Investment growth in many emerging market and developing economies (EMDEs) has slowed sharply since 2010. Investment growth performance has varied significantly across different regions, however. This paper examines the evolution of investment growth in six EMDE regions, documents remaining investment needs, especially for infrastructure, and presents a set of region-specific policy responses to address these needs. It reports three main findings. First, investment growth has been particularly weak in EMDE regions hosting a large number of commodity exporters. In regions with a substantial number of commodity-importing economies, investment growth has been somewhat resilient but has also declined steadily since 2010. Second, sizable investment needs remain in most EMDE regions to make room for expanding economic activity and rapid urbanization. A large portion of these investment needs is in infrastructure and human capital. Finally, while specific policy priorities vary across regions, several policy options to address remaining investment needs apply universally. These include more, and more efficient, public investment and measures to improve overall growth prospects and the business climate. Improved project selection and monitoring, as well as better governance, may enhance the efficiency and benefits from public investment.

This problem is a solar hut photovoltaic cell in the attached and overhead two installation methods, the type of photovoltaic cells and array mode and inverter type optimization design issues. In question 1, since the photovoltaic cells are attached to the roof and exterior surfaces, the direction and angle of the battery are uniquely determined by the direction and angle of the attached surface. The problem is translated to optimize the installation of a certain type on a single surface area (array) of photovoltaic cells, so that the total amount of solar photovoltaic power generation as much as possible, and the unit power generation costs as small as possible, which is a multi-objective optimization problem. The problem can be discussed in the ideal environment in a single surface area of the battery installation optimization program, and then the actual environment of the multi-surface optimization. In the solution to Problem 1, the unit on the south of the roof of the battery at the moment to accept the solar energy formula is generated. The definition of and is the moment of direct radiation intensity, for the moment the sun and the south of the roof of the plane where the angle, for the level of horizontal radiation intensity, for the south of the roof and the horizontal angle, the planefor the plane, the center of the heart, the vertical upward direction is the axis of the positive coordinate system, obtained with the sun height angle , the sun azimuth , red angle, angle and the sun when the relationship is generated. The conclusion is only installed in the small roof surface type of battery C11, and the rest of the surface is not installed. 35 years of electricity generation is 77126 degrees, the economic benefits of 16,488 yuan, the recovery period of 21.3 years. In question 2, because the photovoltaic cells in the roof and the external wall surface can be installed overhead, the panel orientation and tilt will affect the efficiency of photovoltaic cells. Therefore, in the optimization scheme of Problem 1, the orientation and inclination of the panel on each surface are further adjusted to calculate the optimum orientation and inclination of the panel on each surface. The problem can be in the ideal weather environment to establish the sun running and the battery board efficiency model, and then the measured environment test. The optimal orientation of the panel is southward, and the optimal angle with the ground plane is 39.89 degrees. The conclusion is only installed in the small roof surface type of battery C11, and the rest of the surface is not installed. 35 years of generating capacity of 82165.2 degrees, the economic benefits of 18,998 yuan, the recovery period of 13 years. In question 3, by the optimization of the above two issues, in the building to meet the requirements of the hut under the design of the various aspects of the cabin and battery installation, and further optimize the total power generation of the hut, economic benefits. The whole model solver is run in MATLAB7.0.

Coal is important basic energy and important raw materials, the development of coal industry to support the rapid development of the national economy. In the 1950s and 1960s, the proportion of coal in China's primary energy production and consumption structure accounted for 90% and 80% respectively, and the proportion of coal in 2004 was 75.6% and 67.7% respectively. In recent years, with the rapid development of fully mechanized mining equipment manufacturing technology, fully mechanized mining equipment to heavy, strong and automated, so that the reliability of the equipment is guaranteed, a strong impetus to the development of large mining technology, new round of coal mining technology revolution, the current in the East, Jincheng and other mining areas have been the first in the thick coal seam f = 1.5-5 use of large mining height fully mechanized mining equipment, to achieve the highest efficiency, the lowest cost of tons of coal. The main points of this paper are: in the production of coal enterprises to improve the competitiveness of the coal market. Conditions and conditions of coal storage conditions should be allowed to give priority to the use of large mining and mining methods.

The development of flexible, wearable electronic devices is one of the future directions of technology development. Flexible conductive materials are important supporting materials for wearable electronic devices. Polymer has excellent flexibility; it is an important way to prepare flexible conductors from polymer-based conductive composites. In this paper, the research progress of polymer-based flexible conductive composites is summarized in terms of preparation and characterization methods. The key factors to realize flexible conductors are put forward, namely, the maintenance of excellent polymer elasticity and the realization of stability. The design and preparation of the extensible conductor with high-elasticity matrix and nanofiller are introduced in detail, and the problems in the current research are summarized.

The fresh dried pollen of grape and seedless grape varieties were used as the research material. Each cultivar was stored at room temperature, 5 C, 0 C, -18 C and -40 C respectively. Sucrose 200g / L + boric acid 50mg / L + agar 8g / L as the nutrient substrate, and the comparative study on the germination and culture of the nuclear breed and the seedless cultivar. The results showed that the pollen viability decreased with the increase of storage time at different temperatures. The pollen viability decreased at -18 C and -40 , and the pollen viability decreased at the same temperature The There was a significant difference in pollen viability between different cultivars at the beginning of storage, and the pollen viability of the kernel breed was higher than that of the seedless grape.

Benzoxazine resin, a new type of phenolic resin, has many advantages, such as a strong molecular design, no small molecular release in the curing process, excellent thermal stability and mechanical properties, and a high residual carbon ratio. Thus, it is important for electronic communication industry matrix material. To meet the needs of high-frequency and high-speed communication technology for low-dielectric polymer resin, the low-dielectric modification of benzoxazine resin is of great significance to the high frequency and high-speed propagation of the signal, which attracts a wide range of materials researchers’ attention. In this paper, we review a series of studies on the low dielectric modification of benzoxazine resin in recent years, including the synthesis of new monomers, inorganic - organic hybridization, copolymerization with other resins, and low molecular weight benzoxazine resin research trends.