INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
·
2020
·Vol. 107
·期 1
·73-83
·
IF 2.633
Su Guosheng,Xiao Xiaodong,Du Jin,Zhang Jingjie,Zhang Peirong,Liu Zhanqiang,Xu Chonghai
Since Dr. Carl Salomon proposed the well-known hypothesis on cutting temperatures in 1931, the debate on the hypothesis has never stopped. It shows that evolutions of temperatures with the increase of cutting speed measured at different points are different. From the tool wear and surface integrity point of view, this paper focuses on the evolutions of chip temperature (Chip temp.), tool-chip contact temperature (T-C temp.), and tool-workpiece contact temperature (T-W temp.) with the increase of cutting speed from low (100 m/min) to very high (7000 m/min). First, the cutting heat generation and the temperature increment in machining are theoretically analyzed. Then the influences of chip shape and mechanical property variations with the increase of cutting speed on the temperatures are analyzed. Finally, the cutting temperatures are semiquantitatively derived from chip colors and other heat characteristics in the chip and cutting tool obtained in cutting experiments: evolutions of Chip temp., T-C temp., and T-W temp. with the increase of cutting speed are presented based on the experiment results. The influence of chip shape and temperature variation on tool wear are also discussed.
研究领域:
机械工程
·
制造工艺
·
材料加工
·
热力学
·
表面工程
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2013
·
IF 3.334
Guobin Xia,Shan Hong,Songbai Liu
Simultaneous preparation of naturally rare catechins , EGC and EC , has been realized by tannase-mediated biotransformation combining high speed counter current chromatography. In addition, simultaneous preparation of the four catechins, EGCG, ECG, EGC, and EC in green tea extract has also been achieved by HSCCC under the normal phase and the reversed phase modes. The identity of the catechins was determined by HPLC-DAD-ESI-MS and quantification of the catechins was performed by HPLC-DAD. In a typical HSCCC separation, 27.2 mg 98.8% EGCG, 14.1 mg 94.7% EGC, and 9.3 mg 97.5% EC were obtained. This new method is efficient, time-saving and valuable for biological studies.
研究领域:
植物化学
·
生物技术
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHIC SCIENCE
·
2018
·Vol. 57
·期 3
·265-271
·
IF 1.037
Pan Conglei,Lü Haitao
An efficient method for the preparative separation of quercetin, ombuin and kaempferide from Gynostemma pentaphyllum by high-speed countercurrent chromatography (HSCCC) was successfully developed for the first time. The extraction conditions were optimized by an orthogonal array design L9 (34), while quercetin, ombuin and kaempferide were efficiently released from rutin, ombuoside and kaempferide glucoside by hydrochloric acid hydrolysis, respectively. Quercetin was purified by HSCCC with two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (4:5:4:5, v/v) in a single run. From 164.7 mg of the crude extract, 90.5 mg quercetin at 99.23% purity was obtained. Ombuin and kaempferide were purified by HSCCC with two-phase solvent system composed of n-hexane–ethyl acetate–methanol–water (8:2:5:5, v/v) in a single run. From 50 mg of the crude extract, 0.4 mg of ombuin at 95.46% purity and 1.1 mg of kaempferide at 98.78% purity were obtained, respectively. Their structures were identified by ultraviolet, Fourier transform infrared, electrospray ionization mass spectrometry (ESI-MS), 1H nuclear magnetic resonance (NMR) and 13C NMR spectra. The purified quercetin had the strongest 1,1-diphenyl-2-picrylhydrazyl and hydroxyl free radical scavenging activities.
研究领域:
植物化学
·
药物化学
·
分离科学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2024
·
IF 3.8
Wenting Li,Wenjuan Wang,Yun Wei
Rare earth elements with unique magnetic properties and optical properties, known as the ‘industrial vitamin’, has a very high commercial value. As a secondary resource of rare earth elements, low-concentration solution includes mixed rare earth ions, which need to realize efficient separation and recovery urgently. High speed countercurrent chromatography is suitable for the separation and purification of rare earth element ions due to its advantages of large loading, good tolerance to samples, and simple pretreatment. In this study, a carbon dots assisted high speed countercurrent chromatography method was designed and established, the carbon dots were applied to the mobile phase of high speed countercurrent chromatography for the first time. The low concentration of REEs solution was enriched, and the effective separation of La (III), Ce (III), Gd (III) and Er (III) was successfully achieved. The complete separation of La (III), Ce (III), Gd (III) and Er (III) was achieved with a solvent system of 0.05 mol L −1 P507 (PE), 0.05 mol L −1 HNO 3 , and 0.1 mol L −1 CDs2 carbon dots (1:1:0.01, v/v/v), the upper phase as stationary phase, the lower phase as mobile phase. Density functional theory result showed that the binding energy of REEs (III)-CDs2 was larger than that of REEs (III)-P507, so the affinity of CDs2 to REEs (III) was stronger than that of P507. Therefore, with the addition of CDs2, the ability of mobile phase to elute REEs from the stationary phase was enhanced, and the separation effect was improved.
研究领域:
化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
·
2019
·
IF 4.087
Yimou Fu,Haotian Lu,Guodong Nian,Peng Wang,Nan Lin,Xiaocheng Hu,Haofei Zhou,Honghui Yu,Shaoxing Qu,Wei Yang
High-rate loading induced cavitation of soft materials, including brain and muscle, has increasingly been studied due to its importance in a variety of biomedical applications , such as potential impact-related traumatic brain injury and high-intensity focused ultrasound therapy. The size of cavitation nuclei or defects is crucial to the onset of cavitation. However, it remains challenging to introduce gaseous defects with controllable size into soft materials and to understand the underlying mechanism of impact-bubble interaction in soft materials. Here, we set up a drop-tower system to perform impact loading tests on gelatin samples with controllable monodispersed microbubbles, allowing us to mimic the general cavitation behavior of human tissues. The microbubbles are inserted into the soft matrix as cavitation nuclei by taking advantage of microfluidic flow focusing. A high-speed camera paired with a signal acquisition system is utilized to determine the critical pressure at which cavitation initiates for different defect sizes . Meanwhile, we propose a theoretical model based on surface tension to predict the time-dependent spherically symmetric cavitation of a pre-existing gas bubble in elastomers under high-speed loading. Our experiments and theoretical modeling demonstrate the strong effect of gas-filled defects on cavitation and indicate the necessity and significance of controlling defect size in mimicking targeted organs using soft gels. Our work provides a promising route to predict cavitation-induced injury in tissues with variable materials stiffness and initial defect size.
研究领域:
生物力学
·
医学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
NPG Asia Materials
·
2022
·Vol. 14
·期 1
·1-9
·
IF 10.761
Xiong Fangyihan,Zhang Liyun,Xu Lei,Zhao Huan,Lan Jianyang,Ji Chenhao,Chen Linfeng,Xia Fan
Directed transport of a small amount of water is a basic issue and has attracted extensive attention due to its importance in a wide range of applications, such as water collection, microfluidics, printing, bioanalysis, and microchemical reactions. Various strategies based on constructing a surface tension gradient or Laplace pressure gradient have been developed to realize directional water transport. Typically, electrostatic forces and magnetic fields are utilized to achieve high-speed water transport on open superhydrophobic surfaces. However, these methods suffer from water evaporation or contamination. Here, we report a magnetic superhydrophobic tubular PDMS actuator for directional water transport. The actuator deformed under an applied external magnetic field and actuated the water droplet to transport along the moving direction of the magnet. The water transport velocity reached 16.1 cm/s. In addition, as the inner surface of the actuator is superhydrophobic, the water droplet showed weak interactions with the surface and presented negligible mass loss during the transport process. The results of this work may inspire new design of actuators for directional water transport with high speeds.
研究领域:
材料科学
·
流体力学
·
生物工程
✓ 已验证
产品关联
DOI
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 3.8
Meng Xianghe,Wang Shuyi,Lu Yuanchao,Nie Xiaohua,Ye Qin
Sciadonic acid (△5,11,14–20:3, SCA) is a rare versatile non-methylene-interrupted polyunsaturated fatty acid. To prepare high purity SCA from Torreya oils with 8.04 % purity, Ag + -assisted high-speed countercurrent chromatography (HSCCC) combined with urea complexation (UC) or argentation column chromatography (CC) was investigated. Results showed that n -hexane: acetonitrile (1:1, v/v) was suitable mobile phase for HSCCC, and SCA with purity of 23.74 % and recovery of 61.74 % (SCA purity>20 %) were obtained. When the Ag + addition was 0.50 %, one round of Ag + -HSCCC resulted in a recovery of SCA up to 95.38 % with purity around 21 %. It was believed that the enhanced performance originated from the reversible complexes between Ag + and C C in SCA through π-s * and d-π* bonds. Starting with low purity SCA of 8.04 %, HSCCC (23.74 %), UC (62.67 %), or Ag + -CC (60.41 % ) alone failed to produce SCA with high-purity (>90 %). However, Ag + -HSCCC combined with Ag + -UC or Ag + -CC yielded SCA with purities of 76.21 % and 97.74 %, and overall recovery of 21.38 % and 19.31 %, respectively. Thus, Ag + -HSCCC was an efficient method for the pre-enrichment of SCA, which could effectively facilitate coupling with UC, Ag + -CC or other PUFA purification techniques, resulted in significant improved purification performances.
研究领域:
植物化学
·
分离技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2011
·Vol. 123
·期 6
·3255-3260
·
IF 1.24
Hongbo Liu,Shaoguo Wen,Jihu Wang,Yu Zhu
Composite particles of carbon black-polystyrene with controllable size were successfully prepared using high-speed homogenization-assisted suspension polymerization. The carbon black particles were modified by oleic acid to make it more hydrophobic and more compatible with polymers before the encapsulation process. The effects of homogenization speed, homogenization time, agitation speed, pigment concentration, and stabilizer concentration on the properties of complex spheres were investigated in detail. The results of orthogonal experiments proved that the stabilizer concentration plays the most important role in controlling the size of complex particles. The particles were also characterized by FTIR and SEM. SEM photographs proved that the complex particles had good spherical forms with smooth surfaces. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2016
·
IF 4.052
Lanxin Luo,Yan Cui,Shuting Zhang,Lingxi Li,Yuanyuan Li,Peiyu Zhou,Baoshan Sun
To develop an efficient method for large preparation of various individual polyphenols from white grape skins (Fernão Pires; Vitis vinifera ) by preparative high-speed counter-current chromatography (HSCCC) and preparative-HPLC, an optimized preparative HSCCC condition with two-phase solvent system composed of Hex-EtOAc-H 2 O (1:50:50, v/v) was used to separate grape skin polyphenols into various fractions. Both the tail-head and head-tail elution modes were used with a flow rate of 3.0 ml/min and a rotary speed of 950 rpm. Afterwards, a preparative-HPLC separation was applied to isolate individual polyphenols in each of the fractions from HSCCC. Total of 7 fractions (Fraction A to G) were obtained from grape skin extract by HSCCC. After preparative-HPLC isolation, fifteen individual compounds were obtained, most of which presented high yields and purity (all over 90%). The HSCCC method followed with preparative-HPLC appeared to be convenient and economical, constituting an efficient strategy for the isolation of grape skin polyphenols.
研究领域:
食品科学
·
植物化学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Manufacturing Processes
·
2024
·
IF 6.1
Qing Wang,Pengfei Su,Zhenyu Lei,Mingxiang Chen,Xiaobing Luo
The copper pattern electroplating rate significantly impacts electronic packaging substrate preparation efficiency. The direct current (DC) electroplating technique has great potential in economy and convenience but faces challenges in improving the electroplating rate and coating properties, thus making electroplating additives the most critical parameters for controlling the electroplating process and coating properties. Convection and cathodic polarization are two essential parameters influencing the additives' interactions, but the electrolyte flow field distribution is complicated by the changed pattern size, and most electrolyte formulas cannot withstand such strong cathodic polarization. Therefore, we presented a novel electrolyte formula for ultra-high-rate DC copper pattern electroplating and employed three-dimensional flow field simulation to investigate the flow field distribution throughout the patterns. An ultra-high current density of 8 A/dm 2 was applied, ensuring a stable electroplating process. The pattern size-stimulated electrolyte flow rate trend was discovered by simulations. The mechanism of simultaneously achieving ultra-high-rate electroplating and coating property improvement was thoroughly investigated. An ultra-high rate of 150 μm/h and the dense, uniform copper pattern coating were achieved synchronously with weak convection and strong cathodic polarization. Utilizing the ultra-high-rate copper electroplating method offers a viable approach to expedite the production of electronic packaging substrate with enhanced efficiency.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
Food Analytical Methods
·
2017
·Vol. 11
·期 3
·693-702
·
IF 2.038
Qiu Bo,Wang Xiaochen,Li Haipu,Shu Bin,Li Shan,Yang Zhaoguang
A simple and rapid method applying acetonitrile extraction, dispersive-solid-phase extraction (d-SPE) cleanup, and dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) was developed for determination of organochlorine pesticides in vegetables. In order to simplify operation, d-SPE cleanup was integrated to DLLME-SFO concentration procedure, and a protection device for glass tube was applied to achieving high-speed centrifugation. The comparison study between the integrated d-SPE and normal d-SPE showed that the former could shorten the sample preparation time without decrease of cleanup efficiency. Subsequently, the necessity of using a high-centrifugation speed (more than 8603 g) for complete separation of the d-SPE sorbents, water phase, and organic phase was confirmed through turbidity analysis. The recoveries of the proposed method ranged from 77.2 to 112.5%, and the relative standard deviations were less than 15%. The limits of detection were in the range of 0.45 ~ 1.33 μg kg −1 , while the limits of quantitation were from 1.35 to 3.99 μg kg −1 , respectively. Finally, the method was successfully applied to analyze real vegetable samples.
研究领域:
分析化学
·
食品科学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2025
·
IF 12.1
Jianing Song,Yao Luo,Jinlong Yang,Yong Li,Harry Qi,Ningyuan Xu,Huijuan Shao,Yishen Zhang,Yan Zhou,Zhenbing Luo,Deuhui Wang,Xu Deng
Window screens serve the multiple purposes of enabling ventilation while preventing the ingress of solid objects and insects. However, their intrinsic porosity makes them susceptible to fluid intrusion while maintaining ventilation, notably evident in the infiltration of high-velocity raindrops during inclement weather, flooding the room. Addressing this challenge, bilayer synergistic mesh featuring an upper superhydrophilic (SHPi) surface and a bottom Janus wettability designed is presented to withstand puncture from continuous high-speed droplets. This innovative design incorporates a dual waterproof mechanism, providing instantaneous penetration resistance through energy dissipation and long-term infiltration resistance by a stable liquid film against high-speed droplets. The SHPi-Janus bilayer synergistic mesh demonstrates exceptional capability in repelling droplet penetration at a vertical high velocity of 4.5 m s −1 , significantly mitigating droplet infiltration under most rainfall conditions in the real world. Experimental findings reveal that the droplet penetration ratio of SHPi-Janus mesh is a mere 3.6% under sustained high-velocity droplet impact, a substantial leap forward compared to the 61.1% observed with commercial screen.
研究领域:
材料科学
·
流体力学
·
界面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）