Counter-current chromatography of lipoproteins with a polymer phase system using the cross-axis synchronous coil planet centrifuge

AbstractIn recent years, research has begun to focus on the development of non-resonant elliptical vibration-assisted cutting (EVC) devices, because this technique offers good flexibility in manufacturing a wide range of periodic microstructures with different wavelengths and heights. However, existing non-resonant EVC devices for diamond turning can only operate at relatively low frequencies, which limits their machining efficiencies and attainable microstructures. This paper concerns the design and performance analysis of a non-resonant EVC device to overcome the challenge of low operational frequency. The structural design of the non-resonant EVC device was proposed, adopting the leaf spring flexure hinge (LSFH) and notch hinge prismatic joint (NHPJ) to mitigate the cross-axis coupling of the reciprocating displacements of the diamond tool and to combine them into an elliptical trajectory. Finite element analysis (FEA) using the mapped meshing method was performed to assist the determination of the key dimensional parameters of the flexure hinges in achieving high operational frequency while considering the cross-axis coupling and modal characteristics. The impact of the thickness of the LSFH on the sequence of the vibrational mode shape for the non-resonant EVC device was also quantitatively revealed in this study. Moreover, a reduction in the thickness of the LSFH can reduce the natural frequency of the non-resonant EVC device, thereby influencing the upper limit of its operational frequency. It was also found that a decrease in the neck thickness of the NHPJ can reduce the coupling ratio. Experimental tests were conducted to systematically evaluate the heat generation, cross-axis coupling, modal characteristics and diamond tool’s elliptical trajectory of a prototype of the designed device. The test results showed that it could operate at a high frequency of up to 5 kHz. The cross-axis coupling ratio and heat generation of the prototype are both at an acceptable level. The machining flexibility and accuracy of the device in generating microstructures of different wavelengths and heights through tuning operational frequency and input voltage have also been demonstrated via manufacturing the micro-dimple arrays and two-tier microstructured surfaces. High-precision microstructures were obtained with 1.26% and 10.67% machining errors in wavelength and height, respectively.

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Design Approach for Reducing Cross-Axis Sensitivity in a Single-Drive Multi-Axis MEMS Gyroscope

Micromachines ◽

10.3390/mi12080902 ◽

2021 ◽

Vol 12 (8) ◽

pp. 902

Author(s):

Hussamud Din ◽

Faisal Iqbal ◽

Byeungleul Lee

Keyword(s):

Microelectromechanical Systems ◽

Reduction Rate ◽

Design Technique ◽

Matching Method ◽

Mems Gyroscope ◽

Mode Split ◽

The Cross ◽

The Individual ◽

Cross Axis ◽

Ratio Matching

In this paper, a new design technique is presented to estimate and reduce the cross-axis sensitivity (CAS) in a single-drive multi-axis microelectromechanical systems (MEMS) gyroscope. A simplified single-drive multi-axis MEMS gyroscope, based on a mode-split approach, was analyzed for cross-axis sensitivity using COMSOL Multiphysics. A design technique named the “ratio-matching method” of drive displacement amplitudes and sense frequency differences ratios was proposed to reduce the cross-axis sensitivity. Initially, the cross-axis sensitivities in the designed gyroscope for x and y-axis were calculated to be 0.482% and 0.120%, respectively, having an average CAS of 0.301%. Using the proposed ratio-matching method and design technique, the individual cross-axis sensitivities in the designed gyroscope for x and y-axis were reduced to 0.018% and 0.073%, respectively. While the average CAS was reduced to 0.045%, showing a reduction rate of 85.1%. Moreover, the proposed ratio-matching method for cross-axis sensitivity reduction was successfully validated through simulations by varying the coupling spring position and sense frequency difference variation analyses. Furthermore, the proposed methodology was verified experimentally using fabricated single-drive multi-axis gyroscope.

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Counter-Current Distribution of Proteins in Aqueous Polymer Phase Systems

Nature ◽

10.1038/1841465b0 ◽

1959 ◽

Vol 184 (4697) ◽

pp. 1465-1468 ◽

Cited By ~ 38

Author(s):

PER-AKE ÅLBERTSSON ◽

ED. JACQUES NYNS

Keyword(s):

Current Distribution ◽

Polymer Phase ◽

Aqueous Polymer ◽

Phase Systems ◽

Counter Current ◽

Counter Current Distribution

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A New Design of a Piezoelectric Triaxial Micro-Accelerometer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.645-646.841 ◽

2015 ◽

Vol 645-646 ◽

pp. 841-846 ◽

Cited By ~ 1

Author(s):

Jian Yan Wang ◽

Ting Ting Wang ◽

Hang Guo

Keyword(s):

Simulation Analysis ◽

Structural Parameters ◽

Sol Gel ◽

Triaxial Accelerometer ◽

Response Frequency ◽

Pzt Films ◽

New Type ◽

The Cross ◽

Cross Axis ◽

Micro Accelerometer

Accelerometer in MEMS always is made by capacitive or piezoresistive, whose dynamic response is not good, the operating frequency is narrow, and the cross-axis sensitivity is low. A new type of piezoelectric micro-accelerometer is designed, and its structure is “x” type. The sensing unit is piezoelectric PZT films, which is achieved by sol-gel method. The accelerometer is a triaxial accelerometer. The theoretical and simulation analysis is used to achieve the charge sensitivity and response frequency, and also get the optimal structural parameters. A new circuit connection is proposed to improve the sensitivity and avoid the cross-axis sensitivity. The design achieves the z-axis sensitivity with more than 40 pC/g, x, y-axis sensitivity with more than 8pC/g, and the response frequency is about 3000Hz.

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Extraction and Purification of Capsaicin from Capsicum Oleoresin Using a Combination of Tunable Aqueous Polymer-Phase Impregnated Resin (TAPPIR) Extraction and Chromatography Technology

Molecules ◽

10.3390/molecules24213956 ◽

2019 ◽

Vol 24 (21) ◽

pp. 3956 ◽

Cited By ~ 1

Author(s):

Lu ◽

Cui

Keyword(s):

Sodium Citrate ◽

Extraction Process ◽

Fractional Factorial ◽

Phase System ◽

Polymer Phase ◽

Macroporous Resin ◽

Two Phase ◽

Aqueous Polymer ◽

Extraction And Purification ◽

Extraction Step

Capsaicin, which mainly comes from pepper, exhibits anticancer, antioxidant, and anti-obesity properties. This work aims to construct a comprehensive technology for the extraction and purification of capsaicin from capsicum oleoresin. The tunable aqueous polymer phase impregnated HZ816 resins were selected in extraction step. In the extraction process, 3 g of impregnated HZ816 macroporous resin was employed per system. The results showed that a higher molecular weight of Polyethylene glycol (PEG) and 1-ethyl-3-methyl imidazolium acetate ([Emim] [OAc]) are more beneficial to the improvement of the yield of capsaicin. Screening experiment using fractional factorial designs indicated that the amount of sample loading, pH, and concentration of [Emim] [OAc] and PEG 6000 significantly affect the yield of capsaicin. Mathematical models of capsaicin yield in tunable aqueous polymer-phase impregnated resins were established and optimum condition was obtained using response surface methodology. The optimum impregnated phase was the polymer phase of an aqueous two-phase system which contained 18.5% (w/w) PEG6000, 15% (w/w) sodium citrate, and 10% (w/w) [Emim] [OAc] at pH 6.5. Under the optimal conditions, the yield of capsaicin reached 95.82% when the extraction system contains 0.25 g capsicum oleoresin. Ultimately, capsaicinoids extract was purified by reverse-phase resin (SKP-10-4300) chromatographic column. The capsaicin recovery and purity achieved 85% and 92%, respectively.

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Cross-Axis Coupling Effects in Single-Axis Nuclear Magnetic Resonance Gyroscopes

Sensors ◽

10.3390/s20030734 ◽

2020 ◽

Vol 20 (3) ◽

pp. 734

Author(s):

Zhiguo Wang ◽

Yi Zhang ◽

Xiang Zhan ◽

Qiyuan Jiang ◽

Hui Luo

Keyword(s):

Magnetic Field ◽

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Vibration Frequency ◽

Coupling Effects ◽

Rotation Rates ◽

Angular Vibration ◽

The Cross ◽

Cross Axis ◽

Nuclear Magnetic

Nuclear magnetic resonance gyroscopes (NMRGs) may be operated in an environment with violent vibration that usually contains both linear components and angular components. To analyze the influence of angular vibration on an NMRG, cross-axis coupling effects are studied. The cross-axis rotation rates induce an equivalent magnetic field. Its influence can be described by the Bloch equations. The approximate frequency shift and amplitude of the spin oscillator with an equivalent magnetic field in the cross-axis were obtained, which was validated by numerical simulation. The findings show that the angular vibration component leads to a remarkable error for the NMRG. When the angular vibration frequency is near the Larmor frequency, the oscillation frequency of the spins may be locked to the angular vibration frequency, destroying the NMRG’s ability to measure rotation rates. The cross-axis coupling problem should be considered in the design of an NMRG and corresponding inertial navigation systems.

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