Analysis of Second-Harmonic Generation of Low-Frequency Dilatational Lamb Waves in a Two-Layered Composite Plate

We analyze the effect of second-harmonic generation（SHG） of primary Lamb wave propagation in a two-layered composite plate, and then investigate the influence of interfacial properties on the said effect at low frequency. It is found that changes in the interfacial properties essentially affect the dispersion relation and then the maximum cumulative distance of the double-frequency Lamb wave generated. This will remarkably influence the efficiency of SHG. To overcome the complications arising from the inherent dispersion and multimode natures in analyzing the SHG effect of Lamb waves, the present work focuses on the analysis of the SHG effect of low-frequency dilatational Lamb wave propagation. Both the numerical analysis and finite element simulation indicate that the SHG effect of low-frequency dilatational Lamb wave propagation is found to be much more sensitive to changes in the interfacial properties than primary Lamb waves. The potential of using the SHG effect of low-frequency dilatational Lamb waves to characterize a minor change in the interfacial properties is analyzed.

Effect of graph generation on slope stability analysis based on graph theory

Limit equilibrium method （LEM） and strength reduction method （SRM） are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of benchmark examples and a rock slope show good accuracy and efficiency of the presented method.

Forecasting promising technology using analysis of patent information:Focused on next generation mobile communications

In order to forecast promising technologies in the field of next generation mobile communication, various patent indicators were analyzed such as citation per patent, patent family information, patent share, increase rate, and patent activity. These indicators were quantified into several indexes and then integrated into an evaluation score to provide promising technologies. As a result of the suggested patent analysis, four technologies out of twenty two in details classification were selected, which showed outstanding technology competitiveness, high patent share and increasing rates as well as high recent-patent-ratios and triad-patent-family-ratios. Each of the selected technologies scored more than 10 points in total, and the following four technologies were suggested as promising ones in the field of next generation mobile communication: 1) 3GPP based mobile communication, 2) beyond 4G mobile communication, 3) IEEE 802.16 based mobile communication, which are in medium classification of broadband mobile communication system, and 4) testing/certification system of mobile communication, which is in medium classification of mobile communication testing/certification system.

Genetics of biochemical attributes regulating morpho-physiology of upland cotton under high temperature conditions

Background Cotton is a strategically important fibre crop for global textile industry.It profoundly impacts several countries’industrial and agricultural sectors.Sustainable cotton production is continuously threatened by the unpre-dictable changes in climate,specifically high temperatures.Breeding heat-tolerant,high-yielding cotton cultivars with wide adaptability to be grown in the regions with rising temperatures is one of the primary objectives of modern cotton breeding programmes.Therefore,the main objective of the current study is to figure out the effective breed-ing approach to imparting heat tolerance as well as the judicious utilization of commercially significant and stress-tolerant attributes in cotton breeding.Initially,the two most notable heat-susceptible(FH-115 and NIAB Kiran)and tolerant(IUB-13 and GH-Mubarak)cotton cultivars were spotted to develop filial and backcross populations to accom-plish the preceding study objectives.The heat tolerant cultivars were screened on the basis of various morphological(seed cotton yield per plant,ginning turnout percentage),physiological(pollen viability,cell membrane thermostabil-ity)and biochemical(peroxidase activity,proline content,hydrogen peroxide content)parameters.Results The results clearly exhibited that heat stress consequently had a detrimental impact on every studied plant trait,as revealed by the ability of crossing and their backcross populations to tolerate high temperatures.However,when considering overall yield,biochemical,and physiological traits,the IUB-13×FH-115 cross went over particularly well at both normal and high temperature conditions.Moreover,overall seed cotton yield per plant exhibited a posi-tive correlation with both pollen viability and antioxidant levels(POD activity and proline content).Conclusions Selection from segregation population and criteria involving pollen viability and antioxidant levels concluded to be an effective strategy for the screening of heat-tolerant cotton germplasms.Therefore,understanding acquired from this study can assist breeders identifying traits that should be prioritized in order to develop climate resilient cotton cultivars.

Heat transfer study on solid and porous convective fins with temperature-dependent heat generation using efficient analytical method

A simple and highly accurate semi-analytical method, called the differential transformation method(DTM), was used for solving the nonlinear temperature distribution equation in solid and porous longitudinal fin with temperature dependent internal heat generation. The problem was solved for two main cases. In the first case, heat generation was assumed variable by fin temperature for a solid fin and in second heat generation varied with temperature for a porous fin. Results are presented for the temperature distribution for a range of values of parameters appearing in the mathematical formulation(e.g. N, εG, and G). Results reveal that DTM is very effective and convenient. Also, it is found that this method can achieve more suitable results in comparison to numerical methods.

A DFB Fiber Laser Sensor System with Ultra-High Resolution and Its Noise Analysis

A distributed feedback fiber laser （DFB FL） sensor system with ultra-high resolution is described. The sensor is made by writing distributed feedback structures into a high gain active fiber, and the system employs an unbalanced Michelson interferometer to translate laser wavelength shifts induced by weak measurands into phase shifts. A digital phase generated carrier demodulation scheme is introduced to achieve ultra-high resolution interrogation. A detailed noise analysis of the system is presented, and it is shown that the system resolution is limited by the frequency noise of the DFB FL.

Studies on the Heredity of the Traits Related to the Photoperiod-Sensitive Phenomenon Among the Temperate ×Tropical Crosses in Maize

The genetic study of characters concerning photoperiod sensitivity of the growth and development stages, plant and ear height was carried out from 5 temperate tropical combinations by using P1 , P2, F1, F2, BC1, BC2 generations mean analysis. The results showed that the square sums of additive, of dominance and of epistatic gene effects contributed to total genetic variance were 11. 3 -53. 6%, 36.0 -78. 6% and 5.5 -27.0% respectively for five traits of the insensitive×insensitive combination to photoperiod, which suggested dominance gene effect was the most important among various gene effects. In insensitive X sensitive combination to photoperiod, the square sums of additive gene effect with 66. 9 - 84. 5 %, of dominance gene effect with 11. 6 30. 7% and of epistatic gene effect with 1.4-5. 2% were found for five tested traits, which showed additive gene effect held a dominant position, and dominance and epistatic gene effects were reduced compared with insensitive×insensitive combination. The differences existed among different insensitive×sensitive combinations. The proportion of the genetic component among the insensitive×sensitive crossbreed offspring in the temperate zone had a certain dosage effect on fading photoperiod sensitivity reaction. The sensitivity of BC1 , with 25 % of the tropical genetic component, is extremely weak, but with high application value.

Effect of Heat Flux Distribution on Entropy Generation and Irreversibility of Lead-Bismuth Eutectic(LBE)Forced Convective Heat Transfer

Investigations on entropy generation and thermal irreversibility analysis are conducted for liquid lead-bismuth eutectic(LBE)in an annular pipe.To find better performance in convective heat transfer,the computational fluid dynamics(CFD)code based on the finite volume method(FVM)is adopted to solve this problem.The elevated temperature LBE flows in the annular pipe,and four types of heat flux,including constant,linear increase and decrease,and parabolic distributions are imposed at the inside wall of the annular pipe.The investigations are conducted for the specific average heat input of 200 kW/m^(2),and the different Peclet number Pe is set from 1200 to 3200.The SST k-ωturbulent model and Cheng-Tak Prt model are adopted.The mesh independence validation and models verification are also conducted and the maximum Nu error is 5.43%compared with previous experimental correlations.The results from the local and system scales,respectively,including volumetric dimensionless entropy generation,Ns,Be,and Ep,are discussed.The results indicate that the viscous friction and heat transfer caused by entropy generation can be found in the viscous sub-layer and buffer layer respectively.Heat transfer is the primary factor that leads to irreversible losses.Besides,the results show that the best thermodynamic performance occurs under parabolic distributed heat flux in the research scope.

Pico–nano bubble column flotation using static mixer-venturi tube for Pittsburgh No.8 coal seam

The flotation process is a particle-hydrophobic surface-based separation technique. To improve the essential flotation steps of collision and attachment probabilities, and reduce the step of detachment probabilities between air bubbles and hydrophobic particles, a selectively designed cavitation venturi tube combined with a static mixer can be used to generate very high numbers of pico and nano bubbles in a flotation column. Fully embraced by those high numbers of tiny bubbles, hydrophobic particles readily attract the tiny bubbles to their surfaces. The results of column flotation of Pittsburgh No. 8 seam coal are obtained in a 5.08 cm ID and 162 cm height flotation column equipped with a static mixer and cavitation venturi tube, using kerosene as collector and MIBC as frother. Design of the experimental procedure is combined with a statistical two-stepwise analysis to determine the optimal operating conditions for maximum recovery at a specified grade. The effect of independent variables on the responses has been explained. Combustible material recovery of 85–90% at clean coal product of 10–11% ash is obtained from feed of 29.6% ash, with a much-reduced amount of frother and collector than that used in conventional column flotation. The column flotation process utilizing pico and nano bubbles can also be extended to the lower limit and upper limit of particle size ranges, minus 75 lm and 300–600 lm, respectively, for better recovery.

Analysis of generation of cumulative second harmonics of Lamb modes in a layered planar structure

A technique for analyzing the nonlinear generation of the cumulative second har-monics of generalized Lamb modes in a layered planar structure is developed. A theoretical model for nonlinear generalized Lamb mode propagation in a layered planar structure has been established, based on a partial plane wave approach. The nonlinearity is treated as a second-order perturbation of the linear elastic response. This model reveals some interesting features of the physics of the cumulative second harmonic generation. Although Lamb mode propagation is dispersive in a layered structure, the results of this analysis show that the amplitudes of the second harmonics do accumulate with propagation distance under certain special conditions. On the basis of the boundary and initial conditions of excitation, the formal solution of the cumulative second harmonic has been derived. Using the formal solution, we have performed some numerical simulations and obtained the cumulative second harmonic field patterns, illus-trating the distortion effect along the propagation distance, as well as the dependence of the field patterns on the position of the excitation source.

Breeding Enrichment of Genetic Variation of Grain Yield and Its Attributes in Bread Wheat under Drought Stress and Well Irrigation

Drought stress(DS)is one of the most critical environmental abiotic stresses for wheat production in the arid environments.Selection of high-yielding genotypes tolerant to DS can play a significant role in mitigation the negative impacts associated with DS.In the present study,generation means analysis(GMA)was used to study the performance of two crosses under well irrigation(WI)and deficit irrigation[cross I(Line 44×Shandweel-1)and cross II(Line 20×Sakha 93)].Significant differences were observed for days to heading(DH),days to maturity(DM),plant height(PH),spike length(SL),number of spikes per plant(NS/P),number of grains per spike(NG/S),thousand-grain weight(TGW),grain yield per plant(GY/P),and proline content(PC)in the six populations of the two crosses within each irrigation level.Cross II had early maturity and the highest PC,NS/P,TGW,and GY/P regardless of the irrigation level.Cross I showed positive significant relative heterosis and heterobeltiosis for GY/P under the two irrigation levels.The inheritance of characters of cross I revealed additive,dominant,and epistatic effects,which varied with trait and stress.Additive genetic effects predominated in DH,SL,and PC,while non-additive were found in DM,NS/P,NG/S,and GY/P.Narrow-sense heritability estimates(h^(2) n)were high for DH and PC,moderate to high for PH and SL,moderate for DM,NG/S,NS/P,and TGW,and low for GY/P.Based on different drought indices the populations BC_(1),BC_(2),F_(1),and P1 of cross II and BC1 of cross I were more tolerant to drought stress.Therefore,PC,TGW and DH can be used as selection indicators to improve wheat for drought tolerance in early generations and other yield components traits in late generations.The second cross(Line 20×Sakha 93)shows promise and is of interest to a drought tolerance breeding program,where wheat breeders can use recombinant breeding strategies to construct desirable drought stress genes.Correlation and path coefficient revealed that TGW and PC were the main contributor in grain yield in both environments.

A theoretical analysis on second harmonic generation for transverse and longitudinal slice collagen fiber

Microscopic imaging based on second-harmonic generation has been proving to be a powerful tool for biomedical studies, especially in that tissues with

A sensitive and compact mercury analyzer by integrating dielectric barrier discharge induced cold vapor generation and optical emission spectrometry

An environmentally friendly,low power consuming,sensitive and compact mercury analyzer was developed for the determination of mercury in water samples by integrating a thin film dielectric barrier discharge induced cold vapor reactor and a dielectric barrier discharge optical emission spectrometer into a small polymethyl methacrylate plate（10.5 cm length×8.0 cm width×1.2 cm height）.Mercury cold vapor was generated when standard or sample solutions with or without formic acid were introduced to the reactor to form thin film liquid and exposed to microplasma irradiation and subsequently separated from the liquid phase for transport to the microplasma and detection of its atomic emission.Limits of detection of 0.20 μg L^-1 and 2.6 μg L^-1 were obtained for the proposed system using or not using formic acid,respectively.Compared to the conventional microplasma optical emission spectrometry used for mercury analysis,this system not only retains the good limit of detection amenable to the determination of mercury in real samples,but also reduces power consumption,eliminates the generation of hydrogen and avoids the use of toxic or unstable reductant.Method validation was demonstrated by analysis of a certified reference material of water sample and three real water samples with good spike recoveries（88-102%）.

Theoretical analysis of a collimated hollow-laser-beam generated by a single axicon using diffraction integral

A novel method to generate a collimated hollow-laser-beam (HLB) by only a single axicon is proposed. With some reasonable assumptions, the radial light intensity distribution is calculated in detail by diffraction integral theory.The result of numerical simulation shows that this method is valid.Compared with other methods of generating HLB,this scheme is extraordinarily simple in principle and can be utilized experimentally to construct a light trap in atomic fountain for convenience.