Study on Component Synthesis Active Vibration Suppression Method Using Zero-placement Technique

The component synthesis active vibration suppression method （CSVS） can be applied to suppress the vibration of flexible systems. By this method, several same or similar time-varying components are arranged according to certain rules along the time axis. The synthesized command can suppress the arbitrary unwanted vibration harmonic while achieving the desired rigid body motion. The number of the components increases rapidly when the number of harmonic vibration is growing. In this article, the CSVS based on zero-placement technique is used to construct the synthesized command to suppress the multi-harmonics simultaneously in the discrete domain. The nature of zero-placement method is to put enough zeros to cancel system poles at necessary points. The designed synthesized command has equal time intervals between each component and which is much easier to be implemented. Using this method, the number of components increases linearly with the increasing of the number of being suppressed harmonics. For the spacecraft with flexible appendages, CSVS based on zero-placement is used to design the time optimal large angle maneuver control strategy. Simulations have verified the validity and superiority of the proposed approach.

Limit analysis method for active earth pressure on laggings between stabilizing piles

Stabilizing pile is a kind of earth shoring structure frequently used in slope engineering. When the piles have cantilever segments above the ground,laggings are usually installed to avoid collapse of soil between piles. Evaluating the earth pressure acting on laggings is of great importance in design process.Since laggings are usually less stiff than piles,the lateral pressure on lagging is much closer to active earth pressure. In order to estimate the lateral earth pressure on lagging more accurately,first,a model test of cantilever stabilizing pile and lagging systems was carried out. Then,basing the experimental results a three-dimensional sliding wedge model was established. Last,the calculation process of the total active force on lagging is presented based on the kinematic approach of limit analysis. A comparison is made between the total active force on lagging calculated by the formula presented in this study and the force on a same-size rigid retaining wall obtained from Rankine's theory. It is found that the proposed method fits well with the experimental results.Parametric studies show that the total active force on lagging increases with the growth of the lagging height and the lagging clear span; while decreases asthe soil internal friction angle and soil cohesion increase.

Assessment of Patentability of Inventions Relating to "Rules and Methods for Mental Activities"

Examination of whether an invention is a patentable subject matter or not is one of the main parts of the patent examination. In the recently revised Guidelines for Examination a relatively major change has been made of the benchmark for the examination of inventions relating to "rules and methods for mental activities", for example, limiting the scope of application of Article 25.1 (2) of the Patent Law. As a result, the hitherto non-patentable subject matters are still excluded from patentability. That...

Piezoelectric Actuator/Sensor Wave Propagation Based Nondestructive Active Monitoring Method of Concrete Structures

In order to monitor the basic mechanical properties and interior damage of concrete structures,the piezoelectric actuator/sensor based wave propagation method was investigated experimentally in the laboratory using a specifically designed test setup.The energy attenuation of stress waves was measured by the relative index between the output voltage of sensors and the excitation voltage at the actuator.Based on the experimental results of concrete cube and cylinder specimens,the effect of excitation frequencies,excitation amplitude,wave propagation paths and the curing age on the output signals of sensors are evaluated.The results show that the relative voltage attenuation coefficient RVAC is an effective indicator for measuring the attenuation of stress waves through the interior of concrete.

Parametric vibration stability and active control of nonlinear beams

The vibration stability and the active control of the parametrically excited nonlinear beam structures are studied by using the piezoelectric material. The velocity feedback control algorithm is used to obtain the active damping. The cubic aonlineax equation of motion with damping is established by employing Hamilton＇s principle. The multiple-scale method is used to solve the equation of motion, and the stable region is obtained. The effects of the control gain and the amplitude of the external force on the stable region and the amplitude-frequency curve axe analyzed numerically. From the numerical results, it is seen that, with the increase in the feedback control gain, the axial force, to which the structure can be subjected, is increased, and in a certain scope, the structural active damping ratio is also increased. With the increase in the control gain, the response amplitude decreases gradually, but the required control voltage exists a peak value.

Improved Active Islanding Detection Technique for Multi-Inverter Power System

Due to the increased penetration of multi-inverter distributed generation(DG)systems,different DG technologies,inverter control methods,and other inverter functions are challenging the capabilities of islanding detection.In addition,multi-inverter networks connecting the distribution system point of common coupling(PCC)create islanding at paralleling inverters,which adds the vulnerability of islanding detection.Furthermore,available islanding detection must overcome more challenges from non-detection zones(NDZs)under reduced power mismatches.Therefore,in this study,a new method called parameter self-adapting active islanding detection was utilized to minimize the dilution effect and reduce NDZs in multi-inverter power systems.The method utilizes an active frequency drift(AFD)method and applies a positive feedback gain of adoption parameters,which significantly minimizes NDZs at parallel inverters.The simulation and experimental outcomes indicate that the proposed method can effectively weaken the dilution effect in multi-inverter networks connecting the distribution system PCC.

Technique and experiment of active direct gas pressure measurement in coal roadway

An active measurement method and its principle was introduced consideringthe low success rate,special difficulty,and long measurement time of the direct gas pressuremeasurement currently used in coal roadways.The technology of drilling,boreholesealing depth,borehole sealing length,sealing control of the measuring process,compensatorycomputation of gas loss quantity and other key techniques were discussed.Finally,based on the latest instrument the authors developed,a series of experiments of directgas pressure measurement in the coal roadways of the Jincheng and Tongchuanmine district,were carried out.The experimental results show that active gas pressuremeasurement technique has advantages as follows:(1) the application scope of direct gaspressure measurement technique is wide and it does not have the restriction of coalhardness,coal seam fissure and other conditions;(2) the measured results are credible,which can be tested by the same gas pressure value acquired from a different borehole inthe same place;(3) the measurement process is convenient and quick,it takes about 2 to3 days to acquire the gas pressure value in a coal seam.

Comparative Study of the Geomagnetic Activity Effect on foF2 Variation as Defined by the Two Classification Methods at Dakar Station over Solar Cycle Phases

This paper aims to establish a comparison between both geomagnetic activity classification methods on foF2 diurnal variation over solar cycle phases. It concerns first a comparison of geomagnetic activity occurrences according to both classification methods;and second the geomagnetic effect on foF2 diurnal variation profiles as defined for the equatorial latitudes. The occurrences of the different disturbed geomagnetic activities (recurrent activity (RA), shock activity (SA) and fluctuant activity (FA)) according to both classifications (ancient classification (AC) and new classification (NC)) have been studied at Dakar ionosonde station (Lat: 14.8°N;Long: 342.6°E). Regarding both classifications, the RA occurs more during the decreasing phase. And it’s observed that the RA occurs the most during the increasing phase for the AC and during the minimum phase for the NC. The maximum gap of occurrence () between both classifications is -11.1% (for the negative value which is observed during the increasing phase) and +16.74% (for the positive one which is observed during the decreasing phase). The occurrence of the SA in relation with both classifications is the lowest during the minimum phase and the maximum occurrence is observed during the maximum and decreasing phases, for the AC, with a value close to 37% and for the NC at the maximum phase with a percentage of 54.47%. The maximum gap of occurrence () between both classifications is -17.85% (for the negative value which is observed at maximum phase) and +13.53% (for the positive one which is observed during the decreasing phase). For both classifications, the FA occurs the least during the minimum phase and the most during the maximum phase for the AC and at maximum and decreasing phases with percentage values of occurrence of roughly 37% for the NC. The maximum gap of occurrence () between both classifications is -10% (for the negative value which is observed during the decreasing phase) and +20.11% (for the positive one which is observed during the maximum phase). foF2 diurnal profiles throughout solar cycle phases concerning the AC and the NC have been compared. The FA diurnal profiles don’t present a difference. The RA and the SA present a difference during minimum and increasing phases and the least at maximum and decreasing phases.

An experimental indoor phasing system based on active optics using dispersed Hartmann sensing technology in the visible waveband

A telescope with a larger primary mirror can collect much more light and resolve objects much better than one with a smaller mirror, and so the larger version is always pursued by astronomers and astronomical technicians. Instead of using a monolithic primary mirror, more and more large telescopes, which are currently being planned or in construction, have adopted a segmented primary mirror design. Therefore, how to sense and phase such a primary mirror is a key issue for the future of extremely large optical/infrared telescopes. The Dispersed Fringe Sensor （DFS）, or Dispersed Hartmann Sensor （DHS）, is a non-contact method using broadband point light sources and it can estimate the piston by the two-directional spectrum formed by the transmissive grating＇s dispersion and lenslet array. Thus it can implement the combination of co-focusing by Shack-Hartmann technology and phasing by dispersed fringe sensing technologies such as the template-mapping method and the Hartmann method. We introduce the successful design, construction and alignment of our dis- persed Hartmann sensor together with its design principles and simulations. We also conduct many successful real phasing tests and phasing corrections in the visible waveband using our existing indoor segmented mirror optics platform. Finally, some conclusions are reached based on the test and correction of experimental results.

Low-temperature Denitration Mechanism of NH_(3)-SCR over Fe/AC Catalyst

To study the modification mechanism of activated carbon(AC)by Fe and the low-temperature NH_(3)-selective catalytic reduction(SCR)denitration mechanism of Fe/AC catalysts,Fe/AC catalysts were prepared using coconut shell AC activated by nitric acid as the support and iron oxide as the active component.The crystal structure,surface morphology,pore structure,functional groups and valence states of the active components of Fe/AC catalysts were characterised by X-ray diffraction,scanning electron microscopy,nitrogen adsorption and desorption,Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy,respectively.The effect of Fe loading and calcination temperature on the low-temperature denitration of NH_(3)-SCR over Fe/AC catalysts was studied using NH_(3)as the reducing gas at low temperature(150℃).The results show that the iron oxide on the Fe/AC catalyst is spherical and uniformly dispersed on the surface of AC,thereby improving the crystallisation performance and increasing the number of active sites and specific surface area on AC in contact with the reaction gas.Hence,a rapid NH_(3)-SCR reaction was realised.When the roasting temperature remains constant,the iron oxide crystals formed by increasing the amount of loading can enter the AC pore structure and accumulate to form more micropores.When the roasting temperature is raised from 400 to 500℃,the iron oxide is mainly transformed fromα-Fe_(2)O_(3)toγ-Fe_(2)O_(3),which improves the iron oxide dispersion and increases its denitration active site,allowing gas adsorption.When the Fe loading amount is 10%,and the roasting temperature is 500℃,the NO removal rate of the Fe/AC catalyst can reach 95%.According to the study,the low-temperature NH_(3)-SCR mechanism of Fe/AC catalyst is proposed,in which the redox reaction between Fe~(2+)and Fe~(3+)will facilitate the formation of reactive oxygen vacancies,which increases the amount of oxygen adsorption on the surface,especially the increase in surface acid sites,and promotes and adsorbs more reaction gases(NH_(3),O_(2),NO).The transformation from the standard SCR reaction to the fast SCR reaction is accelerated.

Preparation, Characterization and Photocatalytic Activity of Fe, La Co-doped Nanometer Titanium Dioxide Photocatalysts

A series of photocatalysts of un-doped, single-doped and co-doped nanometer titanium diox- ide （TiO2） have been successfully prepared by template method using Fe（NO3）3.9H2O, La（NO3）3.6H2O, and tetrabutyl titanate as precursors and glucan as template. Scanning electron microscopy, X-ray diffraction, and N2 adsorption-desorption measurement were employed to characterize the morphology, crystal structure and surface structure of the samples. The photo-absorbance of the obtained catalysts was measured by UV-Vis absorption spectroscopy, and the photocatalytic activities of the prepared samples under UV and visible light were estimated by measuring the degradation rate of methyl orange in an aqueous solution. The characterizations indicated that the prepared photocatalysts consisted of anatase phase and possessed high surface area of ca. 163-176 m2/g. It was shown that the Fe and La co-doped nano-TiO2 could be activated by visible light and could thus be used as an effective catalyst in photo-oxidation reactions. The synergistic effect of Fe and La co-doping played an important role in improving the photocatalytic activity. In addition, the possibility of cyclic usage of co-doped nano-TiO2 was also confirmed, the photocatalytic activity of codoped nano-TiO2 remained above 89.6% of the fresh sample after being used four times.

Extraction of Pumpkin Polysaccharide by Complex Enzyme Method and Its Antioxidant Research

[Objective] This paper aims to study a new method of extracting pumpkin polysaccharide from pumpkin. Single factor experiments were conducted to examine the effects of extracting time,temperature,the solid-liquid ratio and pH value on the extraction yield of polysaccharide from pumpkin. [Method] The best enzyme ratio and extraction conditions for complex enzymes extraction were determined through orthogonal tests. Scavenging ·OH and O-2 activities of pumpkin polysaccharides were also investigated by salicylic acid and improved self-oxidation of o-pheno methods respectively. [Results] The results showed that the biggest extraction yield of polysaccharide from pumpkin can be got when adding 1% cellulose enzyme,1.5% pectinase,1.0% papain and Na2HPO4-citric acid buffer solution (pH was 4.6),and oscillating for 30 min under water at 40 ℃ with the solid-liquid ratio of 1:30. In addition,pumpkin polysaccharides had a strong activity of eliminating ·OH,but very weak activity to scavenge O-2. [Conclusion] This study provided basic data for research and application of Pumpkin polysaccharide.

Development in vitro in Reconstitution of Embryo from Porcine Somatic Cell Nuclear Transfer

In present paper,a study on reconstitution of porcine oocytes by using nuclear transfer with cumulus cells(CC) and fibroblast cells(FC) was carried out.Reconstituted oocytes which were the fusion with CC and showed a cleavage rate of 56.7%,developed into morula (11.7%) and blastocysts (6.7%) phases which were higher than those derived from the fusion with FC( P <0.05).The results of this study also involved the effects of oocyte collection method,activation protocol and maturational age of recipient oocytes during the in vitro develpoment of nuclear transfer embryos which were reconstituted with cultured cumulus cells.The cumulus cells synchronized in G 0/G 1 phases through serum starvation culture,were transferred into enuclated oocytes which were collected by aspiration or dissection method and cultured for 33 or 44 h.Reconstituted embryos were activated with a combination of calcium ionophore A23187 or electric pulsation and 6 DMAP,and cultured for 6 days.As for the oocyte collection methods,activation treatment in the presence of cytochalasin B and activation protocols did not affect the developmental rate of embryos reconstituted with 44 h mature recipients.However,the development rate of reconstituted embryos with 33 h mature recipients were significantly higher( P <0.05) by activation with the combination of electric pulsation and 6 DMAP.These results suggest that the reconstituted porcine embryos derived from cultured cumulus cells can develop into the blastocyst stage and that the development of the former could be improved for the reconstitution with young oocyte cytoplast after the activation with the combination of electric pulsation and 6 DMAP.

Function Projective Synchronization of Two Identical New Hyperchaotic Systems

A function projective synchronization of two identical hyperchaotic systems is defined and the theorem of sufficient condition is given. Based on the active control method and symbolic computation Maple, the scheme of function projective synchronization is developed to synchronize the two identical new hyperchaotic systems constructed by Yan up to a scaling function matrix with different initial values. Numerical simulations are used to verify the effectiveness of the scheme.

Optical quasi-periodic oscillation and color behavior of blazar PKS 2155–304

PKS 2155-304 is a well studied BL Lac object in the southern sky. The historical optical data during different periods have been collected and compiled. Light curves spanning 35 yr have been constructed. The R-band light curve has been ana- lyzed by means of three methods： the epoch folding method, the Jurkevich method and the discrete correlation function method. It is derived that there is an evident periodic component of 317 d （i.e. 0.87 yr） superposed on a long-term trend with large- amplitude variation in the light curve. The variability of this source is accompanied by a slight color variation, and the brightness and color index are correlated with each other. On a long-term time scale, PKS 2155-304 exhibits a tendency of bluer-when- brighter, which means the spectrum becomes flatter when the source brightens.

Preparation and Photocatalytic Activity of Ce, H3PW12O40 co-doped TiO2 Hollow Fibers

A series of Ce, H3PW12O40 co-doped TiO2 hollow fibers photocatalysts have been prepared by sol-gel method using ammonium ceric nitrate, H3PW12O40 and tetrabutyltitanate as precursors and cotton fibers as template, followed by calcination at 500 ℃ in N2 atmosphere for 2 h. Scanning electron microscopy, X-ray diffraction, nitrogen adsorption-desorption mea- surements, and UV-Vis spectroscopy are employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The photo- catalytic performance of the samples has been studied by photodegradation phenol in water under UV and visible light irradiation. The results show that the TiO2 fiber materials have hollow structures, and the co-doped TiO2 hollow fibers exhibit higher photocatalytic activities for the degradation of phenol than un-doped, single-doped TiO2 hollow fibers under UV and visible light. In addition, the recyclability of co-doped TiO2 fibers is also confirmed that the TiO2 fiber retains ca. 90% of its activity after being used four times. It is shown that the co-doped TiO2 fibers can be activated by visible light and may be potentially applied to the treatment of water contaminated by organic pollutants. The synergistic effect of Ce and H3PW12O40 co-doping plays an important role in improving the photocatalytic activity.

Wavelet Analysis of Several Important Periodic Properties in the Relative Sunspot Numbers

We investigate the wavelet transform of yearly mean relative sunspot number series from 1700 to 2002. The curve of the global wavelet power spectrum peaks at 11-yr, 53-yr and 101-yr periods. The evolution of the amplitudes of the three periods is studied. The results show that around 1750 and 1800, the amplitude of the 53-yr period was much higher than that of the the 11-yr period, that the ca. 53-yr period was apparent only for the interval from 1725 to 1850, and was very low after 1850, that around 1750, 1800 and 1900, the amplitude of the 101-yr period was higher than that of the 11-yr period and that, from 1940 to 2000, the 11-yr period greatly dominates over the other two periods.

Why are halo coronal mass ejections faster?

Halo coronal mass ejections （CMEs） have been to be significantly faster than normal CMEs, which is a long-standing puzzle. In order to solve the puzzle, we first investigate the observed properties of 31 limb CMEs that clearly display loopshaped frontal loops. The observational results show a strong tendency that slower CMEs are weaker in white-light intensity. Then, we perform a Monte Carlo simulation of 20000 artificial limb CMEs that have an average velocity of ～523km s -1. The Thomson scattering of these events is calculated when they are assumed to be observed as limb and halo events, respectively. It is found that the white-light inten-sity of many slow CMEs becomes remarkably reduced when they turn from being viewed as a limb event to being viewed as a halo event. When the intensity is below the background solar wind fluctuation, it is assumed that they would be missed by coronagraphs. The average velocity of ＂detectable＂ halo CMEs is ～922km s -1, very close to the observed value. This also indicates that wider events are more likely to be recorded. The results soundly suggest that the higher average velocity of halo CMEs is due to that a majority of slow events and some of narrow fast events carrying less material are so faint that they are blended with the solar wind fluctuations, and therefore are not observed.

Long-term variation time scales in OJ 287

The light curve data from 1894 to 2008 are compiled for the BL Lacertae object OJ 287 from the available literature. Periodicity analysis methods （the Discrete Correlation Function-DCF, the Jurkevich method, the power spectral （Fourier） analysis, and the CLEANest method） are performed to search for possible periodicites in the light curve of OJ 287. Significance levels are given for the possible periods. The analysis results confirm the existence of the 12.2 ± 0.6 yr time scale and show a hint of a -53 yr time scale. The 12.2 ± 0.6 yr period is used as the orbital period to investigate the supermassive binary black hole system parameters.

Phase analysis of sunspot group numbers on both solar hemispheres

Cross-correlation analysis and wavelet transform methods are proposed to investigate the phase relationship between the monthly sunspot group numbers in the solar northern and southern hemispheres. It is found that （1） the monthly sunspot group numbers in the northern hemisphere begin two months earlier than those in the southern one, which should lead to phase asynchrony between them but with a slight effect; （2） the Schwabe cycle length for the monthly sunspot group numbers in the two hemispheres obviously differs from each other, and the mean Schwabe cycle length of the monthly sunspot group numbers in the northern hemisphere is slightly larger than that in the southern one; （3） the monthly sunspot group numbers in the northern hemisphere precede those in the southern hemisphere during the years of about 1874- 1927, after which, the southern hemisphere leads the northern hemisphere in the years 1928-1964, and then the northern hemisphere leads in time till the present.