Showing papers by "Lei Wang published in 2018"

Warming-induced upward migration of the alpine treeline in the Changbai Mountains, northeast China

Abstract: Treeline responses to environmental changes describe an important phenomenon in global change research. Often conflicting results and generally too short observations are, however, still challenging our understanding of climate-induced treeline dynamics. Here, we use a state-of-the-art dendroecological approach to reconstruct long-term changes in the position of the alpine treeline in relation to air temperature at two sides in the Changbai Mountains in northeast China. Over the past 160 years, the treeline increased by around 80 m, a process that can be divided into three phases of different rates and drives. The first phase was mainly influenced by vegetation recovery after an eruption of the Tianchi volcano in 1702. The slowly upward shift in the second phase was consistent with the slowly increasing temperature. The last phase coincided with rapid warming since 1985, and shows with 33 m per 1°C, the most intense upward shift. The spatial distribution and age structure of trees beyond the current treeline confirm the latest, warming-induced upward shift. Our results suggest that the alpine treeline will continue to rise, and that the alpine tundra may disappear if temperatures will increase further. This study not only enhances mechanistic understanding of long-term treeline dynamics, but also highlights the effects of rising temperatures on high-elevation vegetation dynamics.

Maximum precipitation altitude on the northern flank of the Qilian Mountains, northwest China

Abstract: Investigation of the altitude of maximum precipitation (AMP) and the factors that determine this height supports the understanding of vertical precipitation distribution in mountains. Based on the field precipitation measurement on the northern flank of the Qilian Mountains, the AMP was investigated at vertical profiles from 1,483 to 4,484 m. It found a 2,300 m-AMP in winter and a 4,200 m-AMP in other seasons and on a yearly scale. The AMPs increase from the cold and dry season to the warm and wet season and therefore increase with precipitation. During winter, the interaction of the predominant high-pressure system, the thermal inversion layer below 2,200 m, and the westerly lead to the 2,300-m AMP. In other seasons, the convergent Tibetan Plateau monsoon causes the water vapor move to the Qilian Mountains, and the enhanced uplifting by the mountain produces greater precipitation with altitude, forming the AMP at the higher areas. The front steepest terrain is the primary factor causing the formation of 4,200-m AMP in the study area. The annual AMP may be roughly equal to seven-eighths of the altitude of the mountain top on the north flank of the Qilian Mountains.

Liquid metal fractals induced by synergistic oxidation

Abstract: Ga-based liquid metal has drawn attention in the field of interface science due to its large deformability. However, the spreading and shaping of liquid metal still remain a huge challenge to be solved owing to its large surface tension. Here, an intriguing synergistic oxidation-driven liquid metal fractal phenomenon was discovered and the general mechanisms were interpreted, which provides a new strategy for manipulating liquid metal. Experimental results demonstrate that the liquid metal placed on the graphite plate exhibited fractal characteristics with the addition of hydrogen peroxide. Here, it is of significance that hydrogen peroxide and graphite plates synergistically oxidize liquid metal. In addition, we predicted that liquid metal fractals can also be achieved on other eligible substrates based on the proposed general mechanism, which was confirmed by relevant experiments. Furthermore, the fractal dimensions of liquid metal fractal pattern were obtained and evaluated, distinguishing the synergistic oxidation-driven liquid metal fractals from the voltage-driven liquid metal fractals. Besides, we initially gave the best concentration range in which dendritic fractals can occur in order to guide practice. The ability to achieve liquid metal fractals promises rich opportunities in freely driving the liquid metal for soft machines and manufacturing the shape-reconfigurable electronic circuits.

Precipitation–altitude relationships on different timescales and at different precipitation magnitudes in the Qilian Mountains

Abstract: It is generally accepted that altitude is the main variable governing the spatial distribution of precipitation in the mountains. This study mainly discusses the precipitation–altitude relationships on different timescales and at different individual precipitation magnitudes in the entire study period (April 2012 to September 2015), wet season (May to September), and dry season (October to April), and tries to find a threshold to determine whether the correlation between precipitation and altitude is significant. In this study, the half-hourly data, including precipitation, wind speed, and air temperature, from April 2012 to September 2015 are obtained by six automatic meteorological stations located on the north slope of Qilian Mountains, which range from 2980 to 4484 m a.s.l., and horizontal distance is approximately 7000 m. Results indicate that (i) if all samples in the entire study period are to be investigated, the individual precipitation had to reach about 30 or 40 mm, then the sample may pass the significance test at p < 0.05 or at p < 0.01, respectively. The thresholds in wet season are same as that during entire study period. The thresholds in dry season are about 10 and 15 mm (ii) with increasing timescale, the percentage of samples that pass the test increases. However, it is until the monthly scale whether it is wet or dry season or the entire study period, the precipitation–altitude relationships have statistical significance and using the monthly or yearly scale as the time unit can be better applied to the research, which is based on the precipitation–altitude relationships.

Liquid Metal Enabled Flexible Electronic System for Eye Movement Tracking

Abstract: Eye movement tracking is concerned with many important areas of research, of which tracking with a traditional scleral search coil system is deemed the gold standard. However, since such coil system requires anaesthetic use due to the stiffness of the copper wire coil in the system, it is of great importance to improve the wearing sensation experience. Here, an innovative electronic system for eye movement recording is proposed and realized, in which a liquid metal coil is introduced as the core element, attempting to provide a comfortable eye sensation. Theoretical investigation shows that this type of coil has performance similar to the traditional copper coil, which implies it is suitable for eye movement tracking. It has been demonstrated that such liquid metal coil is soft, flexible, and easy to produce, indicating that the coil is potentially favorable as a wearable medical device. Experiments show that the variance fitting curve between the induced voltage and rotation angle measured with the liquid metal coil during eye movement accords well with that of the classical copper scleral search coil, with both determination coefficients over 0.98, which confirms the reliability of the new coil. Overall, the feasibility of the liquid metal coil system suggests a useful approach for detecting human eye movement behavior and related diseases, which may facilitate disease diagnosis and prediction.

Water and CO2 fluxes over semiarid alpine steppe and humid alpine meadow ecosystems on the Tibetan Plateau

Abstract: Based on eddy covariance flux data from July 15, 2014, to December 31, 2015, the water and CO2 fluxes were compared over a semiarid alpine steppe (Bange, Tibetan Plateau) and a humid alpine meadow (Lijiang, Yunnan) on the Tibetan Plateau and its surrounding region. During the wet season, the evaporative fraction (EF) was strongly and linearly correlated with the soil water content (SWC) at Bange because of its sparse green grass cover. In contrast, the correlation between the EF at Lijiang and the SWC and the normalized difference vegetation index (NDVI) was very low because the atmosphere was close to saturation and the EF was relatively constant. In the dry season, the EF at both sites decreased with the SWC. The net ecosystem exchange (NEE) at Bange was largely depressed at noon, while this phenomenon did not occur at Lijiang. The saturated NEE at Bange was 24% of that at Lijiang. The temperature sensitivity coefficient of ecosystem respiration at Bange (1.7) was also much lower than that at Lijiang (3.4). The annual total NEE in 2015 was 21.8 and −230.0 g C m−2 yr−1 at Bange and Lijiang, respectively, and the NEE was tightly controlled by the NDVI at the two sites. The distinct differences in the water and CO2 fluxes at Bange and Lijiang are attributed to the large SWC difference and its effect on vegetation growth.

Differences of the changes in soil temperature of cold and mid-temperate zones, Northeast China

Abstract: Rapid changes in soil temperature are unequivocal under global change, especially in mid-high latitudes. Studies on the relationships between soil temperature and climate system are lacking at regional climatic scale. Here, changes in shallow soil temperature (0, 5, 10, 15, 20 cm), both in the cold temperate zone (CTZ) and the mid-temperate zone (MTZ) in Northeast China, were compared and analyzed using daily data from growing seasons (May to September) from 1964 to 2011. The influences of air temperature and precipitation on soil temperature were analyzed. The results showed that for nearly half a century, the increasing trend of surface soil temperature in the CTZ was lower than that in the MTZ, with + 0.17 and + 0.54 °C/decade, respectively. Air temperature increased faster for the MTZ than the CTZ. Precipitation increased in the CTZ but decreased in the MTZ. Since 1996, the temperature increase and precipitation decrease were more obvious in the MTZ. In summary, given the complex effects of temperature and precipitation, the response of soil temperature was more significant in the MTZ than in the CTZ. These results emphasize the importance of independently researching soil temperature of different climate zones. Susceptibility of soil temperature to global warming will advance our understanding on utilization of climatic resources in the development of agricultural production.

Predicting Wetland Distribution Changes under Climate Change and Human Activities in a Mid- and High-Latitude Region

Abstract: Wetlands in the mid- and high-latitudes are particularly vulnerable to environmental changes and have declined dramatically in recent decades. Climate change and human activities are arguably the most important factors driving wetland distribution changes which will have important implications for wetland ecological functions and services. We analyzed the importance of driving variables for wetland distribution and investigated the relative importance of climatic factors and human activity factors in driving historical wetland distribution changes. We predicted wetland distribution changes under climate change and human activities over the 21st century using the Random Forest model in a mid- and high-latitude region of Northeast China. Climate change scenarios included three Representative Concentration Pathways (RCPs) based on five general circulation models (GCMs) downloaded from the Coupled Model Intercomparison Project, Phase 5 (CMIP5). The three scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) predicted radiative forcing to peak at 2.6, 4.5, and 8.5 W/m2 by the 2100s, respectively. Our results showed that the variables with high importance scores were agricultural population proportion, warmness index, distance to water body, coldness index, and annual mean precipitation; climatic variables were given higher importance scores than human activity variables on average. Average predicted wetland area among three emission scenarios were 340,000 ha, 123,000 ha, and 113,000 ha for the 2040s, 2070s, and 2100s, respectively. Average change percent in predicted wetland area among three periods was greatest under the RCP 8.5 emission scenario followed by RCP 4.5 and RCP 2.6 emission scenarios, which were 78%, 64%, and 55%, respectively. Losses in predicted wetland distribution were generally around agricultural lands and expanded continually from the north to the whole region over time, while the gains were mostly associated with grasslands and water in the most southern region. In conclusion, climatic factors had larger effects than human activity factors on historical wetland distribution changes and wetland distributions were predicted to decline remarkably over time under climate change scenarios. Our findings have important implications for wetland resource management and restoration because predictions of future wetland changes are needed for wetlands management planning.

Employee Competitive Attitude and Competitive Behavior Promote Job-Crafting and Performance: A Two-Component Dynamic Model.

Abstract: While competition has become increasingly fierce in organizations and in the broader market, the research on competition at an individual level is limited. Most existing research focuses on trait competitiveness. We argue that employee competitiveness can be state-like and can be demonstrated as an attitude toward and behavior representative of competition. We therefore propose a dynamic model with two separate components: competitive attitude and competitive behavior. Drawing upon self-determination theory and the person-environment interaction perspective, we examine how employee competitive attitude and competitive behavior can be influenced by both personal characteristics and team climate, which in turn leads to different work outcomes, as demonstrated in two studies. Study 1 developed measures for competitive attitude and competitive behavior. Study 2 collected data from salespeople in a large insurance company in three waves. The results showed that employee competitive attitude and behavior could be predicted by personality. Moreover, employee competitive attitude and behavior were related to sales performance in differential ways via job crafting, and these mediated relationships could be moderated by team climate. These findings support the two-component dynamic model combining competitive attitude and behavior, which helps promote understanding of the dynamics of competition and its consequences at the individual level. Theoretical and practical implications are also discussed.

Variations in the start, end, and length of extreme precipitation period across China

Abstract: Using the daily precipitation records during 1961–2013 from 686 meteorological stations across China and the atmospheric circulation indexes, this study investigates the spatio-temporal changes in the occurrence time and length of the extreme precipitation period (EPP), as well as their influencing factors. The results show the following aspects: (1) In the last 53 years, the start dates of the extreme precipitation period (EPPS) generally advanced. The end dates of the extreme precipitation period (EPPE) are delayed, which show an increasing trend. The lengths of the extreme precipitation period (EPPL) in most of the China meteorological stations increased. (2) The spatial patterns of the trends in the occurrence time and length of the extreme precipitation period are similar and show obvious clustering. The occurrence time and length of the extreme precipitation period have obvious spatial gradient differences in their average values. In southeastern China, the average EPPS is earlier, EPPE is later than those in other regions, and their EPPL is prolonged. The EPP in northeastern China begins later and ends earlier, and its EPPL is shorter than that in other regions. (3) The western Pacific subtropical high, Northern Hemisphere polar vortex, Antarctic Oscillation, and western Pacific warm pool have significant effects on the occurrence time and length of EPP over China, and different regions show different effects.

Cryospheric Hydrometeorology Observation in the Hulu Catchment (CHOICE), Qilian Mountains, China

Abstract: Understanding cryospheric hydrology and the effects of cryospheric changes on river runoff is critical for sustainable water management especially in arid inland river basins such as those in northwest China where water resources mainly come from alpine areas. A cryospheric hydrometeorology observation system (CHOICE) has been established since 2008 in the Hulu catchment, which is a well-instrumented experimental and representative catchment in the upper reaches of the inland Hei River, Qilian Mountains, northwest China. The CHOICE includes dense meteorological measurements from 2980 to 4800 m asl (e.g. glacier, snow, and permafrost hydrology) and water and heat balance in the vertical landscape zones including alpine grassland, meadow, shrub, coniferous forest, marshy meadow, and moraine-talus zones. The comprehensive long-term observations available for the CHOICE provide the basis for model development and application in cryospheric hydrological research. We focus on cryospheric hydrometeorological process of precipitation, freeze–thaw cycle, energy balance, soil–vegetation–atmosphere transfer (SVAT), runoff, groundwater reservoir, and hydrological resiliency within vertical elevation in CHIOCE. Data from CHOICE, an open cryospheric hydrology observation and research system, is accessed through a website (http://hhsy.casnw.net/) and the WestDC database (http://westdc.westgis.ac.cn/).

Long-Term Impacts of China’s New Commercial Harvest Exclusion Policy on Ecosystem Services and Biodiversity in the Temperate Forests of Northeast China

Abstract: Temperate forests in Northeast China have been severely exploited by timber harvesting in the last century. To reverse this trend, China implemented the Classified Forest Management policy in the Natural Forest Conservation Program in 1998 to protect forests from excessive harvesting. However, the policy was unable to meet the 2020 commitment of increasing growing stock (set in the Kyoto Protocol) because of high-intensity harvesting. Accordingly, China banned all commercial harvesting in Northeast China in 2014. In this study, we investigated the long-term impacts of the no commercial harvest (NCH) policy on ecosystem services and biodiversity using a forest landscape model, LANDIS PRO 7.0, in the temperate forests of the Small Khingan Mountains, Northeast China. We designed three management scenarios: The H scenario (the Classified Forest Management policy used in the past), the NCH scenario (the current Commercial Harvest Exclusion policy), and the LT scenario (mitigation management, i.e., light thinning). We compared total aboveground forest biomass, biomass by tree species, abundance of old-growth forests, and diversity of tree species and age class in three scenarios from 2010 to 2100. We found that compared with the H scenario, the NCH scenario increased aboveground forest biomass, abundance of old-growth forests, and biomass of most timber species over time; however, it decreased the biomass of rare and protected tree species and biodiversity. We found that the LT scenario increased the biomass of rare and protected tree species and biodiversity in comparison with the NCH scenario, while it maintained aboveground forest biomass and abundance of old-growth forests at a high level (slightly less than the NCH scenario). We concluded there was trade-off between carbon storage and biodiversity. We also concluded that light thinning treatment was able to regulate the trade-off and alleviate the negative effects associated with the NCH policy. Our results highlighted limitations of the NCH policy and provided new insights into sustainable forest management and the interdependence between human society and the forest ecosystem.

Epoxy composites with functionalized molybdenum disulfide nanoplatelet additives

Abstract: As a typical layered inorganic analogue of graphene, molybdenum disulfide (MoS2) has gained intensive attention and become a research hotspot due to its unique two dimensional nanostructure and excellent properties. The enhancement in the thermal and mechanical properties of polymer/inorganic nanosheet composites depends strongly on their interfacial interaction. In this study, we exfoliated bulk MoS2 into nanosheets which were subsequently functionalized using 3-mercaptopropyltriethoxysilane. The functionalized MoS2 (f-MoS2) were dispersed in epoxy polymers at loading fractions of up to 1% by weight via ultrasonication and three roll mills. We characterized the tensile, fracture and adhesive properties of the composite and show that f-MoS2 nanoplatelets are highly effective at enhancing the mechanical properties of the epoxy at very low nanofiller loading fractions (0.1–0.7% by weight). Our results show the potential of functionalized 2D sheets of transition metal dichalcogenides as reinforcing additives in polymeric composites. The results indicate that the glass transition temperature increases significantly for the lower weight fraction composites, from 135 °C for the baseline (unfilled) epoxy to 146 °C at 0.7% f-MoS2 loading. The apparent shear strength at 120 °C increases significantly for the lower weight fraction composites, from 13.8 MPa for the baseline (unfilled) epoxy to 24.9 MPa at 0.7% f-MoS2 loading.

A catalyst-controlled switchable reaction of β-keto acids to silyl glyoxylates.

Abstract: A catalyst-controlled switchable reaction of β-keto acids to silyl glyoxylates was developed under mild conditions, providing two distinct products in good yields. Compared to decarboxylative addition-Brook rearrangement, the decarboxylative addition products could be controlled by using a simple bifunctional organocatalyst thiourea derivative instead of DABCO. This new reaction model of silyl glyoxylates offered a facile and alternative route to organosilicon compounds.

Tourism resource assessment and spatial analysis of wine tourism development: a case study of the eastern foothills of China’s Helan Mountains

Abstract: The reasonable development and utilization of mountainous regions closely relates to local economic development and ecological security. The wine production region in the eastern foothills of the Helan Mountains in Ningxia, Ningxia Hui Autonomous Region, with its excellent terroir, is emerging as one of China’s three major geographical attractions. Based on surveys of tourism resources and spatial analysis for this wine producing region, we propose a highly representative and practicable path for wine tourism development. Based on China’s national standard in Classification, Investigation and Evaluation of Tourism Resources (GB/T 18972-2003), which recommended the types and grades of tourism resources in one area, we conduct an analysis of resource characteristics and the current state of development. Using ArcGIS software, spatial autocorrelation analysis, average nearest neighbor analysis, as well as clustering and outlier analysis, we are able to derive the spatial distribution characteristics of tourism resources. Our survey showed that tourism resources in this area are relatively abundant and have good quality and clear combination advantages. Nonetheless, there are resources shortage for wine tourism and poor integration of wine production with the tourism industry. Regarding the spatial distribution of resources, we revealed the current states of and issues surrounding regions with concentrated resources, as well as characteristics of this clustering. Finally, we proposed a development path for wine tourism in this region based on the five dimensions of management mode, industrial path, product development, spatial optimization, and market development.

The monsoon effect on energy and carbon exchange processes over a highland lake in the southwest of China

Abstract: . Erhai Lake is a subtropical highland shallow lake on the southeast margin of the Tibetan Plateau, which is influenced by both South Asian and East Asian summer monsoons. Based on 4 years of continuous eddy covariance (EC) data over Erhai Lake, the monsoon effect on water–atmosphere exchange processes is investigated by comparing the energy and CO2 flux patterns and their main drivers during pre-monsoon (March–April), monsoon (May–October) and post-monsoon (November–December) periods. The results show that the atmospheric properties display a large difference during the three different periods. There is a negative difference between water surface and air temperature ( T ) during the pre-monsoon period, while a positive T during the post-monsoon period. The diurnal sensible heat flux ( Hs ) is larger during the post-monsoon period, while the latent heat flux (LE) is larger during the monsoon period. The monthly average Hs and heat storage ( Q ) in the lake remain negative during the pre-monsoon period and the early monsoon period, and they become positive in the middle monsoon period, which indicates that the lake absorbs heat at first and releases it subsequently. LE plays a dominating role in the energy partitioning of the lake. The Bowen ratio is higher during the post-monsoon period. The uptake of CO2 flux is observed in the middle of the day during monsoon and post-monsoon periods. The ΔT is the main driver for Hs and the effect of ΔT is increased as timescales are extended from half-hourly to monthly. The wind speed has a weak effect on Hs but a strong effect on LE and CO2 fluxes. Similar main drivers for Hs are found during the pre-monsoon and post-monsoon periods, which is also found for CO2 flux, indicating a large impact of the monsoon on the heat and carbon exchange processes over Erhai Lake.

Adjusting precipitation measurements from the TRwS204 automatic weighing gauge in the Qilian Mountains, China

Abstract: With the popularity of the automatic precipitation gauges in national weather stations, testing their performance and adjusting their measurements are top priorities. Additionally, because different climatic conditions may have different effects on the performance of the precipitation gauges, it is also necessary to test the gauges in different areas. This study mainly analyzed precipitation measurements from the single-Alter-shielded TRwS204 automatic weighing gauge (TRwSSA) relative to the adjusted manual measurements (reference precipitation) from the Chinese standard precipitation gauge in a double-fence wind shield (CSPGDF) in the Hulu watershed in the Qilian Mountains, China. The measurements were compared over the period from August 2014 to July 2017, and the transfer function derived from the work by Kochendorfer et al. (2017a) for correcting wind-induced losses was applied to the TRwSSA measurements. The results show that the average loss of TRwSSA measurements relative to the reference precipitation decreased from 0.55 mm (10.7%) to 0.51 mm (9.9%) for rainfall events, from 0.35 mm (8.5%) to 0.22 mm (5.3%) for sleet events, and from 0.49 mm (18.9%) to 0.33 mm (12.7%) for snowfall events after adjustment. The uncorrected large biases of TRwSSA measurements are considered to be mainly caused by specific errors of TRwSSA, different gauge orifice area and random errors. These types of errors must be considered when comparing precipitation measurements for different gauge types, especially in the mountains.

Electromagnetic Design of HTS Insert for Ultrahigh Field NMR Magnet

Abstract: In this paper, an electromagnetic design of a 27 T nuclear magnetic resonance (NMR) magnet composed of a low-temperature superconducting outsert magnet and a high-temperature superconducting (HTS) insert magnet is carried out. An optimization code is improved according to the fabrication form of the HTS magnet. Concerns about the radial magnetic field, the hoop stress, the current margin, length of tape used, and outer diameter of the HTS insert are investigated with respect to the magnet length, inner radius, and current density. The screening current effect is taken into consideration for the sensitivity analysis. The results predict that the larger the inner radius of the HTS insert, the better the real field homogeneity can be obtained. Screening current effect can deteriorate the field homogeneity zonally by about 1 order of magnitude.

An Improved Starting Strategy for a Spherical Superconducting Rotor

Abstract: Due to the absence of friction, a superconducting rotor can achieve a very high speed to obtain a large angular momentum for high-precision measurement of the angular displacement and angular velocity. However, in practice, the superconducting rotor will do vibration and collide with the inner wall of the rotor cavity at a certain speed during startup, which will result in the failure of the rotor’s acceleration. In this paper, an improved starting strategy was proposed. This new method can avoid the peak of vibration amplitude by changing the bearing stiffness of the rotor quickly. The startup and shutdown process of the rotor was redesigned. Several experiments were carried out to verify its correctness. The results show that the superconducting rotor can be accelerated to the rated speed of 200 Hz (12 000 r/min) successfully by the proposed method. Furthermore, the start time of the rotor was greatly reduced to 20 minutes from more than one hour for the original method.

General Component Analysis (GCA): A new approach to identify Chinese corporate bond market structures.

Abstract: PCA has been widely used in many fields to detect dominant principle components, but it ignores the information embedded in the remaining components. As a supplement to PCA, we propose the General Component Analysis (GCA). The inverse participation ratios (IPRs) are used to identify the global components (GCs) and localized components (LCs). The mean values of the IPRs derived from the shuffled data are taken as the natural threshold, which is exquisite and novel. In this paper, the Chinese corporate bond market is analyzed as an example. We propose a novel network method to divide time periods based on micro data, which performs better in capturing the time points when the market state switches. As a result, two periods have been obtained. There are two GCs in both periods, which are influenced by terms to maturity and ratings. Besides, there are 382 LCs in Period 1 and 166 LCs in Period 2. In the LC portfolios there are two interesting bond collections which are helpful to understand the thoughts of the investors. One is the supper AAA bond collection which is believed to have implicit governmental guarantees by the investors, and the other is the overcapacity industrial bond collection which is influenced by the supply-side reform led by the Chinese government. GCA is expected to be applied to other complex systems.

Evaluation of nutritional quality in different varieties of green and purple leaf lettuces

Abstract: To determine the quality difference in different varieties of leaf lettuces, we investigated the characteristics of 74 varieties of leaf lettuces (55 green and 19 purple varieties). Both domestic and foreign varieties of lettuce were included in this study. We determined six nutritional indicators of these varieties: such as total soluble sugar, starch, cellulose, proteins, and vitamin C. The grey correlation analysis was used to analyze the 74 varieties of leaf lettuces. Thus, the merits of these traits were compared. The results indicate that the purple leaf lettuce P-S23 had grey comprehensive evaluation value of about 0.8, which was the highest among all varieties. For green leaf lettuces G-S68 and G-S10, grey comprehensive evaluation values were less than 0.5. This indicates that nutritional quality and nutritional value of the purple leaf varieties were higher than that of the green leaf varieties. Furthermore, the quality of green varieties of G-S68 and G-S10 were of poor quality, whereas the purple variety P-S23 was most suitable for commercial production.

Softening Theory of Matter Tuning Atomic Border to Make Soft Materials

Abstract: Regulation of material softness has both theoretical and practical significances due to irreplaceable applications of soft matter in rather diverse areas. This article is dedicated to draft a theoretical category on interpreting the mechanisms lying behind all soft matters, which can be termed as Softening Theory. A technical strategy with generalized purpose was proposed for softening desired matter, i.e. the melting point of matter can be significantly reduced through tuning its interior boundaries in atomic level. This theory accords well with the classical nuclear droplet model that treats the nucleus as a droplet which had successfully explained many phenomena. It also explained the experimental fact that, the material's melting point is drastically reduced as the particles become smaller enough, in which situations effects of the atomic borders become much weaker. Along this direction, many phenomena existing in nature can be well understood. For example, if keeping in mind the fact that an atom consisting of nucleus and electronics can be regarded as fluid, all the matter consisted of atoms should maintain fluidic state in their macroscopic scale, according to the consistency between macro and micro worlds. However, many substances just cannot remain their original atomic fluidic behavior due to breaking of the consistency between macro and micro states. Based on the current softening theory, it is now easy to understand that the breaking of such consistency is just caused due to generated forces from the atomic interactions. To resolve such intrinsic confinement, a group of potential technical approaches can be developed to tune the atomic borders of the matter and thus make desired soft materials. This work provides a theoretical foundation to partially address the nature of the material which will aid to make future soft matters in the coming time.