Investigation on the Evolution of Nano-Scale Defects of CL-20 Crystals under Thermal Treatment by Wide/Small-Angle X-ray Scattering

Nano-scale crystal defects extremely affect the security and reliability of the explosive charges of weapons. In order to understand the evolution of nano-scale defects of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane (CL-20) explosive crystals under thermal treatments, the specific surface, volume fraction and size distribution of the nano-scale defects were studied by using Wide Angle X-ray Scattering (WAXS) and Small Angle X-ray Scattering (SAXS) during the temperature range from 30 °C to 200 °C. The results showed that the number and size of the pores in CL-20 powder did not change significantly during the heating process before phase transformation (30–160 °C). At 170 °C, CL-20 began to convert from ε- to γ- phase, and the specific surface and volume fraction of the nano-scale defects increased significantly. Further investigation of the pore size distribution showed that the number of pores with a small size (radius 9–21 nm) changed particularly significantly, resulting from the cracking of the CL-20 crystal powder during phase transition. At 200 °C, the phase transition was completed and γ-CL-20 was created, and the small-sized pores gradually grew into medium-sized (radius 21–52 nm) pores over time when the temperature was fixed at 200 °C.     

Numerical Investigation of the Influence of Ultimate-Strength Heterogeneity on Crack Propagation and Fracture Toughness in Welded Joints

The mechanical properties of dissimilar metal-welded joint materials are heterogeneous, which is an obstacle to the safety evaluation of key welded structures. The variation of stress–strain conditions at the crack tip caused by mismatch of material mechanical properties in dissimilar metal-welded joints is an important factor affecting crack propagation behavior. To understand the influence of uneven distribution of ultimate strength of the base metal and the welded metal on the crack propagation path, fracture toughness, as well as the mechanical field at the crack tip in the small-scale yield range, the user-defined field variable subroutine method is used to express continuous variation characteristics of welded joint ultimate strength in finite element software. In addition, the J-integral during crack propagation is calculated, and the effect of the ultimate strength on the J-integral and the stress field at the crack tip are analyzed. The results show that as the crack propagation direction is perpendicular to the direction of ultimate strength, the gradient of ultimate strength increases from |G_y|= 50 to |G_y|= 100 MPa/mm, the crack deflection angle increases by 0.018%, and the crack length increases by 1.46%. The fracture toughness of the material decreased slightly during crack propagation. Under the condition that the crack propagation direction is the same as the direction of ultimate strength, the crack propagation path is a straight line. As the gradient of ultimate strength increases from G_x = 50 to G_x = 100 MPa/mm, the crack propagation length decreases by 5.17%, and the slope of fracture toughness curve increases by 51.63%. On the contrary, as the crack propagates to the low ultimate strength side, the crack propagation resistance decreases, the ultimate strength gradient increases from G_x = −100 to G_x = −50 MPa/mm, and the slope of the fracture toughness curve decreases by 51.01%. It is suggested to consider the relationship between crack growth behavior and ultimate strength when designing and evaluating the structural integrity of cracks at the material interface of dissimilar metal-welded joints.     

Prognostic value of selected platelet parameters of patients operated for non-small cell lung cancer

BackgroundPlatelets play a vital role in the neoplastic process. Platelet parameters are hence an important source of information concerning ongoing neoplastic disease. The aim of the study is to assess the impact of selected platelet parameters on the survival of patients with non-small cell lung cancer (NSCLC).MethodsThe study included 532 (174 female and 358 male) patients aged 36–84 years (mean age 63.6 years) operated on due to NSCLC, staged IA–IIIA. Before the operation, all patients received a blood morphology test. The following parameters were subjected to statistical analysis: platelet count, mean platelet volume (MPV) parameter, platelet distribution width (PDW) parameter, platelet-to-lymphocyte ratio (PLR) and systemic immune-inflammation (SII) index. These findings were compared with the clinical data of the patients, and the probability of overall survival was analyzed.ResultsThe univariate analysis revealed a correspondence between PDW, MPV, PLR and SII index and patient survival. The multivariate analysis including patient clinical data found the following factors to have negative prognostic value for patients operated on due to NSCLC: male sex, advancement stage of neoplastic disease and Charlson Comorbidity Index (CCI) above 4, and PLR >144.ConclusionsPDW value, PLR and SII index are independent prognostic factors. In the multi-factor model, male sex, the advancement stage of the neoplastic disease, CCI above 4 and PLR lower than 144 had the greatest prognostic value.     

Determinants of Complex Regional Pain Syndrome Type I among Radial Head Fracture Patients with Unilateral Arthroplasty

ObjectiveThis study aims to assess the proportions of complex regional pain syndrome type I (CRPS I) in radial head fracture patients undergoing unilateral arthroplasty and to explore associated factors.MethodsThis is a prospective observational study. From March 2016 to May 2019, a total of 221 adult patients with radial head fracture patients were included in consecutive studies and completed the 1‐year follow‐up. All patients were treated by unilateral arthroplasty. At each follow‐up visit, the visual analogue scale was used to measure patients'' pain level. Occurrence of CRPS I, which was diagnosed by Budapest criteria, was the main outcome collected at baseline and the 1‐, 3‐, 6‐, and 9‐month follow‐ups. The baseline data were collected before surgery and included demographic and clinical data. Independent t‐tests and χ ² tests were used as univariate analyses to compare the baseline data of patients with and without CRPS I. Multivariate analysis (Backword‐Wald) was used to identify factors independently associated with CRPS I.ResultsThe proportion of CRPS I cases among radial head fracture patients undergoing unilateral arthroplasty was 11% (n = 24). A total of 19 (79%) patients were diagnosed with CRPS I within 1 month after surgery. Multivariable logistic regression analysis revealed that female gender (odds ratios [OR]: 1.537; 95% confidence interval [CI]: 1.138–2.072), age younger than 60 years (OR: 1.682; 95% CI: 1.246–2.267), moderate and severe Mayo Elbow Performance Score (MEPS) pain (OR: 3.229; 95% CI: 2.392–4.351) and anxiety (OR: 83.346; 95% CI: 61.752–112.320) were independently associated with CRPS I.ConclusionsThis exploratory study reported that the incidence of CRPS I developing after radial head arthroplasty was 11%. Female sex, younger age, moderate and severe MEPS pain and anxiety patients seems more likely to develop CRPS I.     

鼻咽癌常规放疗中面颈联合野的剂量分布研究

目的分析鼻咽癌常规放疗中面颈联合野的剂量分布图以了解剂量分布上存在的问题。方法采用美国ADAC公司的Pinnacle治疗计划系统对1例鼻咽癌患者(福州分期为T2N0M0Ⅱ期)行双侧面颈联合野和中下颈前切野常规定位,再用CT模拟定位机进行CT扫描,把CT影像传送到Pinnacle治疗计划系统进行图像重建及照射野重建,再进行二维计划剂量运算,从而得到各层的剂量分布曲线。结果100%等剂量曲线仅能全包鼻咽腔和蝶窦底壁;105%等剂量曲线全包口咽和射野内的全部颈段脊髓,110%等剂量曲线包口咽的下部分和颈3、4段部分脊髓;95%和90%等剂量曲线穿过蝶窦和斜坡中央;50%的等剂量曲线与射野各界重叠。两野共线处附近组织位于110%等剂量曲线内,最高剂量达220%。结论面颈联合野剂量分布存在着以下几点缺陷:(1)蝶窦和斜坡均在100%～50%的等剂量曲线之间,故存在颅底和斜坡欠量;(2)口咽部剂量在105%～110%的等剂量曲线之间,为高量区,故放射性咽炎常见;(3)颈段脊髓均位于105%～110%高剂量区,易产生放射性脊髓病;(4)两野共线处出现剂量重叠。     

Quantitative Distribution Characterization and Correlation Study of Composition,Structure and Hardness of Rim Region in Railway Wheel

The railway wheel is the key component of high-speed railway train. To assure the safety in service, higher requirements are put forward in this study for the composition, microstructure uniformity, and comprehensive properties of wheel materials. In this paper, the high throughput quantitative distribution characterization methods of composition, microstructure, inclusions and Vickers hardness of high-speed railway wheel materials based on the spark source original position analysis technique, high throughput scanning electron microscope (SEM) combined with image batch processing technology, and automatic two-dimensional quantitative distribution analysis technique of inclusions and micro hardness have been studied. The distribution trend of the content of nine elements, size and quantity of sulfides and oxides, ferrite area fraction, and Vickers hardness from the wheel tread surface to the radial depth of about 50 mm below the surface has been discussed. The influence of inclusions distribution on the element segregation and the effect of rim-chilling process with different water spraying angle on the distribution of microstructure and micro hardness have been investigated. It was found that unsynchronized cooling on both sides of the rim altered the phase behavior of ferrite and pearlite and obvious inhomogeneity distribution of ferrite appeared, which led to the asymmetrical Vickers hardness in areas near or away from the flange. Based on the quantitative characterization of area fraction and micro hardness on the same location of wheel rim, a statistical mapping relationship between ferrite area fraction and Vickers hardness was established.     

淄博市生活饮用水中硝酸盐暴露及其健康风险的时空分布特征

目的 对饮用水硝酸盐进行健康风险评估,为水质干预决策提供技术依据。 方法 对2016~2020年淄博市2 575份城乡饮用水样品检测硝酸盐含量,采用我国《化学物质环境健康风险评估技术指南》(WS/T 777-2021)的环境健康风险评价模型,分析不同年度、不同监测点类型、不同水源、不同处理方式的硝酸盐含量和非致癌健康风险的时空分布特征。 结果 2016~2020年共检测水样2 575份,硝酸盐超标率为10.76%。饮用水硝酸盐含量具有空间聚集性,高值主要集中在沂源县中部和东部、博山区西南部,低值集中在高青县和桓台县。饮用水硝酸盐含量和非致癌健康风险总体呈现逐年升高趋势,农村水高于城区水、地下水高于地表水、未处理水高于处理水。5年总体平均非致癌风险为0.21,对人体产生的非致癌风险较低;最高非致癌风险为1.99,主要集中在沂源县,对人体存在长期暴露的非致癌健康风险。 结论 淄博市局部区域饮用水硝酸盐污染较严重,存在非致癌健康风险,应引起关注并采取水质干预措施。     

谈高校财力资金的合理配置

在目前我国高校财力资金不足的情况下，如何更好的加以配置，直接关系到高校的办学效益和办学质量。财力资金的合理配置，已成为高校的头等大事。     

Combining a digital design-mediated surgery-first approach and clear aligners to treat a skeletal Class III defect for aesthetic purposes: a case report

This case report introduces digital surgery-first approach orthognathic surgery assisted by three-dimensional virtual planning and combined with invisible orthodontic treatment for a 21-year-old female patient with a skeletal Class III high-angle gummy smile malocclusion. We explored the clinical significance of the widespread application of digital technology for rapid development of the orthodontic/orthognathic field. The regional acceleratory phenomenon and clear aligners were used to achieve fast and aesthetic tooth movement after surgery. The treatment lasted only 8 months, and the patient was satisfied with the aesthetic results. The results remained stable after 1 year of follow-up. This case report highlights the advantages of combining a digital design and a surgery-first approach to produce accurate, rapid, safe, stable, and fulfilling cosmetic results. The combination of the surgery-first approach and clear aligners can facilitate patient-oriented surgical orthodontic treatment.     

Ⅰ、Ⅱ级肝门区域阻断肝叶(段)切除的初步体会

目的 总结区域阻断肝叶、肝段的入肝血管分支,施行各种类型肝切除的经验.方法 回顾性分析2006年～2007年间湖南省人民医院肝胆科行肝门区域血管阻断肝部分切除的319例临床资料.左肝外叶切除127例,左半肝切除(含Ⅰ段切除)89例,右肝前叶切除15例,右肝后叶切除34例,右半肝切除(含Ⅸ段切除)32例,肝血管瘤剥除/肝局部切除19例,肝囊肿剥除/肝局部切除3例.结果 全组无手术死亡,失血量平均(70±15)mL,术后5～7 d复查肝功能无明显损害,未出现肝坏死、胆漏、出血等并发症.结论 区域血管阻断肝叶(段)切除避免了保留肝叶的缺血再灌注损伤,使手术从容不迫的进行,减少了大量失血及肝功能衰竭的发生,是一种安全、有效的切肝手术方法.