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Food security is closely related to individual livelihood and social stability, and assessing the state of food security is essential for making agricultural policies. Nonetheless multi‐scale assessment of national food security state with explicit consideration of availability and access remains to be resolved. In this study, a spatially explicit crop model was used to simulate the production of major crops in China (i.e., wheat, maize, rice, and soybeans). Food production (as simulated by the crop model) and GDP per capita relative to the global average were then used to develop food security indicators to evaluate China's food security levels on grid, provincial, and economic zone scales. The Getis–Ord method was further applied to analyze the spatial aggregation of food security and food insecurity provinces. Results show that food security situation improved in mainland China during 1990–2015, attributed largely to the enhanced purchasing power. On the grid scale, changes in food security state went through two stages: Before 2000, the regions in the eastern part of the Hu Line were food security, while the regions in the western part were food insecurity; after 2000, the state of food security greatly improved from insecurity to security in Northwest China, and the areas of the highest security level considerably increased in eastern China. On the provincial scale, food security state in most provinces improved or almost unchanged over time. Exception was found in coastal provinces, with food security state was greatly affected by urbanization. Food security hot spots were primarily detected in central China, while cold spots were detected in Xinjiang, Qinghai, and Tibet. On the economic zone scale, food security areas in the eastern part decreased during 1990–2010 but increased thereafter, while food security areas in the other three economic zones increased from 1990 to 2015. To ensure food security, China should maintain the arable land areas, improve the quality of farmlands, mobilize farming enthusiasm, and advance agricultural marketization.

Changes in land systems have been shown to affect regional climate, but minimal attention has been paid to landscape patterns as adaptation strategies to climate change. In this study, we introduce alternative futures analysis and coupled land-atmosphere modeling to investigate the effect of landscape patterns on moderating projected climate change in northern China. Three future landscape scenarios are developed, and their impacts on regional climate in the context of climate change are examined. A reference scenario, Business-as-Usual, follows recent landscape trajectory; the Conservation scenario puts greater emphasis on ecosystem protection and restoration to ultimately achieve sustained socioeconomic development; the Degradation scenario ignores current policy to allow broad cropland expansion. The landscape impacts on regional climate under two representative concentration pathways (RCPs) are substantial and dependent on background climate. The Conservation scenario shows considerable decreases in near-surface temperature and extensive increases in rainfall during summer as compared with Business-as-Usual under RCP8.5 (i.e., a high emissions scenario), thus representing a preferred landscape pattern for climate moderation. However, trade-offs between temperature reduction and rainfall enhancement exist under RCP4.5 (i.e., a low-to-moderate emissions scenario), which necessitates careful evaluation. Finally, the Degradation scenario leads to the highest temperature and lowest rainfall among the three alternative futures under both climate conditions. Our study underlines the importance of landscape design/planning as an effective way to moderate climate change, and provides useful scientific information for making land use policies.

Both crop distribution and climate change are important drivers for crop production and can affect food security, which is an important requirement for sustainable development. However, their effects on crop production are confounded and warrant detailed investigation. As a key area for food production that is sensitive to climate change, the agro-pastoral transitional zone (APTZ) plays a significant role in regional food security. To investigate the respective effects of crop distribution and climate change on crop production, the well-established GIS-based Environmental Policy Integrated Climate (EPIC) model was adopted with different scenario designs in this study. From 1980 to 2010, the crop distribution for wheat, maize, and rice witnessed a dramatic change due to agricultural policy adjustments and ecological engineering-related construction in the APTZ. At the same time, notable climate change was observed. The simulation results indicated that the climate change had a positive impact on the crop production of wheat, maize, and rice, while the crop distribution change led to an increase in the production of maize and rice, but a decrease in the wheat production. Comparatively, crop distribution change had a larger impact on wheat (–1.71 × 106 t) and maize (8.53 × 106 t) production, whereas climate change exerted a greater effect on rice production (0.58 × 106 t), during the period from 1980 to 2010 in the APTZ. This study is helpful to understand the mechanism of the effects of crop distribution and climate change on crop production, and aid policy makers in reducing the threat of future food insecurity.

Agricultural ecosystem management needs to ensure food production and minimize soil erosion and nitrogen (N) leaching under climate change and increasingly intensive human activity. Thus, the mechanisms through which climatic and management factors affect crop production, soil erosion, and N leaching must be understood in order to ensure food security and sustainable agricultural development. In this study, we adopted the GIS-based Environmental Policy Integrated Climate (EPIC) model to simulate crop production, soil erosion, and N leaching, and used a partial least squares regression model to evaluate the contributions of climate variables (solar radiation, precipitation, wind speed, relative humidity, and maximum and minimum temperature) and management factors (irrigation, fertilization, and crop cultivation area) on agricultural ecosystem services (AES) in the agro-pastoral transitional zone (APTZ) of northern China. The results indicated that crop production and N leaching markedly increased, whereas soil erosion declined from 1980 to 2010 in the APTZ. Management factors had larger effects on the AES than climate change. Among the climatic variables, daily minimum temperature was the most important contributor to the variations in ecosystem services of wheat, maize, and rice. Spatial changes in the cultivated area most affected crop production, soil erosion, and N leaching for majority of the cultivated areas of the three crops, except for the wheat-cultivated area, where the dominant factor for N leaching was fertilization. Although a tradeoff existed between crop production and negative environmental effects, compromises were possible. These findings provide new insights into the effects of climatic and management factors on AES, and have practical implications for improving crop production while minimizing negative environmental impacts.

Current blood-based approach for gout diagnosis can be of low sensitivity and hysteretic. Here via a 68-member cohort of 33 healthy and 35 diseased individuals, we reported that the intestinal microbiota of gout patients are highly distinct from healthy individuals in both organismal and functional structures. In gout, Bacteroides caccae and Bacteroides xylanisolvens are enriched yet Faecalibacterium prausnitzii and Bifidobacterium pseudocatenulatum depleted. The established reference microbial gene catalogue for gout revealed disorder in purine degradation and butyric acid biosynthesis in gout patients. In an additional 15-member validation-group, a diagnosis model via 17 gout-associated bacteria reached 88.9% accuracy, higher than the blood-uric-acid based approach. Intestinal microbiota of gout are more similar to those of type-2 diabetes than to liver cirrhosis, whereas depletion of Faecalibacterium prausnitzii and reduced butyrate biosynthesis are shared in each of the metabolic syndromes. Thus the Microbial Index of Gout was proposed as a novel, sensitive and non-invasive strategy for diagnosing gout via fecal microbiota.

A bias-temperature cycling technique is developed in the electrical characterization of YBa2Cu307−δ/yttria-stabilized zirconia (YSZ)/Si capacitors. This technique can be used to determine the electrical properties of the material components and their interfaces in the capacitor. Capacitance-voltage (C-V) measurements under no or weak illumination at temperatures ranging from 295 to 80K reveal that hysteresis due to mobile ions decreases with cooling and become vanishingly small at about 220K. Upon further cooling, a different mechanism due to traps in the YSZ/Si interface dominates the low-temperature hysteresis and stretchout of the C-V curves, which is evidenced by measurements for the illuminated device at 80K.

Characterization of a Si1−xGex layer formed by high-dose germanium implantation and subsequent solid phase epitaxy is reported. Properties of this layer are obtained from electrical measurements on diodes and transistors fabricated in this layer. Results are compared with those of the silicon control devices. It was observed that the germanium implantation created considerable defects that are difficult to eliminate with annealing. These defects result in boron deactivation in the p-type regions of the devices, giving rise to larger resistance. Optimization of the device structure and fabrication process is discussed.

The a-Si:H thin film is used for a photosensor in liquid crystal light valve(LCLV). A lumped element model for the layered a-Si:H LCLV is developed. It has been shown that the dark and photo-resistances of the a-Si:H photosensor should be adjusted respectively to within the region between one order of magnitude higher and one order of magnitude lower than that of the liquid crystal(LC) layer to ensure a linear variation of the voltage across the LC with the intensity of the incident write-light beam. For obtaining an optimal operation condition of the LCLV, we can determine the concrete values of the dark resistance of the photosensor from the threshold voltage of the LCLV for the linear change of the LCLVs grey level and the applied voltage of the LCLV, and the photoresistance of the photosensor from the saturation voltage of the LC. As a result, the application of an a-Si:H film by optimization of the deposition condition indicates that the contrast of LCLV can be improved distinctively.

Liquid crystal light valve(LCLV) using an a-Si:H/μc-Si:H heterostructure as the photosensor and the nematic liquid crystal as the modulator has been firstly presented for large screen projection display. The a-Si:H photoconductor and μc-Si:H light blocking layer were prepared by a modified glow discharge CVD method. The optoelectric and structure properties of the μc-Si:H films deposited at different deposition conditions have been studied. The a-Si:H film and the continuously deposited pc-Si:H film possibly form an a-Si:H/μc-Si:H heterojunction. The electrical and optoelectric properties of the heterojunction has been studied.LCLV using a-Si:H/μc-Si:H heterostructure has shown that the most aspects of the device performance can be improved.

A-Si : H and a-Si : H/a-SiGe : H heterojunctions have been prepared as the photoconductors in the liquid crystal light valves. The impedance matching conditions of the a-Si : H and the heterojunction in the valves have been carefully analysed, which has shown that the adjustment for the capacitance of the photoconductor is the key procedure for the matching, but the low photocapacitance effect in the a-Si : H limits the further improvements on the matching. The formation of the a-Si : H/a-SiGe : H diode promotes the photocapacitance effect in the photoconductor, and the matching behavior in the valve is greatly improved.

High density plasma deposited phosphosilicate glass (PSG) films were evaluated for an application as pre-metal gap-fill dielectric material. A high deposition rate (∼600 nm/min) PSG film with 9 at. % of P and a deposition-to-etch ratio of 5:1 was developed for a void-free gap fill down to 0.04 μm. Chemical-mechanical polish, reactive ion etch, and defect test of the PSG film have revealed that as-deposited PSG has performed similar to the annealed one, and PSG has an excellent film stability. A significant device yield improvement was obtained using this 9 at. % PSG process.

A self-aligned contact (SAC) technology is developed for the application of electrical contacts between the local interconnect and the silicon diffusion regions for 0.18 μm static random access memory cells. The key components of this SAC technology include the deposition and gap fill of borophosphosilicate glass (BPSG) films, a selective oxide etch process, and metal-plug contact formation by Ti/TiN-liner silicidation and W filling. The BPSG film, deposited by plasma enhanced chemical vapor deposition, has exhibited an ability of filling 0.04 μm spaces with an aspect ratio (AR) of about 10:1 after reflow at 800 °C. Reduction of the reflow temperature without gap-fill deterioration by increasing the B incorporation in the BPSG film is not feasible due to an increase of BPSG defects. The oxide SAC etch performance is modulated by an oxide-to-nitride etch selectivity which has shown a strong dependence on the wafer temperature. The etch process window is improved by optimization of the process conditions in...