Laser-based micro/nanofabrication in one, two and three dimensions

Advanced micro/nanofabrication of functional materials and structures with various dimensions represents a key research topic in modem nanoscience and technology and becomes critically important for numerous emerging technologies such as nanoelectronics, nanopho- tonics and micro/nanoelectromechanical systems. This review systematically explores the non-conventional material processing approaches in fabricating nanomaterials and micro/nanostructures of various dimensions which are challenging to be fabricated via conventional approaches. Research efforts are focused on laser-based techniques for the growth and fabrication of one-dimensional （1D）, two-dimensional （2D） and three-dimensional （3D） nanomaterials and micro/nanostructures. The following research topics are covered, including： 1） laser-assisted chemical vapor deposition （CVD） for highly efficient growth and integration of 1D nanomaterial of carbon nanotubes （CNTs）, 2） laser direct writing （LDW） of graphene ribbons under ambient conditions, and 3） LDW of 3D micro/nanostructures via additive and subtractive processes. Comparing with the conventional fabrication methods, the laser-based methods exhibit several unique advantages in the micro/nanofabrication of advanced functional materials and structures. For the 1D CNT growth, the laser-assisted CVD process can realize both rapid material synthesis and tight control of growth location and orientation of CNTs due to the highly intense energy delivery and laser-induced optical near-field effects. For the 2D graphene synthesis and patterning, roomtemperature and open-air fabrication of large-scale graphene patterns on dielectric surface has been successfully realized by a LDW process. For the 3D micro/nanofabrica- tion, the combination of additive two-photon polymeriza- tion （TPP） and subtractive multi-photon ablation （MPA） processes enables the fabrication of arbitrary complex 3D micro/nanostructures which tional fabrication methods are challenging for conven- Considering the numerous unique advantages of laser-based techniques, the laser- based micro/nanofabrication is expected to play a more and more important role in the fabrication of advanced functional micro/nano-devices.

Occurrence and health risk assessment of trace heavy metals via groundwater in Shizhuyuan Polymetallic Mine in Chenzhou City, China

The Shizhuyuan Polymetallic Mine in Chenzhou City is an important multi-metal deposit in China. After a dam accident in 1985, there are still a number of mining plants, smelters and tailing ponds in this area. These had the potential to pollute the surrounding groundwater. In this study, groundwater samples were collected from 20 residents＇ wells in this area during both dry and wet seasons. In particular, this study focused on the exposure and the health risk assessment of trace heavy metal in groundwater. Multiple statistical analysis and fuzzy comprehensive method were employed to reveal the distribution characteristics of heavy metal and to assess the groundwater quality. Results indicated that Cr, Fe, Ni, Cu, Zn, As, Cd, Ba, Hg and Pb were widespread with low exposure levels. There were 19 wells with low level exposure and one well with a moderate level exposure in the dry season. All of the wells were in low level exposure during the wet season. As and Mn exhibited potential noncarcinogenic concern, because their maximum hazard quotient （HQ） was higher than 1.0. This may cause adverse health effect on adults in dry season or on children in both seasons. Only As, showed that the maximum carcinogenic risk was more than 10^-4, suggesting a high cancer risk for children in both dry and wet seasons. Therefore, analysis and reduction the concentrations of As and Mn in groundwater are needed in order to protect the health of residents and especially children in the area.

Promoting China’s Industrial Upgrading by Expanding the Opening-Up of Service Industry:Intrinsic Logic and Realization Approach

Tertiarization and service globalization are becoming an irreversible trend,which is highlighted in the following aspects:the value added of service industry is contributing more and more to the GDP of major economies,service industry is becoming the main channel to absorb social employment,and the service trade has become the most active mode of international trade.In building the export-oriented economic development strategy,expanding the opening-up of service industry not only is essential to the high-quality development of service industry,but also can realize the transformation and upgrading of China’s economy by improving the resource allocation efficiency of manufacturing industry through the integration of industry development.It is a huge systematic project to promote the industrial upgrading by expanding the opening-up of service industry,which requires comprehensive measures:continuously optimizing the institutional environment for the development and opening-up of service industry,taking the development of productive service industry and two-way opening-up as the priority,promoting the international competitiveness of service trade by“entering WTO for the second time”,recognizing the role of“digital plus”in the service opening-up and industrial upgrading;building a financial system to meet the needs of an open economy.