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China’s new problems of food security revealed by the Food Equivalent Unit

Huilong LIN,Ruichao LI,Cangyu JIN,Chong WANG,Maohong WEI,Jizhou REN

《农业科学与工程前沿（英文）》 2014年第1卷第1期页码 69-76 doi: 10.15302/J-FASE-2014023

摘要： China's food security has a great influence on the world, and has always been the top priority in China. In recent years, as the concept of food security is evolving into one of nutrition security and the importance of food diversity is increasing, research based on nutrition security and broad food systems are increasingly needed in today’s China. Thus, not only grain for human consumption, but also animal foods have been integrated into the Food Equivalent, which is used to analyze China’s current agriculture system and reveal the water resource distribution. The results indicated that the average animal food consumption has risen by 78.6%, and now China’s daily supply of animal food per capita has reached about 50% of that in the USA and 80% of that in the South Korea. So there exist an obvious disparity in animal food supply between China and these two countries. It is impossible for the China’s current agricultural system to achieve the level in the USA. Under China’s current agricultural system, the consumption proportion of feed grain had surpassed the consumption of food grain, increased sharply from 33% in 1992 to 67% in 2011. However, the growth potential of total grain output is approaching an upper limit, so the continued growth of feed grain demand exerts great pressure on the China’s food supply. The discordance of the spatial distribution of water resource and virtual water revealed that China’s current agriculture system had a low efficiency in being able to achieve food and nutrition security. China’s current “grain farming” cannot meet the demand of increasing nutrition and appropriate resource utilization. The implementation of grassland agriculture appears feasible and necessary for saving feed grain, providing a large number of high-quality animal foods and appropriate water resource utilization.

关键词： food security nutrition security food equivalent unit grassland agriculture China

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Allocation of grassland, livestock and arable based on the spatial and temporal analysis for food demand

Huilong LIN, Ruichao LI, Yifan LIU, Jingrong ZHANG, Jizhou REN

《农业科学与工程前沿（英文）》 2017年第4卷第1期页码 69-80 doi: 10.15302/J-FASE-2017140

摘要： To explore the distribution of food demand and the projected trend in future food demand in China, this paper analyzed the change in current (1998–2012) per-capita demand for grain, grain-consuming and herbivorous livestock products, and predicted the food demand in 2020. The results indicated that in 1998–2012, the national per-capita consumption of grain ration declined by about 36.66%, and the per-capita consumption of grain-consu-ming and herbivorous livestock products increased by about 48% and 34.09%, respectively. The grain-consu-ming livestock products have become the primary source of both calories and protein for consumers. The proportion of herbivorous livestock products in consumer diets has increased steadily and there has been huge potential in substituting beef and mutton for pork in this dynamic market. The demand for food in different provinces of China is highly variable, which is important for planning grassland agriculture development and ensuring food safety. The demand for grain, and grain-consuming and herbivorous livestock products will increase by about 3.3%, 20% and 14% respectively by 2020. Based on the food demand and trend in the development of grassland agriculture, the 31 provinces in China are divided into three priority groups for grassland agriculture development.

关键词： arable land equivalent unit (ALEU) food equivalent unit (FEU) food security grassland agriculture time trend prediction

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Eddy current measurement of the thickness of top Cu film of the multilayer interconnects in the integrated circuit (IC) manufacturing process

Zilian QU,Yonggang MENG,Qian ZHAO

《机械工程前沿（英文）》 2015年第10卷第1期页码 1-6 doi: 10.1007/s11465-015-0325-2

摘要：

This paper proposes a new eddy current method, named equivalent unit method (EUM), for the thickness measurement of the top copper film of multilayer interconnects in the chemical mechanical polishing (CMP) process, which is an important step in the integrated circuit (IC) manufacturing. The influence of the underneath circuit layers on the eddy current is modeled and treated as an equivalent film thickness. By subtracting this equivalent film component, the accuracy of the thickness measurement of the top copper layer with an eddy current sensor is improved and the absolute error is 3 nm for sampler measurement.

关键词： CMP eddy current multilayer wafer Cu interconnects equivalent unit

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A modified zone model for estimating equivalent room thermal capacity

Hua CHEN, Xiaolin WANG

《能源前沿（英文）》 2013年第7卷第3期页码 351-357 doi: 10.1007/s11708-013-0254-x

摘要： The zone model has been widely applied in control analysis of heating, ventilation and air conditioning (HVAC) systems to achieve a high building efficiency. This paper proposed a modified zone model which is much simpler in the HVAC system simulation and has the similar accuracy to the complicated simulation model. The proposed model took into consideration the effect of envelop heat reservoir on the room indoor temperature by introducing the thermal admittance of the inner surfaces of the building enclosure. The thermal admittance for the building enclosure was developed based on the building thermal network analytical theory and transfer function method. The efficacy of the proposed model was demonstrated by comparing it with the complicated model — heat balance method (HTB2 program). The predicted results from the proposed model well agreed with those from the complicated simulation. The proposed model can then make the HVAC system dynamic simulation much faster and more acceptable for control design due to its simplicity and efficiency.

关键词： room model thermal network analysis transfer function heating ventilation and air conditioning (HVAC) system simulation

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Distribution of background equivalent static wind load on high-rise buildings

Jianguo ZHANG , Ming GU ,

《结构与土木工程前沿（英文）》 2009年第3卷第3期页码 241-248 doi: 10.1007/s11709-009-0036-z

摘要： In this paper, the along-wind and cross-wind fluctuating load distributions along the height of high-rise buildings and their correlations are obtained through simultaneous pressure measurements in a wind tunnel. Some typical methods proposed in some relative literatures, i.e., load-response correlation (LRC), and quasi-mean load (QML) and gust load envelope (GLE) methods, are verified in terms of their accuracy in describing the background equivalent static wind load distribution on high-rise buildings. Based on the results, formulae of the distribution of background equivalent static load on high-rise buildings with typical shapes are put forward. It is shown that these formulae are of high accuracy and practical use.

关键词： high-rise buildings along-wind cross-wind background equivalent static wind load close formulae

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Equivalent circuit and characteristic simulation of a brushless electrically excited synchronous wind

Hao WANG, Fengge ZHANG, Tao GUAN, Siyang YU

《机械工程前沿（英文）》 2017年第12卷第3期页码 420-426 doi: 10.1007/s11465-017-0439-9

摘要：

A brushless electrically excited synchronous generator (BEESG) with a hybrid rotor is a novel electrically excited synchronous generator. The BEESG proposed in this paper is composed of a conventional stator with two different sets of windings with different pole numbers, and a hybrid rotor with powerful coupling capacity. The pole number of the rotor is different from those of the stator windings. Thus, an analysis method different from that applied to conventional generators should be applied to the BEESG. In view of this problem, the equivalent circuit and electromagnetic torque expression of the BEESG are derived on the basis of electromagnetic relation of the proposed generator. The generator is simulated and tested experimentally using the established equivalent circuit model. The experimental and simulation data are then analyzed and compared. Results show the validity of the equivalent circuit model.

关键词： wind power brushless electrically excited synchronous generator hybrid rotor equivalent circuit

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A solution to stochastic unit commitment problem for a wind-thermal system coordination

B. SARAVANAN,Shreya MISHRA,Debrupa NAG

《能源前沿（英文）》 2014年第8卷第2期页码 192-200 doi: 10.1007/s11708-014-0306-x

摘要： Unit commitment (UC) problem is one of the most important decision making problems in power system. In this paper the UC problem is solved by considering it as a real time problem by adding stochasticity in the generation side because of wind-thermal co-ordination system as well as stochasticity in the load side by incorporating the randomness of the load. The most important issue that needs to be addressed is the achievement of an economic unit commitment solution after solving UC as a real time problem. This paper proposes a hybrid approach to solve the stochastic unit commitment problem considering the volatile nature of wind and formulating the UC problem as a chance constrained problem in which the load is met with high probability over the entire time period.

关键词： unit commitment (UC) randomness wind generation univariate chance constrained

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Solving unit commitment problem using a novel version of harmony search algorithm

Roozbeh MORSALI,Tohid JAFARI,Amirhossein GHODS,Mohammad KARIMI

《能源前沿（英文）》 2014年第8卷第3期页码 297-304 doi: 10.1007/s11708-014-0309-7

摘要： In this context, a novel structure was proposed for improving harmony search (HS) algorithm to solve the unit comment (UC) problem. The HS algorithm obtained optimal solution for defined objective function by improvising, updating and checking operators. In the proposed improved self-adaptive HS (SGHS) algorithm, two important control parameters were adjusted to reach better solution from the simple HS algorithm. The objective function of this study consisted of operation, start-up and shut-down costs. To confirm the effectiveness, the SGHS algorithm was tested on systems with 10, 20, 40 and 60 generating units, and the obtained results were compared with those of the simple HS algorithm and other related works.

关键词： generation scheduling harmony search (HS) algorithm intelligent technique unit commitment

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A solution to the unit commitment problem—a review

B. SARAVANAN, Siddharth DAS, Surbhi SIKRI, D. P. KOTHARI

《能源前沿（英文）》 2013年第7卷第2期页码 223-236 doi: 10.1007/s11708-013-0240-3

摘要： Unit commitment (UC) is an optimization problem used to determine the operation schedule of the generating units at every hour interval with varying loads under different constraints and environments. Many algorithms have been invented in the past five decades for optimization of the UC problem, but still researchers are working in this field to find new hybrid algorithms to make the problem more realistic. The importance of UC is increasing with the constantly varying demands. Therefore, there is an urgent need in the power sector to keep track of the latest methodologies to further optimize the working criterions of the generating units. This paper focuses on providing a clear review of the latest techniques employed in optimizing UC problems for both stochastic and deterministic loads, which has been acquired from many peer reviewed published papers. It has been divided into many sections which include various constraints based on profit, security, emission and time. It emphasizes not only on deregulated and regulated environments but also on renewable energy and distributed generating systems. In terms of contributions, the detailed analysis of all the UC algorithms has been discussed for the benefit of new researchers interested in working in this field.

关键词： unit commitment (UC) optimization deterministic load stochastic load evolutionary programming (EP) hybrid

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Fault classification and reconfiguration of distribution systems using equivalent capacity margin method

K. Sathish KUMAR, T. JAYABARATHI

《能源前沿（英文）》 2012年第6卷第4期页码 394-402 doi: 10.1007/s11708-012-0211-0

摘要： This paper investigates the capability of support vector machines (SVM) for prediction of fault classification and the use of the concept of equivalent capacity margin (ECM) for restoration of the power system. The SVM, as a novel type of machine learning based on statistical learning theory, achieves good generalization ability by adopting a structural risk minimization (SRM) induction principle aimed at minimizing a bound on the generalization error of a model rather than the minimization of the error on the training data only. Here, the SVM has been used as a classification. The inputs of the SVM model are power and voltage values. An equation has been developed for the prediction of the fault in the power system based on the developed SVM model. The next steps of this paper are the restoration and reconfiguration by using the ECM concept, the development of a code, and the testing of the results with various load outages, which have been executed for a 12 load system.

关键词： support vector machines (SVM) structural risk minimization (SRM) equivalent capacity margin (ECM) restoration fault classification

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TRANSFORMING CHINESE FOOD AND AGRICULTURE: A SYSTEMS PERSPECTIVE

《农业科学与工程前沿（英文）》 2023年第10卷第1期页码 4-15 doi: 10.15302/J-FASE-2023493

摘要：

● The goals of Chinese food and agriculture have shifted from grain self-sufficiency to diversified goals, including protecting natural resources, reducing pollution and greenhouse gas emissions, and improving food safety and nutrition.

关键词： food systems food security nutrition climate change

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Energy saving design of the machining unit of hobbing machine tool with integrated optimization

《机械工程前沿（英文）》 2022年第17卷第3期 doi: 10.1007/s11465-022-0694-2

摘要： The machining unit of hobbing machine tool accounts for a large portion of the energy consumption during the operating phase. The optimization design is a practical means of energy saving and can reduce energy consumption essentially. However, this issue has rarely been discussed in depth in previous research. A comprehensive function of energy consumption of the machining unit is built to address this problem. Surrogate models are established by using effective fitting methods. An integrated optimization model for reducing tool displacement and energy consumption is developed on the basis of the energy consumption function and surrogate models, and the parameters of the motor and structure are considered simultaneously. Results show that the energy consumption and tool displacement of the machining unit are reduced, indicating that energy saving is achieved and the machining accuracy is guaranteed. The influence of optimization variables on the objectives is analyzed to inform the design.

关键词： energy saving design energy consumption machining unit integrated optimization machine tool

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Soil security and global food security

《农业科学与工程前沿（英文）》 doi: 10.15302/J-FASE-2023530

摘要：

● Much of the world’s agricultural land has been degraded through soil loss and degradation of soil organic matter.

关键词： Agriculture soil security food security regenerative

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Low crosstalk switch unit for dense piezoelectric sensor networks

Lei QIU, Shenfang YUAN,

《机械工程前沿（英文）》 2009年第4卷第4期页码 401-406 doi: 10.1007/s11465-009-0047-4

摘要： Structural health monitoring (SHM), on the basis of piezoelectric (PZT) sensors and lamb wave method, is efficient in estimating the state of monitored structures. Furthermore, to monitor large-scale structures, dense piezoelectric sensor networks are required, which usually contain many piezoelectric sensor pairs called actuator-sensor channels. In that case, considering the few data acquisition channels especially in the data acquisition board with a high sampling rate and limited quantity of signal amplifiers used in an integrated computer system, a switch unit is adopted to switch to different channels. Because of the high frequency and power of the lamb wave excitation signal, there exists a crosstalk signal in the switch unit. A large crosstalk signal is mixed into the response signal so that the on/off-line signal processing task is difficult to achieve. This paper first analyzes the crosstalk signal phenomenon, describes its production mechanism, and proposes a method to reduce it. Then a 24-switch channel low crosstalk switch unit based on a digital I/O board PCI7248 produced by Adlink technology is developed. An experiment is implemented to validate it. Its low crosstalk characteristics make it promote the real application of the SHM based active lamb wave method. Finally, a general software program based on LabVIEW software platform is developed to control this switch unit.

关键词： structural health monitoring (SHM) piezoelectric (PZT) sensor networks switch unit crosstalk signal

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Review on drivers, trends and emerging issues of the food wastage in China

Lin MA,Wei QIN,Tara GARNETT,Fusuo ZHANG

《农业科学与工程前沿（英文）》 2015年第2卷第2期页码 159-167 doi: 10.15302/J-FASE-2015066

摘要： China has successfully achieved food self-sufficiency over the past 50 years, however, with large inputs and losses. To meet the challenge of feeding a growing population with limited resources, many studies have explored options for improving productivity and efficiency of the food production. However, there have been few studies into the potential of reducing food loss along the whole food production-consumption chain. Here we review the literature on food waste in China. We briefly analyze (1) the drivers that influence levels of food waste in the food chain, (2) examine trends in the volumes and types of food wasted at different stages in the food chain, (3) assess the environmental and resource consequences of food waste in the food chain, and (4) evaluate the policy and stakeholder responses to the emerging challenges. It is concluded that reducing food loss and meeting food security in China requires a coherent institutional structure that promotes the synergistic outcomes of research, policy and education. Suggested key actions include (1) improving machinery and facility for sowing, harvesting, transportation and storage, which can reduce food loss by up to 50%, and (2) improving food waste recycling management, based on coupled food production and consumption systems.

关键词： food security food chain food wastes and losses environmental impacts