Increasing tree cover while losing diverse natural forests in tropical Hainan,China

To protect biodiversity and improve environmental conditions, China has invested billions of dollars in reforestation and payments for ecosystem service programs. Here, we examine the Sloping Land Conversion Program, the largest such program in the world and found that after 13 years of implementation at our study site, it has had negative impacts on natural tropical forests. GIS and remote sensing techniques revealed that both natural forests and natural shrub and grasslands were replaced by non-native monocultural plantations on Hainan Island, China, a key tropical biodiversity hotspot. Under current Chinese policy, these plantations are classified simply as “forests”, with the assumption that they are equivalent to natural forests. This lack of a distinction in forest quality has led to substantial deforestation and plantation expansion, including encroachment into protected areas on Hainan. Additional social and economic drivers of these changes were identified by examining the participants in this program and their actions. Without a new ecologically based definition of forests and new goals for reforestation, such programs designed to improve ecosystem services, and forest quality may actually threaten remaining natural forests and other vegetation types in Hainan and in other areas of mainland China.     

Transport of butyltins at the water‐air interface and the adsorptive behavior of tributyltin in the surface microlayer

The transfer dynamics and enrichment phenomena of monobutyltin chloride(MBT), dibutyltin chloride(DBT) and tributyltin chloride(TBT) at the water‐surface microlayer (SM) interface were studied. The transport processes of the three compounds at the interface are very fast in the estuarine environment. The mass transfer coefficients are 1.54 m/h for MBT, 2.16 m/h for DBT, 1.56 m/h for TBT. The effect of various factors, including pH, salinity, suspended particulate and temperature, on the adsorptive behavior of TBT in the water's surface microlayer was also studied.     

The progress and challenges in sustainable forestry development in China

Forestry development in China has undergone a series of reforms over the past six decades. This article examines temporal changes in forest resources and policies, the current status of forestry, and future challenges toward sustainable forest management in China. Excessive logging in the 1950s to 1980s badly damaged the nation’s forests, but the adoption of enlightened forest policies in the late 1990s has led to increases in China’s total forest area and growing stock. Forest degradation was ecologically and economically costly, and rehabilitation processes have become increasingly more expensive. The low quality and young age of forest resources, loss of natural forests, and more difficulties in afforestation and reforestation pose severe challenges for China’s sustainable forestry. It is critically important for China to enhance forest productivity through intensive management, strengthen enforcement, and educational programs for protecting and restoring natural forests, narrow the gap between domestic timber supply and rapidly expanding consumption, improve coordinating networks for management, finance, and technology transfer, and accelerate efforts to clarify and stabilize tenure arrangements for non-state forests. China’s experience and lessons in forestry may be helpful for other developing countries that are seeking to achieve the goal of sustainable forest management.     

电梯门区故障案例软件研发及其风险研究

电梯门区故障是电梯整体主要故障之一。基于目前电梯门区常见故障或者已经发生的事故,本文系统性地建立电梯门区故障案例库并进行其软件研发;根据故障案例库中已知的案例信息得到故障类型风险的相关信息,进行风险分析;将故障案例中实际出现的故障类型组合种类归纳后,计算出每种组合的危害程度,按照危害程度值进行降序排列;软件系统根据用户输入的设备信息给出风险较高的故障组合和相应的预防措施。     

Life-cycle assessment of two sewage sludge-to-energy systems based on different sewage sludge characteristics: Energy balance and greenhouse gas-emission footprint analysis

Anaerobic digestion and incineration are widely used sewage sludge(SS) treatment and disposal approaches to recovering energy from SS, but it is difficult to select a suitable technical process from the various technologies. In this study, life-cycle assessments were adopted to compare the energy-and greenhouse gas-(GHG) emission footprints of two sludge-to-energy systems. One system uses a combination of AD with incineration(the AI system),whereas the other was simplified by direct incineration...     

成都市生态环境与社会经济协调发展分析

以成都市为研究区域,采用主成分分析法(PCA)确定选取的生态环境与社会经济各项指标的权重,在此基础上建立可持续发展模型,对该区域生态环境与社会经济的协调发展度进行了分析。分析结果表明:成都市生态环境与社会经济之间属于协调发展类环境滞后型,且2001~2004年协调发展值逐年下降,可持续发展情况呈下降趋势。说明成都市在发展经济的同时,必须进一步增加环保投资,加强生态环境建设,还应将循环经济理论应用到区域规划中,调整产业结构,促进生态工业、生态社会、生态服务业等的建设,减少污染物的产生,实现环境、经济的"双赢",做到真正的可持续发展。     

Nb2O5 nanowires in-situ grown on carbon fiber: A high-efficiency material for the photocatalytic reduction of Cr(VI)

Niobium oxide nanowire-deposited carbon fiber (CF) samples were prepared using a hydrothermal method with amorphous Nb₂O₅·nH₂O as precursor. The physical properties of the samples were characterized by means of numerous techniques, including X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), UV–visible spectroscopy (UV–vis), N₂ adsorption–desorption, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy. The efficiency for the removal of Cr(VI) was determined. Parameters such as pH value and initial Cr(VI) concentration could influence the Cr(VI) removal efficiency or adsorption capacity of the Nb₂O₅/carbon fiber sample obtained after hydrothermal treatment at 160°C for 14 hr. The maximal Cr(VI) adsorption capacity of the Nb₂O₅ nanowire/CF sample was 115 mg/g. This Nb₂O₅/CF sample also showed excellent photocatalytic activity and stability for the reduction of Cr(VI) under UV-light irradiation: the Cr(VI) removal efficiency reached 99.9% after UV-light irradiation for 1 hr and there was no significant decrease in photocatalytic performance after the use of the sample for 10 repeated cycles. Such excellent Cr(VI) adsorption capacity and photocatalytic performance was related to its high surface area, abundant surface hydroxyl groups, and good UV-light absorption ability.     

A comparative investigation of NdSrCu1-xCoxO4-σ and Sm1:8Ce0:2Cu1-xCoxO4-σ(x: 0-0.4) for NO decomposition

A series of single-phase T-structured NdSrCu1??xCoxO4?? with oxygen vacancies and T0-structured Sm1:8Ce0:2Cu1??xCoxO4?? (x: 0–0.4) with oxygen excess were prepared using ultrasound-assisted citric acid complexing method, and characterized by means of techniques such as thermogravimetric analysis and NO temperature-programmed desorption (NO-TPD). The catalytic activities of these materials were evaluated for the decomposition of NO. It was found that the NdSrCu1??xCoxO4?? catalysts were of oxygen vacancies whereas the Sm1:8Ce0:2Cu1??xCoxO4?? ones possessed excessive oxygen (i.e., over-stoichiometric oxygen); with a rise in Co doping level, the oxygen vacancy density of NdSrCu1??xCoxO4?? decreased while the over-stoichiometric oxygen amount of Sm1:8Ce0:2Cu1??xCoxO4?? increased. The NO-TPD results revealed that NO could be activated much easier over the oxygen-deficient perovskite-like oxides than over the oxygen-excessive perovskite-like oxides, with the NdSrCuO3:702 catalyst showing the best e ciency in activating NO molecules. Under the conditions of 1.0% NO/helium, 2800 hr??1, and 600–900°C, the catalytic activity of NO decomposition followed the order of NdSrCuO3:702 > NdSrCu0:8Co0:2O3:736 > NdSrCu0:6Co0:4O3:789 > Sm1:8Ce0:2Cu0:6Co0:4O4:187 > Sm1:8Ce0:2Cu0:8Co0:2O4:104 > Sm1:8Ce0:2CuO4:045, in concord with the sequence of decreasing oxygen vacancy or oxygen excess density. Based on the results, we concluded that the higher oxygen vacancy density and the stronger Cu3+/Cu2+ redox ability of NdSrCu1??xCoxO4?? account for the easier activation of NO and consequently improve the catalytic activity of NO decomposition over the catalysts.     

Au − Pd/mesoporous Fe2O3: Highly active photocatalysts for the visible-light-driven degradation of acetone

Three-dimensionally ordered mesoporous Fe_2O_3(meso-Fe_2O_3) and its supported Au, Pd,and Au-Pd alloy(xA uP dy/meso-Fe_2O_3; x = 0.08–0.72 wt.%; Pd/Au molar ratio(y) = 1.48–1.85)photocatalysts have been prepared via the KIT-6-templating and polyvinyl alcohol-protected reduction routes, respectively. Physical properties of the samples were characterized, and their photocatalytic activities were evaluated for the photocatalytic oxidation of acetone in the presence of a small amount of H_2O_2 under visible-light illumination. It was found that the meso-Fe_2O_3 was rhombohedral in crystal structure. The as-obtained samples displayed a high surface area of 111.0–140.8 m~2/g and a bandgap energy of 1.98–2.12 eV. The Au, Pd and/or Au–Pd alloy nanoparticles(NPs) with a size of 3–4 nm were uniformly dispersed on the surface of the meso-Fe_2O_3 support. The 0.72 wt.% AuP d1.48/meso-Fe_2O_3 sample performed the best in the presence of 0.06 mol/L H_2O_2 aqueous solution, showing a 100% acetone conversion within4 hr of visible-light illumination. It was concluded that the good performance of 0.72 wt.%AuPd_(1.48)/meso-Fe_2O_3 for photocatalytic acetone oxidation was associated with its ordered mesoporous structure, high adsorbed oxygen species concentration, plasmonic resonance effect between AuPd_(1.48) NPs and meso-Fe_2O_3, and effective separation of the photogenerated charge carriers. In addition, the introduction of H_2O_2 and the involvement of the photo-Fenton process also played important roles in enhancing the photocatalytic activity of 0.72 wt.%AuPd_(1.48)/meso-Fe_2O_3.