Balance and Sharing:Women's Childcare Time and Family's Help

It is of crucial importance for professional women to strike a balance between childcare and work.Help from family can effectively reduce women's time spent on childcare.Based on relevant survey,this paper successively analyzes the time of mother,father and grandparents invested in childcare and explores how women are supported by their family in this duty.Infant and childcare can be as time-consuming as a full-time job.Mothers have always played a primary role in infant and childcare,while grandparents,offering a helping hand to effectively alleviate the mother's workload,can play an alternative role,which is of great significance.This is particularly true in early childhood,when more than 40% of Chinese children are under the care of grandparents,with relatively limited participation of their fathers.Childcare gap between mothers and fathers is even larger in rural China.It is quite common for a family to turn to nursery services when their child are three years old to significantly alleviate the mother's childcare burden.When it comes to the design of relevant public policies and projects,consideration should be given to the role of each family member in taking care of infants and children in different growth stages to explore more options for childcare.More specifically,in addition to motherhood,grandparents' support should be valued,and fatherhood should be enhanced.

Soil Evolution Features of Debris Flow Waste-Shoal Land

The reclamation and utilization of debris flow waste-shoal land plays an important role in the mitigation and control of debris flow hazards, which thus contributes a lot to the exploitation of insufficient land resources in mountainous areas and the reduction of losses caused by debris flow. The aim of this paper is to discuss the features and mechanism of soil evolution of debris flow waste-shoal land so as to search for the available modes of its reclamation and utilization. The Jiangjiagou Ravine, a typical debris flow ravine, was selected to study soil evolution features of debris flow waste-shoal land based on the analysis of soil physicochemical properties and soil microstructure. It was found that the soil evolution rates of debris flow waste-shoal land varied with different modes of reclamation. For the land which had been reclaimed for less than 10 years, soil evolved most rapidly in paddy fields, and more rapidly in dry farmland than in naturally restored waste-shoal land. For the land which had been used for more than 10 years, the soil evolution rates of dry farmland, naturally restored waste-shoal land and paddy farmland decreased in the file. For the same utilization period of time, significant differences were recognized in soil evolution features under different modes of reclamation. Analysis data showed that soil clay content, soil thickness, the psephicity of skeleton particles and contents of microaggregates (<0.02 mm) in paddy farmland were all highest. Soil nutrients and porosity of dry farmland were better than those of paddy farmland and naturally restored waste-shoal land, and those of paddy farmland were superior to those of naturally restored waste-shoal land. Paddy farmland characterized by rapid pedogenesis, stable evolution and high utilizability was the priority candidate for the reclamation and utilization of debris flow waste-shoal land.

Statistics and Analysis on Reliability of HVDC Transmission Systems of SGCC

Reliability level of HVDC power transmission systems becomes an important factor impacting the entire power grid.The author analyzes the reliability of HVDC power transmission systems owned by SGCC since 2003 in respect of forced outage times,forced energy unavailability,scheduled energy unavailability and energy utilization eff iciency.The results show that the reliability level of HVDC power transmission systems owned by SGCC is improving.By analyzing different reliability indices of HVDC power transmission system,the maximum asset benef its of power grid can be achieved through building a scientif ic and reasonable reliability evaluation system.

A novel timing synchronization for CO-OFDM systems using CAZAC sequences

A novel symbol timing synchronization algorithm based on constant amplitude zero auto correlation(CAZAC) sequences is proposed for coherent optical orthogonal frequency division multiplexing(CO-OFDM) systems. The training symbol of the proposed algorithm is comprised of four different parts, utilizing even symmetry property of each part to accomplish timing synchronization. The performance of the proposed algorithm is demonstrated by means of simulations in OFDM and CO-OFDM systems. The proposed algorithm is shown to eliminate the timing sidelobes of Park's algorithm and has a more accurate timing estimation. In the condition of chromatic dispersion(CD), the timing metric of the proposed method still maintains its peak value at the correct timing point, while the values are almost 0 at all the other positions. Meanwhile, the timing mean square error(MSE) of the proposed algorithm remains around 10^(-6).