关于出早操对当代学生的影响的调查

我国有句俗话:"一日之计在于晨"。早晨象征着美好,象征着希望,标志着新的一天的开始。学校教育从我们孩童时期到青年时期一直伴随着我们的生活,学校的早操也伴随着我们度过了无数岁月。各个学校的早操风格各异,有做操的,有跑步的,但是大体相同的一点就是各学校的早操都是比较"早",一般都会在清晨进行。可是,清晨进行锻炼真的对学生的身体和精神有好处吗?

Research of Biomass Accumulation and Saccharification Characteristics of Triarrhena lutarioriparia in Dongting Lake

[Objective] The aim was to analyze biomass accumulation, degradation and saccharification characteristics of Triarrhena lutarioriparia. [Method] With Triarrhena lutarioriparia as materials, samples were collected from April 2012 to November 2012 to explore monthly biomass changes and degradation and saccharification of Triarrhena lutarioriparia. [Result] Plant height was improving upon time; holocellulose and cellulose contents were increasing with dry weight of shoot system increasing and achieved the peak at 78.1% and 40% in September. It can be concluded that NaOH pre-treatment efficiency is better, when Triarrhena lutarionparia was treated with 2% NaOH at 100 ℃ for 20 min and reducing sugar yield achieved 178,42 mg/g. [Conclusion] Triarrhena lutarioriparia can be materials for ethyl alcohol production and the optimal harvest time is from middle September to middle October.

深圳卫视《极速前进》市场竞争力分析

一、《极速前进》市场竞争的核心优势 1、最为真实的真人秀 美国真人秀节目的领头羊《The Amazing Race》曾经10次获得艾美奖＂黄金时间最佳竞技类实境节目＂,比赛环节的惊险刺激和对比赛规则的严格遵守让它成为了大家公认的＂最为真实的真人秀＂。

Bioleaching of chalcopyrite by UV-induced mutagenized Acidiphilium cryptum and Acidithiobacillus ferrooxidans

The original strains Acidithiobacillusferrooxidans GF and Acidiphilium cryptum DXI-1 were isolated from the drainage of some caves riched in chalcopyrite in Dexing Mine in Jiangxi Province of China. The optimum temperature and pH for growth were 30 ℃ and 3.5 for Ac. cryptum DXI-1, and 30 ℃ and 2.0 for At. ferrooxidans GF, respectively. For Ac. cryptum DXI-1, the optimum UV radiating time was 60 s and the positive mutation rate was 22.5%. The growth curves show that Ac. cryptum after mutagenesis reached stationary phase within 60 h, which was 20 h earlier than the original strain. For At. ferrooxidans GF, the optimum mutation time was 60 s and the positive mutation rate was 35%. The most active UV-mutated strain At. ferrooxidans GF oxidized all the ferrous after 48 h. The bioleaching experiments showed that bioleaching with the mixture of UV-mutated strains of At. ferrooxidans GF and A c. cryptum DX1-1 （1：1） could extract 3.01 g/L of copper after 30 d, while the extracted copper was 2.63 g/L with the mixture of the original strains before UV-mutation. At the end of the bioleaching experiments, the proportion of the cell density in the cultures ofAc. cryptum DXI-1 andAt.ferrooxidans GF was approximately 1：5.

Patients with ST-segment elevation of myocardial infarction miss out on early reperfusion： when to undergo delayed revascularization

Objective There are still a high proportion of patients with ST-segment elevation myocardial infarction （STEMI） missing out early reperfusion even in the primary percutaneous coronary intervention （PCI） era. Most of them are stable latecomers, but the optimal time to undergo delayed PCI for stable ones remains controversial. Methods We investigated all STEMI patients who underwent delayed PCI （2-28 days after STEMI） during 2007-2010 in Beijing and excluded patients with hemodynamic instability. The primary outcome was maj or adverse cardiovascular events （MACEs）. Results This study finally enrolled 5,417 STEMI patients and assigned them into three groups according to individual delayed time （Early group, 55.9%; Medium group, 35.4%; Late group, 8.7%）. During 1-year follow-up, MACEs occurred in 319 patients. The incidence of MACEs were respectively 7.1%, 5.6% and 6.7% among three groups. The Medium group had less recurrent myocardial infarction plus cardiac death （hazard ratio, 0.525; 95% confidence interval, 0.294-0.938, P = 0.030） than Late group and less repeat revascularization （hazard ratio, 0.640; 95% confidence interval, 0.463-0.883, P = 0.007） than Early group in pairwise comparisons. We depicted the incidence of major adverse cardiovascular event （MACE） by delayed time as a quadratic curve and found the bottom appeared at day 14. Conclusions The delayed PCI time varied in the real-world practice, but undergoing operations on the second week after STEMI had greater survival benefit and less adverse events for whom without early reperfusion and hemodynamic instability.

Long-term stability analysis of large-scale underground plant of Xiangjiaba hydro-power station

Numerical analysis of the optimal supporting time and long-term stability index of the surrounding rocks in the underground plant of Xiangjiaba hydro-power station was carried out based on the rheological theory. Firstly,the mechanical parameters of each rock group were identified from the experimental data; secondly,the rheological calculation and analysis for the cavern in stepped excavation without supporting were made; finally,the optimal time for supporting at the characteristic point in a typical section was obtained while the creep rate and displacement after each excavation step has satisfied the criterion of the optimal supporting time. Excavation was repeated when the optimal time for supporting was identified,and the long-term stability creep time and the maximum creep deformation of the characteristic point were determined in accordance with the criterion of long-term stability index. It is shown that the optimal supporting time of the characteristic point in the underground plant of Xiangjiaba hydro-power station is 5-8 d,the long-term stability time of the typical section is 126 d,and the corresponding largest creep deformation is 24.30 mm. While the cavern is supported,the cavern deformation is significantly reduced and the stress states of the surrounding rock masses are remarkably improved.

Development of fractures in soft rock surrounding a roadway and their control

As the excavation of roadway, new fractures will be formed and the pre-existing fractures extend with the redistribution of stress in surrounding rocks. Eventually, fracture zone and bed separation are formed in rocks because of the developed fractures. Therefore, mastering the fracture evolution of surrounding rocks is very important to maintain the stability of roadway. The surrounding rocks of main haulage road- way in a certain coal mine is so broken and loose that the supporting is very difficult. Based on compre- hensive anal[ysis of the engineering geological conditions, a sight instrument was used to observe the fractures of internal surrounding rocks, Four indices, i.e., the width of fracture zone W, the number of fractures n, the width of fractures d and rock fracture designation RFD, are put forward to evaluate the fracture dewelopment. According to the evolution rules of the soft rock roadway from this paper, control principles by stages and by regions are presented through the research. At the same time, the best time of grouting reinforcement is determined on the basis of fracture saturation. Field practice shows that the roadway can satisfy normal production during service periods by suitable first support and grouting reinforcement.

Decode-and-Forward Relay Based Bidirectional Wireless Information and Power Transfer

In this paper, we propose the decode-and-forward(DF) based bidirectional wireless information and power transfer(BWIPT) in two-hop relay systems, where the bidirectional relay can decode and forward information from the user to the access point(AP), and assist the wireless power transfer from the AP to the user. To maximize the information rate from the user to the AP, we derive the closed form expression of the optimal power splitting(PS) factor, and the time allocation scheme to obtain the optimal time switching(TS) factor. Simulation results show that for both PS and TS protocols, the proposed DF based bidirectional relay systems can improve the information rate as compared with the amplify-and-forward(AF) based bidirectional relay systems.

四种芽苗蔬菜的栽培比较试验

随着人们生活水平的日益提高,对食品质量的要求也越来越高,芽苗蔬菜作为一种新兴的无公害绿色蔬菜,已成为人们青睐的餐桌上佳肴.

Regeneration of Spent Activated Carbon by Yeast and Chemical Method

In this study,spent activated carbon(AC) saturated with caramel was regenerated by using yeast and NaOH.The efficiency of regeneration was evaluated under parameters such as amount,treatment time,temperature,pH value,stirring temperature of yeast and NaOH concentration.The optimum condition for AC regeneration was 8 h for yeast treatment time,35 ℃ for 0.075% yeast culture temperature,a pH value of 6 for the yeast dealing with the spent AC,90 ℃ for NaOH stirring temperature of AC and 6% NaOH for washing after the spent AC was treated by yeast.Under these conditions,methylene blue(MB) adsorption was 213 mg·g-1 in comparison with 60 mg·g-1 of spent AC.The micro structure and surface area of the regenerated AC were characterized by scanning electron mi-croscope(SEM) and N2 sorption,respectively.The pore size distributions of virgin and regenerated AC were ana-lyzed by means of H-K equation,resulting in a mean pore diameter of 1.28 nm and a pore volume of 1.13 cm3·g-1.This study provides data for theoretical support of the AC regeneration technology.

Extraction Optimization of Polysaccharides from Pitaya Stems

[Objective]The aim was to describe the extraction of polysaccharides from pitaya stems.[Method]The hot water,enzyme-assisted and microwave-assisted methods were used,with the microwave-assisted extraction being deemed optimal by general evaluation.[Result]The main factors affecting the yield of polysaccharides in the microwave-assisted extraction,by order of magnitude,were as follows:time >microwave power >temperature;additionally,optimal conditions included a 10 min extraction time,an 80℃ extraction temperature and a microwave setting of 200 W.Using these optimal conditions,the yield of PSPS(Polysaccharides from Pitaya Stems) was 1.42%.After purification,the yield of PSPS was 0.74%.[Conclusion]The PSPS was analyzed by IR,MALDI-TOF-MS and an element analysis technique.It was shown to be a polysaccharide mixture,and the molecular weight was between 3 900 and 4 300 Da.

Control strategy of simultaneous nitrification and denitrification in SBR system

The influence of main process parameters on simultaneous nitrification and denitrification （SND） in a sequencing batch reactor （SBR） were investigated while treating actual municipal sewage. The influent average concentration of CODcr and total nitrogen was 350mg-L-l and 35mg.L-l. The experiment indicated the following four operation control strategies： （1） When operation cycle was 6 hours, oxidation of organic pollutants and simultaneous nitrification and denitrification could well completed in the SBR reactor; （2） TN removal rate could be increased significantly, 40% higher than traditional SBR processes when idle period was set between influent and aeration; （3） The time of idle period could affect simultaneous nitrification and denitrification and the best time is 30 minutes; （4） Increase of sludge organic load may improve TN removal efficiency, but NH3-N removal efficiency declines.

Optimum Condition Selection of Xylitol Candida tropicalis Conversion Production

[Objective] The aim was to select the optimum conditions of xylitol Candida tropicalis conversion production. [Method] The effect of cell culture time,conversion time,conversion pH value,conversion initial sugar concentration,speed and inoculation rate were determined respectively.[Result] Optimum fermentation conditions were obtained as follows:cell culture 16 h,conversion time 10 h,conversion pH value 5.5,conversion initial sugar concentration 20 g/L,conversion shaking speed 150 r/min,inoculation rate 10% (volume ratio). The yield of xylitol has increased to 90%. [Conclusion] This study had provided basis for the further study on xylitol.

Synthesis and Scheduling of Optimal Batch Water-recycle Networks

This work develops an optimization-based methodology for the design and scheduling of batch water recycle networks. This task requires the identification of network configuration, fresh-water usage, recycle assignments from sources to sinks, wastewater discharge, and a scheduling scheme. A new source-tank-sink representation is developed to allow for storage and dispatch tanks. The problem is solved in stages by first eliminating scheduling constraints and determining minimum usage of fresh water and wastewater discharge. An iterative procedure is formulated to minimize the total annual cost of the system by trading off capital versus operating costs. The work overcomes limitations in previous literature work including restricted recycle within the same cycle, lumped balances that may not lead to feasible solutions, and unrealistic objective functions. A case study is solved to illustrate the usefulness of the devised procedure.

Manganese extraction from high-iron-content manganese oxide ores by selective reduction roasting-acid leaching process using black charcoal as reductant

Reduction roasting-acid leaching process was utilized to process high-iron-content manganese oxide ore using black charcoal as reductant. The results indicate that, compared with the traditional reductant of anthracite, higher manganese extraction efficiency is achieved at lower roasting temperature and shorter residence time. The effects of roasting parameters on the leaching efficiency of Mn and Fe were studied, and the optimal parameters are determined as follows: roasting temperature is 650 °C, residence time is 40 min, and black charcoal dosage is 10%(mass fraction). Under these conditions, the leaching efficiency of Mn reaches 82.37% while that of Fe is controlled below 7%. XRD results show that a majority of MnO2 and Fe2O3 in the raw ore are reduced to MnO and Fe3O4, respectively.

Catalytic synthesis of acetals and ketals with H3PW6Mo6O40/TiO2

A new environmental friendly catalyst, H3PW6Mo6O40/TiO2 was prepared. The optimum conditions have been found, that is, mass ratio of m （TiO2）： m （H3PW6Mo6O40） is 1：2.0, volume of water is 30 mL, the reflux reaction time is 2 h, and activated temperature is 150 ℃. H3PW6Mo6O40/TiO2 was used as catalyst in catalytic synthesis ofacetals and ketals. Effects ofn （aldehyde（ketone））： n （glycol）, catalyst dosage and reaction time on yield were investigated. Optimal conditions were： n（aldehyde （ketone））： n （glycol）=1.0 ： 1.4; mass fraction of catalyst to reactants, 0.8%; reaction time, 1.0 h and cyclohexane as water-stripped reagent, 10 mL. Under these conditions, yields of acetals and ketals can reach 53.0% -86.9 0%

Analytic study on the optimal control of water hammer waves in pipes

To realize the accurate control of water hammer in pipes by valve stroking, based on basic differential equations of water hammer subjected to initial and boundary conditions, the traveling solution of wave equations in finite region was applied to the linear water hammer problem. With the given velocity function at the valve and the introduction of curve integration independent of integral path, the exact analytic solution of dimensionless water hammer pressure was obtained in the course of valve closing. Based on the definition of eigen wave height, optimal eigen wave height and observation time, the control goal of water hammer pressure and the judgment rule of the optimal eigen wave height were determined, then the optimal velocity function in the calculated example was derived, which can reduce the water hammer pressure maximally. According to this function, a valve closing program was set, and the optimal control of water hammer could be realized.

Optimization of Enzyme-assisted Extraction Technology for Tartary Buckwheat Shell Procyanidins with Response Surface Methodology

This study was conducted to investigate the effects of cellulase dosage, enzymolysis time, pH and enzymolysis temperature on procyanidin extraction rate by single factor experiment, with tartary buckwheat shell as an experimental material.Main process parameters were optimized to obtain a regression model by response surface methodology. The results of variance analysis indicated that the regression model reflected the relationship between buckwheat shell procyanidin extraction rate with enzyme dosage, enzymolysis time, pH and enzymolysis temperature; and the optimal process parameters were enzyme dosage of 6.5 mg/g, enzymolysis time of 1.5 h, pH at 4.7 and enzymolysis temperature at 46 ℃. Three parallel experiments were conducted under these process parameters. In practice, the highest procyanidin extraction rate was 6.78 g/100 g. The relative error between the predicted value of regression model and the actual value was 1.3%. The regression equation fitted the real situation better.

Research on Algae Removal by Ultrasonic and Jet Combined Process

Ultrasonic and jet combined process was studied to remove determined by static experiments, and stability of this combined process algae in lake type raw water. The optimum reaction time was was checked by dynamic experiments. The results was showed that ultrasonic/jet combined process has excellent removal efficiency on algae in lake type raw water, and it＇s a simple operation, and has no secondary pollution. When the pH, temperature, chlorophyll-a（Chl-a） and cell concentration（OD560） of raw water are 7.69, 25.8 ℃, 29.003 mg/m^3 and 0.091, the average removal efficiency on Chl-a and OD560 are 81.60% and 80.22%, respectively, which are stable by this combined process when it is operating in 36 hours, and samples are analyzed each 4 hours.