Renewable Energy Legislation in China:Politicaland Institutional Strategy for EffectiveImplementation

Over the past decade, the Chinese government has developed several plans regulations and policy measures related to the development of renewable energy technologies and has implemented a series of pilot projects. Chinese policymakers have spent several years studying how renewable energy policy models that have been used internationally could be implemented in China. Programs are currently underway to implement pilot renewable portfolio standards, or mandatory market shares (MMS) for renewable energy, in several provinces. This paper examines the primary institutions that are involved in promoting renewable policies in China, the structure of the policies that currently are being drafted, and the status of the complementary, national-level renewable energy law being drafted to provide a legal basis for ongoing local and national-level policies. It then examines the legal requirements for promoting renewable energy legislation under the Chinese law-making system. Finally, it provides recommendations

Evaluation of Energy-Efficiency Standards for Room Air Conditioners in the US

This article describes an analysis of the energy and economic impacts of possible energy efficiency standards for room air conditioners on both U.S. consumers and the nation as a whole. We used two metrics to determine the effect of standards on a representative sample of U.S. consumers: life-cycle cost change and payback period. For the national impact analysis, we evaluated national energy savings attributable to each potential standard, the monetary value of the energy savings to consumers of room air conditioners, the increased total installed costs because of standards, and the net present value of the difference between the value of energy savings and increased total installed costs. Our analysis indicates that standards for room air conditioners at efficiency level 3, which is 17% more efficient than today’s typical unit in the case of room air conditioners less than 6000 Btu/h with louvers and 12% more efficient in the case of room air conditioners 8000 - 13,999 Btu/h with louvers, would save close to one quad of energy over 30 years and have a net present value of consumer benefit of between ?$0.14 billion and $1.82 billion, depending on the discount rate. In addition, such standards would reduce carbon dioxide emissions and NOx emissions.

无模板剂合成用于超级电容器的二氧化锰/石墨烯复合材料(英文)

以尿素、四水合氯化锰和氧化石墨烯为原料,采用水热法并通过热分解制备了一种具有石墨烯包覆结构的石墨烯-二氧化锰复合材料,利用扫描电子显微镜、X射线衍射、比表面积(BET)、拉曼光谱和热失重等技术对其形貌、晶体结构及表面结构进行了表征;在三电极条件下利用循环伏安法、恒流充放电法和交流阻抗法测试了材料的电化学性能,并考察了不同石墨烯含量对材料比电容的影响.结果表明,在不添加模板剂的条件下制备的复合材料中二氧化锰是具有介孔结构的α-MnO2,当复合15%(质量分数)的石墨烯后材料的比表面积从109 m2·g-1提高到168 m2·g-1.复合材料具有更好的电化学性能,在0.2 A·g-1电流密度下复合材料的比电容达到最大值(454 F·g-1),远高于纯二氧化锰的值(294 F·g-1).在2 A·g-1的电流密度下恒流充放电2000次后复合材料的比电容保持率为92%.

Infiltration of Black Carbon Particles from Residential Woodsmoke into Nearby Homes

In many communities, residential wood burning is the source of a significant fraction of wintertime PM2.5 and produces exposures to nearby residents inside their homes. To evaluate the magnitude of this effect, black carbon particles were measured as a proxy for woodsmoke indoors and outdoors in a community where residential woodsmoke is the only significant particle source. Thirteen indoor/outdoor measurement pairs were obtained at 4 different residences and showed an average indoor/outdoor concentration ratio of 0.78 ± 0.21 for residences without indoor generation. In addition, a time dependent mass balance model was used in conjunction with aethalometer measurements taken over 16 nights at a single residence to estimate an average air exchange rate of 0.26 ± 0.08 h-1, an average deposition loss rate of 0.08 ± 0.03 h-1, and an average penetration factor of 0.97 ± 0.02. Using a mechanistic approach which utilizes these average values in a steady state model, the predicted average infiltration factor was 0.74 for the residence studied. The high values for both measured I/O ratio and modeled infiltration factor show that residential environments provide inhabitants with relatively little protection from recently generated wood smoke particles.

Near-Field Variability of Residential Woodsmoke Concentrations

In many regions, wood combustion is a significant source of wintertime aerosols. However, since wood combustion sources are interspersed within neighborhoods, near-field concentration variability has the potential to cause large variations in the exposure levels between residents over a relatively small area. This field study compared filter samples and aethalometer measurements of black carbon concentration within a 1 km2 study region with no significant aerosol sources except wood combustion. Sampling occurred on 15 nights over two winter seasons in a small California coastal town. Even over the small distances in the study area, large spatial and temporal variations were observed. Measured black carbon concentrations varied by as much as a factor of 10 over a 12-hour night-time period. The spatial variability was non-random, with the highest location in the study area experiencing 4 times the average concentration within the neighborhood, when averaged over all sample periods. The results of this study indicate that within neighborhoods with residential wood combustion sources using an average concentration for a region to predict exposure may significantly undervalue the exposure of some residents and overvalue the exposure for others.

Optimization of Dimples in Microchannel Heat Sink with Impinging Jets Part A： Mathematical Model and the Influence of Dimple Radius

With increasing heat fluxes caused by electronic components, dimples have attracted wide attention by researchers and have been applied to microchannel heat sink in modem advanced cooling technologies. In this work, the combination of dimples, impinging jets and microchannel heat sink was proposed to improve the heat transfer performance on a cooling surface with a constant heat flux 500 W/cm2. A mathematical model was ad- vanced for numerically analyzing the fluid flow and heat transfer characteristics of a microchannel heat sink with impinging jets and dimples （MHSIJD）, and the velocity distribution, pressure drop, and thermal performance of MI-ISIJD were analyzed by varying the radii of dimples. The results showed that the combination of dimples and MHSIJ can achieve excellent heat transfer performance; for the MHSIJD model in this work, the maximum and average temperatures can be as low as 320 K and 305 K, respectively when mass flow rate is 30 g/s; when dimple radius is larger than 0.195 mm, both the heat transfer coefficient and the overall performance h/AP of MHSIJD are higher than those of MHSIJ.

Optimization of Dimples in Microchannel Heat Sink with Impinging Jets-Part B： the Influences of Dimple Height and Arrangement

The combination of a microchannel heat sink with impinging jets and dimples(MHSIJD) can effectively improve the flow and heat transfer performance on the cooling surface of electronic devices with very high heat fluxes. Based on the previous work by analysing the effect of dimple radius on the overall performance of MHSIJD, the effects of dimple height and arrangement were numerically analysed. The velocity distribution, pressure drop, and thermal performance of MHSIJD under various dimple heights and arrangements were presented. The results showed that: MHSIJD with higher dimples had better overall performance with dimple radius being fixed; creating a mismatch between the impinging hole and dimple can solve the issue caused by the drift phenomenon; the mismatch between the impinging hole and dimple did not exhibit better overall performance than a well-matched design.

Effect of traffic tidal flow on pollutant dispersion in various street canyons and corresponding mitigation strategies

Increasing traffic emission presents a high risk of exposure to residents in near-road buildings.Traffic tidal flow(TTF)has gradually become one of the most important components of urban traffic congestion.By computational fluid dynamics simulation,the present study examines the airflow,spatial distribution of pollutant concentration,and personal intake fraction(IF_p)of CO in five street canyon structures(shallow,regular,deep,step-up,and step-down street canyons),with non-uniform TTF-induced traffic emission considered.Optimal urban design devices(wind catchers)are subsequently introduced to reduce IF_p.The results suggest that leeward IF_p is far higher in concentration than the windward wall in the shallow,regular,step-up,and step-down street canyons but lower than the windward side in the deep street canyon under different TTF conditions.Moreover,the TTF condition S L(leeward source)/S W(windward source)=3/1 leads to a higher leeward IF_p in the shallow,regular,deep,and step-up street canyons,compared with S L/S W=1/3;however,no significant difference in windward IF_p is found under the different TTF conditions.The highest IF_p and lowest IF_p for both TTF configurations occur in the step-down and shallow street canyons,respectively.Finally,the effect of wind catchers(WCs)varies between the street canyon structures under different TTF conditions.WCs can lead to at least 30.6%reduction in leeward overall average IF_p(<IF_p>)in the shallow,regular,step-up,and step-down street canyons,as well as 12.8%-78.4%decrease in windward<IF_p>owing to the WCs in the regular,deep,step-up,and step-down street canyons.

Excitation and propagation of surface plasmon polaritons on a non-structured surface with a permittivity gradient

Accompanied by the rise of plasmonic materials beyond those based on noble metals and the development of advanced materials processing techniques,it is important to understand the plasmonic behavior of materials with large-scale inhomogeneity(such as gradient permittivity materials)because they cannot be modeled simply as scatterers.In this paper,we theoretically analyze the excitation and propagation of surface plasmon polaritons(SPPs)on a planar interface between a homogeneous dielectric and a material with a gradient of negative permittivity.We demonstrate the following:(i)free-space propagating waves and surface waves can be coupled by a gradient negative-permittivity material and(ii)the coupling can be enhanced if the material permittivity variation is suitably designed.This theory is then verified by numerical simulations.A direct application of this theory,‘rainbow trapping’,is also proposed,considering a realistic design based on doped indium antimonide.This theory may lead to various applications,such as ultracompact spectroscopy and dynamically controllable generation of SPPs.