高阶数控运动轴的弧齿锥齿轮全工序法加工研究

为解决弧齿锥齿轮全工序法加工齿面误差修正的难题,本文将开展高阶数控运动轴的弧齿锥齿轮全工序法加工研究。首先由刀具和工件的相对空间位置关系完成了传统摇台式机床调整参数到全数控机床运动轴的等效转换,并通过泰勒展开的方法获得了数控机床运动轴6阶表达式;随后推导了6阶多项式表达的齿面方程,分析了多项式系数对齿面拓扑结构的影响。结果表明,同等量的系数变化,随着系数的阶次增高,对齿面偏差影响的程度变小。建立了多项式系数对齿面误差影响的敏感性矩阵,对工作面与非工作面引入权重系数构建了齿面误差协同修正模型。最后通过算例进行了实验验证,经修正后齿面误差得到有效减小。本文的研究为弧齿锥齿轮全工序法加工修正提供了方法,同时本方法也适用于弧齿锥齿轮其他的加工方式。

指向表达进阶的数学课堂教学实践策略

数学表达是数学活动中主体观察、思考的结果。数学表达能力进阶是学生的数学核心素养发展的外在综合体现,其过程是学生的数学核心素养发展的过程。在小学数学课堂教学中,促进学生表达进阶的实践策略主要有:提供支架,让表达经验化;深度辨析,让表达概念化;沟通联系,让表达结构化;多元开放,让表达创新化。

助推儿童数学表达力进阶的实践探寻

当下,在数学学习中,不少儿童存在着不敢说、不会说、会说但不会写、会说会写但流于浅表层等问题。在数学教学中,教师可以从激发儿童的问题意识,引导儿童建立表达框架、明晰表述方式,促进儿童深层表达等方面着手,助推儿童的数学表达力进阶,促进他们敢说、会说、说好。

方阵的阶迹及其它的特征多项式的阶迹表达式

在本文中引入一个谓之为K阶迹的新术语从而拓广了矩阵迹的概念,然后利用多项式的行列形式证明了方阵特征多项式的阶迹表达式。

球面谐和函数Y_(lm)(θ,φ)的降阶表达式

本文给出连带勒让特函数P_1(x)的二个新递推公式,由它只需经简单的代数运算就可从一阶连带勒让特函数P_1~0(x)与P_1~1(x)逐次求得任意高阶连带勒让特函数。并在这两个新公式基础上导得球面谐和函数Y_l(θ,φ)的降阶表达式。

基于变精度粗糙集的改模知识分层递阶归纳

应用基本粗糙集理论对改模方案进行改模知识归纳可以得到改模决策规则集。为解决其规则集规模大、实用性不强的问题,提出了一种基于变精度粗糙集的改模知识分层递阶归纳方法。首先,在研究改模知识的分层递阶层次表达模型的基础上,给出改模方案特征值具体化、完备化和层次化方法,并据此构建了基于分层递阶的改模方案特征决策表集;其次,在特征约简过程中,引入分类质量/误差矩阵,通过基于变精度粗糙集的改模方案特征层次约简,得到符合用户分类质量要求的核心特征集;然后,进一步利用基于分层递阶的规则层次生成和知识获取方法,得到规模小且实用性强的规则集;最后,通过实例验证了该方法的实用性和有效性。

关于广义等差数列性质的探讨

对广义等差数列的性质进行探讨,并提出广义等差数列的一阶递归表达式。

Expression of Livin and vascular endothelial growth factor in different clinical stages of human esophageal carcinoma

AIM： To investigate the role of Livin and vascular endothelial growth factor （VEGF） in human esophageal carcinoma, and analyze its relationship to clinical stages.METHODS： Expression of Livin in fresh esophageal cancer tissues was detected by immunohistochemistry （IHC）, Western blotting and reverse transcriptasepolyrnerase chain reaction （RT-PCR）, and VEGF by Western blotting and RT-PCR. All statistical analyses were performed by SPSS version 11.0. RESULTS： Livin positivity was also significantly correlated with tumor stages, increasing with tumor progression. Expression of Livin and VEGF increased with the process of esophageal carcinoma. In the fourth clinical stage, expression of Livin and VEGF was the most significant. Expression of Livin was positively correlated with VEGF. CONCLUSION： Over-expression of Livin and VEGF contributes to the pathogenesis of esophageal carcinoma.

Molecular cloning and mRNA expression analysis of myosin heavy chain(MyHC)from fast skeletal muscle of grass carp,Ctenopharyngodon idella

The myosin heavy chain(MyHC)is one of the major structural and contracting proteins of muscle.We have isolated the cDNA clone encoding MyHC of the grass carp,Ctenopharyngodon idella. The sequence comprises 5 934 bp,including a 5 814 bp open reading frame encoding an amino acid sequence of 1 937 residues.The deduced amino acid sequence showed 69%homology to rabbit fast skeletal MyHC and 73%–76%homology to the MyHCs from the mandarin fish,walleye pollack,white croaker,chum salmon,and carp.The putative sequences of subfragment-1 and the light meromyosin region showed 61.4%–80%homology to the corresponding regions of other fish MyHCs.The tissue-specific and developmental stage-specific expressions of the MyHC gene were analyzed by quantitative real-time PCR.The MyHC gene showed the highest expression in the muscles compared with the kidney,spleen and intestine.Developmentally,there was a gradual increase in MyHC mRNA expression from the neural formation stage to the tail bud stage.The highest expression was detected in hatching larva.Our work on the MyHC gene from the grass carp has provided useful information for fish molecular biology and fish genomics.

Clinicopathological characteristics of human epidermal growth factor receptor 2-positive Barrett's adenocarcinoma

AIM:To compare the clinicopathological characteristics of human epidermal growth factor receptor 2 (HER2)-positive and HER2-negative Barrett's adenocarcinoma in Japan. METHODS:We performed immunohistochemical analysis of HER2 in 30 samples taken from patients with Barrett's adenocarcinoma and dual color in situ hybridization in cases showing 2+ reactions. We compared the clinicopathological characteristics of HER2-positive and HER2-negative patients.RESULTS:HER2 positivity was identified in 8 (27%) carcinoma samples. We found that HER2 expression was associated with p53 overexpression (100% vs 52.6% in pT1 tumor; 100% vs 54.5% in all stage tumor, P < 0.05) and protruding lesions at the early disease stage. There was no association between the mucin phenotype of the carcinomas and prognosis. HER2 expression and low clinical stage were unexpectedly different between Barrett's adenocarcinoma patients and gastric cancer patients, but the macroscopic features may be associated with earlier diagnosis in these patients. CONCLUSION:Our results suggest that HER2-positive Barrett's adenocarcinomas are associated with p53 overexpression and lesion protrusion at the early disease stage.

Cloning and stage-specific expression of CK-M1 gene during metamorphosis of Japanese flounder,Paralichthys olivaceus

The symmetrical body of flatfish larvae changes dramatically into an asymmetrical form after metamorphosis. The molecular mechanisms responsible for this change are poorly understood. As an initial step to clarify these mechanisms, we used representational difference analysis of cDNA for the identification of genes active during metamorphosis in the Japanese flounder, Paralichthys olicaceus. One of the up-regulated genes was identified as creatine kinase muscle type 1 (CK-M1). Sequence analysis of CK-M1 revealed that it spanned 1 708 bp and encoded a protein of 382 amino acids. The overall amino acid sequence of the CK-M1 was highly conserved with those of other organisms. CK-M1 was expressed in adult fish tissues, including skeletal muscle, intestine and gill. Whole mount in-situ hybridization showed that the enhanced expression of CK-M1 expanded from the head to the whole body of larvae as metamorphosis progressed. Quantitative analysis revealed stage-specific high expression of CK-M1 during metamorphosis. The expression level of CK-M1 increased initially and peaked at metamorphosis, decreased afterward, and finally returned to the pre-metamorphosis level. This stage-specific expression pattern suggested strongly that CK-M1 was related to metamorphosis in the Japanese flounder. Its specific role in metamorphosis requires further study.

Analytic Method to Study Influence of Finite Chemical Potential in QED_3~*

Adopting the approximation to the first order of chemical potential μ, we resolve rigidly the influence on fermion condensate from μ in QED3. We show that this condensate does not respond linear expression to μ. Moreover, the influence on fermion chiral condensate from chemieal potential is investigated.

The Study on the Gene Expression of Preimplantation IVF Bovine Embryos

The cattle different stage embryos obtained from in vitro was studied using the technology of single preimplantation embryo mRNA different display:single 8-cell and blastocyst stage embryos were studied using technology of mRNA different display and one different fragment was found. The result suggested that this fragment displayed high homology (99%) to cattle mRNA for ribosomal protein L31. Then to detect the expression of RPL31mRNA in 8 cell and blastocyst stage embryos by real-time quantitative PCR,the result showed the relative amount of 8 cells was 3.2 times of blastocyst's.

Identification of differentially expressed proteins in human stage Ⅰ lung adenocarcinoma and tumor-adjacent tissues with two-dimension gel electrophoresis profiling

Objective： The aim of this study was to establish reproducible two-dimensional electrophoretic assay used for profiling and identification of differentially expressed proteins in human stage I lung adenocarcinoma and paired normal tumor-adjacent tissue. Methods： The proteins from 12 human stage I lung adenocarcinoma tissues and normal tumor-adjacent tissues were separated using isoelectric focusing electrophoresis （the first dimension） and the subsequent homogeneous SDS-polyacrylamide gel electrophoresis （SDS-PAGE） （the second dimension）. The differentially expressed proteins were determined with PDQuest image analysis software, and identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF-MS） and database searching. Results： The well-reproducible 2-DE gel patterns of human stage I lung adenocarcinoma and normal tumor-adjacent tissues were profiled and 26 differentially expressed proteins uncovered. Nine of these 26 protein spots were cut out from the preparation gels and determined with MALDI-TOF-MS. Searching against the protein database, four candidate proteins were identified. They were 60S acidic ribosomal protein P2, Cathepsin B1, Apolipoprotein A-I precursor, and La 4.1 protein. Conclusion： In this study, high reproducible 2-DE gel protein images of human stage I lung adenocarcinoma and paired normal tumor-adjacent tissues were achieved successfully, and 4 differentially expressed proteins were revealed. These data will be helpful for screen of early biomarker and study of molecular mechanisms of human lung adenocarcinoma.

任务型教学与高三英语复习

《英语课程标准》提出了任务型教学的理念,这对推动外语教学改革起着重要作用。笔者在近一年的见习活动中发现,高三复习课中,新课程标准规定的任务型教学仍然体现很少。一、高三英语复习中存在的问题1.教学模式陈旧。

Lee discrepancy on asymmetrical factorials with two-and three-levels

Lee discrepancy has been employed to measure the uniformity of fractional factorials.In this paper,we further study the statistical justification of Lee discrepancy on asymmetrical factorials.We will give an expression of the Lee discrepancy of asymmetrical factorials with two-and three-levels in terms of quadric form,present a connection between Lee discrepancy,orthogonality and minimum moment aberration,and obtain a lower bound of Lee discrepancy of asymmetrical factorials with two-and three-levels.

Global gene expression profiles for the growth phases of Trichophyton rubrum

Trichophyton rubrum （T. rubrum） is a common superficial fungus. Molecular and genetic studies of T. rubrum are still limited. In this paper, we report the global analysis of gene expression profiles at different growth phases using cDNA microarray technology. A total of 2044 differentially expressed genes were obtained and clustered into three expression patterns. Our data confirmed previous results that many mRNAs were pre-stored in the conidia of T. rubrum. Transcriptional profiling and function analysis showed that some glycolytic enzymes share similar expression patterns and may be coregulated during the transi- tion of growth phases. Some genes involved in small GTPase signaling pathways, and in cAMP-dependent and MAPK regulation pathways were induced in response to the growth dynamics of T. rubrum. Although the detailed biological roles of these Z rubrum genes are still unknown, our results suggest that these genes may be involved in regulation mechanisms in the life cycle of the fungus.

Detection of gene expression pattern in the early stage after spinal cord injury by gene chip

Objective: To study the changes of the gene expression pattern of spinal cord tissues in the early stage after injury by DNA microarray (gene chip). Methods: The contusion model of rat spinal cord was established according to Allen’s falling strike method and the gene expression patterns of normal and injured spinal cord tissues were studied by gene chip. Results: The expression of 45 genes was significantly changed in the early stage after spinal cord injury, in which 22 genes up regulated and 23 genes down regulated. Conclusions: The expression of some genes changes significantly in the early stage after spinal cord injury, which indicates the complexity of secondary spinal cord injury.

The role of miR156 in developmental transitions in Nicotiana tabacum

Plants undergo a series of developmental transitions during their life cycle. After seed germination, plants pass through two distinct phases: the vegetative phase in which leaves are produced and the reproductive phase in which flowering occurs. Based on the reproductive competence and morphological changes, the vegetative phase can be further divided into juvenile and adult phases. Here, we demonstrate that the difference between juvenile and adult phase of Nicotiana tabacum is characterized by the changes in leaf size, leaf shape as well as the number of leaf epidermal hairs(trichomes). We further show that miR156, an age-regulated microR NA, regulates juvenile-to-adult phase transition in N. tabacum. Overexpression of miR156 results in delayed juvenile-to-adult transition and flowering. Together, our results support an evolutionarily conserved role of miR156 in plant developmental transitions.

Significant variations in alternative splicing patterns and expression profiles between human-mouse orthologs in early embryos

Human and mouse orthologs are expected to have similar biological functions; however, many discrepancies have also been reported. We systematically compared human and mouse orthologs in terms of alternative splicing patterns and expression profiles. Human-mouse orthologs are divergent in alternative splicing, as human orthologs could generally encode more isoforms than their mouse orthologs. In early embryos, exon skipping is far more common with human orthologs, whereas constitutive exons are more prevalent with mouse orthologs. This may correlate with divergence in expression of splicing regulators. Orthologous expression similarities are different in distinct embryonic stages, with the highest in morula. Expression differences for orthologous transcription factor genes could play an important role in orthologous expression discordance. We further detected largely orthologous divergence in differential expression between distinct embryonic stages. Collectively, our study uncovers significant orthologous divergence from multiple aspects, which may result in functional differences and dynamics between human-mouse orthologs during embryonic development.