Design and experiments of a compact electrostatic low energy beam transport with a double Einzel-lens for a transportable neutron source.

A transportable, compact, accelerator-based neutron source is under development at Xian Jiaotong University. An electrostatic low energy beam transport (LEBT) structure with a double Einzel-lens setup was adopted due to its short length and low power consumption. It can transport a pulsed proton beam to the radio frequency quadrupole with a required beam current of 15 mA and an energy of 30 keV. We performed detailed structure optimization and beam tracking to achieve beam matching and small emittance growth. In addition, the fast chopper, beam steering, and diagnostic devices are integrated into the LEBT. The fabrication and assembly of the proton injector have been completed, and beam commissioning was carried out to measure the beam current and Twiss parameters. The design strategy, beam simulation, and experimental results are presented and discussed in this paper.

[Clinical effects of plantar split-thickness skin grafts in repairing the deep burn wounds in the back and buttocks].

Objective: To explore the clinical effects of plantar split-thickness skin grafts in repairing the deep burn wounds in the back and buttocks. Methods: A retrospective observational study was conducted. From January 2011 to February 2022, 98 patients with deep burn who met the inclusion criteria were admitted to the 910th Hospital of Joint Service Support Unit of PLA, including 64 males and 34 females, aged 17 to 78 years, with total burn areas of 35%-95% total body surface area (TBSA). The area of full-thickness burns in the back and buttocks ranged from 5% to 17% TBSA and the wounds were repaired only using stamp-shaped split-thickness skin grafts from plantar areas of both feet or combined with Meek microskin grafts or stamp-shaped skin grafts from other sites. According to the times of skin graft harvesting from both soles, these patients were divided into one-harvesting group (29 cases), two-harvesting group (38 cases), three-harvesting group (21 cases), and four-harvesting group (10 cases). The area of skin grafts harvested each time from both soles, the healing time of donor sites after each skin graft harvesting, and the survival rate of plantar skin graft in recipient site at 7 days after each skin graft harvesting in 98 patients, the interval between two adjacent skin graft harvesting in 69 patients with skin grafts harvested twice or more, as well as the healing time of donor site and survival rate of skin graft in recipient site after the last skin graft harvesting from both soles of patients in the 4 groups were recorded. The patients were followed up to observe the appearance, texture, and scar in recipient site of plantar skin grafts as well as the scar and function in plantar donor sites. Data were statistically analyzed with one-way analysis of variance, Kruskal-Wallis test, and chi-square test. Results: In the 98 patients, the area of skin graft was 2.0%-4.5% ((3.4±0.6)%) TBSA harvested each time from both soles, the healing time of donor site after each skin graft harvesting was 7-10 (7.8±1.1) d, and the survival rate of plantar skin graft in recipient site at 7 days after each skin graft harvesting was 93% (92%, 95%). The interval between two adjacent skin graft harvesting in the 69 patients was 7-38 (11.2±0.5) d. The healing time of donor site and survival rate of skin graft in recipient site after the last skin graft harvesting from both soles of patients in the 4 groups showed no statistically significant differences (P>0.05). A total of 88 patients were followed up for 3 months to 5 years, the appearance in recipient site of plantar skin graft was smooth, the texture was firm, the scar hyperplasia was mild, and the area was compressive- and wear-resistant. Among them, the plantar donor site recovered well in 85 patients, without obvious scar hyperplasia and only 3 patients had small area of scar hyperplasia in the non-weight-bearing areas which did not affect walking or wearing shoes or socks. Ten patients were lost in the follow up after discharge. Conclusions: Stamp-shaped split-thickness skin grafts can be repeatedly harvested from both soles of patient to repair the deep burn wounds in the back and buttocks, with high survival rate of skin grafts, thus can reduce the burden of other donor sites. Moreover, the skin grafts have good wear-resistance and pressure-resistance, without affecting postoperative normal walk.

[Performance evaluation and validation of automated digital image analysis in peripheral blood cells morphology examination].

Objective: To verify and evaluate the performance of automated digital image(DIA) for peripheral blood cell morphology examination. Methods: Three hundred and seventy-nine routine peripheral blood smears and 18 plasmodium positive peripheral blood smears were collected. Blood smears were made and stained by Wright -Giemsa method.White blood cell (WBC) differentiation of blood smears were pre-classified by DIA (DIA direct classification), re-classified (manually reviewed after DIA classification), and artificially classified under microscope. the inter-assay and intra-assay coefficients of variation (CV) of DIA were respectively calculated for repeatability verification. Taking the artificial microscopy as the gold standard, the sensitivity、specificity and accuracy of DIA were calculated. The DIA ability of peripheral blood blast cell morphological count, platelet (PLT) morphological count and morphological examination of plasmodium were also verified. Results: Except for eosinophils and basophils, the inter-assay and intra-assay CV of WBC classification by DIA in normal samples were < 10%. The CV of WBC classification in abnormal samples increased with the decrease of cell percentage. The sensitivity, specificity and accuracy of DIA pre-classification were 90.5%, 99.2%, 98.2%. Through pre-classification and re-classification by DIA,the results of the blood smears which triggered blast cell alarm had a good correlation with manual classification(r=0.812, 0.983, both P<0.01). The PLT morphological count by DIA had high correlation with hematology analyzer (r=0.946, P<0.01). The deviation absolute value of two methods of PLT count was < 15%, while in PLT aggregation or giant thrombocytosis samples,the deviation absolute value of PLT count by two methods was > 15%. After image acquisition by DIA, 17 plasmodium trophozoites were detected in 18 plasmodium-positive peripheral blood smears, and the images were clear. Conclusions: The DIA system has good repeatability, high sensitivity, specificity and accuracy in peripheral blood WBC classification. Its pre-classification and re-classification results have high correlation with the manual classification results.

Surface acoustic wave ammonia sensor based on ZnO/SiO2 composite film.

A surface acoustic wave (SAW) resonator with ZnO/SiO2 (ZS) composite film was used as an ammonia sensor in this study. ZS composite films were deposited on the surface of SAW devices using the sol-gel method, and were characterized using SEM, AFM, and XRD. The performance of the sensors under ammonia gas was optimized by adjusting the molar ratio of ZnO:SiO2 to 1:1, 1:2 and 1:3, and the sensor with the ratio of ZnO to SiO2 equaling to 1:2 was found to have the best performance. The response of sensor was 1.132 kHz under 10 ppm NH3, which was much higher than that of the sensor based on a pristine ZnO film. Moreover, the sensor has good selectivity, reversibility and stability at room temperature. These can be attributed to the enhanced absorption of ammonia and unique surface reaction on composite films due to the existence of silica.

Characterization of microstructural morphology of austempered ductile iron by electron microscopy.

Mechanical properties of austempered ductile iron (ADI) are mainly controlled by its unique microstructure. The objectives of this paper are to characterize the microstructural morphology and the phase distribution of ADI using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and to determine the mechanism of strengthening and toughening of ADI. The experimental results show that, in the microstructure of ADI composing of upper bainite, retained austenite, graphitic nodule, and a small amount of martensite, the upper bainite is composed of sub-units of ferrite in the shape of "wheat ears" on which the "wheat grains" grow at an angle of about 60 degrees to the long axis of the "wheat ears." The retained austenite is connected with each other in the shape of a continuous net. The wheat-ear like bainite with a homogeneous distribution in the continuous austenite net plays an important role to the strengthening and toughening of ADI. The metastable austenite appears in the shape of a large plate in which the martensite is preferentially formed. The appearance of martensite can be suppressed at the time when retained austenite remains stable, which is of benefit to the continuity and homogeneity of austenite net.