Chinese small towns are usually developed with single core industry,and the urban brand is the identity of a town that formed with the development of its industry.However,when the core industry representing its urban ...Chinese small towns are usually developed with single core industry,and the urban brand is the identity of a town that formed with the development of its industry.However,when the core industry representing its urban brand is facing a changing situation or market,will the brand be a motivation or an obstruction of the development of a town?The paper combined top-down and bottom-up research method to study the function of the urban brand in Wangqingtuo town in Tianjin,China.We studied over 400 samples(including government staff and town citizens)to make questionnaire investigation about the town’s branding.And we found that the solidified urban brand is a complicated emotional symbol for both government and citizens.The town has demand of exploring and developing new dominant industry,and it has the expectation to keep branding and upgrade its current core industry.展开更多
We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 104...We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 1045 mm. We applied a new analysis method for the steam state equation to analyze the molar quantity change in steam over the course of the experiment and determined the transient steam variation. We also investigated the influence of flow rates and temperatures ofcooling water on the efficiency ofsteam condensation. Our experimental results show that appropriate increasing of the cooling water flow rate can significantly accelerate the steam condensation. We achieved a rapid increase in the total volumetric heat transfer coefficient by increasing the flow rate of cooling water, which indicated a higher thermal convection between the steam and the cooling water with higher flow rates. We found that the temperature ofcooling water did not play an important role on steam condensation. This method was confirmed to be effective for rapid recovering ofsteam.展开更多
The accelerated life test was carried out to investigate the change of spectral transmittance of di-methyl silicon oil and the effects on the electrical performance of silicon solar cell. The di-methyl silicon oil sam...The accelerated life test was carried out to investigate the change of spectral transmittance of di-methyl silicon oil and the effects on the electrical performance of silicon solar cell. The di-methyl silicon oil samples before and after accelerated life test were analyzed by FT-IR, GC-MS and LC-MS. The ring compounds and linear compounds with larger molecular weight were detected. The spectral transmittance of di-methyl silicon oil decreased because the chromophore and auxochrome of the products made a sunlight receive decrease on the surface of the solar cell, and resulted in the reduction of cell performance. According to the decrease of spectral transmittance of di-methyl silicon oil, two recovery methods were proposed. The results showed that extraction was superior to vacuum distillation in recovering the aged di-methyl silicon oil.展开更多
Wind-solar hybrid systems are employed extensively due to certain advantages. However, two problems exist in their application: the PV modules operate at high temperatures, particularly during summer, and low wind pow...Wind-solar hybrid systems are employed extensively due to certain advantages. However, two problems exist in their application: the PV modules operate at high temperatures, particularly during summer, and low wind power cannot be utilized. To solve these two problems, a novel hybrid system is designed based on PV/thermal systems, in which PV modules are cooled with fans driven by a wind turbine. This paper studies the practicability of the novel hybrid system. First, the electrical performance of the wind turbine is compared using a fan and battery load,respectively. Second, different types and numbers of fans are tested to obtain the largest air volume. Third, the height of the air duct on the back of the PV module is optimized and the cooling effect is studied. Results show that a 24 V DC fan is more appropriate for the novel system than a 12 V DC fan, as it provides a greater air volume, and with a switch wind speed of 3.0 m/s the power of PV module shows a maximum increase of 8.0%.展开更多
文摘Chinese small towns are usually developed with single core industry,and the urban brand is the identity of a town that formed with the development of its industry.However,when the core industry representing its urban brand is facing a changing situation or market,will the brand be a motivation or an obstruction of the development of a town?The paper combined top-down and bottom-up research method to study the function of the urban brand in Wangqingtuo town in Tianjin,China.We studied over 400 samples(including government staff and town citizens)to make questionnaire investigation about the town’s branding.And we found that the solidified urban brand is a complicated emotional symbol for both government and citizens.The town has demand of exploring and developing new dominant industry,and it has the expectation to keep branding and upgrade its current core industry.
文摘We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 1045 mm. We applied a new analysis method for the steam state equation to analyze the molar quantity change in steam over the course of the experiment and determined the transient steam variation. We also investigated the influence of flow rates and temperatures ofcooling water on the efficiency ofsteam condensation. Our experimental results show that appropriate increasing of the cooling water flow rate can significantly accelerate the steam condensation. We achieved a rapid increase in the total volumetric heat transfer coefficient by increasing the flow rate of cooling water, which indicated a higher thermal convection between the steam and the cooling water with higher flow rates. We found that the temperature ofcooling water did not play an important role on steam condensation. This method was confirmed to be effective for rapid recovering ofsteam.
基金Supported by the National Natural Science Foundation of China(No.51478297)Program of Introducing Talents of Discipline(No.B13011)
文摘The accelerated life test was carried out to investigate the change of spectral transmittance of di-methyl silicon oil and the effects on the electrical performance of silicon solar cell. The di-methyl silicon oil samples before and after accelerated life test were analyzed by FT-IR, GC-MS and LC-MS. The ring compounds and linear compounds with larger molecular weight were detected. The spectral transmittance of di-methyl silicon oil decreased because the chromophore and auxochrome of the products made a sunlight receive decrease on the surface of the solar cell, and resulted in the reduction of cell performance. According to the decrease of spectral transmittance of di-methyl silicon oil, two recovery methods were proposed. The results showed that extraction was superior to vacuum distillation in recovering the aged di-methyl silicon oil.
文摘Wind-solar hybrid systems are employed extensively due to certain advantages. However, two problems exist in their application: the PV modules operate at high temperatures, particularly during summer, and low wind power cannot be utilized. To solve these two problems, a novel hybrid system is designed based on PV/thermal systems, in which PV modules are cooled with fans driven by a wind turbine. This paper studies the practicability of the novel hybrid system. First, the electrical performance of the wind turbine is compared using a fan and battery load,respectively. Second, different types and numbers of fans are tested to obtain the largest air volume. Third, the height of the air duct on the back of the PV module is optimized and the cooling effect is studied. Results show that a 24 V DC fan is more appropriate for the novel system than a 12 V DC fan, as it provides a greater air volume, and with a switch wind speed of 3.0 m/s the power of PV module shows a maximum increase of 8.0%.
