Measurement of the squeezed vacuum state by a bichromatic local oscillator

We present the experimental measurement of a squeezed vacuum state by means of a bichromatic local oscillator (BLO). A pair of local oscillators at $\pm$5 MHz around the central frequency $\omega_{0}$ of the fundamental field with equal power are generated by three acousto-optic modulators and phase-locked, which are used as a BLO. The squeezed vacuum light are detected by a phase-sensitive balanced-homodyne detection with a BLO. The baseband signal around $\omega_{0}$ combined with a broad squeezed field can be detected with the sensitivity below the shot-noise limit, in which the baseband signal is shifted to the vicinity of 5 MHz (the half of the BLO separation). This work has the important applications in quantum state measurement and quantum informatio

Identifying primary energy requirements in structural path analysis: A case study of China 2012

Primary energy requirements have close interaction with resource, technology, environment, infrastructure, as well as the socio-economic development. This study links the entire supply chain of the Chinese economy from energy extraction to final consumption by using input-output analysis and structural path analysis. The results show that the domestic primary energy input amounted to 3318.7 Mtce in 2012, of which 49.5% was induced by investment demands. Despite being one of the world's largest energy importers, embodied energy uses (EEUs) in China’s exports were equivalent to about one fourth of its total domestic supply. All Manufacturing sectors accounted for 44.3% of the total EEUs, followed by Construction for 33.3%, Services for 11.6% and Power & Heat for 3.9%. After examining the embodied energy paths, critical economic sectors such as Construction of Buildings, Construction Installation Activities, Transport Via Road, Production and Supply of Electricity and Steam and Processing of Steel Rolling Processing, and supply chain routes starting from final uses to resource extraction such as “Capital formation → Construction of Buildings → Production and Supply of Electricity and Steam → Production and Supply of Electricity and Steam → Mining and Washing of Coal”, were identified as the main contributors to China’s raw coal and other primary energy requirements. Restructuring Chinese economy from manufacturing industries to construction and services with huge economic costs cannot fundamentally conserve energy, owing to their almost identical structures in higher production tiers; more appropriate policies on technology efficiency gains, energy mix improvement, economic structure adjustment and green consumption deserve to be considered in the light of upstream and downstream responsibilities from a systematic viewpoint

Research on Aircraft Cable Defects Locating Method Based on Time-Frequency Domain Reflection

AbstractThis paper presents an aircraft cable fault detection and location method based on TFDR in order to detect the intermittent faults effectively and to cope with the serial and after-connector faults being difficult to be detected in time domain reflection. In this method, the correlation function of reflected and reference signal is utilized to detect and locate the aircraft fault according to the characteristics of reflected and reference signal in time-frequency domain, so the hit rate of detecting and locating intermittent faults can be improved effectively. In the work process, the reflected signal is interfered by the noise and false alarm takes place frequently, so the threshold de-noising method based on wavelet decomposition is utilized to decrease the noise interference and reduce the fault alarm rate. Then the time-frequency cross correlation function of the reference signal and the reflected signal based on Wigner-Ville distribution is computed in order to locate the fault position. At last, LabVIEW is applied to implement operation and control interface, the main function of which is to link and control MATLAB and LABSQL. Utilizing the strong calculating capability and the abundant function library of MATLAB, the signal processing turn to be easily realized, moreover LabVIEW help the system to be more reliable and updated easily

Mathematical and experimental evaluation of a mini-channel PV/T and thermal panel in summer mode

In this paper, a mini-channel PV/T and mini-channel thermal panel hot water system is presented. The thermal panels in this system use mini-channel tube as the heat exchanger, which has a small hydraulic diameter and large heat exchanger area, and this special structure can improve the heat transfer coefficient at the same flow rate than the conventional type. The performance of this system for generating hot water and electricity in summer has been tested, and a simulation model of this operating mode has been developed. Based on a typical day's weather data, the simulation model is verified, and the experimental and simulated results agree with each other very well. The results reveal that the experimental and simulated electrical efficiencies of PV/T panels are 11.5% and 12.6%, respectively. The experimental and simulated thermal efficiencies of thermal collectors are 46.8% and 48.0%, respectively. The experimental and simulated final water temperatures in the tank are 59.3 °C and 60.9 °C, respectively. Based on these results, an error analysis is carried out. The experimental and simulation results of the system in summer provide a fundamental data and method for predicting the annual performance of the system in the future

Operational performance of a novel heat pump coupled with mini-channel PV/T and thermal panel in low solar radiation

Here we describe a heat pump system coupled with novel PV/T and thermal panels for space heating in low solar radiation conditions. Existing solar indirect-expansion systems connect the solar panels and evaporator of the heat pump in parallel with the heat storage tank. For our system these three components are instead connected in series, which can stabilize the temperature at the inlet of the evaporator and decrease the inlet temperature of the solar panels, leading to improved energy efficiency and the production of much more thermal energy. The experimental results of this system show that the average electrical, thermal and overall efficiency of the PV/T panels are 15.9%, 33.4% and 49.3%, respectively. The average thermal efficiency of the thermal panels is 60.4%, the COP of heat pump is 4.7 and the room temperature is constantly over 18 °C. Based on the experimental results, some improvements are analyzed. We conclude that this operating model can meet the requirement of space heating in low solar radiation environments

AsdKB: A Chinese Knowledge Base for the Early Screening and Diagnosis of Autism Spectrum Disorder

To easily obtain the knowledge about autism spectrum disorder and help its early screening and diagnosis, we create AsdKB, a Chinese knowledge base on autism spectrum disorder. The knowledge base is built on top of various sources, including 1) the disease knowledge from SNOMED CT and ICD-10 clinical descriptions on mental and behavioural disorders, 2) the diagnostic knowledge from DSM-5 and different screening tools recommended by social organizations and medical institutes, and 3) the expert knowledge on professional physicians and hospitals from the Web. AsdKB contains both ontological and factual knowledge, and is accessible as Linked Data at https://w3id.org/asdkb/. The potential applications of AsdKB are question answering, auxiliary diagnosis, and expert recommendation, and we illustrate them with a prototype which can be accessed at http://asdkb.org.cn/.Comment: 17 pages, Accepted by the Resource Track of ISWC 202

Feasibility of an innovative amorphous silicon photovoltaic/thermal system for medium temperature applications

Medium temperature photovoltaic/thermal (PV/T) systems have immense potential in the applications of absorption cooling, thermoelectric generation, and organic Rankine cycle power generation, etc. Amorphous silicon (a-Si) cells are promising in such applications regarding the low temperature coefficient, thermal annealing effect, thin film and avoidance of large thermal stress and breakdown at fluctuating temperatures. However, experimental study on the a-Si PV/T system is rarely reported. So far the feasibility of medium temperature PV/T systems using a-Si cells has not been demonstrated. In this study, the design and construction of an innovative a-Si PV/T system of stainless steel substrate are presented. Long-term outdoor performance of the system operating at medium temperature has been monitored in the past 15 months. The average electrical efficiency was 5.65%, 5.41% and 5.30% at the initial, intermediate and final phases of the long-test test, accompanied with a daily average thermal efficiency from about 21% to 31% in the non-heating season. The thermal and electrical performance of the system at 60 °C, 70 °C and 80 °C are also analyzed and compared. Moreover, a distributed parameter model with experimental validation is developed for an inside view of the heat transfer and power generation and to predict the system performance in various conditions. Technically, medium temperature operation has not resulted in interruption or observable deformation of the a-Si PV/T system during the period. The technical and thermodynamic feasibility of the a-Si PV/T system at medium operating temperature is demonstrated by the experimental and simulation results