Microfluidic phenotyping methods have been of vital importance for cellular characterization,especially for evaluating single cells.In order to study the deformability of a single cell,we devised and tested a tunable microfluidic chip-based method.A pneumatic polymer polydimethylsiloxane(PDMS)membrane was designed and fabricated abutting a single-cell trapping structure,so the cell could be squeezed controllably in a lateral direction.Cell contour changes under increasing pressure were recorded,enabling the deformation degree of different types of single cell to be analyzed and compared using computer vision.This provides a new perspective for studying mechanical properties of cells at the single cell level.
Ruiyun ZhangXuexin DuanShuaihua ZhangWenlan GuoChen SunZiyu Han
To address the need for the on-site measurement of aging oil, in this paper, we propose an impedance-based microsensor for analyzing the moisture content in engine oil. Using a microfabrication process, we fabricated an interdigitated microelectrode and integrated it with a 3 D-printed microcontainer to produce a microsensor that can detect changes in the permittivity of oil. When the moisture content in oil increases, this sensor can detect the resulting change in the oil impedance, which is related to its permittivity, and then determine the degree to which the oil has aged. The test results show that the proposed microsensor has the advantages of being small and having high sensitivity, good accuracy, and the ability to be combined with hand-held instruments.The proposed method is expected to be used for the rapid, low cost, on-site determination of oil aging.
To investigate the effect of dislocation structures on the initial formation stage of helium bubbles, molecular dynamics(MD) simulations were used in this study. The retention rate and distribution of helium ions with 2 ke V energy implanted into silicon with dislocation structures were studied via MD simulation. Results show that the dislocation structures and their positions in the sample affect the helium ion retention rate. The analysis on the three-dimensional distribution of helium ions show that the implanted helium ions tend to accumulate near the dislocation structures. Raman spectroscopy results show that the silicon substrate surface after helium ion implantation displayed tensile stress as indicated by the blue shift of Raman peaks.
Li JiLei LiuZongwei XuYing SongJintong WuRongrong LiFengzhou Fang
PEDOT:PSS conductive polymers have received tremendous attention over the last two decades owing to their high conductivity,ease of processing,and biocompatibility.As a flexible versatile material,PEDOT:PSS can be developed into various forms and has had a significant impact on emerging sensing applications.This review covers the development of PEDOT:PSS from material to physical sensors.We focus on the morphology of PEDOT:PSS in the forms of aqueous dispersions,solid films,and hydrogels.Manufacturing processes are summarized,including coating,printing,and lithography,and there is particular emphasis on nanoimprinting lithography that enables the production of PEDOT:PSS nanowires with superior sensing performance.Applications to various physical sensors,for humidity,temperature,pressure,and strain,are demonstrated.Finally,we discuss the challenges and propose new directions for the development of PEDOT:PSS.
We present a review of the development of a compact and high-power broadband terahertz （THz） source optically excited by a femtosecond photonic crystal fiber （PCF） amplifier.The large mode area of the PCF and the stretcher-free configuration make the pump source compact and very efficient.Broadband THz pulses of 150 μW extending from 0.1 to 3.5 THz are generated from a 3-mm-thick GaP crystal through optical rectification of 12-W pump pulses with duration of 66 fs and a repetition rate of 52 MHz.A strong saturation effect is observed,which is attributed to pump pulse absorption;a Z-scan measurement shows that three-photon absorption dominates the nonlinear absorption when the crystal is pumped by femtosecond pulses at 1 040 nm.A further scale-up of the THz source power is expected to find important applications in THz nonlinear optics and nonlinear THz spectroscopy.
