精备教学设计提高物理课堂教学效率与质量

一次成功的教学首先依赖于教学设计，没有教学设计的课堂教学绝不可能是符合素质教育的“好”的课堂教学。“精心策划”是提高物理课堂教学效率与质量的前提，“发挥自主”是提高物理课堂教学效率与质量的关键，“落到实处”是提高物理课堂效率与质量的保证，“创新意识”是提高物理课堂效率与质量的保证。

语文教学的“精备”——浅谈初中语文教师备课的策略

语文课堂中“精备”是“精心备课”的简称,通俗地说,就是精心规划的课前准备,“精”字包含了“取舍、精简、增删”等多种含义。“精备”具体说来就是精心备好一堂语文课,广义包含备教学目标,备教材,备学情等,狭义上还包括预设和生成的统一,备学生的个体差异等等。

浅析本真性课堂的深备精导——以《平面内点的坐标》为例

初中数学课堂不论在哪种课堂形式下,都应提高其有效性。还原课堂的本真就是一种有效途径,也是使得数学学习具有可持续性的方法。因此,教师在课堂教学中应以学生为主体,深备精导课程。

博观而约取 厚积而薄发——也谈构建初中化学生态课堂的高效性策略

新课程标准下的学生观是“一切为了每位学生的发展”。教育工作者要扎实自己的教学基本功，努力做到课前精备、课上精问、精练，构建常态、和谐、形态优美的“生态”课堂。

动手操作,活化数学课堂——以小学数学教学为例

随着新课改的实施与推进,动手操作的实践方式逐渐受到了诸多一线教师的关注,并被广泛应用到了课堂教学中,并产生了事半功倍的效果.为了进一步发挥其优势,本文从创设情境,乐于操作;精备学具,落实操作;多元方法,灵活操作三方面对动手操作在小学数学课堂教学中的应用展开了探讨,以期能够达到抛砖引玉的效果.

Preparation and simulation of a taro flavor

Flavors represent a small but significant segment of food industry.Taro gives a pleasant nut-like odor when cooked.Taro flavor can be used in many products,so developing a taro flavor is of interests.This paper concentrates on preparation and simulation of taro flavor according to the notes of taro,which are distinct flavors or odor characteristics.The results show that the notes of taro flavor can be classified as caramellic note,roast note,milky note,beany note,green note,aldehydic note,sweet note,nutty note,vegetative note,and fruity note.According to the notes of cooked taro odor and the raw materials selected,a typical taro flavor formula is given.The taro flavor blended is pleasant,harmonious,and has characteristics of the odor of cooked natural taro.

Design of a device for precision shaping of grinding wheel macro-and micro-geometry

The selected modifications to the construction of grinding wheels were described which facilitate an increase in the material removal rate （grinding wheels with conic chamfer and grinding wheels with microdiscontinuities on the active surface）. Using these background details, a suggested thesis was put forward regarding the need to develop a device which will allow for the shaping of the macrogeometry of the grinding wheel （cylindrical and conical surfaces） and the microdiscontinuities within the dressing operation simultaneously. The device was presented and prepared in two functional variants （horizontal and vertical mounting of the motor）, then a prototype was described. An example of the grinding wheel active surface, shaped by using this device, was also presented. The theoretical analysis and experimental verification performed determine that the error of shaping the conic chamfer angle within the range of 0-1.5°, using the developed device, is approximately ±3%.

Novel technology on preparation of double-layered pellets for sulfur and arsenic-bearing gold concentrates

Double-layered pellet （DLP） roasting is a novel pretreatment method for sulfur and arsenic-bearing gold concentrates. In this process, preparation of DLPs is a fundamental step which is required to produce DLPs with favorable mechanical strength and thermal stability. Studies were carried out to investigate the affecting factors and conditions on the preparation and properties of DLPs. The results show that moisture content has significant influence on DLPs preparation. With the increase of moisture content in the range of no more than 9.8%, drop resistance and compressive strength of green DLPs are raised and the pelletizing dynamics is improved accordingly. The optimum conditions are determined as moisture content of 9.8%, coating time of 14-16 min, drying temperature 〈80 ℃and drying gas velocity 〈1.2 m/s. When DLPs prepared under these conditions are roasted at 600 ℃ for 1 h, favorable removal and solidifying rates can be obtained, in which the removal rates of arsenic and sulfur are 94.38% and 82.55%, and the solidifying rates of arsenic and sulfur reach 99.62% and 99.79%, respectively. These results promise industrial application of DLP roasting.

Configuration and kinematics analysis of locking-releasing mechanism for side-loaded lunar rover

In order to save space for storing precision equipments,lower the center of mass of Lander and reduce lunar rover's dimension constraint limited by mechanism of Lander,the locking-releasing mechanism of side-loaded lunar rover loaded outside Lander is presented,which is a kind of metamorphic mechanism.To ensure the working of this mechanism as the metamorphic process designed,configuration analysis of the locking-releasing mechanism is carried out,and topological structures are described by Huston lower numbered arrays.A kinematic mathematical model of the mechanism is established through homogeneous transformation matrix.The kinematic simulation validates the feasibility of the locking-releasing mechanism when the configurations are shifted from one to the other.

Periodic Packing Mode for Trickle-Bed Reactors: Experiments and Modeling

A periodic packing mode of trickle-bed reactor (TBR) for the gas limited reaction was proposed. Hy-drogenation of 2-ethylanthraquinone over Pd/Al2O3 in a laboratory-scale TBR was taken as a test reaction for determining whether the periodic packing mode is advantageous. The effects of operating conditions and packing type on TBR performance were experimentally examined to demonstrate the cause-effect relationships. A mathe-matic model of TBR considering axial dispersion and fractional wetting was developed to quantitatively illuminate the reason of performance enhancement.

Isomerization of alkyl naphthalene and refining of 2-methylnaphthalene

A preparation process of 2-methylnaphthalene （2-MN） was proposed by isomerization, side-stream distillation and extractive distillation. The isomerization of alkyl naphthalene was catalyzed by acid-treated HBEA zeolites, and the 2-MN selectivity of isomerization was 92.70%. Side-stream distillation and extractive distillation were investigated by simulation, and effects of operation parameters on 2-MN were studied. Further, the simulated results were verified by experiment. Under the optimal condition, the mass fraction of 2-MN reached to 98.09%; in the oroduct, and the yield was 83.84% in refining orocess.

Speed-assigned Position Tracking Control of SRM With Adaptive Backstepping Control

A novel speed-assigned method is applied to the position tracking control of switched reluctance motor(SRM).A speed control freedom can be drawn into the position control through speed assignment. Adaptive backstepping control is used to design the position controller for the SRM. The accuracy of position tracking of the SRM can be enhanced with speed assignment. A disturbance observer is further designed to enhance the estimation accuracy of the unknown load torque. Simulation results certify that the design scheme is right and effective.

探究以生为本的数学教学

一节课的失败,往往不是因为缺少构成这节课的基本要素,而是因为没有“灵魂”的统领。“灵魂”就是关注学生。从“深备”到“精导”,最重要的是关注学生,教学相长,为孩子的终身发展奠基。

Activity and Stability of Arginine Deiminase for Producing L-citrulline

A novel Enterococcus faecalis strain designated N J402 was found with high activity of arginine deiminase （ADI）. The optimum condition for catalytic activity was determined in terms of temperature （about 40℃）, thermostability （available 37℃） and pH （6-7）. The effects of substrate and product concentration were studied. The effects of various metal ions added in reaction mixtures on the biocatalyst were investigated and ADI of N J402 was found to exhibit Co^2＋ dependence, different from previous reports. Surfactant, cetyl trimethyl ammonium bromide, was one of the most important keys for producing L-citrulline. The enzyme in resting cells possessed the quality of high stability for reuse.

Land Leveling with Modern Machinery for the Implementation of Agricultural Activities in Greece

Incorporating modem and advanced technology （various electronic devices） to excavational machinery led to become more efficient, better quality and cost effective. The continuous development of equipment is also very important in the earth moving procedures which require significant time and expense to achieve the so-called ＂precision agriculture＂ or rather ＂precise management of agricultural inputs＂. One of the ＂precision agricultural＂ works is the land leveling. In recent years, land leveling is done with the use of a scraper （blade） mounted on the agricultural tractor. An electronic system controls the height of the blade automatically, without any operator intervention. In this paper, the field efficiency of the tractor MF6290, of 135 Hp horsepower, is calculated with a leveling blade of 4 m width, in the land leveling of rice cultivation, and in the rotation of different crops in different land preparation conditions （initial and final slope） in the area of Thessaloniki, northern Greece. The raw data revealed that the performance of the tractor ranged from 0.402 to 0.82 lha/h, on a slope 0%, while for surfaces with different initial and final slope, it ranged from 0.107 to 0.118 ha/h.

Development of the Multipurpose Timing Instrument Based on BDS

With the increasingly high requirement of clock source accuracy for seismic data servers and equipment,the development of a multipurpose timing system is urgently needed in the seismic industry. We have developed low-cost timing equipment according to the actual earthquake industry situation. This set of timing equipment can provide a unified solution to the different environment and different earthquake instruments with different timing precision demands.

Exploring the employment readiness and return to work status of breast cancer patients and related factors

Objective:To investigate the employment status,employment readiness,and other factors affecting the ease or difficulty with which breast cancer patients effect their return to work(RTW).Methods:This study adopted a mixed-method design,recruiting participants from among breast cancer patients in a cancer hospital in Hunan from December 2018 to June 2019.We approached 300 individuals,192 of whom ultimately participated in this study.The quantitative part of the study involved several scales:the Patient Health Questionnaire-9(PHQ-9),the Brief Fatigue Inventory(BFI),the Work Ability Index(WAI),and the Lam Assessment of Employment Readiness(LASER).The qualitative part involved a set of open-ended questions and written responses collected from 41 participants who had already returned to work at the time of data collection.Their written responses mainly concerned factors influencing RTW.Results:Forty-one breast cancer patients had returned to work.The results reported a median total Cognitive Symptom Checklist score of 9.00(6.00,15.25),a median WAI score of 5.00(3.50,9.75),a median BFI score of 26.00(14.75,42.00),a median total PHQ-9 score of 8.00(5.25,17.00),and a LASER score of 50.35±11.90.Multiple regression analysis showed that the participants’cancer stage,cognitive limitations,depression,fatigue,and work ability were significant predictors of employment readiness(P<0.05).Exploring the qualitative data,we found that higher skill levels,better social support,and a flexible work schedule facilitated RTW;stress,lack of confidence in one’s work skills,depression,and fatigue are all possible barriers to RTW.Conclusion:The findings indicate that breast cancer patients have a low level of employment readiness.Nurses and other healthcare providers can develop relevant interventions to promote employment readiness and ultimately achieve RTW in this study population.

Dynamic Changes of β Tubulin during the Resumption of Meiosis of Mouse Oocyte

Morphological changes of tubulin during the resumption of meiosis in both mouse oocyte and fertilized egg were revealed by indirect immunofluorescent marking with monoclonal antibody against β tubulin. During germinal vesicle period (GV), tubulin was found to be distributed around the GV menibrane. With the disruption of GV membrane, microtubule complexes (MTCs) appeared in cytoplasm, first around GV membrane later to spread to other portions as well. Quantitative difference was noted among different oocytes. MTCs coexisted with spindlesformed by prometaphase tubulin, while metaphase tubulin polymerized into spindles and anaphase and telophase tubulin was concentrated in the two poles of the meiotic apparatus and the midbody. In egg arrested in the 2nd metaphase, whether maturing in vitro or vivo, all the tubulin went to form spindles with no MTCs left in the cytoplasm. After fertilization in vitro,MTCs reappeared in the egg cytoplasm activated by sperms while no MTCs could be revealed in cytoplasm after formation of pronucleus. As demonstrated by this experiment,cytoplasmic tubulin in eggs are polymerized chiefly into two forms: the star-shaped MTCs and the spindle.Cytoplasmic MTCs are the structure newly formed when the 1st and 2nd oocytes resumed meiosis. With colchicine disrupting the polymerization of tubulin, the maternal chromosomes,instead of orderly arrangement and orderly separation, either formed disordered mass or were divided into multiple chromatin masses. However, the penetration of sperm into egg, and decondensation and formation of pronuclei were not affected.

Process intensification of fine coal separation using two-stage flotation column

Flotation column is widely used as the separation equipment for fine mineral due to its high selectivity. However, this device may be unsuitable for the coarse particle flotation and has high handling ability. A two-stage flotation column with dimensions of 2 000 mm×1 000 mm×4 000 mm was designed to enhance the column flotation process. The energy input was modified by adjusting the flow rate and the head of circulating pump. The flotation column was designed with low energy input in the first stage(speed flotation stage) to recover easy-to-float materials quickly, and high energy input in the second stage(recovery stage) to recover difficult-to-float minerals compulsorily. Contrast experiments on the throughput and coarse coal recovery of high ash coal from the Kailuan Mine were conducted using conventional single-stage flotation column and the two-stage flotation column. The results show that the combustible matter recovery of the two-stage flotation column is 5.25% higher than that of the conventional single-stage flotation column. However, the ash contents of clean coal for both columns are similar. Less coarse coals with low ash are obtained using the two-stage flotation column than that using the single-stage column flotation with the same handling ability. The two-stage flotation column process can enhance coal flotation compared with the conventional single-stage column flotation.

HSCP:a hardware and software combined platform to improve precision in active network measurement

In this paper,an active network measurement platform is proposed which is a combination of hardware and software.Its innovation lies in the high performance of hardware combined with features that the software is easy to program,which retains software flexibility at the same time.By improving the precision of packet timestamp programmable hardware equipment,it provides packet sending control more accurately and supports the microsecond packet interval.We have implemented a model on the NetMagic platform,and done some experiments to analyze the accuracy difference of the user,the kernel and hardware timestamp.