Papers by Author: Ning Pan

Abstract: To achieve continuous yarns formed of nanosized filaments during electrospinning, a chemical liquid in a container was used in this study as the collector (i.e. the negative electrode) to convert nanofiber filaments into yarns. This study focuses on analyzing the impact of the chemical solutions employed in the negative electrode on the Taylor cone and trajectory of the fluid jet during the process of electrospinning. The results indicated that only 5wt peregal O solution produced non-interrupted filaments so the spinning system can work continuously for up to 10 hours. Also, the results showed that both the angle and volume of Taylor cone enlarged along with the increase of the electrical conductivity of the negative electrode. When changing the spinning voltage, both the volume of the Taylor cone and the shape of the spinning jet changed significantly.

Abstract: The low-velocity impact response of Ultra-High Molecular Weight Polyethylene (UHMWPE) laminated composites were studied by drop-weight experiments. Laminated composites were fabricated with unidirectional UHMWPE prepreg using hot-pressing process. Laminated composites of size 150mm×100mm were subjected to low-velocity impact loading at three energy levels of 15J, 25J and 35J. It is found that the slops of load-time and energy-time curves increase with increase in the impact energy. However, load-time curve shows that there are some fluctuations before the peak load was reached. Peak load and absorbed energy increase with increasing impact energy. However, time to peak load decreases linearly with increasing impact energy.

Abstract: Liquid cooling garment (LCG) is treated as one kind of effective form-fitting garment applied to remove and release extra heat efficiently from human body whose internal temperature can be easily maintained at a safe dynamic equilibrium level under the severe boundary conditions. In this paper, firstly, two specialized types of liquid cooling garments, wrapped around thermal manikin, are designed as the three-dimensional heat-flux coupling models that are solved numerically using a finite element method, and then the effective cooling temperatures of the thermal manikin skin are proposed as the characteristic parameter to evaluate the cooling effects of these garments. Finally, A comparison of thus effective cooling temperature with the experiment data from the existing reference are shown that this simulation model develops very reliable results for the heat transfer between liquid cooling garments and thermal manikin.

Abstract: Based on the photographic observation and analysis of different cross section of the materials, it is found that both the section of normal and warp yarns are rectangular in shape, the sections of weft yarns are the convex lens in shape, the weft and normal yarns are kept straight along their directions, the warp yarns are wavy. 3D images and geometry model of normal yarns reinforced 2.5D woven materials are established. This model can be used to calculate the fiber volume fraction of each yarn system. Compared with the experimental data, the computational results show excellent agreement. The work will lay the foundation for prediction of mechanical properties.

Abstract: Thin film samples of multi-walled carbon nanotubes (MWCNTs) were irradiated with 120 MeV gold ions. Transmission electron microscopy (TEM) images of the pristine and irradiated samples were obtained. TEM pictures show that in the irradiated sample, the CNTs are in general shorter and some have their inner cores filled, unlike in the pristine sample. We also find from these images that average inner and outer tube diameters change as a result of ion irradiation. The films were also characterized using Raman spectrometry. Modifications of the disorder mode (D mode) and the tangential mode (G mode) under different irradiation fluences were studied in detail. As fluence increases, the MWCNTs first show damage, then healing under somewhat higher fluences and again amorphization under still higher fluence of ion irradiation.

Abstract: In this paper, existing models of fabric’s optical behaviors are classified and estimated briefly. Then, basing on the optical theories, this paper abstracts the commonness of fabric’s optical behaviors and put forward an improved model of them, which includes a physical model and its corresponding mathematical model. The physical model describes the light falling on fabrics splits into six components, which compose another four components. The ten light components divided by the incident light yields ten light component parameters, which are functions of the wavelength. The mathematical model connects the ten light component parameters and gives formulas to calculate them. Thus, the light component parameters are connected with the basic optical parameters and structural parameters of fabric. This improved model provides a fundamental and theoretical guide for studying fabric’s optical properties systematically, which has been proved to be effective in solving some problems related fabric optical properties.