C bonds. Metallic Ni catalyzed C=O hydrogenation and C–C hydrogenolysis, which could also avoid the coke formation. The EG selectivity was dependent on the synergy of WO x and Ni metal sites. In addition, this synergistic effect between the metal and WO x could promote lignin component degradation in direct conversion of untreated raw lignocellulosic biomass, obtaining the propyl monophenolics including guaiacylpropane, syringylpropane and p-n-propylphenol with a total yield of 17.3 wt% besides EG.
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CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Bingjie Han,Jing Ren,PingPing Teng,JiaBao Zhu,Yu Shen,ZhiAng Li,Xiaoliang Zhu,Xinghua Yang
At present, the combination of red, green and blue light (RGB) is one of the mainstream ways to obtain high-efficiency white light emitting diodes (w-LEDs). In this paper, we have prepared a new type of Sm 3+ activated Ca 2 LaSbO 6 (CLSO) orange-red phosphor by the high-temperature solid-phase method. The phase and morphology of the powders were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The luminescent properties, thermal stability of the materials have been tested and analyzed in detail. The results show that CLSO:Sm 3+ phosphors have several excitation bands in the range of 320–550 nm, and the excitation peak intensity at 405 nm is the largest, indicating that the material can be excited by blue light. The emission peak is composed of 564 nm (yellow), 601 nm (orange) and 648 nm (red), emission intensity reaches the extreme value when the Sm 3+ doping concentration is 5 mol%, the quenching phenomenon is due to the dipole-dipole (d-d) interaction of Sm 3+ ions. The activation energy ( E a ) of Sm 3+ in CLSO is 0.2689 eV. The CIE chromaticity coordinates of CLSO:Sm 3+ located at origin-red region. All results show that CLSO:Sm 3+ phosphor has potential application value in w-LEDs field.
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RSC Advances
·
2019
·Vol. 9
·期 20
·11046-11053
·
IF 3.049
Pengjian Wang,Junfeng Hui,Tingbiao Yuan,Peng Chen,Yue Su,Wenjie Liang,Fulin Chen,Xiaoyan Zheng,Yuxin Zhao,Shi Hu
Ultrafine nanoparticles of W-doped SnO2 with an average diameter of 6 nm were fabricated via a facile hydrothermal method. The material shows a reduced particle size and enhanced response to H2S gas as compared to the pristine SnO2 nanoparticles. The detection limit can be down to 100 ppb while the response time and recovery time of the 5%-doped one are reduced to 17 s and 7 s respectively. In addition, the material shows impressive long-term stability of the response through 40 cycles of injection with 10 ppm H2S, which is attractive for designing a durable hydrogen sulfide sensor. The doping of W results in the reduction of size and modification of the electronic band structure of SnO2, which reduces the response time and recovery time and further improves the sensing durability of the materials.
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高影响因子
FOOD HYDROCOLLOIDS
·
2019
·
IF 5.839
Qi Li,Bing Xie,Yixiang Wang,Yanting Wang,Liangcai Peng,Yan Li,Bin Li,Shilin Liu
For high value utilization of energy crops, in this work, a high stable O/W Pickering emulsion had been prepared successfully by using cellulose nanofibrils (CNFs) obtained from Miscanthus floridulus straw (MFS). The effect of high pressure homogenization time on the physicochemical properties of the resulted CNFs had been investigated. The obtained CNFs had high surface activity and could spontaneously diffuse to the interface of the O/W phase. The particle adsorption kinetics of CNFs was characteristic of soft particles or Pickering emulsifiers, and the adsorption was irreversible. Therefore, stable oil-in-water Pickering emulsion was obtained by using the CNFs as particle emulsifiers, and the emulsion stabilized by CNFs with only 0.15 wt% exhibited outstanding stability. Moreover, the environmental factors, such as pH values, ionic strength, and temperature had little influence on the stability of the emulsion. All the results indicated that CNFs exhibited promising interfacial activity and powerful emulsifying ability. Owing to the flexible shape of the CNFs, it was concluded that MFS as a kind of energy crop was a promising source to obtain the CNFs for the fabrication of novel food-grade Pickering emulsions.
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Micro & Nano Letters
·
2018
·Vol. 13
·期 10
·1373-1377
·
IF 0.841
Hui Zhao,Yuqing Miao
The Ni–W–S nanoparticles (NPs) were synthesised on Ti mesh through the typical hydrothermal method. The obtained Ti/Ni–W–S was characterised on morphology, composition and electrocatalytic property. It showed good electrocatalytic performance towards glucose oxidation in strong alkali electrolyte, exhibiting the potential application in the field of fuel cell. The excellent electrocatalytic activity of Ni–W–S NPs, the favourable electron transfer between electrode and catalysts, as well as the high conductivity of Ti contributed to its final catalytic performance of Ti/Ni–W–S.
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ACS Applied Bio Materials
·
2018
·
IF 0
Xingzhong Zhang,Yixiang Wang,Xiaogang Luo,Ang Lu,Yan Li,Bin Li,Shilin Liu
The increased quantities of fat in plants could allow the cells to inhibit the growth of ice and thus prevent the damages of their tissue structure in winter. In view of the structural buildup of freezing tolerance mechanism, here we presented a facile way of employing O/W Pickering emulsion as a template to produce the freestanding organo-hydrogels with increased mechanical stability and energy storage capacity. The oil droplets stabilized by cellulose nanofibrils were dispersed in the alginate polymer network that cross-linked with Ca2+, which resulted in homogeneous and closely packed microstructures. The prepared organo-hydrogels could maintain original gel structure under frozen conditions and had extraordinary mechanical performance. It could endure compressive stress up to 35 KPa (at 50% strain) and the elastic modulus was around 72 KPa, while the solid content of polysaccharides was only about 0.75%. By using our comprehensive strategy, organo-hydrogels with higher volumes of oil phase exhibited an enhanced cold storage capacity. For alginate hydrogel, it took 8 min when the temperature rose from 0 to 5 °C, while for the organo-hydrogel with oil volume of 30%, it took about 24 min. After 34 min, the inner temperature of alginate hydrogel was close to 25 °C, and about 70 min were needed for the temperature of organo-hydrogel to reach 25 °C. This kind of gel materials with complementary heteronetworks not only will have potential applications in cold chain logistics, but also can be applied in other fields with unusual functions.
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EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY
·
2018
·Vol. 120
·期 5
·1700471
·
IF 2.2
Lingyi Liu,Zhou Jin,Min Wang,Wangyang Shen,Zhenzhou Zhu,Zhan Wang,Lianliang Liu
Natural phenolic compounds have been drawn a wide attention to replace the synthesis antioxidants due to the food safety issues, while, natural phenolic compounds are usually polyhydroxy derivatives which exhibit hydrophilic capacity, limiting their applications directly in lipid systems. In this work, olive leaf phenolics (OLP) are extracted by ultrasound from five cultivars and the optimal cultivar is chosen to prepare W/O nano-emulsions of Sacha Inchi oil (SIO, containing more than 90% polyunsaturated fatty acids). The droplet size could reach 2.15 ± 0.13 nm and remaines stable without phase separation during 30-day storage. Oxidative stabilities of SIO containing 0.02%, 0.05%, and 0.1% OLP (w/w) are evaluated by Rancimat test and accelerated storage test. The release of OLP by preparation of W/O nano-emulsions is capable of controlling the oxidative progress of SIO, by prolonging the induction time, preventing the production of primary and secondary oxidative products and also the deterioration of polyunsaturated fatty acids and tocopherols. Practical Applications : Sacha Inchi oil (SIO) contains approximately 90% of polyunsaturated fatty acids (PUFAs) associated with poor oxidative stability. Olive leaf phenolics (OLP) are considered as a great and cheap source of natural phenolic compounds. This study aimes to select the optimum source of OLP from five cultivars and to prepare a W/O nano-emulsion of OLP. By diluting the W/O nano-emulsion of OLP into SIO, effect of different concentrations OLP on the oxidative stability of SIO is evaluated through thermal oxidative stability and storage oxidative stability in an accelerated storage test. Results indicate that the capacity of OLP to retard the SIO oxidation depends on the incorporated concentration, which means that it is doable to adopt OLP, an abundant and cheap material, to improve the stability of edible oil with high PUFAs in the industry. Olive leaf phenolics are extracted and detected to prepare an efficient and stable W/O nano-emulsion; By diluting W/O nano-emulsion into Sacha Inchi oil, oxidative stability of the high content PUFAs oil is improved.
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