Search

The practical application of 3D inversion of gravity data requires a lot of computation time and storage space. To solve this problem, we present an integrated optimization algorithm with the following components: (1) targeting high accuracy in the space domain and fast computation in the wavenumber domain, we design a fast 3D forward algorithm with high precision; and (2) taking advantage of the symmetry of the inversion matrix, the main calculation in gravity conjugate gradient inversion is decomposed into two forward calculations, thus optimizing the computational efficiency of 3D gravity inversion. We verify the calculation accuracy and efficiency of the optimization algorithm by testing various grid-number models through numerical simulation experiments.

Energy shortage, energy safety, environment pollution and global warming commonly promote the development of biofuels in China. Maize, wheat and rapeseed should be banned gradually as feedstocks. Cassava and sweet sorghum have better environmental benefits for ethanol production and so do jatropha curcas and pistacia chinensis for biodiesel. Evaluation of potential land for the four feedstocks has already been done and they are prior to other sources. Macro polices promote development of fuel ethanol and biodiesel industries. Economic measures including tax cuts, subsidies and compensation mechanisms and sale channels are given to ethanol companies. Rapid development of fuel methanol industry and limited source of feedstocks become the resistance of ethanol industry. Biodiesel can hardly achieve economic supports due to complex sources of feedstocks, variable compositions and different properties. China treats cellulose biomass and microalgae as the best choice for ethanol and biodiesel productions and they are in the research stage.

To study the influence of fuel temperature on performances of biodiesel engine, combustion and emission performances of biodiesel engine at different fuel temperatures are tested and studied. It is found with the increase of fuel temperature, combustion pressure and instantaneous heat release rate curves leave far away from the top dead center and at high loads the combustion delays obviously; peak combustion pressure and peak instantaneous heat release rate decrease and at high loads the reduction increases; the backward combustion increases; at 1500 r/min, compared with 25 °C, NO X emissions of biodiesel at 40 °C and 55 °C averagely decrease by 7.6% and 9.1%, but smoke emissions averagely increase by 29.1% and 54.1%. Results indicate that fuel temperature has important influence on performances of biodiesel and it can be selected as a basic parameter to control the combustion and emission of biodiesel.

In this research, 97 pieces of rock in Xingcheng, Liaoning Province, China were collected to measure the spectral reflectance in 350~2 500 nm, chemical content, and complex dielectric constant of some samples. The absorption depths were calculated by using continuum- removal method. With correlation analysis method, two kinds of correlation curves were obtained based on the theory of spectral characteristics of chemical contents and the principle of dielectric constant. One described the relationship between chemical content and spectral absorption depth, and the other one represented the correlation of complex dielectric constant and reflectance. By summarizing curves morphological characteristics, several conclusions were drawn as follows: (1)There was a strong correlation between the chemical content (SiO2, Al2O3, CaO, K2O, MgO, burnt-loss) and spectral absorption depth in 1 900~2 500 nm, furthermore, at around 1 900, 2 200, 2 300 nm and other identifying characteristic bands, local extreme maximum / minimum values appeared. At Fe3+ characteristic band (400~550 nm), correlation coefficient reached -0.406 between Fe2O3 content and absorption in igneous rock samples collection. Exploring the relationship between rock spectral absorption features and its chemical contents had a positive effect on metallogenic prediction and lithology identification with remote sensing image. (2) Reflectance and complex dielectric constant were negatively correlated totally, compared with the imaginary part; the real part had a better relation reached -0.753 at around 1 900 nm. Curves showed that there were great correlations around 1 900 and 2 200 nm, so, our study adopted different models to simulate response relationships. Dielectric constant of media is one of the basic physical properties, and now most analyses of existing research between electromagnetic characteristics and dielectric constant are studied in microwave band, however, our research is conducted in visible and near infrared range. The conclusions will be useful for further exploration on dielectric characteristics and spectral features of rocks.

Most edge-detection methods rely on calculating gradient derivatives of the potential field, a process that is easily affected by noise and is therefore of low stability. We propose a new edge-detection method named correlation coefficient of multidirectional standard deviations (CCMS) that is solely based on statistics. First, we prove the reliability of the proposed method using a single model and then a combination of models. The proposed method is evaluated by comparing the results with those obtained by other edge-detection methods. The CCMS method offers outstanding recognition, retains the sharpness of details, and has low sensitivity to noise. We also applied the CCMS method to Bouguer anomaly data of a potash deposit in Laos. The applicability of the CCMS method is shown by comparing the inferred tectonic framework to that inferred from remote sensing (RS) data.

By analyzing metallogenic regulation of the deep skarn ore bodies in Laochang ore field,3D metallogenic features model was established with 3D visualization technology. With “the cubic predicting model” method, the major ore-controlling factors in deep include granites, strata, faults and chemical elements abnormal. We delineated prospect area and outlined ten targets through evidence weight method. Calculating the ore-containing probabilities and the quantities of mineral resources ,it realized prediction of mineral resources on quantity, position and probability. It is important for deep mineral exploration of Laochang ore field in Ge jiu.

It chooses 15 kinds of rock from the three major rock categories as the rock samples (the number of rock samples is 208) and obtains the density, susceptibility and reflection spectrum at the wave band of 350~2500 nm. It calculates the correlative coefficients with the aim of studying the characteristic relationship between the property (including the density and the susceptibility) of the rock and the reflectivity. It concludes the wave band of the reflection spectrum which owes the prospect to discuss the density and susceptibility of the rock qualitatively or quantitatively, meanwhile, it sums up the characteristic of the curves of the correlative coefficients. In this paper, the discussion and analysis based on the results show that the study on the character relationship between the property of rock (density and susceptibility) and the reflection spectrum is meaningful and workable.