初中物理教学应把握好十“度”

初中物理教学是学生学习物理的起始阶段,物理教师要想在教学中取得好的教学效果,培养学生学习物理的兴趣与能力,在教学中就要把握好"进度、量度、难度、深度、广度、精度、准度、梯度、角度、效度"这十"度"。

Effect of cooling rates on clustering towards icosahedra in rapidly solidified Cu_(56)Zr_(44) alloy

The rapid solidification processes of liquid Cu56Zr44 alloys at different cooling rates （γ） were simulated by a molecular dynamics （MD） method. In order to assess the influence of cooling rate on the clustering tendency and degree towards icosahedrons, a ten-indices＇ cluster-type index method was suggested to characterize the local atomic structures in the super-cooled liquid and the rapidly solidified solid. And their clustering and ordering degrees as well as the packing density of ieosahedral clusters were also evaluated by an icosahedral clustering degree （fI）, the chemical order parameter （ηαβ） and densification coefficients （D0, DI and DIS）, respectively. Results show that the main local atomic configurations in Cu56Zr44 alloy system are Z12 clusters centered by Cu, and most of which are （12 0 12 0 0 0 0 0 0 0） standard icosahedra and （12 0 8 0 0 0 2 2 0 0） as well as （12 2 8 2 0 0 0 0 0 0） defective icosahedra. Below glass transition temperature （Tg）, these icosahedral clusters will be coalesced to various icosahedral medium-range orders （IMROs） by IS linkages, namely, icosahedral bond, and their number N, size n, order parameter ηαβ as well as spatial distributions vary with y. As the cooling rate exceeds the critical value （γc） at which a glassy transition can take place, a lower cooling rate, e.g., γ1=10^1K/ns, is demonstrated to be favorable to uplift the number of icosahedra and enlarge the size of IMROs compared with the higher cooling rates, e.g., γ5=10^5 K/ns, and their packing density and clustering degree towards icosahedra in the rapidly solidified solid can also benefit from the slow cooling process.

Effect of Mn(II) on quartz flotation using dodecylamine as collector

Quartz is, in most cases, the major gangue mineral found in the manganese ore. Mn iron, dissolved from the surface of ore, will determine the interfacial properties of the particles and, thus, their flotation behavior. In this work, the effect of Mn2+ on quartz flotation was investigated through flotation tests. It was found that quartz can be depressed with Mn2+ and floated with dodecylamine in the pH region 7-8. In order to prove the validity of the findings, UV spectrophotometry, FTIR and SEM-EDS were carried out. UV spectrophotometry tests results show that Mn2+ can competitive adsorb with RNH3+ in the surface of quartz at acidic and neutral pH values. The FTIR measurements and SEM-EDS analysis indicate that Mn2+ forms precipitation and adsorbs on the negatively charged quartz surface, it induces quartz recovery dropping in alkaline pH. Furthermore, in the case of sodium hexametaphosphate(SH), sodium silicate or citric acid, the effects of Mn2+ were also studied. This depression in the given Mn2+ did not disappear. Citric acid is an appropriate modifier to separate quartz depressed by Mn2+ from other ores at pH 7.

Duodenal biopsy may be avoided when high transglutaminase antibody titers are present

AIM:To evaluate the predictive value of tissue transglutaminase (tTG) antibodies for villous atrophy in adult and pediatric populations to determine if duodenal biopsy can be avoided.METHODS: A total of 324 patients with celiac disease (CD; 97 children and 227 adults) were recruited prospectively at two tertiary centers. Human IgA class anti-tTG antibody measurement and upper gastrointestinal endoscopy were performed at diagnosis. A second biopsy was performed in 40 asymptomatic adults on a gluten-free diet (GFD) and with normal tTG levels.RESULTS: Adults showed less severe histopathology (26% vs 63%, P<0.0001) and lower tTG antibody titers than children. Levels of tTG antibody correlated with Marsh type in both populations (r=0.661, P<0.0001). Multiple logistic regression revealed that only tTG antibody was an independent predictor for Marsh type 3 lesions, but clinical presentation type and age were not. A cut-off point of 30 U tTG antibody yielded the highest area under the receiver operating characteristic curve (0.854). Based on the predictive value of this cut-off point, up to 95% of children and 53% of adults would be correctly diagnosed without biopsy. Despite GFDs and decreased tTG antibody levels, 25% of the adults did not recover from villous atrophy during the second year after diagnosis.CONCLUSION: Strongly positive tTG antibody titers might be sufficient for CD diagnosis in children. However, duodenal biopsy cannot be avoided in adults because disease presentation and monitoring are different.

Solubilization of Phenanthrene and Fluorene in Equimolar Binary Mixtures of Gemini/Conventional Surfactants

This study deals with the enhanced solubilization of polycyclic aromatic hydrocarbons （PAHs） such as phenanthrene （PHE） and fluorene （FLR） in a pure cationic gemini （G6） and three conventional surfactants [polyethylene glycol dodecyl ether （Brij35）, cetyltrimethyl ammonium bromide （CRAB） and sodium lauryl sulfate （SDS）] as well as in their equimolar binary combinations （G6-Brij35, G6-CTAB and G6-SDS）. Their solubilization efficiency toward PHE and FLR has been quantified in terms of the molar solubilization ratio （MSR） and the micelle-water partition coefficient （Kin）. The ideality/nonideality of the mixed micelles is discussed with the help of Clint, Rubingh and Rosen＇s approaches. These theories determine the deviation of experimental critical micelle concen- tration （CMC） values from ideal critical micelle concentration, which was measured by evaluating the interaction parameters （/3m and/3）. Negative values ofβm were observed in all the equimolar binary systems, which show synergism in the mixed micelles. Whereas at air/liquid interface synergism was observed in the systems G6-CrAB and G6-Brij35; G6-SDS exhibited an antagonistic effect. The order of MSR and Km was G6-CTAB 〉 G6- Brij35 〉 G6-SDS for phenanthrene as well as for fluorene.

First record of marine crab,Eucrate alcocki Serène,in Serène and Lohavanijaya,1973 (Crustacea,Decapoda,Brachyura,Euryplacidae) from India

This paper reports the occurrence of a marine brachyuran crab species Eucrate alcocki Serene, in Serene et al., 1973, of the family Euryplacidae Stimpson, 1871, for first time from India, based on a male specimen from Parangipettai fish landing centre in Bay of Bengal, Southeast Coast of India. Although morphologically corresponding with what is currently defined as E. alcocki, the color pattern of the carapace of the present specimen is rather different from that of the Chinese material-only the anterior fifth of the carapace is marked with scattered red spots, the rest of the surface is yellowish, with four unusually shaped red blotches which almost look like Sanskrit characters.

Purification of Octacosanol by Agitated Short-Path Distillation

Octacosanol is purified by agitated short-path distillation (SPD). Effects of evaporation temperature,number of SPD steps in series and other distillation method on the octacosanol recovery and decomposition are studied. Although the experimental results indicate some decomposition when the mixture of higher primary aliphatic alcohols is distillated by SPD, SPD is still an effective method to purify octacosanol. It is concluded that evaporation temperature affects greatly on the purity and recovery of octacosanol.

A New Browder Fixed Point Theorem in Noncompact Hyperconvex Metric Spaces and Its Applications to Section Questions and Intersection Questions

In this paper, a new Browder fixed point theorem is established in the noncompact sub-admissible subsets of noncompact hyperconvex metric spaces. As application, a Ky Fan section theorem and an intersection theorem are obtained.

Photocatalytic Reduction of 6-Chloro-3-Nitrotoluene-4-Sulfonic Acid in Presence of Surfactants

Photocatalytic reduction of 6-chloro-3-nitrotoluene-4-sulfonic acid (CNSA) was studied in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. A mixture of CNSA, TiO2, water, additives and surfactants was put into a quartz glass reactor with a jacket, which was irradiated with a high pressure Hg lamp in the purging of nitrogen gas. With methanol, the conversion of CNSA increased from 7.7% to 34.6%. Three surfactants significantly promoted the photocatalytic reduction conversion in reduced order of sodium dodecylbenzenesulfonate (DBS), cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS). In suspensions involving DBS and CTAB respectively, CNSA conversion increased in consistence with the adsorption ratio with methanol, but varied inversely with the adsorption ratio without methanol. But no obvious influence on the adsorption ratio was observed with or without methanol added when the SDS concentration was critical micelle concentration (cmc). The photocatalytic reduction of CNSA was enhanced in UV-irradiated TiO2 suspensions in the presence of methanol and surfactants. Methanol inhibited the recombination of photogenerated holes and electrons efficiently. Surfactants around 1 cmc led to the highest reduction conversion.

Research on the Relationship between Molecular Activity of Additives and Lubricating Performance of Aluminum Rolling Oil

In this paper,an ab initio,local density functional(LDF)method was used to explore the relationship between the molecular properties of additives and the lubricating performance of aluminum rolling oil.The structural properties of butyl stearate,dodecanol,docosanol,and methyl dodecanoate were studied according to the density functional theory.The calculated data showed that the atoms in or around the functional groups might be likely the reacting sites.Because of the different functional groups and structure of ester and alcohol,two types of complex additives,dodecanol and butyl stearate,methyl dodecanoate and butyl stearate,respectively,were chosen for studying their tribological properties and performing aluminum cold rolling experiments.The test results agreed with the calculated results very well.The complex ester,viz.methyl dodecanoate and butyl stearate,had the best lubricating performance with a friction coefficient of 0.084 1 and a permissive-rolling thickness of 0.040 mm as compared with that of dodecanol-butyl stearate-base oil formulation.

Biodegradation of Petroleum Hydrocarbon by Pseudomonas Aeruginosa

A bacterial strain of the genus Pseudomonas aeruginosa was inoculated into a hydrocarbon culture medium and incubated for a definite period of time. The ability of the bacterial strain to biodegrade a hydrocarbon, viz. n-hexadecane, was evaluated through determining the hexadecane concentration in the inoculated culture medium on a gas chromatograph (GC). The effect of pH value on the degrading ability of the bacterial isolate and the impact of temperature on microbial growth were also explored. Test results showed that Pseudomonas aeruginosa was markedly effective in biodegrading n-hexadecane. Furthermore, the ability of Pseudomonas aeruginosa to biodegrade n-hexadecane was different at various pH values. Pseudomonas aeruginosa provided excellent degrading ability at a pH value of 7.0. The microbial cells of Pseudomonas aeruginosa increased with an increasing incubation duration at temperatures ranging from 28 ℃ to 35 ℃, and an exponential phase of microbial growth was observed.

Spectrophotometric Investigation of Complex Formation of Ge（IV） with Bis（2,3,4-Trigidroksifenilazo） Benzidine in the Presence of Cationic Surfactants Active Substances

It is investigated the interaction of Ge（IV） with bis（2,3,4-trigodroksifenolazo） benzidine （R） in the presence of KSAS （cationic surface active substances）-CPCl （cetylpyridinium chloride）, CPBr （cetylpyridinium bromide） and CTMABr （cetyltrimethylammonium bromide）. It is studied the effect pH, time on the formation of ternary complexes. It is determinated of molar absorption coefficients and stability constants of germanium. Binary （Ge-R） and triple （Ge-R-CPCI, Ge-R-CPBr, Ge-R-CTMaBr） complex form at pH 4 and pH 1, respectively. The composition proportion of binar system is 1：2 and the composition proportion triple complex is 1：1：2. The concentration interval of germanium which obeying beer low in the Ge-R 0.12-2.92 mkq/mL, in the Ge-R-CPCI is 0.04-1.46 mkq/mL, in the Ge-R-CPBr is 0.00-1.00 mkq/mL and in the Ge-R-CTMaBr is 0.00-1.00 mkq/mL. Molar absorbtivities of complexes are 45,000, 57,000, 59,000 and 60,000, respectively. The effect of interfering ions and masking agents has been learned. Stability constants of complexes have been determined： lgKl = 7.21 ＋ 0.06 （Ge-R）,＇ lgK1 = 12.08 _＋ 0.05 （Ge-R-CPCI）, lgK1 = 12.12 ＋ 0.07 （Ge-R-CPBr） and lgK1 = 12.85 ＋ 0.06 （Ge-R-CTMaBr）. It is developed highly selective method of photometric determination of trace amounts of Ge（IV） in petroleum coke.

New record of the genus Phycocaris Kemp,1916(Decapoda:Caridea:Hippolytidae)from Hainan Island,China

The monotypic genus Phycocaris Kemp, 1916, which was established based on material from the Indian Ocean and previously only known from the type localities, Australia and Japan, is now newly recorded from the South China Sea. A detailed description of Phycocaris simulans Kemp, 1916 based on the specimen collected from Hainan Island is presented. Specific features and the differences between the Indian Ocean and the present material are described.

Impact of climatic change on sea surface temperature variation in Subei coastal waters,East China

Sea surface temperature （SST） variation in the Subei coastal waters, East China, which is important for the ecological environment of the Yellow Sea where Enteromorphaprolifera blooms frequently, is affected by the East Asian winter monsoon （EAWM）, El Nifio-Southem Oscillation （ENSO）, and Pacific Decadal Oscillation （PDO）. In this study, correlations between climatic events and SST anomalies （SSTA） around the Subei （North Jiangsu Province, East China） Coast from 1981-2012 are analyzed, using empirical orthogonal function （EOF） and correlation analyses. First, a key region was determined by EOF analysis to represent the Subei coastal waters. Then, coherency analyses were performed on this key region. According to the correlation analysis, the EAWM index has a positive correlation with the spring and summer SSTA of the key region. Furthermore, the Nifio3.4 index is negatively correlated with the spring and summer SSTA of the key region 1 year ahead, and the PDO has significant negative coherency with spring SSTA and negative coherency with summer SSTA in the key region 1 year ahead. Overall, PDO exhibits the most significant impact on SSTA of the key region. In the key region, all these factors are correlated more significantly with SSTA in spring than in summer. This suggests that outbreaks ofEnteromorpha prolifera in the Yellow Sea are affected by global climatic changes, especially the PDO.

Synthesis of Polyalphaolefins on AlCl_3/TiCl_4 Catalyst

The oligomerzation reactions on different catalysts were investigated and discussed. 1-Octene, 1-decene, 1-do- decene, a mixture of olefins （with a mass ratio of w（l-octene）： w（1-decenc）：w（1-dodecene） equating to 30：40：30）, and the products from paraffin cracking were oligomerized on the AlCl3/TiC14 catalyst. The results indicated that the AlCl3 catalyst led to severe coking reaction. With an increase in carbon number of alpha-olefins, the freezing point of oligomers increased and the kinematic viscosity decreased. The oligomers formed from the mixed olefins and the paraffin cracking products showed higher kinematic viscosity. Normal paraffins contained in the cracked products could increase the freezing point of oligomers. Furthermore, the distillation range of oligomers obtained from the cracked products was close to those of oligo- mers originated from 1-octene and 1-decene, while the oligomers obtained from the mixed olefins and 1-dodecene had simi- lar distillation ranges.

Bio-solubilization of Chinese lignite I:extra-cellular protein analysis

A white rot fungus strain, Trichoderma sp.AH, was isolated from rotten wood in Fushun and used to study the mechanism of lignite bio-solubilization.The results showed that nitric acid pretreated Fushun lignite was solubilized by T.sp.AH and that extracellular proteins from T.sp.AH were correlated with the lignite bio-solubilization results.In the presence of Fushun lignite the extracellular protein concentration from T.sp.AH was 4.5 g/L while the concentration was 3 g/L in the absence of Fushun lignite.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) of the extracellular proteins detected at least four new protein bands after the T.sp.AH had solubilized the lignite.Enzyme color reactions showed that extracellular proteins from T.sp.AH mainly consisted of phenol-oxidases, but that lignin decomposition enzymes such as laccase, peroxidase and manganese peroxidases were not present.

Spectrophotometric Determination of Compex Formation of Cerium（Ⅲ） with 1-phenyl-2,3-dimethylpyrazolone-5-azo-4-pyrogallole in the Presence of Cetylpyridine Chloride

Complex formation of cerium （Ⅲ） with l-phenyl-2,3-dimethylpyrazolone-5-azo-4-pyrogallole （L） in the presence and absence ofcetylpyridine chloride （CPC） was investigated. Homogeneous CeL- and mixed ligand CeL-CPC compounds are formed at pH 6. Constants of stability of the complexes are （IgKD 5.15±0.02 （CeL）, 7.98±0.03 （CeL-CPC）. Ratio of reagents in composition of homogeneous is （1 ：2） and in different ligand it equals to （1：2：2）. Beer＇s law is observed in interval of concentration 1.12-11.2 μg/ml Ce. The technique for photometric determination of cerium was worked out in artificial mixture.

Investigation of Propene Oligomerization Catalyzed by Phosphotungstic Acid Catalysts

In this paper, the propene oligomerization reaction catalyzed by phosphotungstic acid supported on two kinds of silica gel was studied, it had been found out that the conversion of propene catalyzed by the type A silica gel-phosphotung- stic acid catalyst was 3.38 m%, while the conversion of propene catalyzed by the type B silica gel-phosphotungstic acid catalyst was 90.1 m% with a nonene selectivity of 42.33 m%, and a dodecene selectivity of 31.79 m%. The influence of reaction temperature, pressure and liquid hourly space velocity （LHSV） on the reaction catalyzed by the type B silica gel- phosphotungstic acid catalyst was investigated. It had been verified that when the reaction temperature increased from 170 ~C to 190 ~C, the conversion of propene increased while the selectivity of nonene and dodecene decreased; when the re- action pressure increased from 3.5 MPa to 4.5 MPa, the conversion of propene increased also, and the selectivity of nonene and dodecene changed very little. The conversion of propene at a space velocity of between 0.5 h-1 and 1.0 h-~ was higher than that achieved at 2.0 h-~, but the selectivity of nonene and dodecene did not show regular fluctuations. An optimum conversion of propene （91.05 m%） and an optimum selectivity of nonene and dodecene （89.51 m%） could be achieved at a reaction temperature of 170 ~C, a reaction pressure of 4.5MPa, and a LHSV of 1.0 fit. The experiments on catalyst life showed that the activity of the type B silica gel-phosphotungstic acid catalyst could be only maintained in 25 hours, and the reason was explained also.

A decomposition model to analyze effect of SO_2 emission density of China

A decomposition model was applied to study the resource-saving and environment-friendly effects of air pollutant emissions(taking industrial SO2 emission as an example) in China.From the results,it is found that 38.93% and 61.07% are contributed to environment-friendly and resource-saving effects,respectively,by the dramatic decrease in industrial SO2 emission density(nearly 70% from 2001 to 2010).This indicates that China has achieved important progress during the 11th FYP(five-year plan) compared with the 10th FYP.A simultaneous equations model was also employed to analyze the influencing factors by using data from 30 provinces in China.The results imply that the influence of environmental regulation on environment-friendly effect is not obvious during the 10th FYP but obvious during the 11th FYP.Thus,the government should continue promoting the environment-friendly effect by further enhancing environmental regulation and strengthening the role of environmental management.

Effect of Static Magnetic Field on Extracellular Proteins Synthesis in Escherichia coli

Escherichia coli type 1 was used as a model system to determine whether static magnetic fields are a general stress factor. The bacterial broth culture were exposed to different magnetic force （400, 800, 1200 and 1600 Gauss） with incubation at 37 ℃ for different times （24, 48 and 72 hrs） under aerobic conditions. The response of the cells to the magnetic fields was estimated from the change in total protein synthesis by using spectrophotometer at 550 nm and by using of SDS-PAGE （Sodium dodecyl sulfate- polyacrylamide gel electrophoresis）. Results concluded that was approximately no reproducible changes qualitatively in extracellular proteins were observed in the SDS-PAGE electrophoresis and did not act as a general stress factor. While, increases in the level of extra-cellular synthesis were observed using different magnetic field exposed samples when compared with the control.