Experiment and Theoretical Investigation on Fatigue Life Prediction of Fracturing Pumpheads Based on a Novel Stress-Field Intensity Approach

Fracturing pumpheads are typical pressure vessels that experience frequent fatigue failure under the effect of notches in their cross-bore. To enhance the fatigue life of fracturing pumpheads, the study of the notch effect is indispensable and important to establish a reliable mathematical model to predict their fatigue life. In the present paper, two novel fatigue life prediction models are proposed for notched specimens. In these models, two new geometric fatigue failure regions are defined to improve the weight function. Finally, the elaborated novel stress-field intensity approach was applied to three different types of notched specimens. Experiment results indicate that the new SFI approach achieves 47.82%, 39.48%, and 31.85% higher prediction accuracy than the traditional SFI approach, respectively. It was found that the modified SFI approach provided better predictions than the traditional SFI approach and the TCD method. The II-th novel SFI approach had the highest accuracy, and the I-th novel SFI approach was more suitable for sharply notched specimens.     

气候变暖对阿勒泰地区春玉米播种期和种植布局的影响--测试文章

采用阿勒泰地区7个气象站1961—2010年逐日平均气温资料,使用线性趋势分析、累积距平、t检验并基于Kriging插值法,分析近50年日平均气温稳定通过≥10℃的初日、终日、持续日数和积温的时空变化特征,揭示春玉米播种期及种植布局的变化规律。结果表明,阿勒泰地区近50年≥10℃积温呈现初日提前、终日推迟、持续日数延长、积温增加的现象,其倾向率分别为0.3、1.3、1.6 d·10a^-1和57.1℃·10a^-1,且突变年份均发生在20世纪90年代中期。各县市春玉米播种期提前3～8 d,生长季延长6～11 d。突变前青河东部不能种植春玉米,晚熟品种不能种植或种植风险较大。随着气候不断变暖,春玉米不同熟性品种可种植区逐渐东扩,各县市春玉米在品种熟性上均发生了改变,表现为由不能种植到种植早熟、早熟向中（晚）熟、中晚熟向晚熟品种的变化。     

山区地震医学救援对策

本文结合在汶川地震伤员救治中的实践和教训,提出山区地震医学救援的4个阶段,对救援期间所面临的问题进行了分析,并为山区地震灾害医学救援提出针对性建议,为部队遂行多样化卫勤保障任务提供借鉴。     

Accumulation System: Distributed Neural Substrates of Perceptual Decision Making Revealed by fMRI Deconvolution

Neural substrates of evidence accumulation have been a central issue in decision-making studies because of the prominent success of the accumulation model in explaining a wide range of perceptual decision making. Since accumulation-shaped activities have been found in multiple brain regions, which are called accumulators, questions regarding functional relations among these accumulators are emerging. This study employed the deconvolution method of functional magnetic resonance imaging (fMRI) signals from human male and female participants during object-category decision tasks, taking advantage of the whole-brain coverage of fMRI with improved availability of temporal information of the deconvolved activity. We detected the accumulation activity in many non-category-selective regions (NCSRs) over the frontal, parietal, and temporal lobes as well as category-selective regions (CSRs) of the categorization task. Importantly, the frontal regions mostly showed activity peaks matching the decision timing (classified as “type-A accumulator”), while activity peaks of the parietal and temporal regions were behind the decision (classified as “type-B accumulator”). The CSRs showed activity peaks whose timing depended on both region and stimulus preference, plausibly reflecting the competition among the alternative choices (classified as “type-C accumulator”). The results suggest that these functionally heterogeneous accumulators form a system for evidence accumulation in which the type-A accumulator regions make decisions in a general manner while the type-B and type-C accumulator regions are employed depending on the modality and content of decision tasks. The concept of the accumulation system may provide a key to understanding the universality of the accumulation model over various kinds of decision tasks.SIGNIFICANCE STATEMENT Perceptual decision making, such as deciding to walk or stop on seeing the signal colors, has been explained theoretically by the accumulation model, in which sensory information is accumulated to reach a certain threshold for making decisions. Neural substrates of this model, however, are still under elucidation among candidate regions found over the brain. We show here that, taking advantage of the whole-brain coverage of functional magnetic resonance imaging (fMRI) with improving availability of temporal information by deconvolution method, the accumulation is conducted by a system comprising many regions in different abstraction levels and only a part of these regions in the frontal cortex make decisions. The system concept may provide a key to explaining the universality of the accumulation model.     

Mitochondrial DNA in human hair shafts – existence of intra-individual differences?

The sequences of the hypervariable region 1 (HV1) of the mitochondrial DNA control region from multiple hair shafts from 10 unrelated individuals were compared to determine the frequency of differences in hairs from one individual. The extraction method described herein showed an average success rate of 67% for all 150 hair shafts tested in HV1. The mtDNA sequences from the hair shafts matched the sequences from the corresponding blood and saliva samples taken from the same donor and no evidence of heteroplasmy was found. The results emphasize the reliability of DNA extraction and mtDNA typing from human hair shafts for forensic purposes. Received: 16 July 1998 / Received in revised form: 31 August 1998     

超声科西部地区卫生人才培训方式探讨

探讨超声科的西部地区卫生人才的培训方式。为切实加强西部地区卫生人才队伍建设,促进西部卫生事业发展,严格制定培训方案,采用了一对一的培训方式,取得了良好成绩。     

心理干预对阴部外伤女童家长情绪反应的疗效观察

目的：评估心理干预对女童阴部外伤患儿家长情绪反应的疗效。方法：对42例女童阴部外伤家长的情绪反应进行观察评估,并针对其出现的情绪反应进行心理干预。结果：42例家长的心理反应以激动愤怒型最多（76.2%）,心理干预有效率为95.2%。结论：女童阴部外伤后家长的心理反应较为剧烈,心理干预是减轻家长心理反应的有效措施之一。     

危险区骨骼肌肉系统肿瘤的外科治疗

目的:介绍一种安全处理危险区骨骼肌肉系统良性或低度恶性肿瘤的外科治疗方法。方法:对骶2脊索瘤先施行前路经腹结扎双侧髂内动脉,然后再切除肿瘤,可减少出血。对腹股沟区或腘窝区较大肿瘤与股、腘大血管及神经紧密粘连者,先从肿瘤远近端血管、神经正常部分解剖出血管神经,再向病变区解剖,容易完整切除肿瘤。对锁骨上区肿瘤,先截除一段锁骨,然后从肿瘤远近端正常锁骨下动、静脉及臂丛神经处,向肿瘤部游离并保护好胸膜,可较安全地切除肿瘤。而对于腓骨头、颈及其周围部肿瘤,先解剖出腓总神经及其各肌支,尽可能保留肌支。结果:11例危险区(紧邻大血管、神经区域)良性或低度恶性骨骼肌肉系统肿瘤,采用先从肿瘤远近端正常血管、神经处游离出神经、血管,再向肿瘤部解剖,均顺利解剖出大血管及神经,并完整切除肿瘤。所有病例无复发,亦无肢体功能障碍。结论:对紧邻重要血管及神经的较大良性或低度恶性骨骼肌肉系统肿瘤,先从正常段血管、神经向肿瘤部解剖游离,既可彻底切除肿瘤,又可避免损伤血管、神经引起肢体功能障碍,是一种较好方法。     

度米芬渗透泵片在额面部火器伤软组织损伤的药效学研究

 目的探讨度米芬渗透泵片在额面部火器伤软组织损伤的抗菌作用。方法10只犬采用钢珠弹致伤额面部,度米芬渗透泵片植入伤口,高效液相色谱法测定软组织伤后各时间点的药物浓度,观察用药前后损伤组织的病理改变,并截取用药前后不同时间组织做需氧及厌氧培养。结果度米芬渗透泵片在组织内药物浓度高,伤后24h内放置度米芬渗透泵片的额面伤组织继发损伤轻,无明显感染。未用药的伤口组织近伤道0.8cm内严重坏死,伤口24h周围组织炎性反应明显,坏死呈进行性加重,且6h开始出现细菌感染。随时间的延长,感染的细菌明显增多,以需氧菌为主。结论度米芬渗透泵片是额面部火器伤软组织感染预防用药的有效方法之一。