[en] The rapid growth of small hydro capacity in China is reviewed. At present, the annual generation from rural small hydropower in China equates with the saving of 44 million tonnes of coal, or the emission of 110 million tonnes of carbon dioxide. Other environmental advantages such as a reduction in wood burning, reduced logging and therefore reduced soil erosion, are mentioned. Energy-starved China stood to gain much from the development of small hydro systems and government policy has been supportive in terms of relatively low tax rates and low interest loans. It is expected that due to the rapid economic growth in China, small-scale hydro will maintain its present level of development and continue to be promoted in a sound and rational manner. (author)

[en] We present an experimental setup for generation of entangled-photon pairs via spontaneous parametric down-conversion, based on the femtosecond-pulsed laser. Our entangled-photon source utilizes a 76-MHz-repetition-rate, 100-fs-pulse-width, mode-locked, ultrafast femtosecond laser, which can produce, on average, more photon pairs than a cw laser of an equal pump power. The resulting entangled pairs are counted by a pair of high-quantum-efficiency, single-photon, silicon avalanche photodiodes. Our apparatus s intended as an efficient source/receiver system for the quantum communications and quantum cryptography applications

[en] The effect of laser surface remelting on corrosion resistance and pitting potential of pure titanium (ASTM grade 2) sheets was investigated. A Nd-YAG laser was used to remelt the surface of the titanium sheets. Corrosion performance of laser surface remelted and titanium base sheets were then evaluated qualitatively and quantitatively by both potential dynamic measurements (PDM) and electrochemical impedance spectroscopy (EIS) in a 3% NaCl solution. It was found that there were significant differences in corrosion properties for the two materials. Analyses of the polarization curves obtained from the PDM illustrated that no pitting corrosion could be perceived in laser surface remelted titanium sheet, while clear pitting corrosion could be seen in the base titanium sheet. EIS diagrams also showed that laser surface remelted titanium has higher impedance than the base titanium. Both results are evidence that laser surface remelting can improve the corrosion resistance of titanium. Further observation using optical microscopy and scanning electron microscopy showed clear pitting corrosion on the surface of the base titanium sheet, while no pitting was in evidence on laser surface remelted sheets. The improved pitting corrosion resistance is obtained due to the microstructural changes caused by rapid solidification after laser remelting. The study clearly demonstrates that laser surface remelting can be a potential way to improve pitting corrosion resistance of titanium and to enlarge its application range in harsh environments

[en] Duplex stainless steels are characterized by balanced ferrite/austenite microstructures and are well known for their superior corrosion resistance and higher strength compared with the common austenitic stainless steels. One major concern, however, is that welding might degrade the corrosion resistance by producing unbalanced phase content, detrimental precipitates, and possible embrittlement of the weldment. In this paper, a dual-torch arc welding technique (plasma torch followed by a gas tungsten arc (GTA) torch) was proposed. Effects of the dual-torch technique on the microstructural changes and corrosion properties were investigated. The preliminary study indicated that a correlation between the welding parameters and the microstructural changes and corrosion resistance existed. It was found that the corrosion rate increases with increasing torch pitch and/or decreasing GTA welding current. By adjusting the distance between the torches, modification of weld microstructure may be realized. Although further studies are required to fine-tune the technique, the present study demonstrated the potential of using dual torch technique to improve weldability of duplex stainless steels

[en] This paper described the wind energy industry in China and introduced a Chinese manufacturer of wind turbines that has taken a leading role as a supplier of wind turbines. By the end of 2003, Gold Wind Science and Technology Corp. Ltd. had installed 82 turbine units for a total installed capacity of about 50 MW. In December 2004, the company produced a 1.2 MW direct-drive prototype. Gold Wind shares 23.9 per cent of the wind energy market in China with its competitors NEG-Micon, Vestas, Gamesa and Nordex. The localization process in wind turbine generation was discussed along with future developments in quality control and cost reductions. The total usable wind resource in China is 253,000 MW, of which 576 MW was installed by the end of 2003. China's national development plan is to have 20,000 MW of wind generating capacity installed by 2020. The presentation ended with an invitation to interested Canadian companies to cooperate in wind farm development and clean development mechanism (CDM) projects in China through technology transfer. tabs., figs

[en] In recent years, Canadian wind energy has developed to a total installed capacity of 439 MW. It is possible that by 2012, the cumulative installed wind power capacity may reach 5,600 MW, representing an investment of $8.4 billion. This analysis of the supply-chain structure in the life cycle of a wind farm identified many potential areas where Canadian companies can offer services. Opportunities for both manufacturers and service providers were presented. It was emphasized that although wind energy is a growth industry, Canada has not participated in the development and commercialization of large wind turbine technology. The technical barriers facing Canadian suppliers regarding wind turbine generator (WTG) assembly and component manufacturing were presented. Currently, Canada imports all large WTGs and components. In order to maximize benefits to the Canadian economy, it was recommended that Canadian companies acquire European technology through licences, joint ventures or foreign investment. Technology transfer funding, training and technical assistance funding, tax incentives for capital equipment and support to universities and colleges were also recommended. It was suggested that Canadian companies should focus on manufacturing rotor blades, towers, base frames, nacelle covers and spinners, flexible drive shafts, disk brakes, vibration mounts, inverters, control cabinets, and generators. tabs., figs

[en] Since dl-threo-[¹¹C]methylphenidate (Ritalin) and especially the more active enantiomer, d-threo-[¹¹C]methylphenidate, have favorable properties for PET studies, we prepared two radioiodinated analogs of methylphenidate, p-[¹²³I]iodomethylphenidate and m-[¹²³I]iodo-p-hydroxymethylphenidate with a view to evaluating them as potential SPECT tracers. To prepare p-[¹²³I]iodomethylphenidate, the p-tributyltin derivative was prepared from the previously reported p-bromomethylphenidate and reacted under acidic conditions with I-123 iodide plus chloramine-T at room temperature for 90 seconds. The predomimant radioactive product was obtained in 85% radiochemical yield and > 10 Ci/μmol specific radioactivity after HPLC purification. It had the same HPLC retention time as a spectroscopically characterized non-radioactive p-iodomethylphenidate standard prepared via nitration of methylphenidate and diazotization, after protection of the secondary amino group by benzoylation. A second radioiodinated methylphenidate derivative, m-[123)I]iodop-hydroxymethylphenidate was prepared in 80% radiochemical yield by direct iodination of the known p-hydroxymethylphenidate. In this case the non-radioactive standard was prepared by iodination of p-hydroxyritalinic acid using I₂ and iodic acid, followed by esterification. (author)

[en] Full text: Hexavalent uranium is a prominent radioactive contaminant in both sediments and aquifers around nuclear activity sites, and poses a potential health and environmental risk to the biosphere. Understanding on the detailed interaction at the solid-liquid interface between uranium and granite is crucial for the safety assessment of high level radioactive waste geological repository in granitic terrain, as well as prediction of uranium’s geochemical fate in the environment. However, the interaction between uranium and granite is complicated by the ubiquitous ligands in natural media such as phosphate, humic substances et al, thus the detailed insight into U-granite interface is critical in governing the subsurface mobility of uranium in disposal environment. Full understand on complicated interaction mechanism between uranium and ligands at the granite-water interface requires full identification of surface species with the aid of sensitive spectroscopic techniques. In this work, the adsorption of uranium on granite in both absence and presence of phosphate was investigated by a combination of batch measurements and spectroscopic techniques, including cryogenic time-resolved laser induced fluorescence spectroscopy (TRLFS) and extended x-ray absorption fine structure (EXAFS). Results showed that phosphate is beneficial for uranium immobilization, the spectroscopic confirmation revealed that multiple surface species including inner-sphere complexes and surface precipitates were formed on granite surface with their abundances varying as a function of acidity. The EPMA results showed that uranium mainly located on mica mineral, thus the detailed interaction between uranium and mica was further investigated. The results showed that uranium sorption on phlogopite mica was strongly dependent on pH while minimally affected by the ionic strength, multiple inner-sphere surface species (including ≡SOUO₂⁺, ≡SO(UO2)₂(OH)₂CO₃- and ≡SOUO₂(CO₃)_x^1-2x) were formed with their abundance varying as a function of pH, and a portion of uranium precipitated as uranyl oxyhydroxides at pH > 9. The presence of HA made significant difference on uranium sorption behavior as well as surface species. The finding in this work is helpful for understanding on the geochemical fate of uranium in granitic environment as well as setting a reliable reference for surface complex models. (author)

[en] The Accelerator Systems String Test (ASST) program is a research and development effort located at the SSCL N15 Site. Its purpose is to support the evaluation of key subsystems required in the Superconducting Super Collider (SSC). A procedure has been generated to allow SSCL scientists and engineers to request testing at the facility and, if approved by the ASST Steering Committee, perform their tests as schedule time and priorities permit. Implementation of approved test requests is the responsibility of the ASST test group. Since the ASST magnet string is highly instrumented, it is critical that the test group keep accurate records of the configuration. Failure to do so would result in program chaos and the recording of incorrect test data

[en] Electroactive methylene blue (MB) entrapped in alpha-zirconium phosphate (ZrP) were first synthesized by a simple chemical method. Room-temperature ionic liquid (IL) was used as a matrix to immobilize ZrP-MB composite on pyrolytic graphite (PG) electrode and the resulting modified electrode can be utilized in electrocatalytic oxidation of NADH. Because of the combination of the excellent electroactivity of MB, the good chemical and mechanical properties of ZrP and the good ionic conductivity of IL, the response current of NADH at PG/ZrP-MB/IL electrode is much larger than that in bare and ZrP-IL electrode and the interference of ascorbic acid can be avoided efficiently. The PG/ZrP-MB/IL electrode displayed high sensitivity (76.5 mA M-1 cm-2), low detection limit (6 microM), fast response time (within 5s) and wide linear range (6-540 microM). (author)