Effect of Fibers on the Flow Property of Turbulent Fiber Suspensions in a Contraction

Lin, Jianzhong,Zhang Shanliang,Olson James A. The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.1

In the flow of turbulent fiber suspensions flowing through a contraction with rectangular cross-section, the Reynolds averaged Navier-Stokes equation with the term of additional stress resulting from fibers was solved with the Reynolds stress model to get distributions of the mean velocity, mean pressure, turbulent kinetic energy and turbulent dissipation. It is found that the mean velocities at exit are small around the center and large near the wall for higher concentration. Fibers reduce turbulent intensity and turbulent dissipation at central line, but enhance them over the cross section at exit. Fibers have no effect of restraint on the turbulence in the contraction flow. The additional stress resulting from fibers plays a role in the increase of drag.

Non-resonant 3D Elliptical Vibration Cutting Induced Submicron Grating Coloring

Jianzhong Chen,Mingming Lu,Jieqiong Lin,Jiakang Zhou,Xifeng Fu,Xiaoqin Zhou 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.4

Surface Submicron grating manufacturing has broad application prospects, which has also been the subject of intensive research and development by scholars with many eff orts. In this paper, a grating coloring manufacturing method is proposed based on three-dimensional elliptical vibration cutting and non-resonant piezoelectric actuator. Based on the mechanism of elliptical motion, an effective cutting depth model was established. Nonlinear interaction of machining parameters (overlap rate, nominal cutting speed, vibration frequency) on the geometry of the grating were analyzed and controllable modulation model of grating geometry was established. The geometrical dimensions of the grating were predicted and grooved experiments were performed on brass and aluminum surfaces. A set of angle-adjustable detection device was designed independently to check the diffraction quality of the grating. The quantitative experimental results show that grating distances of copper and aluminum rods are 752 nm and 684 nm, respectively. The average width of the aluminum rod overall grating is 764 nm, the accuracy error is 9.25%. In addition, aluminum rod gratings can diffractred light at non-specific angles, which is more effective at viewing angle of 70°. The experimental results are in agreement with the theory which have positive significance for expanding the functional surface.

Closed T-Spline Surface Reconstruction from Medical Image Data

Ce Shang,Jianzhong Fu,Zhiwei Lin,Jiawei Feng,Bin Li 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.11

The reconstruction from medical image data to CAD model is an essential process of Bio-medical engineering. So far, it is still challenging to create medical model which is suitable for both design and manufacturing. This paper introduces a process of constructing a single-patched closed T-spline surface model based on medical image data. The image data is first converted into triangular mesh and then parameterized onto a rectangular domain. An iterative least-squares fitting process is proposed to finally obtain the T-spline surface model with a user-specified tolerance. In this fitting process, the smoothing part of the algorithm is redesigned, considering the flexible structure of T-mesh and the geometric complexity of the T-spline surface. Local smoothness weighting factors are introduced to the fitting formula to locally adjust the smoothness of the surface. An adaptive smoothness checking points distribution method is proposed to reduce the computational cost. These algorithms are easy to implement and the obtained model is simple in form. Compared with the STL and NURBS model, the T-spline surface model requires less storage space and can be easily modified. The obtained model is suitable for Bio-medical engineering applications like bone scaffolds design, surgical planning and related manufacturing process.

Particle trajectory and orientation evolution of ellipsoidal particles in bounded shear flow of Giesekus fluids

Bingrui Liu,Jianzhong Lin,Xiaoke Ku,Zhaosheng Yu 한국유변학회 2021 Korea-Australia rheology journal Vol.33 No.4

The migration of ellipsoidal particles in bounded shear flow of Giesekus fluids is studied numerically using the direct forcing/fictitious domain method for the Weissenberg number ranging from 0.1 to 3.0, the mobility parameter α which quantifies the shear-thinning effect ranging from 0.1 to 0.7. The model and numerical method are validated by comparing the present results with available theoretical and numerical results in other literatures. The results show that the trajectory of particles depends on their initial orientation and vertical position, and the particle migration can be roughly classified into returning and passing pattern. The values of initial vertical position of particle corresponding to the separatrix between the returning and passing pattern decrease with increasing Weissenberg number regardless of the initial orientation of particle, and the shear thinning has the opposite effect. The evolution of particle orientation depends on the initial particle orientation. For the particles whose initial orientation is parallel to the shear plane, the particle rotates with the semi-major axis as radius in the shear plane. For the particles whose initial orientation is perpendicular to the shear plane, the particle rotates with the semi-minor axis as radius. For the particles whose initial orientation has a certain angle with the shear plane, the particle rotates with the vorticity axis and the orientation vector is gradually close to the vorticity vector. The evolution of the particle orientation becomes slow with increasing Wi whether it is in passing behavior or in returning behavior.

MIMO Precoding in 802.16e WiMAX

Li, Qinghua,Lin, Xintian Eddie,Zhang, Jianzhong (Charlie) The Korea Institute of Information and Commucation 2007 Journal of communications and networks Vol.9 No.2

Multiple-input multiple-output (MIMO) transmit pre-coding/beamforming can significantly improve system spectral efficiency. However, several obstacles prevent precoding from wide deployment in early wireless networks: The significant feedback overhead, performance degradation due to feedback delay, and the large storage requirement at the mobile devices. In this paper, we propose a precoding method that addresses these issues. In this approach, only 3 or 6 bits feedback is needed to select a precoding matrix from a codebook. There are fifteen codebooks, each corresponding to a unique combination of antenna configuration (up to 4 antennas) and codebook size. Small codebooks are prestored and large codebooks are efficiently computed from the prestored codebook, modified Hochwald method and Householder reflection. Finally, the feedback delay is compensated by channel prediction. The scheme is validated by simulations and we have observed significant gains comparing to space-time coding and antenna selection. This solution was adopted as a part of the IEEE 802.16e specification in 2005.

Fiber orientation distribution and rheological properties of fiber suspension in a turbulent jet

Zhenyu Ouyang,Jianzhong Lin,Yelong Wang,Fangyang Yuan 한국유변학회 2018 Korea-Australia rheology journal Vol.30 No.1

The fiber orientation distribution and rheological properties of fiber suspension in a turbulent jet are numerically studied. The results show that, as the flow develops, more fibers align themselves with the flow direction. Few fibers orient with the flow direction with the increase of the fiber volume fraction and the Reynolds numbers. The fibers with large aspect ratio tend much easier to align with the flow direction, and the fiber orientation distribution is not sensitive to the aspect ratio when it is larger than 5. The shear stress increases along the flow direction and decreases from the center to the outside. The addition of fibers makes an increase of the shear stress, and the magnitude of increase is directly proportional to the fiber volume fraction, Reynolds number and fiber aspect ratio. The first normal stress difference is much less than the shear stress, and increases along the flow direction and from the center to the outside. It increases with increasing the fiber volume fraction and aspect ratio, and decreasing Reynolds number. The differences in the shear stress and the first normal stress difference for different parameters are the most and the least obvious at the centerline and the outside, respectively.

Heterologous Expression of a Gibberellin 2-Oxidase Gene from Arabidopsis thaliana Enhanced the Photosynthesis Capacity in Brassica napus L.

Bo Zhou,Dan Peng,Jianzhong Lin,Xingqun Huang,Wusheng Peng,Reqing He,Ming Guo,Dongying Tang,Xiaoying Zhao,Xuanming Liu 한국식물학회 2011 Journal of Plant Biology Vol.54 No.1

Gibberellins (GAs) are endogenous hormones that play an important role in regulating plant stature by increasing cell division and promoting seed germination. The GA2-oxidase gene from Arabidopsis thaliana (AtGA2ox8) was introduced into Brassica napus L. by Agrobacterium-mediated floral-dip transformation with the aim of decreasing the amount of bioactive GA and hence reduced the plant height. As anticipated, the transgenic plant exhibited dwarf phenotype. Importantly, compared with the wild type, the transgenic plants had delayed the seed germination, increased the chlorophyll content (28.7–36.3%) and photosynthesis capacity (14.3–18.7%) in a single leaf. At the same time, the photosynthesis capacity of the whole plants was significantly enhanced (35.7–48.6%) due to the extra leaves and branches.

Development of High-specificity Antibodies against Renal Urate Transporters Using Genetic Immunization

Xu, Guoshuang,Chen, Xiangmei,Wu, Di,Shi, Suozhu,Wang, Jianzhong,Ding, Rui,Hong, Quan,Feng, Zhe,Lin, Shupeng,Lu, Yang Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.6

Recently three proteins, playing central roles in the bidirectional transport of urate in renal proximal tubules, were identified: two members of the organic anion transporter (OAT) family, OAT1 and OAT3, and a protein that designated renal urate-anion exchanger (URAT1). Antibodies against these transporters are very important for investigating their expressions and functions. With the cytokine gene as a molecular adjuvant, genetic immunization-based antibody production offers several advantages including high specificity and high recognition to the native protein compared with current methods. We fused high antigenicity fragments of the three transporters to the plasmids pBQAP-TT containing T-cell epitopes and flanking regions from tetanus toxin, respectively. Gene gun immunization with these recombinant plasmids and two other adjuvant plasmids, which express granulocyte/macrophage colony-stimulating factor and FMS-like tyrosine kinase 3 ligand, induced high level immunoglobulin G antibodies, respectively. The native corresponding proteins of URAT1, OAT1 and OAT3, in human kidney can be recognized by their specific antibodies, respectively, with Western blot analysis and immunohistochemistry. Besides, URAT1 expression in Xenopus oocytes can also be recognized by its corresponding antibody with immuno-fluorescence. The successful production of the antibodies has provided an important tool for the study of UA transporters.