突出“三重”,引导有效探究

探究性学习作为《语文课程标准》积极倡导的一种学习方式,强调学生知识的获得过程应该是"深入探讨"、"反复研究"的过程。它要求我们的教学不仅要重视学生知识的最终获得,更要重视学生获得知识的探究过程。这种学习方式的积极倡导是为了让学生个性得到张扬。

梅涅劳斯定理的推广

本文对平面几何中著名的梅涅劳斯定理进行剖析,然后作出推广。定理一(梅涅劳斯定理)一直线l分别截△ABC的三边(或边的延长线)AB、BC、CA于D、E、F.则AD/DB·BE/EC·CF/FA=1 在许多教科书里的介绍中,都是直线l与△ABC的两条边相交,与第三边的延长线相交.其实,若直线l与三角形三条边都不相交,其结论仍是成立的。

Transmission Electron Microscopy Observation of Different Callus Structures in Heiya No.14

[ Objective] The aim was to observe the ultrastructure of different callus structures in Heiya No. 14 by transmission electron microscopy. [Methods] Sample preparation and observation were both carried out by conventional transmission electron microscopy. [ Results] It was showed by transmission electron microscopy that the initial callus cells had a large central vacuole, which squeezed its cytoplasm to be a thin layer around the brim of cell, Meanwhile the nuclear was also squeezed to distribute in the corner of cell, but its nucleolus could be still observed; Compared embryogenic callus with initial callus, its cell wall became thick, and many starch grains and chloroplasts including starch grains could be observed in the cytoplasm area of cell membrane; In non-embryoenic callus, no organelles except for the vacuole could be observed; In browning callus, there was almost no organelles in cells. [ Conclusion] There are significant differences in different types of flax callus at the cell ultrastructure level, which can be as an index for reflecting the differentiation ability of callus cell.

西夏及其周边吐蕃语地名考释举隅

本文尝试运用藏语安多方言,对西夏及其周边来自吐蕃语的三个地名做了考释,同时对清四库馆臣的改译做了验证。一是汉文史籍中的"卓罗""卓啰""斫龙""庄浪",西夏文献中的"■",都是吐蕃语■的音译,意思是"野牛沟"。清人改译为"喀罗",得不到合理的解释,疑误。至于把"庄浪"解释为"庄山浪水",纯属囿于汉语母语而做出的臆测。二是汉文史籍中的"讲朱""讲珠",是吐蕃语■的音译,意思是"大海、湖泊"。清人改译为"嘉木卓",是由于后一音节的前加字■使前一音节增加了韵尾"木"。三是汉文史籍中的"珠结龙",是吐蕃语■的音译,意思是"十八谷"。《宋史·夏国传》"结珠龙"乃"珠结龙"之误倒。清人改译为"聚卜结隆",是由于后一音节■(八)的前加字■使前一音节增加了韵尾"卜"。

Effect of Thermal Treatment on the PA-6 in the Blends

Aim To investigate the multiple melting behavior of polyamide 6(PA 6) in polyamide 6/linear low density polyethylene blends crystallized from the crystal amorphous state. Methods\ The effects of annealing temperature, annealing time, heating rate, and the step wise annealing were measured by DSC. Results and Conclusion\ There exists a critical heating rate affecting the middle temperature melting peak. When annealed at the temperature close to the melting peak, the main melting peak of PA 6 shifted to a higher temperature. Within a short time, annealing time has much effect on neat PA 6 but little effect on PA 6 in the blends. Addition of PE results in a decreasing in the height of melting peak. These phenomenon show that the melting behavior of PA 6 was affected by PE, compatibilizer, as well as thermal treatment.

Study on Flowering, Cultivation, and Reproduction of Agave americana Var. Marginata Hort. (Agavaceae)

Agave americana Var. Marginata Hort. （Agavaceae） is a perennial herb. This paper summarized its classification, distribution, morphological characteristics, habit, flowering and fruiting, cultivation and reproduction, as well as multiple uses in daily life, which provided references for the exploitation and utilization of Agave americana Vat. Marginata Hort. （Agavaceae）.

Thermotics Study of the Semimetallic Nylon1010 Composite

Thermal expansion characteristics of semimetal nylon composites (nylon 1010 incorporated with metal oxides) were analyzed with thermal expansion instrument. The changes of composite weight after being heated and the heat absorption and release of the composites were analyzed by carrying out TG-DSC experiments. Experimental results show that the average thermal expansion coefficient of the composites rises as the average diameter of the metal oxides decrease from room temperature to 160 ℃. Thermal dynamics and physical properties of the nylon composites change with the addition of the oxides; the crystallization temperature rises from 180 ℃ of pure nylon to 190 ℃ (maximum) and the melting point of the oxide composites also increases continuously with the addition of the oxides. The water content of the oxide/nylon composite is related to the kind and content of the oxide. The water content reaches its maximum when the content of oxide is 10%, and the 10% Al2O3/nylon composite has a water absorption ratio up to 1%.

Megacolon in adulthood after surgical treatment of Hirschsprung's disease in early childhood

Hirschsprung＇s disease （HD） is a disorder associated with congenital malformation of the enteric nervous system with segmental aganglionosis. Prevailing therapy includes a resection of the affected part of the bowel, However, patients often do not obtain complete functional improvement after surgical treatment. We present the case of a 25-year-old woman who had surgical treatment of lid in early childhood. After that procedure she had clinical features of constipation for years in the end, passing of stool once a week, requiring laxatives and enemas. We diagnosed an incomplete resection of the aganglionic bowel via rectal biopsy and resected the remaining aganglionic segment. Two months after surgery the patient＇s bowel function improved to a frequency of 1-4 stools per day. We conclude that regular follow-up is required to identify lid patients with persistent alterations of bowel function after surgery. In patients presenting with constipation, recognition of a remaining aganglionic segment or other alterations of the enteric nervous system should be aimed at in an early stage. 2005 The WJG Press and Elsevier Inc. All rights reserved

Atypical presentation of pioderma gangrenosum complicating ulcerative colitis: Rapid disappearance with methylprednisolone

Piodermal gangrenosum (PG) is an uncommon ulcerative cutaneous dermatosis associated with a variety of systemic diseases, including inflammatory bowel disease (IBD), arthritis, leukaemia, hepatitis, and primary billiary cirrhosis. Other cutaneous ulceration resembling PG had been described in literature. There has been neither laboratory finding nor histological feature diagnostic of PG, and diagnosis of PG is mainly made based on the exclusion criteria. We present here a patient, with ulcerative colitis (UC) who was referred to the emergency section with a large and rapidly evolving cutaneous ulceration. Laboratory and microbiological investigation associated with histological findings of the ulcer specimen allowed us to exclude autoimmune and systemic diseases as well as immuno-proliferative disorders. An atypical presentation of PG with UC was diagnosed. Pulse boluses of i.v. methyl-prednisolone were started, and after tapering steroids, complete resolution of the skin lesion was achieved in 3 wk. The unusual rapid healing of the skin ulceration with steroid mono-therapy and the atypical cutaneous presentation in this patient as well as the risk of misdiagnosis of PG in the clinical practice were discussed.

Isothermal and nonisothermal crystallization kinetics of bio-sourced nylon 69

Bio-sourced nylon 69,one of promising engineering plastics,has a great potential in developing sustainable technology and various commercial applications.Isothermal and nonisothermal crystallization kinetics of nylon 69 is a base to optimize the process conditions and establish the structure–property correlations for nylon 69,and it is also highly bene ficial for successful applications of nylon products in industry.Isothermal and nonisothermal crystallization kinetics has been investigated by differential scanning calorimetry for nylon 69,bio-sourced even–odd nylon.The isothermal crystallization kinetics has been analyzed by the Avrami equation,the calculated Avrami exponent at various crystallization temperatures falls into the range of 2.28 and 2.86.In addition,the Avrami equation modi fied by Jeziorny and the equation suggested by Mo have been adopted to study the nonisothermal crystallization.The activation energies for isothermal and nonisothermal crystallization have also been determined.The study demonstrates that the crystallization model of nylon 69 might be a twodimensional(circular)growth at both isothermal and nonisothermal crystallization conditions.Furthermore,the value of the crystallization rate parameter(K)decreases signi ficantly but the crystallization half-time(t1/2)increases with the increase of the isothermal crystallization temperature.To nonisothermal crystallization,the crystallization rate increases as the cooling rate increases according to the analysis of Jeziorny's theory.The results of Mo's theory suggest that a faster cooling rate is required to reach a higher relative degree of crystallinity in a unit of time,and crystallization rate decreases when the relative degree of crystallinity increases at nonisothermal crystallization conditions.

Heart-shaped anastomosis for Hirschsprung's disease: Operative technique and long-term follow-up

AIM: To study the long-term therapeutic effect of 'heartshaped' anastomosis for Hirschsprung's disease.METHODS: From January 1986 to October 1997, we performed one-stage 'heart-shaped' anastomosis for 193 patients with Hirschsprung's disease (HD). One hundred and fiftytwo patients were followed up patients (follow-up rate 79%).The operative outcome and postoperative complications were retrospectively analyzed.RESULTS: Early complications included urine retention in 2patients, enteritis in 10, anastomotic stricture in 1, and intestinal obstruction in 2. No infection of abdominal cavity or wound and anastomotic leakage or death occurred in any patients. Late complications were present in 22 cases,including adhesive intestinal obstruction in 2, longer anal in 5, incision hernia in 2, enteritis in 6, occasional stool stains in 7 and 6 related with improper diet. No constipation or incontinence occurred in any patient.CONCLUSION: The early and late postoperative complication rates were 7.8% and 11.4% respectively in our 'heartshaped anastomosis' procedure. 'Heart-shaped'anastomosis procedure for Hirschsprung's disease provides a better therapeutic effect compared to classic procedures.

Stroke optimization of a novel multi-station rotary polishing robot based on workspace analysis

In order to meet the polishing requirement of faucets and other products,a novel multi-station rotary polishing robot is designed,which is a PPPR + RR type of degree of freedom( DOF) distribution structure,and is similar to dual-arm robot. Forward and inverse kinematic analysis is carried out by robot modeling. In order to make this robot structure more compact,first of all,X,Y and Z three moving degrees of freedom( DOF) limit stroke polishing need is calculated by using an artificial fish swarm algorithm,which analyzes dexterous workspace of this robot. Then,on the basis of the above analysis,the three DOF stroke is optimized. Simulation and polishing experimental results verify that this polishing robot with optimized stroke parameters can meet the polishing needs of faucets and other bathroom pieces.

Polymerase chain reaction-single strand conformational polymorphism analysis of rearranged during transfection proto-oncogene in Chinese familial hirschsprung's disease

AIM: To investigate the relationship between mutations of rearranged during transfection (RET) proto-oncogene and Chinese patients with Hirschsprung's disease (HD), and to elucidate the genetic mechanism of familial HD patient at the molecular level.METHODS: Genomic DNA was extracted from venous blood of probands and their relatives in two genealogies.Polymerase chain reaction (PCR) products, which were amplified using specific primers (RET, exons 11, 13, 15and 17), were electrophoresed to analyze the single-strand conformational polymorphism (SSCP) patterns. The positive amplified products were sequenced. Forty-eight sporadic HD patients and 30 normal children were screened for mutations of RET proto-oncogene simultaneously.RESULTS: Three cases with HD in one family were found to have a G heterozygous insertion at nucleotide 18 974 in exon 13 of RET cDNA (18 974insG), which resulted in a frameshift mutation. In another family, a heterozygosity for T to G transition at nucleotide 18 888 in the same exon which resulted in a synonymous mutation of Leu at codon 745 was detected in the proband and his father. Eight RET mutations were confirmed in 48 sporadic HD patients.CONCLUSION: Mutations of RET proto-oncogene may play an important role in the pathogenesis of Chinese patients with HD. Detection of mutated RET proto-oncogene carriers may be used for genetic counseling of potential risk for HD in the affected families.

《秋思》教学及评析

颁奖词他,曾是一所重点实验小学的优秀校长,举足轻重,影响颇大。如今,他甘愿放弃校长职务,当一名普通的一线语文老师。他,是一个行者,在教学的路上执着而虔诚。27年来,他用爱和智慧,编织着以＂学＂为基点的语文教学之梦,为孩子们营造了一个充满快乐而又多彩的语文世界。他笔耕不辍。先后发表了100多篇教学论文,出版了多部教学专著,他领衔的名师工作室一片红火。

考场作文得分五法

考场作文,时间大约只有50分钟左右,要在这50分钟的时间内写出一篇精彩的作文,除了平时苦练基本功,累计雄厚的写作基础,以求在考场上可以下笔有神之外,恐怕只得看阅卷教师是否喜欢了。笔者在多年的教学中,摸索出了一些考场作文得分的小技巧,在此奉献给大家,或能助各位考生一臂之力。卷面干净又整洁,阅者愉快给高分考场作文卷面干净整洁,一定会博得阅卷者的青睐。在众多的试卷中,有那么一份字迹清秀漂亮、书写工整认真的试卷突然冒出来,让昏昏欲睡的评卷老师双眼一亮,试想会有什么结果呢?大笔一挥,给点褒奖分绝对不会错吧?于是,你便多得了三至五分。反之,如果作文书写"龙飞凤舞"

Crustal P-wave velocity structure of the Longmenshan region and its tectonic implications for the 2008 Wenchuan earthquake

The P-wave velocity structure of the crust in the Longmenshan region has been imaged by seismic travel time tomography us ing local and regional first P-wave arrivals recorded from 2000 to 2008. The tomographic model provides a way to analyze the deep tectonics of the Longmenshan fault belt and the tectonic implications for the 2008 Ms8.0 Wenchuan earthquake. The P-wave velocity images indicate that the initial rupture site and focal depth of the Wenchuan earthquake, together with the di rection of rupture propagation, closely relate to the crustal structure of the Longmenshan region. The Pengguan massif to the west of the Longmenshan fault belt is characterized by high velocity anomalies, suggesting that the crust has a strong strain strength that can accumulate large stresses over a long period. The Ms8.0 Wenchuan earthquake is located at the southwestern end of the Pengguan massif and the western edge of the Sichuan Basin. The collision between the Pengguan massif and the Sichuan Basin becomes the primary reason for the occurrence of the Ms8.0 Wenchuan earthquake. To the north of Wenchuan, the occurrence and propagation of rupture benefit from low velocity anomalies along the Longmenshan fault belt; whereas to the south of Wenchuan, the brittle rupture can occur with more difficulty in relatively weak crust with low velocities. This may be one of the reasons for the absence of aftershocks to the south of Wenchuan, and the rupture induced by the Ms8.0 Wenchuan earthquake propagating from the north to the south along the Longmenshan fault belt. The deep geodynamics of the Ms8.0 Wenchuan earthquake may occur due to the discrepancy of crustal structures on the two sides of the Longmenshan fault belt. Ductile deformation and crustal flow can easily occur in the weak middle-lower crust beneath the Songpan-Garze orogenic belt. The eastward movement of the Tibetan Plateau is obstructed by the rigid lithosphere of the Sichuan Basin, and then the thick ening of the middle-lower crust and vertical deformation occur in the crust of the Longmenshan fault belt. In addition, the down-warping of the Moho and the basement thrusting onto the range front induced crustal deformation and strain accumula tion, which provided the potential energy to trigger the occurrence of the Ms8.0 Wenchuan earthquake.

The crustal structures of the central Longmenshan along and its margins as related to the seismotectonics of the 2008 Wenchuan Earthquake

In 2010,a 500-km-long wide-angle reflection/refraction seismic profile was completed,running northwest from the central Sichuan Basin.This profile orthogonally crosses the meizoseismal area of great Wenchuan earthquake of 12 May 2008,which occurred in the central part of the Longmenshan.The profile also passes through the northwestern Sichuan Plateau,along which a new deep seismic sounding observation system was set up that was much improved over previous datasets and enabled abundant observations to be recorded.Seismic wave phase records that reflect the structural characteristics of different tectonic blocks,especially the complicated phase features associated with the Wenchuan earthquake,were calculated and analyzed in detail.A 2D crustal P-wave velocity model for the orogenic belt in the central Longmenshan and its margins was determined,and crustal structure differences between the stable Sichuan Basin and the thickened northwestern Sichuan Plateau were characterized.Lithological variations within the upper and lower crust in the interior of the plateau,especially a great velocity decrease and plastic rheological properties associated with strong lithologic weakening in lower crust,were detected.From west to east in the lower crust beneath the orogenic belt lying between the Sichuan Basin and the northwestern Sichuan Plateau,a giant shovel-like upwelling is observed that dips gently in the lower part and at higher angles in the upper part;this is inferred to be related to the fault systems in the central Longmenshan.An upwelling in the upper-middle crust along the eastern margin of the orogenic belt is associated with steeply dipping thrusts that strongly uplift the upper crust and crystalline basement beneath a central fault system in the Longmenshan.The data,combined with an understanding of the regional tectonic stress field and previous geological results,enable a discussion of basin-and-range coupling,orogenic tectonics,the crustal fault system,and the seismogenic tectonic environment of the central Longmenshan along the eastern margin of the Qinghai-Tibet Plateau.

Structure and mechanical properties of pincers for freshwater lobster

The mineral phases and structure of pincer for the freshwater lobster were analyzed and observed by using X-ray diffraction and field-emission scanning electronic microscope with energy dispersive spectroscopy, and the mechanical properties of pincer were determined by using nano-indenter and micro-tribometer. The results showed that the pincers contained Ca, Mg, C, O, Na, etc. elements and there were many amorphous mineral phases in the lobster pincers. There were many concave hollows and convex domes with seta on the surface of pincer, and some spines were observed on the surface of seta, which exhibited non-smooth surface. The exoskeleton of pincer consisted of epicuticle, exocuticle and endocuticle, and the microstructure of exocuticle and endocuticle displayed the twisted plywood structure with chitin protein fibers. The mean hardness and elastic modulus on the surface of fresh pincers were 0.27 GPa and 5.28 GPa, respectively. With the increase in distance from the surface, the hardness and elastic modulus all decreased gradually. This indicated that the transition of hardness and elastic modulus occurred from exocuticle to endocuticle. When the heat treatment temperature was lower than 200°C, the values of hardness and elastic modulus fluctuated slightly, while they increased at the temperature beyond 200°C. As the pincers slid against Si3N4 balls in water and air, the friction coefficients in water were higher than those in air. The research could provide a bio-inspired basis for the structural design of composite materials and anti-friction surface.