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In this perspective, we outline that a space borne gravitational wave detector network combining LISA and Taiji can be used to measure the Hubble constant with an uncertainty less than 0.5% in ten years, compared with the network of the ground based gravitational wave detectors which can measure the Hubble constant within a 2% uncertainty in the next five years by the standard siren method. Taiji is a Chinese space borne gravitational wave detection mission planned for launch in the early 2030 s. The pilot satellite mission Taiji-1 has been launched in August 2019 to verify the feasibility of Taiji. The results of a few technologies tested on Taiji-1 are presented in this paper. Gravitational wave astronomy has opened the door to test general relativity and the effect of gravity in the Universe. The authors present the capabilities of an overlap between space gravitational wave detectors LISA and Taiji to constrain the Hubble constant to 0.5%, in 10 years, and what can be learned from the satellite pilot Taiji-1 launched in 2019.

Background Since the 1990s, families from the ecologically hostile mountainous southern areas of Ningxia Province, China, have been migrating to the northern areas of the province. This study compared the prevalence of behavioral problems among migrant adolescents to those among host adolescents (adolescents from the northern areas) and adolescents in the region of origin (adolescents from the southern areas), to determine whether ecological migration is related to adolescent behavioral problems, and possible changes in such problems over time. Methods We used the Children and Adolescents Ecological Migration Survey on Mental Health, administered to 4805 students aged 12–16 years and their parents between 2012 and 2014 (W1), of whom 1753 students and their parents completed the follow-up between 2014 and 2017 (W2). Parents answered questions related to adolescent behavioral problems, main source of family income, parents’ desire to reverse migrate, improved standard of living, and parents’ educational attainment, while children completed the Eysenck Personality Questionnaire and a classroom environment questionnaire. Results The prevalence of behavioral problems among the migrant adolescents (28.04%) was significantly higher than among host adolescents (21.59%) or adolescents in the region of origin (24.37%; p Conclusion Ecological migration will increase children’s behavioral problems in the early stage, with various factors influencing the extent of these problems.

A series of new dithiocarbamates containing a 2(5H)-furanone-piperazine group was synthesized. These compounds show good in vitro cytoxic activity. Among them, compound 6c exhibits the best inhibitory activity against HeLa cell lines with an IC50 of 0.06 ± 0.01 μM for 72 h, and it has good inhibitory activity against SMMC-7721 cell lines with an IC50 of 0.006 ± 0.04 μM for 72 h, but the toxicity was lower against LO2 cell lines with an IC50 of 45.76 ± 0.01 μM. The result showed that compound 6c is far more cytoxic towards cancer cell lines than towards benign cell lines compared with cytosine arabinoside (ARA) in vitro.

The Elastic Modulus and Poisson's ratio of corncob were Measured by electrical method.The sensor was electric-resistance strain gauge.When the corncob was applied by force,the strain of corncob transformed into resistance changing of the sensor.Then,measure the resistance by SINOCERA YE253 programmable static strain gauge and transmit the resistance into the strain.It was found that the Elastic Modulus of corncob under the moisture content of 10.5% is 1.208×109 Pa and the Poisson's ratio is 0.33.

In order to find the best impact head and threshing moisture content to damage the arrangement law of maize ear,the impact test with different varieties and different moisture of the maize ear is carried out in the drop impact test bench. The experimental result shows that the breakage rate of kernel is smaller and the discrete effect of kernel is better than others in the the action of impact head when moisture content of the maize ear belongs to 14%-20% or less than 12%. The wedge impact head is the most suitable for maize kernel threshing than other impact heads.The effect of maize varieties to the breakage rate is not obvious. The research results can provide a theoretical reference for the low damage threshing method of further research.

This paper studies the microstructure of 16 group samples from three different sites of North-west region in P. R. China. Pictures of microstructure were processed with imaging processing program to acquire the geometer parameter and fractal dimension of pores. The range of pores’ fractal dimension is between 1.816~1.936. The pore distribution function of unsaturated soil is established based on fractal geometry theory. The pore water distribution of loess under natural moisture is analyzed. The relationships of collapsibility coefficient with fractal dimension and porosity of unsaturated pores are analyzed with the method of regression analysis. A larger fractal dimension represents a more complex pore-structure. The collapsibility coefficient of loess increases with the increase of fractal dimension and porosity of unsaturated pores.

The degree of compaction is usually used as the compaction quality and control indicator of backfill in practical project. However, as the degree of compaction is affected by various internal and external factors, its accuracy is difficult to guarantee. In this paper, compacted loess samples were prepared under different compaction energies by normal compaction method. The curves of compression coefficient and dry density, the compression coefficient and porosity of compaction loess samples under different compaction energy are analyzed while the water content is constant. The air porosities of compaction loess samples under different compaction energy and water content are calculated and summed up. The air porosity of compaction loess samples under different compaction energy is more stable than the degree of compaction when the water content is exactly equal to the optimum water content. The rationality of using air porosity as the loess compaction quality control indicator is discussed. It is proposed using air porosity as additional indicator of compaction quality control on the condition of the loess compacted dry density meeting the requirements. The air porosity less than 6.5% is suggested as the additional quality control indictor for region backfill compaction.