Construction and modification of chloroplast ultrastructure of a special albino rice mutant W25 during the seedling greenish process

W25 was a gamma-irradiation induced albinorice mutant line, which only expressed in thespecial temperatures (see figure). At 30 Cand 35 C, the seedling leaves of W25 showedgreenish or normal green, but they exhibitedalbino at 25℃, which could be greenish afterthe fourth leaf extension and recovered to be

Applications of seismic techniques to gas hydrates prediction

Based on the sensitivity of geophysical response to gas hydrates contained in sediments, we studied the prediction of gas hydrates with seismic techniques, including seismic attributes analysis, AVO, inverted velocity field construction for dipping formations, and pseudo-well constrained impedance inversion. We used an optimal integration of geophysical techniques results in a set of reliable and effective workflows to predict gas hydrates. The results show that the integrated analysis of the combination of reflectivity amplitude, instantaneous phase, interval velocity, relative impedance, absolute impedance, and AVO intercept is a valid combination of techniques for identifying the BSR （Bottom Simulated Reflector） from the lower boundary of the gas hydrates. Integration of seismic sections, relative and absolute impedance sections, and interval velocity sections can improve the validity of gas hydrates determination. The combination of instantaneous frequency, energy half attenuation time, interval velocity, AVO intercept, AVO product, and AVO fluid factor accurately locates the escaped gas beneath the BSR. With these conclusions, the combined techniques have been used to successfully predict the gas hydrates in the Dongsha Sea area.

Exploring the Wenchuan earthquake fault through the accurate location of WFSD-4#Well using seismic reflection

Deep drilling data on seismogenic faults that are obtained directly can help in understanding earthquake mechanisms and the resulting changes in deep structure and material composition.However,geophysical data are necessary to ensure that the planned borehole accurately drills through the target faults.In this study,the deep crustal structure of the Longmenshan fault is explored to obtain seismogenic fault characteristics of the Wenchuan earthquake.A scientific drilling project,Wenchuan Earthquake Fault Scientific Drilling No.4 Borehole(WFSD-4)is proposed with a borehole designed to drill through the north section of the fault zone while penetrating as many geological bodies and target layers related to seismogenic fault slip as possible.High-precision seismic exploration is then carried out to study the deep structure of the fault zone and achieve the scientific objective of the borehole.Two high-precision deep seismic reflection lines were arranged perpendicularly to the fault zone,and data were obtained through special acquisition schemes and processing methods.Finally,the surface position and drilling depth route of WFSD-4 are determined based on the interpretation results of seismic profiles.The seismic reflection method for site selection of the Wenchuan earthquake fault scientific drilling is proven feasible by comparing the interpretation with the actual drilling results,laying the foundation for further study on the deep structures of fault zones.

Preface to the special issue： Friction stir welding and processing

Friction stir welding （FSW）, invented at The Welding Institute, UK, in 1991, is a highly efficient solid-state joining technique, involving frictional and adiabatic heating, plastic deformation and solid-state diffusion. It has been widely accepted as a ＂green＂ technology due to its energy efficiency and environment friendliness, and is considered the most significant development in the field of material joining over the past two decades. Friction stir processing （FSP） was later developed based on the basic principles of FSW. FSP has proven to be an effective and versatile metalworking technique for modifying and fabricating metallic materials.

Call for Papers Special Section on Deep Learning for Natural Language Processing

The publication of Tsinghua Science and Technology was started in 1996.Since then,it has been an international academic journal sponsored by Tsinghua University and published bimonthly.This journal aims at presenting the state-of-the-art scientific achievements in computer science and other IT fields.

Acknowledgments

Epilepsy is the most common neurological disorder of the brain that affects people worldwide at any age from newborn to adult. It is characterized by recurrent seizures, which are brief episodes of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. The electroencephalogram, or EEG, is a physiological method to measure and record the electrical