36例新生儿环状胰腺的诊治分析

目的 总结小儿环状胰腺的产前诊断、围产期管理、早期手术的系统化诊疗.方法 选取2007年9月至2015年3月我院收治的36例产前诊断为环状胰腺患儿的病例资料,对其产前诊断、围产期管理、影像学检查、手术治疗及预后等资料进行回顾性分析.结果 同期收治产前超声诊断为十二指肠梗阻的52例患儿中,36例手术证实为环状胰腺.产前超声检查显示“双泡征”30例,“羊水过多”24例.其中30例分娩后当日即转运至我院,行十二指肠一十二指肠菱形吻合术治疗,均痊愈出院.结论 产前诊断、生后按计划转诊、早期手术治疗逐渐成为环状胰腺的主流管理模式.新生儿腔镜技术的发展应用进一步提高了本病疗效.     

Improvement in Hardness and Wear Behaviour of Iron-Based Mn–Cu–Sn Matrix for Sintered Diamond Tools by Dispersion Strengthening

The work presents the possibility of fabricating materials for use as a matrix in sintered metallic-diamond tools with increased mechanical properties and abrasion wear resistance. In this study, the effect of micro-sized SiC, Al₂O₃, and ZrO₂ additives on the wear behaviour of dispersion-strengthened metal-matrix composites was investigated. The development of metal-matrix composites (based on Fe–Mn–Cu–Sn–C) reinforced with micro-sized particles is a new approach to the substitution of critical raw materials commonly used for the matrix in sintered diamond-impregnated tools used for the machining of abrasive stone and concrete. The composites were prepared using spark plasma sintering (SPS). Apparent density, microstructural features, phase composition, Young’s modulus, hardness, and abrasion wear resistance were determined. An increase in the hardness and wear resistance of the dispersion-strengthened composites as compared to the base material (Fe–Mn–Cu–Sn–C) and the commercial alloy Co-20% WC provides metallic-diamond tools with high-performance properties.     

Fabrication of Functionally Graded Diamond/Al Composites by Liquid–Solid Separation Technology

The electronic packaging shell, the necessary material for hermetic packaging of large microelectronic device chips, is made by mechanical processing of a uniform block. However, the property variety requirements at different positions of the shell due to the performance have not been solved. An independently developed liquid–solid separation technology is applied to fabricate the diamond/Al composites with a graded distribution of diamond particles. The diamond content decreases along a gradient from the bottom of the shell, which houses the chips, to the top of the shell wall, which is welded with the cover plate. The bottom of the shell has a thermal conductivity (TC) of 169 W/mK, coefficient of thermal expansion (CTE) of 11.0 × 10⁻⁶/K, bending strength of 88 MPa, and diamond content of 48 vol.%. The top of the shell has a TC of 108 W/mK, CTE of 19.3 × 10⁻⁶/K, bending strength of 175 MPa, and diamond content of 15 vol.%, which solves the special requirements of different parts of the shell and helps to improve the thermal stability of packaging components. Moreover, the interfacial characteristics are also investigated. This work provides a promising approach for the preparation of packaging shells by near-net shape forming.     

Multilayer Diamond Coatings Applied to Micro-End-Milling of Cemented Carbide

Cobalt-cemented carbide micro-end mills were coated with diamond grown by chemical vapor deposition (CVD), with the purpose of micro-machining cemented carbides. The diamond coatings were designed with a multilayer architecture, alternating between sub-microcrystalline and nanocrystalline diamond layers. The structure of the coatings was studied by transmission electron microscopy. High adhesion to the chemically pre-treated WC-7Co tool substrates was observed by Rockwell C indentation, with the diamond coatings withstanding a critical load of 1250 N. The coated tools were tested for micro-end-milling of WC-15Co under air-cooling conditions, being able to cut more than 6500 m over a period of 120 min, after which a flank wear of 47.8 μm was attained. The machining performance and wear behavior of the micro-cutters was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Crystallographic analysis through cross-sectional selected area electron diffraction patterns, along with characterization in dark-field and HRTEM modes, provided a possible correlation between interfacial stress relaxation and wear properties of the coatings. Overall, this work demonstrates that high adhesion of diamond coatings can be achieved by proper combination of chemical attack and coating architecture. By preventing catastrophic delamination, multilayer CVD diamond coatings are central towards the enhancement of the wear properties and mechanical robustness of carbide tools used for micro-machining of ultra-hard materials.     

Unusual Dependence of the Diamond Growth Rate on the Methane Concentration in the Hot Filament Chemical Vapor Deposition Process

Although the growth rate of diamond increased with increasing methane concentration at the filament temperature of 2100 °C during a hot filament chemical vapor deposition (HFCVD), it decreased with increasing methane concentration from 1% CH₄ –99% H₂ to 3% CH₄ –97% H₂ at 1900 °C. We investigated this unusual dependence of the growth rate on the methane concentration, which might give insight into the growth mechanism of a diamond. One possibility would be that the high methane concentration increases the non-diamond phase, which is then etched faster by atomic hydrogen, resulting in a decrease in the growth rate with increasing methane concentration. At 3% CH₄ –97% H₂, the graphite was coated on the hot filament both at 1900 °C and 2100 °C. The graphite coating on the filament decreased the number of electrons emitted from the hot filament. The electron emission at 3% CH₄ –97% H₂ was 13 times less than that at 1% CH₄ –99% H₂ at the filament temperature of 1900 °C. The lower number of electrons at 3% CH₄ –97% H₂ was attributed to the formation of the non-diamond phase, which etched faster than diamond, resulting in a lower growth rate.     

施源器材料对192Ir后装源水中吸收剂量的影响

目的 应用3D打印支架联合人造金刚石探头测量施源器材料对高剂量率后装¹⁹²Ir源水中吸收剂量的影响。方法 将金刚石探头与塑料插植针分别固定在3D打印支架上,金刚石探头的中心轴与塑料插植针的中心轴在一个平面内相互垂直。采用模拟源尺测量实测驻留位置为248 mm,该驻留位置与逐点测量的最大响应位置吻合。测量材料有304不锈钢、聚亚苯基砜树脂（PPSU）材料、有机玻璃（PMMA）材料和3D打印聚乳酸（PLA）材质。测量水中不同厚度或不同填充率的材料对吸收剂量的衰减。结果 304不锈钢和PPSU材料厚度与相对剂量的线性拟合公式分别为y=-0.029 7x+1.000 3,y=-0.002 3x+1.010 2;拟合优度R²分别为0.925 3和0.722 2。10 mm以内PMMA材料对剂量的影响均<1.5%。3D打印材料填充率（%）与相对剂量的线性拟合公式为y=-0.000 4x+1.024 6,拟合优度R²为0.854 5。结论 施源器材料,尤其是高密度材料（如304不锈钢）和新型技术材料（如3D打印PLA）,对¹⁹²Ir后装源的吸收剂量影响需引起施源器开发人员和临床应用者的足够重视。     

两种不同的牵引推拿方式治疗腰椎间盘突出的临床研究

目的:研究观察"两种不同的牵引推拿方式治疗腰椎间盘突出的临床效果.方法:将2005年1月至2005年12月在我院就诊的332例患者,随机分为甲、乙两组,各166例.甲组:采用"牵引推拿于一体的治疗方法"(2004年临沂市科技局鉴定的科研成果).乙组:采用传统的骨盆牵引之后再推拿的方法.结果:甲组:有效率为98.39%.乙组:有效率为89.56%.两组比较,甲组优势明显(P＜0.01).结论:治疗腰椎间盘突出病一牵引推拿于一体的方法优于传统的骨盆牵引之后再推拿的方法.     

Improved Mechanical and Tribological Properties of Metal-Matrix Composites Dispersion-Strengthened by Nanoparticles

Co- and Fe-based alloys produced by powder technology are being widely used as a matrix for diamond-containing composites in cutting, drilling, grinding pplications, etc. The severe service conditions demand that the mechanical and tribological properties of these alloys be improved. Development of metal-matrix composites (MMCs) and alloys reinforced with nanoparticles is a promising way to resolve this problem. In this work, we have investigated the effect of nano-sized WC, ZrO₂, Al₂O₃, and Si₃N₄ additives on the properties of sintered dispersion-strengthened Co- and Fe-based MMCs. The results show an increase in the hardness (up to 10 HRB), bending strength (up to 50%), wear resistance (by a factor of 2–10) and a decrease in the friction coefficient (up to 4-fold) of the dispersion-strengthened materials. The use of designed alloys as a binder of cutting diamond tools gave a 4-fold increment in the service life, without reduction in their cutting speed.     

Skin barrier function recovery after diamond microdermabrasion

Microdermabrasion is a popular method for facial rejuvenation and is performed worldwide. Despite its extensive usage, there are few publications on skin barrier change after microdermabrasion and none concerning diamond microdermabrasion. Our object was to see changes in transepidermal water loss (TEWL), hydration and erythema of the face following diamond microdermabrasion. Twenty-eight patients were included in this spilt face study. TEWL, stratum corneum hydration and the degree of erythema were measured from the right and left sides of the face (forehead and cheek) at baseline. One side of the face was treated with diamond microdermabrasion and the other side was left untreated. Measurements were taken right after the procedure and repeated at set time intervals. Diamond microdermabrasion was associated with a statistically significant increase in TEWL immediately after the procedure and at 24 h. However, on day 2, levels of TEWL were back to baseline. An increase in hydration and erythema was observed right after microdermabrasion, but both returned to baseline on day 1. The results show that skin barrier function of the forehead and cheek recovers within 2 days of diamond microdermabrasion. Diamond microdermabrasion performed on a weekly basis, as presently done, is expected to allow sufficient time for the damaged skin to recover its barrier function in most parts of the face.     

Phasic reward responses in the monkey striatum as detected by voltammetry with diamond microelectrodes

Reward-induced burst firing of dopaminergic neurons has mainly been studied in the primate midbrain. Voltammetry allows high-speed detection of dopamine release in the projection area. Although voltammetry has revealed presynaptic modulation of dopamine release in the striatum, to date, reward-induced release in awakened brains has been recorded only in rodents. To make such recordings, it is possible to use conventional carbon fibres in monkey brains but the use of these fibres is limited by their physical fragility. In this study, constant-potential amperometry was applied to novel diamond microelectrodes for high-speed detection of dopamine. In primate brains during Pavlovian cue-reward trials, a sharp response to a reward cue was detected in the caudate of Japanese monkeys. Overall, this method allows measurements of monoamine release in specific target areas of large brains, the findings from which will expand the knowledge of reward responses obtained by unit recordings.