颅脑外伤疾病诊断专家系统的设计与实现

医学专家系统是人工智能和专家系统理论和技术在医学领域的重要应用,具有极大的科研和应用价值,它可以帮助医生解决复杂的医学问题,作为医生诊断,治疗的辅助工具.本文主要阐述了本专家系统的结构,需要面对的问题及实现方法.     

Tang Yijie： China＇s Top Philosopher and Master of Chinese Learning

Tang Yijie was born in Tanjin on February 16, 1927. He graduated from the Department of Philosophy of Peking University, in 1951. He successively served as professor and advisor to Ph.D. candidates at Peking University＇s Philosophy Department, vice chairman of China Oriental Culture Society, vice chairman of China Society on the Studies of Yan and Huang Culture, and vice chairman of Chinese Confucius Society. In 1983, he worked at Harvard University as visiting scholar. In 1986, he was engaged as research jellow by New York State University. in 1990, he was conferred with honorary doctor by McMaster University of Canada. In 2006, he was conferred with honorary doctor by Kansai University of Japan. He served as guest projessor at University of Oregon, McMaster University, Hong Kong University of Science and Technology, and Melbourne University respectively.     

电感和电容对电流的影响

1 改进演示实验的思考 基于学生已经具有"电阻对直流电有阻碍作用"的认识基础,学习电感和电容对直流电的影响时,只须将电阻替换为电感或者将电阻替换为电容进行对比,通过表现的现象认知电感和电容对直流电的影响.同理,学习电感和电容对交变电流的影响时,再把直流电源用交流电源替代进行对比,还是通过表现的现象认知电感和电容对交变电流的影响.总之,设定的教学方法是比较、归纳法.根据教学方法的需要,教学中采取了同一时刻将电阻、电感和电容对电流的影响的现象同时表现出来,并进行对比.达到了实验现象对比度非常鲜明的效果.     

1988年奥运会体操比赛跳马手翻团身前空翻腾越技术

本课题研究目的是:(a)确定在1988年奥运会体操比赛中与跳马手翻团身前空翻成功动作相关连的力学因素;和(b)把这次研究结果与86年美国体操锦标赛的研究结果进行对比,得到改进该动作的有关见解。本课题的研究对象是1988年奥运会体操比赛中51名男子运动员。值得注意的相互关系表明,决定动作成功的重要因素如下:(a)在蹬离地面和跳板时,有较大的由快速助跑获得的水平速度(V_H);(b)在触马期间垂直速度(V_v)有较大的变化,即手臂和肩的制动作用;(c)离     

Chemosensory conditioning in molluscs: II. A critical review

We critically review chemosensory conditioning studies with molluscs and find that, in many studies, the influence of nonassociative processes complicates, obscures, and renders ambiguous the unique contribution of associative learning. These nonassociative processes include sensory adaptation, habituation, sensitization, and changes in feeding motivation. They arise from both the food extracts that have often been used as conditioned stimuli and the aversive stimuli that have been used as unconditioned stimuli.     

Association of p53 codon 72 polymorphism with liver metastases of colorectal cancers positive for p53 overexpression

Objective: To evaluate the association between p53 codon 72 polymorphism (R72P) and the risk of colorectal liver metastases. Methods: The p53 R72P genotype was identified by polymerase chain reaction-restriction fi'agment length poly-morphism (PCR-RFLP) method in 78 consecutive colorectal cancer patients with liver metastases and 214 age- and sex-matched cases with nonmetastatic colorectai cancer. Results: The R allele of the p53 R72P polymorphism was more frequently found in metastatic cases than in nonmetastatic cases (P=0.075). Carriers of the 72R allele had a 2.25-fold (95% CI (confidence inter-val)=1.05～4.83) increased risk of liver metastases. On the stratification analysis, 72R-carrying genotype conferred a 3.46-fold (95% CI=1.02～11.72) and a 1.05-fold (95% CI=0.36～3.08) increased risk of liver metastases for p53 overexpression-positive and negative colorectal cancers, respectively. Conclusion: These results demonstrate for the first time that the 72R allele of the p53 polymorphism has an increased risk for liver metastases in colorectal cancers positive for p53 overexpression.     

Experimental investigation of external explosion in the venting process

INTRODUCTION Venting technology provides possible protectivemeasures against the effect of explosions. The essen-tial point is to release the high pressure throughproper venting to ensure pressure vessel safety. In acombustion system, when abnormal pressure occursand the venting orifice is opened, a lot of combustiblemixtures venting from the vessel lead to a series ofchanges inside and outside the vessel, and may resultin serious explosion disasters. During the venting proc…     

Chemosensory conditioning in molluscs: I. Failure of contextual conditioning in<Emphasis Type="Italic">Hermissenda</Emphasis>

Aversive chemosensory conditioning altersHermissenda’s feeding behavior. But opposite behavioral changes have been reported, depending on whether discrete-trial or context-conditioning paradigms were used, raising questions about the roles of associative and nonassociative processes. We attempted to produce chemosensory contextual conditioning but failed to do so across a wide range of conditions. In Experiments 1–3, we observed large, nonspecific bite latency increases to shellfish extracts, regardless of whether they had signaled the presence or absence of shaking. In Experiment 4, we found that mere exposure to shellfish extract produced latency increases; vestibular stimulation was unnecessary. In a final experiment, using Y-maze choice tests, we failed to observe selective reductions in animals’ preference for shellfish paired with shaking. Nonassociative processes stemming from prolonged exposure to concentrated shellfish extracts appear to be major factors in our failure to demonstrate associative chemosensory contextual conditioning.     

无芯模旋压旋轮轨迹曲线对其成形精度影响的仿真研究

研究目的：验证无芯模旋压工艺可行性,同时深入探究此新型工艺机理,研究并获取旋轮轨迹曲线参数化控制及其对于零件成形精度的影响趋势。创新要点：基于贝塞尔曲线实现对于无芯模旋压旋轮轨迹曲线的参数化控制;通过构建包括成形与回弹工艺过程的无芯模旋压仿真模型,研究参数化轨迹曲线对成形件壁厚及形状精度的影响趋势及关系,同时对成形过程变形区应力应变进行了深入探究分析。研究方法：1．基于三次贝塞尔曲线实现对于旋轮轨迹曲线的拟合以及参数化控制（图3）;2．利用LSDYNA软件实现对无芯模旋压成形及回弹工艺综合仿真及其过程、结果数据的提取;3．研究不同参数化轨迹曲线下成形件壁厚及形状精度变化趋钟（图12和13）,获取量化轨迹曲线对于零件成形精度影响关系（表3）,并通过增加实验组验证所获关系模型;4．提取成形过程中及成形后板料变形区应力及应变数据（图14-19）,深入探究上述变形机理。重要结论：凹轨迹曲线下,坯料中部出现最大减薄及变形程度,且降低曲线曲率,形状精度提高;凸轨迹曲线下,最大减薄及变形区域出现在坯料后部,且降低曲线曲率,壁厚及形状精度均提高。     

Effect of the scale of quantitative trait data on the representativeness of a cotton germplasm sub-core collection

A cotton germplasm collection with data for 20 quantitative traits was used to investigate the effect of the scale of quantitative trait data on the representativeness of plant sub-core collections.The relationship between the representativeness of a sub-core collection and two influencing factors,the number of traits and the sampling percentage,was studied.A mixed linear model approach was used to eliminate environmental errors and predict genotypic values of accessions.Sub-core collections were constructed using a least distance stepwise sampling(LDSS) method combining standardized Euclidean distance and an unweighted pair-group method with arithmetic means(UPGMA) cluster method.The mean difference percentage(MD),variance difference percentage(VD),coincidence rate of range(CR),and variable rate of coefficient of variation(VR) served as evaluation parameters.Monte Carlo simulation was conducted to study the relationship among the number of traits,the sampling percentage,and the four evaluation parameters.The results showed that the representativeness of a sub-core collection was affected greatly by the number of traits and the sampling percentage,and that these two influencing factors were closely connected.Increasing the number of traits improved the representativeness of a sub-core collection when the data of genotypic values were used.The change in the genetic diversity of sub-core collections with different sampling percentages showed a linear tendency when the number of traits was small,and a logarithmic tendency when the number of traits was large.However,the change in the genetic diversity of sub-core collections with different numbers of traits always showed a strong logarithmic tendency when the sampling percentage was changing.A CR threshold method based on Monte Carlo simulation is proposed to determine the rational number of traits for a relevant sampling percentage of a sub-core collection.