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This study aimed to compare the outcomes of three surgical techniques for the treatment of patients with benign parotid tumours: superficial parotidectomy (SP; group 1), partial superficial parotidectomy (PSP; group 2), and ultrasonic scalpel-assisted minimal extracapsular dissection (US-MECD; group 3). Groups 1 and 2 received the conventional surgical technique, while group 3 underwent surgery with an ultrasonic scalpel. A total of 281 patients treated during 2012-2016 were included: 98 in group 1, 91 in group 2, and 92 in group 3. The mean surgical time and blood loss during surgery, as well as drainage time and amount, were significantly lower for US-MECD (P0.01). The great auricular nerve and parotid fascia were both preserved with US-MECD (P0.01), while the rate of capsule rupture with US-MECD was slightly higher than in the other groups (P0.05). There was less transient facial nerve paralysis and Frey syndrome with US-MECD (P0.01). No significant difference in wound infection, sialocele, or permanent facial nerve paralysis was observed among the three groups. Patients enrolled during 2012-2013 were selected to evaluate the recurrence rates, and no statistically significant differences were found among the groups. In conclusion, US-MECD showed similar effectiveness and fewer side effects than SP and PSP. The long-term effects of the new technique require further study.

Combined cooling, heating and power (CCHP) is a promising technology to provide energy for various energy consumers for its good economic, energy and environmental performance. However, the widely promotion of CCHP is hindered by its complex design and varying performance under different situations. In this paper, the influence of energy demands, operation strategy and thermal energy storage strategy on optimal design and performance of CCHP systems is studied by using statistical methods 13,472 energy demand samples for 16 types of building across 7 climate zones in the U.S. are used in the paper. On the whole, building energy demands are the most influential factor. Among the building types, the performance of large hotel, hospital and outpatient healthcare is outstanding. Among the climate zones, CCHP systems have better performance in cold and very cold climate zones. For operation strategies, the ATCSR and PESR values of the FTL mode are averagely less than those of the FEL mode, and the differences between the two modes for ATCSR and PESR are on average 0.25% and 1.03%, respectively. Besides, the use of thermal energy storage can improve the integrated performance of CCHP. In the FEL-TES mode, the average increments of ATCSR and PESR are 0.82% and 0.79%, respectively. In the FTL-TES mode, the average increments of ATCSR and PESR mode can reach 3.42% and 3.46%, respectively. The relationship between building energy demand indexes and the design and performance parameters of the CCHP is also explored by stepwise regression method to build regression models and determine the most effective parameters.

A combined cooling, heating, and power (CCHP) system based on biomass-derived gas has great potential in reducing fossil fuels consumption and CO2 emission. However, heating value of various biomass-derived gases is relatively low, which might restrict performance of the system. Hence, effect of LPG addition on a CCHP system based on different biomass-derived gases (including gasification gas, pyrolysis gas and anaerobic digestion gas) is evaluated in this article. Cooling and power mode of the system is focused on. The power generation unit and the mixed effect absorption chiller are modeled to anticipate electricity and cooling output. Furtherly, performance of the system on energy, exergy and CO2 emission aspects when LPG volume fraction varies from 0% to 100% is evaluated. For biomass-derived gas from gasification, pyrolysis and anaerobic digestion, due to the addition of LPG: (1) energy and exergy efficiency can be improved by up to 7.4% and 5.1%, 0.6% and 0.1%, 2.0% and 0.6%, respectively; (2) energy saving ratio can be increased by up to 17.8%, 0.3% and 1.9%, respectively; (3) the maximum difference of CO2 emission reduction ratio is 49.2%, 30.7%, and −10.1%, respectively.

Under the thermal storage strategies in present studies, the power generation unit (PGU) in combined cooling, heating, and power (CCHP) system is turned on/off only based on the state of storage tank; or the operation state of PGU is determined by thermal demand or/and electric demand, which has no relationship with the state of storage tank. For these traditional strategies, either energy demands or state of storage tank is considered for the operation of system. This paper proposes a novel thermal storage strategy (TSS2) for CCHP systems, which determines the operational state of the PGU based upon electric demand, thermal demand and the state of thermal storage device. In this paper, the operation principle of TSS2 is described and compared with the traditional strategies. A hospital in Shanghai was used to evaluate and compared the performance of the system operating under different storage strategies. The results show that TSS2 improves the performance of CCHP system more significantly compared with the traditional strategies. TSS2 can make both PGU and capacity of thermal storage tank be fully used by CCHP system to produce more electric and thermal energy to meet demands of building. Compared with system without thermal storage, the minimum and maximum increase rates of annual total cost saving for traditional strategies are 0% and 14.84%, respectively. However, for TSS2, they can reach 3.79% and 20.22%. Similar conclusions could be achieved for CO2 emission reduction and primary energy saving. The effect of TSS2 on the CCHP system performance is different under different operation strategies.

High- k HfO x N y and HfO 2 have been applied to amorphous InGaZnO ( a -IGZO) metal–oxide–semiconductor (MOS) capacitors as high-k gate dielectrics by using radio-frequency sputtering at room temperature. Effects of nitrogen incorporation on the optical band gap, band alignment and electrical properties of HfO x N y /IGZO/Si gate stacks have been systematically investigated by spectroscopic ellipsometry (SE), UV–vis spectroscopy, x-ray photoemission spectroscopy (XPS) and electrical measurements. Experimental results have confirmed the successful incorporation of nitrogen into HfO 2 films and reduction in band gap with the incorporation of nitrogen for HfO x N y thin films. Reduction in valence band offset and increase in conduction band offset have been observed for HfO x N y /IGZO gate stack. Electrical properties measurements for a -IGZO MOS capacitors based on HfO x N y gate dielectrics have indicated that nitrogen incorporation leads to the improved interface quality, increased dielectric constant, reduced hysteresis voltage, and decreased leakage current density. Meanwhile, the leakage current mechanism under gate injection for MOS capacitors based on HfO 2 and HfO x N y high-k gate dielectrics has been investigated systematically.

In this paper, a feed-in tariff policy which can contribute to both energy and economic performance of a CCHP system is proposed. By applying this feed-in tariff policy, the impact on design optimization (power generation unit capacity and operation strategy) and system performance (economic, energy, and matching performance) of a hospital CCHP system used in different climate zones are evaluated and analyzed. In policy one ( Pol 1 ), no electricity is allowed to be sold. In policy two ( Pol 2 ), the electricity selling price is constant. In policy three ( Pol 3 ), the selling price of electricity is proportional to the PER (Primary Energy consumption Ratio) of the system when the PER is not lower than a critical value. Otherwise, the selling price is zero. The results show that Pol 3 can ensure both energy and economic performances of CCHP system. The effect of feed-in tariff policy to improve the performance of CCHP system reduces gradually from the cold zone to the hot zone. Multi-criteria decision making results show that Pol 3 with reasonable parameters is the best choice in all climate zones except for the hottest zone in this study. When improving PER is attractive, following thermal load operation strategy is the best choice under Pol 3 . In the hottest zone of this study, little excess electricity would be produced and sold to the grid. Feed-in tariff policy has little help to improve the economic and energy performance in this zone.

A dynamic simulation model for the micro-cogeneration unit based on ICE (internal combustion engine) is built as a new component on TRNSYS. This model considers dynamic processes including start-up, cool-down, and overheat protection controls. Through an experiment study, the steady and dynamic performances of the unit are presented and analyzed for calibrating the parameters of the dynamic model. Then the model is validated by the experiment data during steady and dynamic processes. The improvement of prediction accuracy of the model by considering dynamic processes is analyzed. The validation results show that the dynamic model can well predict the characteristics of the unit during start-up, cool-down, and overheat protection control processes. The cumulative prediction errors of the dynamic model decrease with the increase of the start–stop interval. By considering the dynamic processes, 5.18% and 3.2% of Qth and ηtotal cumulative prediction errors are decreased respectively when the start–stop interval is 0.5 h. The primary energy saving ratio and CO2 emission reduction ratio increases with the increase of the start–stop interval. The start–stop interval for the unit in this paper should be longer than 0.5 h, or the energy consumption of micro-cogeneration unit would be larger than that of conventional system.

Unicystic ameloblastoma is a unique histopathological type of ameloblastoma, and treatment is controversial. Marsupialisation is effective in reducing the size of cystic lesions and their complications. We have retrospectively analysed the clinical, histopathological, and prognostic data of affected patients who were treated by marsupialisation between 2003 and 2013 in three Chinese hospitals. Our aim was to evaluate the effects and prognosis, and the factors associated with outcome. A total of 116 patients with mandibular unicystic ameloblastomas were included, and 74, 26, and 16 patients were histopathologically classified as being luminal, intraluminal, and mural subtypes, respectively. Most responded well to marsupialisation, with an overall recurrence rate of 12%. Resorption of the root (p

Combined cooling, heating and power (CCHP) systems are thought to be highly efficient in energy utilization. But there are still potentials to further improve system performance. This work proposed a CCHP system based on internal combustion engine (ICE) for power generation, refrigeration and domestic hot water production. Thermoelectric generator (TEG) and condensing heat exchanger are applied to efficiently recover the exhaust gas waste heat of ICE. All the energy flows are designed based on energy cascading utilization principle. Basing on the test results of a 16 kW ICE, CCHP system characteristics are investigated by simulation from idling condition to full load condition. Especially, the part load performance of TEG and absorption chiller are simulated and discussed. The feasible operating zone of ICE and feed water flow rate are figured out to keep the domestic hot water temperature within a certain range. Results show that the primary energy efficiency of system can reach 0.944, thanks to the condensing heat recovery from exhaust gas. The primary energy saving ratio and cost saving ratio can reach 0.304 and 0.417, respectively. Considering some more equipment is incorporated, the total investment increment is about 11.1%.

A novel operation strategy based on minimum distance was proposed. Also, an integrated evaluation criterion which can reflect the matching performance between the CCHP (combined cooling, heating and power) system and the building was presented. A hospital in Shanghai was used to evaluate the CCHP system with the proposed strategy using the proposed evaluation criterion. The proposed operation strategy was compared with FEL (following the electric load), FTL (following the thermal load) and FHL (following hybrid electric-thermal load) strategies. The results show that the matching performance evaluation criterion is reasonable and integrated. The system with a better matching performance would be fully used and maintain high efficiency. Compared with FEL, FTL and FHL strategies, the proposed operation strategy is flexible and adaptable, which can lead to a better matching performance for a CCHP system. In the case study, the optimized power generation unit capacity and weightings of the optimized operation strategy are 900 kW and w1,above equals to 0.4, w1,below equals to 0.1, respectively.

Tri-generation system is efficient in supplying thermal energy and electricity. But it is very difficult to satisfy multiple load demands simultaneously in real applications. Therefore, the benefit of tri-generation system is not so easy to realize. If the electric load is separated from the thermal load, difficulty of control would be avoided. In this work, combined cooling and heating (CCH) mode of tri-generation system is proposed. The generated electricity is only used to power the HVAC device, which converts all the electricity into thermal energy. Namely, there is only thermal output in this kind of mode. As for the rest electric load of user, it can be ensured by the public grid. Considering 20% of total energy consumption and 50% of building energy consumption may come from the HVAC system in developed countries. The CCH mode of tri-generation system would be potential in energy saving. The influences of system capacity, HVAC performance, public grid efficiency, and energy prices on system performances are analyzed. Results show that the CCH mode of tri-generation system can be much better than an independent HVAC system. For a system with generator capacity over 100 kW, the payback period could be less than 4 years.

In this paper, system description of a three-phase Neutral-Point-Clamped (NPC) rectifier is briefly given by depicting its power circuit and controller. In consideration of tracking target current and minimizing current ripples, the allowable parameters of inductor-capacitor-inductor (LCL) filter are calculated. The filter inductor is then adopted to investigate the influences from LCL filter on dynamic behaviors of this three-phase three-level rectifier. Based on proportional-integral control method, the simulation analysis is carried out to explore the operational behavior differences caused by the variation of filter inductor. The curves of output variables and their phase trajectories are comparatively addressed in terms of different parameters of the LCL filter. The simulated results indicate that the filter parameters has significant impacts on the operational performance of rectifier system, which implies that suitable control method is required to eliminate unexpected influences.

A newly developed ejector refrigeration-rotary desiccant air-conditioning (ERRD A/C) system is proposed to recover ship waste heat as far as possible. Its configuration is built firstly, then its advantages are analyzed, after that, with the help of psychrometric chart, some important parameters such as power consumption, steam consumption and COP of ERRD A/C system are calculated theoretically under design conditions of a real marine A/C, and comparative analysis with conventional A/C is deployed. The results show that the power consumption of ERRD A/C system is only 32.87% of conventional A/C, which meant that ERRD A/C system has potential to make full use of ship waste heat to realize energy saving and environmental protection when using green refrigerant such as water.