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Based on a plastic scintillator and an optic streak camera,a measuring system for fusion reaction-rate was designed,then the working princile and design method of the measuring system were addressed in detail.A piece of fused silica window was set just behind the plastic scintillator to protect optical elements from darkening after a long time exposure in scatted X rays and the ultraviolet crystals and other ultraviolet glass were selected to ensure the high system transmission.Furthermore,the image plane of the optical system was put onto a photocathode of the streak camera directly to remove the aperture non-matching of input optic system of the streak camera.Finally,a field mirror was put on the first image plane to reduce the max diameter of optical element from 160 mm to 120 mm.The designed optical system has a total length of 2 660 mm,magnification of 3∶1 and its final lens is F/0.667 and transmission is 67%.Moreover,the time dispersion of the optical system is less than 7.3 ps.These results meet the experimental needs of different neutron yields and good experimental results have been obtained in a laser targeting experiment.

Cervical lymph nodes are common sites of metastatic involvement in head and neck cancers. These lymph nodes are superficially located and palpation is a common practice for assessing nodal hardness and staging cancer which is, however, too subjective and with limited accuracy. In this study, the mechanical properties of pig lymph node tissues were investigated using ultrasound elastography and indentation test. Lymph nodes were excised from fresh pork pieces and embedded in an agar-gelatin phantom for strain imaging by elastography. A strain ratio reflecting the strain contrast of lymph node over agar-gelatin phantom was used to assess the elasticity of the lymph node. A cutting device was then custom-designed to slice the phantom into uniform slices for indentation test. The measurements revealed that there were significant differences in both the strain ratio and Young’s modulus between the peripheral and middle regions of the lymph nodes (both p < 0.05); however, the results appeared contradictory. Correlation between the results of the two measurements (modulus ratio vs. inversed strain ratio) showed their association was moderate for both the peripheral and middle regions (R2 = 0.437 and 0.424 respectively). As the tests were only performed on normal lymph nodes, comparison in stiffness between healthy and abnormal lymph nodes could not be made. Future studies should be conducted to quantify the stiffness change in abnormal lymph nodes.

Electromyography (EMG) and ultrasonography have been widely used for skeletal muscle assessment. The muscle thickness change detected using ultrasound has been recently defined as sonomyography. In this study, the performances of one dimensional sonomyography (1-D SMG) and surface EMG signal in tracking the guided patterns of wrist extension were compared, and the potential of 1-D SMG for skeletal muscle assessment and prosthesis control was investigated. Sixteen normal subjects were instructed to perform the wrist extension under the guidance of displayed sinusoidal, square and triangular waveforms at movement rates of 20, 30, 50 cycles per minute. SMG and EMG root mean squares (RMS) were collected from the extensor carpi radialis respectively and their RMS errors in relation to the guiding signals were compared. Paired t-test showed that the RMS errors of SMG tracking were significantly smaller than those of EMG. The results suggest that SMG signal has great potential to be an alternative method of EMG to evaluate muscle function and control prosthesis.