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This paper presents an antenna of loaded with metamaterial to enhance the gain and directivity of antenna to improve the performance of the ground-penetrating radar system (GPR). By adjusting the parameters of the antenna to change the antenna equivalent capacitance, inductance, and designed the operating frequency of 0.5GHz-1.2GHz ultra-wideband antenna. On the basis of this operating frequency, we also designed the corresponding negative permittivity and permeability materials, and realized the design and simulation of patch antenna and material working in the 1GHz frequency band. The high gain and directivity of the antenna loaded with single negative material are verified by simulation. Compared to the original antenna increased the maximum gain of 7dB, the direction has also been greatly improved.

By filling high refractive thermal liquid (toluene) into the total internal reflection dual-core photonic crystal fiber (DC-PCF), the coupling behaviors of the DC-PCF for different temperature is analyzed by using finite element method, and then a tunable wavelength division multiplexer realized for 980/1550 nm and 1310/1550 nm is obtained at a fixed DC-PCF length of 2475 μm.

To solve the problem of poor fracture identifying effect on electrical logging in oil-based mud, the application of acoustic logging to the quantitative characterisation of fractures is expanded from three aspects, namely, Stoneley waves, longitudinal and transverse waves and cross dipole acoustic waves, and a fracture logging evaluation model closely related to production capacity is established considering the radial extension characteristics of fractures. The Stoneley reflection coefficient is used to determine fractures locations to help detect fractures during normal micro-resistivity imaging logging. Based on the experiment on the relationship between fracture width and acoustic attenuation coefficient, empirical formulae for calculating fracture width have been established by primary wave and shear wave energy information considering the effect of porosity. The new parameters, including spectrum correlation coefficient and energy difference from cross dipole array acoustic logging data, can be used for fractures evaluation. The more developed the fractures are, the greater the energy difference becomes, and the smaller the spectrum correlation coefficient is, the higher the production is. The fracture effective evaluation parameters can be separated into two components, specified as the degree of fracture vertical opening and radial extension. Combining the conventional logging and array acoustic logging (including cross dipole array acoustic logging), a fracture radial extension evaluation model is presented closely related to productivity. Key words: tight sandstone reservoir, fracture evaluation, acoustic logging, oil-based mud, radial extension, Kuqa, Tarim Basin

Longan (Dimocarpus longan Lour.), an important subtropical fruit in the family Sapindaceae, is grown in more than 10 countries. Longan is an edible drupe fruit and a source of traditional medicine with polyphenol-rich traits. Tree size, alternate bearing, and witches' broom disease still pose serious problems. To gain insights into the genomic basis of longan traits, a draft genome sequence was assembled. The draft genome (about 471.88 Mb) of a Chinese longan cultivar, “Honghezi,” was estimated to contain 31 007 genes and 261.88 Mb of repetitive sequences. No recent whole-genome-wide duplication event was detected in the genome. Whole-genome resequencing and analysis of 13 cultivated D. longan accessions revealed the extent of genetic diversity. Comparative transcriptome studies combined with genome-wide analysis revealed polyphenol-rich and pathogen resistance characteristics. Genes involved in secondary metabolism, especially those from significantly expanded (DHS, SDH, F3΄H, ANR, and UFGT) and contracted (PAL, CHS, and F3΄5΄H) gene families with tissue-specific expression, may be important contributors to the high accumulation levels of polyphenolic compounds observed in longan fruit. The high number of genes encoding nucleotide-binding site leucine-rich repeat (NBS-LRR) and leucine-rich repeat receptor-like kinase proteins, as well as the recent expansion and contraction of the NBS-LRR family, suggested a genomic basis for resistance to insects, fungus, and bacteria in this fruit tree. These data provide insights into the evolution and diversity of the longan genome. The comparative genomic and transcriptome analyses provided information about longan-specific traits, particularly genes involved in its polyphenol-rich and pathogen resistance characteristics.

During laser manufacturing, the inevitably generated thermal stress may lead to cracks and defects, thus resulting in work-piece damages. In order to optimize laser manufacturing to inhibit the stress, detailed analysis on the time-varying stress field is necessary. Compared to experimental stress measurement requiring expensive setups and complicated procedures, numerical stress calculation techniques attract much attentions because of their simple and cost-effective requirements as well as multi-parameter analysis capability. However, most of them can only numerically calculate the residual strain in steady state, ignoring the time-varying stress analysis during the laser fabrication. Besides, they did not consider the thermal softening effect with stress release, thus decreasing the accuracy in laser fabrication analysis. In order to realize real time stress analysis inside the work-piece with high accuracy, in this paper, we designed an online monitoring method composing of level set method for free surface monitoring, thermal transfer theory for temperature field calculating and thermo-elasticity theory for stress field retrieving. Proved by the comparisons between the numerical simulations and practical measurements, it is believed that the proposed model can provide quantitative stress with high precision for future stress analyze and laser manufacturing optimization.

Understanding spatter and melt pool dynamics during laser drilling remains a topic of considerable importance to determine the quality of processed materials. Due to metallic materials’ opacity to visible radiation, we studied the spatter dynamics outside of holes during laser drilling using shadow mapping. A 2D transient model for simulating laser material processing was implemented using COMSOL commercial Multiphysics software and the spatter phenomena and melt pool dynamics were assessed. The results can be used as a basis to explain the different processes involved in the material properties during laser processing, which is a powerful tool to understand spatter’ formation mechanism and provide theoretical references for optimizing processing parameters.

A new method of cement bond quality evaluation was proposed by combining numerical simulation and calibrated cased hole acoustic logging data. The effects of the cement channel angle and the quality of the second bond interface (the interface of cement with formation) on acoustic variable density logging data were analyzed. Based on the analysis result, a new cement bond evaluation standard was presented after revising the traditional CBL/VDL method. The axisymmetric acoustic field was simulated by real axis integral method, while the non-axisymmetric acoustic field was simulated by 2.5-D finite differential method. After comparing with the calibrated cased hole acoustic logging data, the research has the below results: the numerical simulation result matches with the calibrated well logging data very well and the new method is reliable; the amplitude of the first acoustic arrival in the case hole decreases as the angle of cement channel decreases, and the denser the cement is, the faster the amplitude of cased hole acoustic waveform decays; the lower limit of cement channel angle is around 45 degrees which can be detected by acoustic logging; the formation acoustic waveform is not easy to be detected in time domain, however it is easy to be detected in frequency domain, especially in limestone formation, the first arrival only can be detected when the annulus width of the second bond interface is small. According to the research result of the numerical simulation of cased hole acoustic field and acoustic variable density logging data, new evaluation criteria of cement bound quality were presented. Key words: cement bond quality, acoustic variable density logging, acoustic field in cased well, cement channel angel, interface bond index