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Data collected from 24 marine monitoring stations in Luanhekou-Beidaihe ecological monitoring marine area from 1999 to 2014 reveal a substantial change in the nutrient of this region. The content of nitrogenous nutrients has increased, but phosphate and silicate have decreased. The average N:P ratios have increased from 4.951 in 1999 to 47.188 in 2014;while the Si:N ratios have decreased. The nutrient structure has substantially changed over a period of 16 years. Before 2004, phosphate was relative surplus but inorganic nitrogen was relative lack, while relative surplus of inorganic nitrogen and relative lack of phosphate after 2004. The water quality changed from low nitrogen and high phosphorus (before 2004) to high nitrogen and low phosphorus (after 2004).This finding shows that the nutrient structure may be related to anthropogenic influence.

There are a series of problems in using explosive source in land oil seismic exploration at present. Aiming at this problem, a new hammer source system which can replace explosive source was proposed. Function of the hammer source system was analyzed and a typical pneumatic control circuit was designed. With the advantages of strong impact, high speed and small gas consumption, quick air exhaust impact cylinder was used in the hammer source system. An electronic control system was designed based on PLC, including the hardware component and software design. The pneumatic control system was simulated and analyzed in AMESim, and the results showed that the system can meet the design requirements, provide a reference for engineering application.

In order to provide a theoretical basis for the research on processing tomato harvester, three kinds of processing tomatoes which were largely cultivated and suitable for mechanization harvest in Xinjiang location of China were sampled, and after measuring the red-ripe fruit weight, fruit transverse and longitudinal diameter, the regression equations about the fruit weight and the fruit transverse diameter, fruit longitudinal diameter, fruit shape were established, and the fruit-stem separation force test on the samples was carried out, so the regression equations about the processing tomato fruit-stem separation force and the fruit weight were established. Finally, the mathematical models about fruit-stem separation force and fruit shape of processing tomatoes were built.

Against the backdrop that wind power is always abandoned in heat supply period in winter after wind power is taken into power grid in northern areas of China and there exists a big proportion of large-scale heat supply units in power grid, a method for in-depth peak regulation of large-scale heat supply unit based on characteristics of thermal storage of heat supply network and buildings is put forward in this paper, and a mathematical model for in-depth peak regulation is established. The calculation in a case indicates that the change of heat production of large-scale heat supply unit will not affect the quality of heat supply to a certain extent. During heat supply period, thermal load of heat supply network shall be moderately lowered to coordinate with the in-depth peak regulation when power grid is at its low ebb, and heat supply shall be moderately decreased based on characteristics of thermal storage of heat supply network and buildings when the peak regulation capacity of power grid is very limited, which indicates that it is feasible and practical to help power grid go through its low ebb with the peak regulation capacity gained here. Through the mathematical model established in this paper, time of thermal storage and thermal release as well as such units capacity of in-depth peak regulation can be calculated, which provides a scientific basis for dispatcher of power grid to conduct in-depth peak regulation of heat supply unit.

This paper means to provide an innovative design of aero-engine after investigating existing aero-engines. It is a late model power plant design which is based on the watercraft electromagnetic propulsion technology and the theory that in electromagnetic field magnetic field generates Ampere force to current flow and in combination with specific structures of aero-engines. The design principle of this engine is that when the air working medium with high conductivity goes through an arc generator, it will ionize and produce plasma, which actions in the magnetic field that produced by built-in superconducting magnetic and generates forward push. This design will provide a theoretical reserve for future development of aero-engines and has potential market prospects.

Posterior capsular opacification is the most frequent complication after cataract surgery, which is induced by the proliferation, differentiation and migration of lens epithelial cells. Inhibiting the proliferation of human lens epithelial cells could reduce the occurrence of posterior capsular opacification. To explore the possible potential of ZnO nanoparticles in treating posterior capsular opacification, we investigated the effect of ZnO nanoparticles on the human lens epithelial cell proliferation in the presence and absence of ultraviolet B (UVB) irradiation via 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. The results indicate that ZnO nanoparticles could apparently inhibit the proliferation of human lens epithelial cells in a dose-dependent manner, and UVB irradiation can further enhance this inhibitory role for the human lens epithelial cell proliferation, indicating the great potential of ZnO nanoparticles in treating posterior capsular opacification in clinical application.

Spatial distributions of chlorophyll-a (Chl-a), secchi disc transparency (SD), and total nitrogen (TN) were estimated using Landset7 ETM+ SLC-OFF data before and after the connection project of Donghu Lake and Shahu Lake in Wuhan, China. Results show that water quality in the two lakes is improved in most area, especially in the joint connection. There are 23%, 19%, 18% in average improvement for Chl-a, SD, and TN respectively. This study suggests that besides controlling of point and non-point sources pollution, water network connection project is effective on water quality in lakes.

Acoustic emission (AE) testing (AET) is an effective, nondestructive testing (NDT) method which is widely used throughout the petrochemical industry. It especially plays an important role in inspecting of atmospheric storage tank floor corrosion, oil and gas pipeline leakage and pressure vessel cracking. The AET methods and evaluation of storage tank, pipeline, sphere and other equipment in oil and gas storage and transportation system are reviewed in this paper, and the development trends of AE technique also be introduced. This technique has important significance in ensuring the security.

CO2 corrosion is the main safety problem of production process in gathering, delivering and treating of oil and gas. Injecting inhibitors to suppress CO2 corrosion in oil and gas fields is an easy-to-use, low investment, quick solution method. The goal of this study is to summarize the already established research results of controlling CO2 corrosion, inhibition mechanism of CO2 corrosion inhibitors is reviewed, application status of inhibitor technology in CO2 corrosive environment is discussed. Research status of amides, imidazoline derivatives, quatemary ammonium salts and schiff bases overseas and domestic is highlighted. Finally, an outlook on the development trend of CO2 corrosion inhibitors is presented.

For applications of single supply, a digital interface circuit of resolver based on AD2S1200 is designed in a single 5V system. According to the given resolver, the amplification factor and driver capability of excitation signal is calculated and verified. In order to adjust the excitation signals amplitude and provide enough drive current to the resolvers primary winding, an operational amplifier with high current output capability AD8532 is chosen to set an excitation signal buffer circuit which works as a unity gain inverting proportional amplifier. Besides, the design greatly reduces the amount of components which is especially appropriate for the installation in a constriction space. To give a test for the interface circuit, the microcontroller ATmega16 is used to read the 12-bit parallel angle position data of resolver. The test result shows that the interface circuit can not only work well but also obtain an accuracy of angle position within 0.1°.

The corrosion acoustic emission (AE) source location is one of the main purposes of acoustic emission testing (AET), corrosion detection and location can guarantee the safety and integrity of pipeline, storage tank and other equipment in the petrochemical industry. The computed source location and zonal location methods are reviewed in this paper, and also new source location method based on modal acoustic emission (MAE) is introduced and this new method will be more widely used in the field of corrosion detection in future.

The measured Frequency Response Functions (FRFs) often have errors due to the support effects in free-free modal testing. In [1], elimination of support effects from the measured FRFs has been investigated and both stiffness and damping have been considered in support conditions. However, the method is only applicable for single point support occasion while the test structure is usually supported from more than one location in a practical testing. Therefore, this paper further investigates this method to extend its application to multi-points support conditions. Firstly, general formulas of removing the multipoint support effects from the measured FRFs are derived based on the dynamic substructure method. Then a simulated modal test of free-free beam with two points suspension is proposed to verify this method. Finally, the performance of the method is investigated with simulated noisy data. It is shown that the proposed method is effective in removing support stiffness as well as support damping from the measured FRFs as long as the measured data are not heavily contaminated by the noise.

Titanium dioxide (TiO2) nanoparticles have been widely used in many fields, including biomedicine, cosmetics and environmental engineering. Recently, it was reported that TiO2 nanoparticles could exert genotoxicity on organisms via the generation of reactive oxygen species (ROS). In the present study, we investigated the effect of TiO2 nanoparticles on RGC-5 cells with or without ultraviolet (UV) B irradiation through MTT assay and determination of hydroxyl radical production. The results demonstrated that TiO2 nanoparticles could efficiently inhibit the growth of RGC-5 cells in the presence of UVB irradiation, whereas there was little impact on target cells in the absence of UV irradiation; UV irradiation could apparently increase the level of hydroxyl radicals in RGC-5 cells and further efficiently inhibit the growth of RGC-5 cells, suggesting that UV irradiation plays an important role in growth inhibition in RGC-5 cells exposed to TiO2 nanoparticles.

In modal testing, the measured Frequency Response Functions (FRFs) are often inaccurate due to the adverse mechanical effects, such as mass-loading effects of transducers, shaker-structure interaction and the support effects. This paper deals with the elimination of the support effects from measured FRFs using dynamic substructure method. Both stiffness and damping are considered in the support effects. The validity of the method is proved in a simulated modal test. It is shown that with the given support conditions the affected FRFs can be corrected provided that some additional FRFs concerned with the support point are also measured. Finally, performance of this method is assessed with noisy measured data. Simulation shows that 1% white noise is acceptable in the proposed correction method.

In this paper, double crank mechanism is put forward to achieve separation of the processing tomato fruit-stem on the basis of analysis of the existing separation mechanism kinematic characteristics, and the rod length ratio of the desired motion characteristics has been gotten by virtual simulation platform based on ADAMS, and the rod lengths of the double crank mechanism ultimately determined are as follows, driving crank is 148mm, active crank is 178mm, link is 222mm, and driven crank is 200mm on the basis of the testing determination of the maturity processing tomato fruit-stem separation force. It is able to meet the fruit and stem separation requirements when the angular velocity of driven crank is 60r/min. It can provide a theoretical basis for engineering practice.

The basic configuration and control method of the humanoid robot SCUT-I are presented. SCUT-I, developed by the Robot and Intelligent Software Laboratory in South China University of Technology, 58.2 centimeter tall and 3.9 Kg weight with 21 degree of freedom (DoF), was designed to be humanlike including two legs, two arms, a trunk and a head. The mechanical design, hardware description, sensor fusion and motion control schemes of SCUT-I are represented, and a kind of dynamical walking control schemes based on linear inverted pendulum model (LIPM) and attitude sensor feedback control is proposed.

This research focuses on investigating the high performance concrete containing slag with different fineness and dosage. For this purpose, the workability, compressive strength at different ages, and chloride ion penetration were investigated, with slag surface area 420m2/kg, 530m2/kg, 610m2/kg, and 720m2/kg, and replacement percentage 0%, 20%, 40%, and 60%, respectively. It was found that the workability and chloride ion penetration resistance were affected by the fineness and dosage of slag. The 7-day compressive strength decreased with slag replacement increasing when the fineness of slag is lower than 530m2/kg, and 28-day and 56-day compressive strength increased; For the fineness higher than 530m2/kg, the 7-day compressive strength is higher than that of control concrete, when the slag replacement was 40%, the concrete reached the highest value, and the 28-day and 56-day compressive strength increased with slag incorporation.

This paper analyzes the necessity of the research on recycled concrete, origins and properties of the recycled aggregate, the research status of material properties of recycled concrete, such as recycled concrete workability and mix design, mechanical properties, drying shrinkage and concrete creep of recycled concrete, durability etc, and the research status of structural members of recycled concrete, including columns of recycled concrete, beam-column joint of recycled concrete, frame structure seismic performance and so on, thus proves the research significance is great, moreover points out the future direction of the research on recycled concrete.

Compliant elements play an important role in running and hopping legged robots for improving their speed and energy efficiency. The dynamic model of the compliant legged robot was developed by taking into account the slipping, vibration and distributed compliance of the legs. The parameter variations of the system after impacts were researched for different dropping height and angles by numerical method. Meanwhile, the effectiveness of the model was verified through explicit dynamics analysis software. All these results will provide a theoretical guide for the energy efficiency analysis and mechanical design of the compliant legged robots.

Compliant actuators are widely used in industrial robots due to the fact that the compliant elements have the capacity to absorb excessive collision force and guarantee the robot safety. Moreover, the compliant elements can be also employed as force/torque sensors in the control loops. Therefore, the research on the compliant actuators is of importance in the theory and application sides. Specifically, it is required that the robot systems should have a low stiffness when the subjected collision force is greater than the prescribed injury tolerance. But, in the normal status, the systems maintain the required capability. In this paper, the system stiffness of a compliant actuator is defined as a mechanical impedance (the ratio between output force and output shaft angle). A cascade controller is well designed by following the results on analyzing the characteristic of compliant actuator impedance stability and collision. At the end, simulation results show the effectiveness of the analytic results and designed controller.

Compliant mechanism is a kind of new type mechanism and its analysis is very complex because flexible links often under large deflections which introduce geometry nonlinearities. A new model (2R PRBM) can simulate accurately both the deflection path and angle of the flexible link. A new dynamic model of compliant mechanism is developed using the 2R PRBM. The dynamic equation of planar compliant mechanism is derived. The dynamic analysis on the natural frequency of compliant mechanism is obtained in the example of a planar compliant parallel-guiding mechanism. The numerical results show the advantage of the proposed method for the dynamic analysis of compliant mechanisms.

Compliant mechanisms gain at least some of their mobility from the deflection of flexible members rather than from movable joints only. Dynamic effects are very important to improving the design of compliant mechanisms. An investigation on the dynamics and synthesis of the compliant mechanisms is presented. The dynamic model of compliant mechanisms is developed at first. The natural frequency and sensitivity are then studied based on the dynamic model. Finally, optimal design of compliant mechanism is investigated. The experimental study of natural frequency is performed. The comparison between the experiment results and the theoretical results verifies the validity of the experiment system and theoretical model.

Anti-floating checking calculation is indispensable in the design of buried horizontal tank, in addition to the structure strength and stability to meet the requirements. A new checking calculation method propounded by synthesizing analysis and comparison drawbacks in the several existing anti-floating checking methods, and this method takes into account the effect of different environmental conditions to the anti-floating stability of buried tank. The calculation shows that the new method can effectively improve the anti-floating stability of buried tank. Anti-floating measures must be adopted to prevent tank floating if the anti-floating stability conditions are not being met.

Pyramid shaped pyrolysis flame is a new method for carbon nanotubes (CNTs) synthesis, using this method has successfully produced high properties carbon nanotubes. But, because at the first 1min of sampling time, there are not tubes produced, so catalyst particles and carbon atom clusters assemble on the sampling substrate in the first 1min. Also, lots of amorphous carbon, deformity tubes, and graphite segment were produced in the experimental. In order to eliminate these impurities, ultrasonic treatment, aether cleaning, acid pickling, and co-processing were used. Ultrasonic treatment can separate particles from tubes, aether can clear amorphous carbon and graphite segment while acid pickling can dissolve catalyst particles. Using ultrasonic oscillation separation and aether as diluent can gain pure sample. Ultrasonic oscillation and nitric acid as diluent can purify products also, but not as good as aether as diluent. Concentrated nitric acid and long time immersion will destroy the structure of carbon nanotubes.

Flame offer potential for synthesis of carbon nanotubes in large quantities at significantly lower cost than that of other methods currently available. Catalyst can decide the produces category, structure, capability, etc. This study aimed to examine catalyst for carbon nanotubes synthesis. In this experimental, oxy-acetylene flame is used as the source of heat, and CO as the source of carbon. Nebulized Fe(CO)5 as catalyst gets straight, uniform, and long tubes while coated iron-aluminum compound as catalyst gets nanoparticles coated tubes, although these tubes are thin, long, and straight. Coated Fe(CO)5 as catalyst only can gets curly and short tubes, directly introduced into synthetic chamber gets particles, and Fe2O3 powder as catalyst mainly gets curly tubes. Although the tubes which iron-aluminum compound as catalyst are high capability, they must be purified before use while Fe(CO)5 as catalyst can gets smooth tubes.

Pyramid sharp pyrolysis flame is a new method for carbon nanotubes synthesis. Oxy-acetylene flame outside the frustum of pyramid sharp reactor provides the necessary high temperature circumstance for carbon nanotubes synthesis, while inside the interior mixture of CO, H2, He, and iron pentacarbonyl (Fe(CO)5) is heated. CO is used as the source of carbon, Fe(CO)5 as the source of catalyst precursor. Special structure of the frustum of pyramid sharp reactor makes the oxy-acetylene flame folded gradually above the reactor. And it meets the condition that the interior mixture which has reacted initially under high temperature and will flow out of reactor avoids exposing to air completely and burning abundantly. Immersing a sampling substrate into the incomplete burning flame can gain carbon nanotubes. By adjusting the distance between the oxy-acetylene flame jet and the synthesis area, achieved the purpose that just changing one factor of synthesis or pyrolysis temperature while the other one constant, then respectively studied the effects of them on experimental. The perfect synthesis temperature in experimental is about 595°C, while the pyrolysis temperature is about 1000°C.

This paper presents a numerical study of the effects of surface structure geometrical parameters on the tribological performance of a laser surface textured mechanical seal. Seal performance such as seal clearance which is corresponding to hydrodynamic effect and friction torque is calculated for a range of sealed pressures, dimples area density and dimple depth over dimple diameter ratio. The results indicated that laser surface textured mechanical seals substantially improve the tribological performance in the lower sealed pressure than in high pressure. Area density of dimples has little effect on the tribological performance, however, dimple depth over dimple diameter ratio has significant effect on the tribological performance.

During the drilling of stacked materials, burrs forming on both the surface layer and the interlayer have some undesirable characters with regard to assembly quality, and deburring is a time-consuming and costly operation. This paper presented an experimental study on dry drilling of Ti-6Al-4V titanium alloy and 7075-T6 aluminium alloy stacked materials, which was performed by using uncoated cemented carbide drills. The burr size was evaluated at various spindle speeds, feed rates, stacking sequence and clamp force. Finally, the burr morphology was observed and analyzed. The best process parameters recorded in this paper were at the spindle speed of 2000r/min, the feed rate of 0.075mm/r, the pressure of 0.3MPa and the stacking sequence of the Ti-6Al-4V titanium alloy on top of the 7075-T6 aluminium alloy.