“博取”“微作”“精批”提高小学生写作能力的有效途径

在我国素质教育理念的深入推进下,学生写作能力的提升不仅只能依靠写作训练活动,而更应该通过提升语文综合素养,以进一步强化学生自身的写作能力。基于此,本文以“博取”“微作”“精批”三部曲来探究如何在语文教学中有效提升小学生的写作能力,并提出几点重要的指导策略,以期进一步促进学生的根本能力提升,从而有效推动语文教学的深入改革。

自媒体书写对高中作文的影响与对策

随着微博、 微信等新媒体的出现, 智能手机的普及, 高中生已经成为自媒体书写一支相当活跃的队伍.自媒体的书写特点对高中作文产生了从长度到深度, 从字面到内在的广泛影响. 这些影响如果能善加引导, 对高中作文教学将会产生积极地促进作用.

NEW ROD-SHAPED ULTRASONIC MICROMOTOR AND ITS DRIVING PRINCIPLE

A new rod-shaped traveling wave ultrasonic micromotor is developed. In the micromotor, five pieces of piezoelectric ceramics clamped by two metal cylinders are used as its stator. The driving principle of the rodshaped ultrasonic motor is simulated. The stator structure and the position to lay these piezoelectric ceramics are calculated to improve the electro mechanical conversion efficiency. A flexible rotor is designed to reduce the radial slip between the stator and the rotor, and to improve the motor efficiency. The prototype motor and its micror driver are tested. The motor is 9 mm in out-diameter, 15 mm in length and 3.2 g in weight. When the motor operates with the first bending frequency （72 kHz） of the stator, its maximal rotational speed and the torque reach 520 r/rain and 4.5 mN · m. Results show that the motor has good stability. The speed fluctuation is controlled within 3% by the frequency automatic tracking technique.

Effects of Different Agricultural Managements on Characteristics of Soil Microbial Community under Continuous Cropped Strawberry(Fragaria ananassa Duchesne)

[Objective] The objective of this study was to investigate the effects of different agricultural managements on soil microbial population,activity,functional diversity and soil enzyme activity in continuous mono-cropping field of strawberry.[Method]A field plot experiment was carried out to evaluate characteristics of soil microbial community by soil enzyme analysis,microbial cultivation and Biolog analysis.[Result]The results showed that bacteria population proportion,the ration of bacteria to fungi,microorganism amount,AWCD,soil dehydrogenase activity,the Shannon,Simpson,and Mcintosh indices of soil microbial communities were obviously increased under strawberry-rice rotation,soil solarization with rice bran,and calcium cyanamide（CaCN2）treatments,in addition,soil urease activity was significantly increased under strawberry-rice rotation and soil solarization with rice bran treatment,when compared with no fertilization.When compared with conventional fertilization treatment,strawberry-rice rotation and soil solarization with rice bran both significantly increased AWCD and Mcintosh index of soil microbial communities,meanwhile respectively increased soil urease and dehydrogenase activity.PCA analyses suggested that carbon utilization of soil microbial communities under strawberry-rice rotation,soil solarization with rice bran,and calcium cyanamide treatment was obviously different from that of conventional fertilization and no fertilization treatment.[Conclusion] strawberry-rice rotation and soil solarization with rice bran were effective agricultural managements to control soil biological degradation under Continuous Cropped Strawberry.

Effects of Different Fertilization Treatments on Soil Microbial Biomass,Soil Enzyme Activities and Related Nutrients in Continuous-cropping Sugarcane Field

[Objective] This study was conducted to expound the fertility improvement effect in continuous-cropping sugarcane field and provide reference for establishment of rational sugarcane fertilization system and improvement of soil quality in continuous-cropping sugarcane field. [Method] The soil in the experimental region is latosolic red soil which was planted with sugarcane for 11 years continuously, and 8 treatments including sole application of chemical fertilizers, sole application of organ- ic fertilizer, and combined application of organic fertilizer and chemical fertilizers were designed according to different fertilization measures. The effects of different fertilization treatments on soil microbial biomass, soil enzyme activities and related fertility factors were determined. [Result} Different fertilization treatments all showed soil microbial biomass N, C and P and activities of soil acid phosphatase, catalase, sucrase and urease higher than the CK. Soil microbial biomass N increased by 5.56%-67.13%, soil microbial biomass C increased by 4.01%-20.40%, and soil mi- crobial biomass P increased by 6.39%-67.02%. The activity of acid phosphatase was improved by 12.96%-35.19%, the activity of catalase was improved by 18.24% -78.93%, the activity of sucrase was improved by 3.00%-42.00%, and the activity of urease was improved by 1.21%-23.43%. However, the soil nutrients of different fertilization treatments increased non-significantly （P〉0.05）. Soil microbial biomass N, C and P and activities of acid phosphatase, catalase and urease were in significant （P〈0.05） or very significant correlation （P〈0.01） with contents of soil rapidly available P, rapidly available K and total N. [Conclusion] The evaluation of improvement of soil fertility in continuous-cropping sugarcane field using soil microbial biomass and enzyme activities as indexes is more comprehensive and sensitive.

Fabrication and Simulation of an Electromagnetic Microrelay

The fabrication and simulation of an electromagnetic microrelay are presented based on micro electromechanical systems (MEMS) technique.The microrelay dimensions of about 4mm×4mm×0 5mm are fabricated with the common technique of micromachining.Compared with the traditional relays,a planar coil is substituted for a solenoid coil to favor the MEMS fabrication.Moreover,a bi supporter cantilever beam with high sensitivity is fabricated to act as the movable electrode of the microrelay.Theoretical calculations and simulations are also carried out with respect to the electromagnetic force yielded by the exciting electromagnetic coil.The structure and parameters concerning the electromagnetic microrelay can be optimized using the results.

Effects of Microporous Structure of Activated Carbon on Adsorption Performance of N-butane

[Objective] The paper was to study the effect of microporous structure of ac- tivated carbon on adsorption performance of n-butane. [Method] Using 8 activated car- bons prepared from different materials and technologies, the effects of physical prop- erties of activated carbon on butane adsorption performance were investigated. [Result] Specific surface area, pore volume and pore size distribution of activated carbon exert- ed remarkable effects on butane adsorption. The activated carbon with high percent- age of micropore volume within the range of 1.2-2 nm possessed high butane activity. The level of butane retentivity rose with the increase of the volume of pore within the range of 0.5-0,9 nm, which led to smaller butan working capacity （BWC）. [Conclusion] The study provided reference for the adsorption research for activated carbon.

Effects of Nitrogen Fertilizer on Rhizosphere Microbial Populations under Cotton Intercropped with Red Date in Arid Desert Oasis of Southern Xinjiang

[Objective]This study aimed to determine the number of microorganisms of cotton rhizosphere in a soil at various amounts of applied nitrogen fertilizer in a red date-cotton intercropping system. [Method] In the field experiment, nitrogen fer-tilizer was applied at 0, 150, 300, 450, 600, and 750 kg/hm2, respectively. The dy-namic changes of the populations of bacteria, fungi and actinomycetes at the rhizo-sphere of cotton intercropped with red date were investigated. [Result] Microbial populations significantly increased at nitrogen fertilizer of 300 and 450 kg/hm2 during bud, flowering and bol opening periods. The numbers of bacteria and actinomycetes were higher during flowering and bol opening stages than at bud stage. The num-ber of fungi slightly changed during the entire growth period. Appropriate amount of nitrogen fertilizer （300 to 600 kg/hm2） was favorable to the survival of the microor-ganisms in the soil under the intercropping system. [Conclusion] The study provides a guideline for screening and determining the optimum amount of applied nitrogen fertilizer.

The Preliminary Study of Certain Pharmacological Effects of Xi Xin Oil

细辛油能松弛兔离体主动脉条,使去甲肾上腺素所致主动脉收缩的量效曲线右移并效能降低;使离体兔耳灌流量减少;能延长小鼠常压耐缺氧时间;用其1/2 LD_(50)之剂量腹腔注射给药3天,可致小鼠骨髓微核形成增加。

Effect of Chitosan-Cysteine Conjugate on Enzymatic Degradation and Hypoglycemic effect of Insulin

Aim To evaluate the inhibitory effect of chitosan-cysteine conjugate onenzymatic degradation and hypogly-cemic enhancement effect of insulin. Methods Chitosan-cysteineconjugate was synthesized. The protective effect of the conjugate against degradation of insulin byα-chymotrypsin and trypsin was evaluated in vitro. Insulin enteric- microspheres were prepared byusing O_1 /Q_2 emulsion solvent evaporation method. The hypoglycemic enhancement effect of theconjugate was studied by oral administration of insulin solution or enteric-microspheres to rats.Results The thiol group content of the synthesized conjugate was about 200 μmol·g^(-1) polymer,which showed a strong protective effect on insulin from enzymatic degradation in vitro. Almost allthe insulin incubated in a-chymotrypsin solution or trypsin solution without chitosan-cysteineconjugate was degraded entirely within 1 h and 5 h respectively, whereas above 75% of insulinremained in the same content of the enzymatic solution containing 4 mg·mL^(-1) conjugate. The drugloading of insulin enteric-microspheres was about 7% . In vivo experiment, chitosan-cysteineconjugate (85 μg·kg^(-1)) prolonged the hypoglycemic time of insulin solution orenteric-microspheres when administered simultaneously with the absorption enhancer SNAC. ConclusionChitosan-cysteine conjugate has a marked inhibitory effect on the enzymatic degradation of insulinin vitro, and it displays a significant hypoglycemic enhancement effect on insulin oral formulationin vivo.

Heparin improves organ microcirculatory disturbances in caerulein-induced acute pancreatitis in rats

AIM:Microcirculatory disturbances are important early pathophysiological events in various organs during acute pancreatitis.The aim of the study was to evaluate changes in microperfusion of the pancreas,liver,kidney,stomach, colon,skeletal muscle,and to investigate the influence of heparin on the organ microcirculation in caerulein-induced experimental acute pancreatitis. METHODS:Acute pancreatitis was induced by 4 intraperitoneal injections of caerulein(Cn)(15 μg/kg).The organ microcirculation was measured by laser Doppler flowmetry.Serum interleukin 6 and hematocrit levels were analysed. RESULTS:Acute pancreatitis resulted in a significant drop of microperfusion in all examined organs.Heparin administration(2×2.5 mg/kg)improved the microcirculation in pancreas(36.9±4% vs 75.9±10%),liver(56.6±6% vs 75.2±16%),kidney (45.1±6% vs 79.3±5%),stomach (65.2±8% vs 78.1±19%),colon(69.8±6% vs 102.5±19%), and skeletal muscle (59.2±6% vs 77.9±13%).Heparin treatment lowered IL-6(359.0±66 U/mL vs 288.5±58 U/mL) and hematocrit level(53±4% vs 46±3%). CONCLUSION:Heparin administration has a positive influence on organ microcirculatory disturbances accompanying experimental Cn-induced acute pancreatitis.

Effects of strontium-induced stress on marine microalgae Platymonas subcordiformis (Chlorophyta: Volvocales)

Strontium-induced stress in growth and chlorophyll contents of Platymonas subcordiformis was investigated under laboratory condition. The results showed that strontium exposure had little influ- ences in general on growth and chlorophyll contents of the algae except for very high Sr concentrations. The maximum biosorption capacity of strontium ranged from 69.62 to 269.18 mg Sr2+/g dry weight. The algal biomass exhibited high uptake capacity of strontium. Total superoxide dismutase (SOD) activity and the content of lipid peroxidation products malondialdehyde (MDA) were significantly different in differ- ent treatments. SOD activity reached the highest level at 0.09 mmol/L that was about 55.8 % higher than that in the control. The MDA content increased significantly at 0.36 mmol/L, which was 2.15 times higher than that in the control, indicating a state of oxidative stress. With the increase of strontium concentration, the amount of fatty acids decreased.

A collision detection approach in virtual environment of micromanipulation robot

Operators suffer much diffieulty in manipulating miero-size objects without the assistance of friendly interfaces due to the scaling effects in micro worht. The paper presented a general framework for mieromanipulation robot hased on virtual reality technology. With the framework we brought forward a FDH （Fixed Direction Hulls） based hounding box method to handle the eollision ,teteetion of the peg-in-hole mieroassembly. The eollision response model for the collision between micro needle and hole was presented. The virtual three and corresponding displacement were calculated with the model of bending deformation and pressing ,teformation. Experiments verify the validity of collision response model.

Influence of Sb modification on microstructures and mechanical properties of Mg2 Si/AM60 composites

The refining effect and mechanism of Sb on Mg2Si and the microstructure of the matrix were investigated.The results indicate that there are Mg3Sb2 particles in the composites with the addition of Sb,and Mg3Sb2 can promote the formation of fine polygonal type Mg2Si by providing nucleation site.Meanwhile,the grain size of Sb modified alloy is finer than that of the matrix. The improved microstructure results in the improvement of mechanical properties.The ultimate tensile strength is increased by 12.2%with the addition of 0.8%Sb.

Effect of post-weld heat treatment on microstructure and properties of Ti-23Al-17Nb alloy laser beam welding joints

The mechanical properties of Ti-23Al-17Nb (mole fraction,%) laser beam welding alloy joint at room temperature are comparable to that of the base materials.However,the strength and ductility of the as-welded joint deteriorate seriously after high temperature circulation.The effect of post-welded heat treatment on the microstructure and mechanical properties of the joint was investigated.The heat treatment was taken at 980 ℃ for 1.5 h,then furnace cooling and air cooling were performed separately.The results indicate that proper post-welded heat treatment improves the ductility of the joint at high temperature.

Personal Review:Sources of sulfide in waste streams and current biotechnologies for its removal

Sulfide-containing waste streams are generated by a number of industries. It is emitted into the environment as dis- solved sulfide (S2- and HS-) in wastewaters and as H2S in waste gases. Due to its corrosive nature, biological hydrogen sulfide removal processes are being investigated to overcome the chemical and disposal costs associated with existing chemically based removal processes. The nitrogen and sulfur metabolism interacts at various levels of the wastewater treatment process. Hence, the sulfur cycle offers possibilities to integrate nitrogen removal in the treatment process, which needs to be further optimized by appropriate design of the reactor configuration, optimization of performance parameters, retention of biomass and optimization of biomass growth. The present paper reviews the biotechnological advances to remove sulfides from various environments.

Comparisons of extraction and purification methods of soil microorganism DNA from rhizosphere soil

Microorganism DNA of rhizosphere soil from Pinus koraiensis and Pinus sylvestriformis were extracted by proteinase K based on SDS method, CTAB method, PVP （polyvinylpolypyrrolidone） method, and freezing and thawing method and the crude DNA from rhizosphere soil were purified by dialysis method, silver beads absorption method, and squeezing DNA gel method. The results of different extracting and purifying methods were compared and evaluated. Results indicated that the best method of extraction for microorganism DNA in rhizosphere soil was proteinse K based on SDS method with high salt concentration of 1.0% （w/v） NaCl, which could effectively eliminate humic acids and other impurities. The dialysis method was suitable to purify DNA from rhizosphere soil because of effectively removing brown matters and humic acids and the purified products were suited to PCR amplification. Squeezing DNA gel method was also a good purification method with the advantage of inexpensive in cost and efficient in use.

Impact of pH on Microbial Biomass Carbon and Microbial Biomass Phosphorus in Red Soils

The impact of pH changes on microbial biomass carbon (Cmic) and microbial biomass phosphorus (Pmic)were examined for 3 red soils under citrus production with different lengths of cultivation. Soil pH significantly affected Cmic and Pmic. The Cmic and Pmic changes, as a function of soil pH, appeared to follow a normal distribution with the original soil pH value at the apex and as pH increased or decreased compared to the original soil pH, Cmic and Pmic declined. Moreover, there were critical pH values at both extremes (3.0 on the acidic side and 8.0 to 8.5 on the alkaline side), beyond which most of microorganisms could never survive.The effect of pH on Cmic and Pmic was also related to the original soil pH. The higher the original soil pH was, the less Cmic or Pmic were affected by pH change. It is suggested that soil microorganisms that grow in a soil environment with a more neutral soil pH range (I.e. pH 5.5-7.5) may have a greater tolerance to pH changes than those growing in more acidic or more alkaline soil pH conditions.

Influence of a microscopic positive proximal margin in the treatment of gastric adenocarcinoma of the cardia

AIM： To investigate the influence of a positive proximal margin in total gastrectorny patients with gastric adenocarcinorna of the cardia. METHODS： Medical records of 191 patients with total gastrectornies for adenocarcinorna of the cardia between 1995 and 2000 were reviewed. The clinicopathologic features associated with a positive margin were determined, and the predictors for survival were analyzed. RESULTS： The incidence of positive proximal margin was 8.4% （16/191）. The positive margins were associated with advanced diseases. The tumor size and the depth of tumor invasion were independent risk factors for a positive margin. The mean survival in the positive margin group was 33.9 mo as compared.with 62.4 mo in the negative group （P 〈 0.001）. However, the difference in survival lost significance in subgroup analysis according to stage. Multivariate analysis identified that a positive margin was not an independent prognostic factor for survival. CONCLUSION： A positive margin is more of an indication of advanced disease in patients with gastric adenocarcinoma of the cardia rather than an independent prognostic factor for survival.

Magnetic Helical Micro-and Nanorobots:Toward Their Biomedical Applications

Magnetic helical micro- and nanorobots can perform 3D navigation in various liquids with a sub- micrometer precision under low-strength rotating magnetic fields （〈 10 rer）. Since magnetic fields with low strengths are harmless to cells and tissues, magnetic helical micro/ nanorobots are promising tools for biomedical applications, such as minimally invasive surgery, cell manipulation and analysis, and targeted therapy. This review provides general information on magnetic helical micro/nanorobots, including their fabrication, motion control, and further functionalization for biomedical applications.