Search

Abstract Background Gene flow is crucial for enhancing economic traits of livestock. In China, breeders have used hybridization strategies for decades to improve livestock performance. Here, we performed whole-genome sequencing of a native Chinese Lijiang pig (LJP) breed. By integrating previously published data, we explored the genetic structure and introgression of genetic components from commercial European pigs (EP) into the LJP, and examined the impact of this introgression on phenotypic traits. Results Our analysis revealed significant introgression of EP breeds into the LJP and other domestic pig breeds in China. Using a haplotype-based approach, we quantified introgression levels and compared EP to LJP and other Chinese domestic pigs. The results show that EP introgression is widely prevalent in Chinese domestic pigs, although there are significant differences between breeds. We propose that LJP could potentially act as a mediator for the transmission of EP haplotypes. We also examined the correlation between EP introgression and the number of thoracic vertebrae in LJP and identified VRTN and STUM as candidate genes for this trait. Conclusions Our study provides evidence of introgressed European haplotypes in the LJP breed and describes the potential role of EP introgression on phenotypic changes of this indigenous breed.

New ore pulverizing technology was proposed by the Institute of mechanics, Chinese Academy of Sciences. In order to study the applicability of the new ore pulverizing technology to different materials, several experiments were carried out. In this paper, the author used the new ore pulverizing technology to pulverize iron ore, kaolin, wood and PVC, and finds that the new ore pulverizing technology has good application for iron ore, kaolin wood but for PVC. The experimental results show the application scope of the new ore pulverizing technology.

In our living environment, we frequently encounter natural disasters such as typhoons, floods, earthquakes, drought, petrochemical plant safety accident, stripping accident and so on. Due to global climate change, natural disasters have become even more devastating. Thus, it is important to look for ways to mitigate disasters. This study employs the concept of resilience to examine the ability of parks to recover from natural disasters. According to previous disaster history, the damage caused by natural disasters in the parks is mainly water and wind. Therefore, this study first conducted a literature review to find out relevant resilience criteria that are advantageous for combating water and wind disasters, and to recognize the degree of resilience achieved by each criterion. Then, based on the elements of the resilience criteria, the study establishes a preliminary resilience grading system. Furthermore, three different types of parks are evaluated under the grading system. This study provides a theoretical basis for resilience grading and suggestions for improving parks in the future.

Microwave absorbing material was prepared using epoxy resin as matrix and spherical carbonyl iron powder (s-CIP), flaky carbonyl iron powder (f-CIP) as absorbing agent. Microwave absorbing, mechanical properties and structure of the composites containing different kinds of carbonyl iron powder (CIP) were investigated. The results show that the microwave absorber with flaky CIP have better electromagnetic properties than composites with spherical CIP. With concentration of spherical CIP increasing the electromagnetic properties of composites becomes better, except for the mechanical performance. The flaky CIP/epoxy resins composites with a loading of 79 wt% plate-like CIP has attenuation constant of 25.443 dB/cm in 3 GHz. The absorber prepared using flaky CIP has homogenous, dense structure and has excellent mechanical properties.

The determination of the sweet spot of tight sandstone reservoir is the primary problem in the exploration and development of tight sandstone reservoir. Practice has proved that the prediction of reservoir spatial pore characteristics, thickness distribution and oil and gas potential (i.e. geological sweet spot) of tight sandstone reservoir can not meet the demand of exploration and development of tight sandstone reservoir. In view of the requirements of tight sandstone fracturing engineering, it is also necessary to analyze the engineering field of the reservoir. In this paper, based on seismic data preprocessing and petrophysical analysis, thin reservoir quantitative characterization and AVO fluid prediction are used to evaluate the tight reservoir. At the same time, combining with the fracture analysis method of FMI imaging logging, pre stack fracture description and brittleness prediction, the “engineering sweet spot” prediction is carried out. Finally, the multi-attribute RGB digital fusion visualization research method is used to comprehensively evaluate the tight reservoir. The practice shows that the research method has guiding significance for the exploration and development of tight reservoir.