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ZnO-Bi2O3-Co2O3-NiO-Mn3O4-SiO2-Cr2O3 varistor ceramics were prepared by solid-phase sintering method.The effects of different doping amounts of Cr2O3 on the microstructure and electrical properties of ZnO varistor ceramics were investigated, and the phases, microstructures and electrical properties of samples were characterized. The results indicate that the addition of Cr2O3 effectively inhibits the abnormal growth of ZnO grains, enhances the uniformity of grain distribution, reduces the ZnO grain resistance and increases the grain boundary resistance.In the range of 0%-0.21% (molar fraction, the same below) of Cr2O3 addition, the nonlinear coefficient of the varistor ceramics increases first and then decreases as the addition amount increases. When the Cr2O3 doping amount is 0.14%, the ZnO varistor ceramics exhibit excellent electrical properties, with a potential gradient E1 mA=216 V·mm-1, leakage current JL=0.36 μA·cm-2, nonlinear coefficient α=25, residual voltage ratio K=1.815, and aging coefficient Kct=0.647. In addition, the initial U1 mA value of varistor ceramics still maintains 96.75% after impacted by 100 kA pulse current twice with 4/10 μs waveform. The Cr2O3 doped ZnO varistor ceramics demonstrate excellent impulse stability and significant application potential for lightning arresters of power distribution systems.

Porosity is a key parameter that affects the heat and moisture transfer within a grain pile. In order to investigate the distribution law of porosity in bulk grain piles in grain silos, grain compression experiment was carried out to obtain the porosity of different grain types under different moisture content and vertical pressure conditions. A porosity prediction model for grain cell based on GWO-BP neural network was proposed, and the model was compared with the porosity prediction results of BP neural network model and random forest model. Finally, the generalization ability of the model was verified using the grain cell box test. The results showed that the porosity prediction performance of the GWO-BP neural network model was the best, and the evaluation indexes of the model, including R2 of 0.960 5, RMSE of 0.013 7 and MAE of 0.013 1, were all within the permissible range. This study has provided a neural network prediction method for the determination of grain porosity, which could provide an important foundation for in-depth multi-field coupling analysis of grain piles and theoretical support for safe grain storage.

Rockfall in limestone mines is a common geohazard in the Changdu area of eastern Tibet and one of the leading geo-safety issues that mining enterprises and railway projects are faced with. We carried out a detailed geohazard survey using the methods of general geology, structural geology, and geohazard geology. We found the rockfall development pattern, characterized rock mass structural planes, discussed the collapse's mechanism, and established its failure mode. The results show that rockfall sites in the study area show a linear spreading along the fold and thrust zone. Five groups of steep-dip structural planes have developed in the rock body, including the longitudinal joint (S1), the transverse joint (S2), the X-type conjugate shear joints (S3 and S4), and the interlayer shear joint (S5). Paired with regional folds and hedging faults, these structural planes cut the rock mass into broken blocks. The collapses are the product of coupled internal and external dynamic geological processes. The sedimentary foundation of the rockfalls in the Qamdo area is the limestone from the upper Triassic Bolila Formation (T3b) formed in the intracontinental rift basin. The strongly folded orogeny triggered by the Cenozoic (Cz) India-Eurasia collision laid down the tectonic framework in the region, which is the essential condition for rockfall development. The strong Neotectonic movement since the Quaternary (Q), frequent hot and humid climate alternations with abundant rainfall since the Late Pleistocene (Q3), everyday human activities, and other internal and external dynamic coupling effects are the main triggering factors of the rockfall disaster. Three failure modes of rockfall are identified, namely toppling, falling, and sliding. The research results have specific guiding significance for rockfall prevention and control in the karst area and the railway construction in the Sichuan-Tibet area.

Passive indoor human localization is the basis for implementing ubiquitous wireless sensing systems.However,commercial WiFi signals are easily affected by the surrounding environment in our life,which makes it difficult for existing WiFi-based indoor localization works to accurately separate the dynamic human components from the complex received signals.To address this problem,this paper proposes the WiPasLoc,a passive indoor human localization system,which achieves high accuracy indoor localization by using the channel state information(CSI) extracted from commercial WiFi devices.Firstly,the Doppler frequency shift(DFS) estimation is carried out in combination with the signal quality of the CSI subcarriers.Then,the target person signal component is precisely separated from the channel state information by using a double-window-based angle of arrival(AoA) estimation method.Finally,combined with the initial position information of the personnel,accurate passive indoor human localization is achieved by the proposed trajectory fitting algorithm.Experimental results show that the median error of WiPasLoc for indoor personnel trajectory positioning is 80cm,which is 25.9% higher than the existing typical Widar2.0 positioning accuracy.

The research progress of the influence of fermentation temperature, fermentation humidity, fermentation time and exogenous additives on the formation of black tea pigment were reviewed. The future research and development trend of black tea pigment formation was prospected.

The rare earth conversion film has attracted more and more attention in recent years because of its good corrosion resistance and non - toxicity. The concept and film forming mechanism of rare earth conversion film were briefly introduced, and the application of rare earth in corrosion prevention for ferrous metals as well as the nonferrous metals of aluminum, magnesium, zinc and their alloys was summarized. This study found that the corrosion resistance of composite rare earth conversion film was better than that of the single rare earth conversion film. Moreover, it also explained the reason why cerium conversion film had better corrosion resistance than other rare earth conversion films. Finally, it pointed out that the composite rare earth conversion film, rare earth composite alloy coating and densification of rare earth conversion film would be the development direction.

To solve the sparse channel estimation problem in Orthogonal Frequency Division Multiplexing (OFDM) systems, this paper presents a pilot design algorithm based on multi-pilot parallel searching and binary coding. Under the Mutual Incoherence Property (MIP), we consider the deterministic pilot design problem by minimizing the coherence of the dictionary matrix. The pilot is also required to be placed within the effective subcarrier range for more practical purposes. In this scheme, the pilot set is binary coded. In each iteration, the sequence of the binary code segment is recombined to update the approximately optimal pilot position. The update of some coding segments can change multiple pilot positions at the same time. It can increase the diversity of pilots, and reduce the complexity of computation. Experimental results show that, compared with the existing pilot optimization methods, this algorithm can find a smaller MIP measurement matrix. Therefore, the corresponding pilot mode can significantly improve the performance of channel estimation.

BACKGROUND The northern Anhui region is located north of the Huaihe River in Anhui. It was an important channel for cultural exchanges between the north and the south during the pre-Qin Period. It was also a necessary area for transporting copper resource on the Yangtze River to the Central Plains. Bronzes in this area are very important for exploring the relationship between copper mines in the Middle-Lower Yangtze River and the bronze culture of the Central Plains. OBJECTIVES In order to understand the diachronic changes of mineral resources in different periods in northern Anhui and the interaction with the surrounding bronze culture. METHODS Laser ablation multiple-collector plasma-mass spectrometry (LA-MC-ICP-MS) and X-ray fluorescence spectrometry (XRF) were used to analyze the composition and the lead isotope ratios of 4 bronzes unearthed in northern Anhui and 4 bronzes unearthed from the Warring States Chu Tomb in Jijiayuan, Hubei Province. RESULTS Results showed that among the 4 bronzes in northern Anhui, there were 3 lead-tin bronzes and 1 tin bronze. The copper content ranged from 60.69% to 76.65%. The tin content was generally higher, 9.66% to 33.24%, and the lead content was 0.43% to 18.07%. The composition had a large variation. The lead isotope analysis results showed that the lead isotope ratios of the samples were within the range of common lead. Two tin bronzes (WB-3, JJY-1) indicated the source of copper materials, and the rest of the samples reflected the source information of lead materials. Comparing the ores in different region, it was found that the data of the bronzes in the northern Anhui during the Western Zhou Period and the Tonglushan mining area in Hubei were relatively close. During the Warring States Period, the bronzes in the northern Anhui began to use minerals from the southern Anhui mining area. Therefore, from the Western Zhou Period to the Warring States Period, the metal resources used in the northern Anhui area began to gradually change from the Tonglushan area in Hubei to the area along the Yangtze River in southern Anhui. CONCLUSIONS This research provides a new scientific basis for the source of minerals used in bronzes in the Zhou Dynasty in the region, and the exchange of bronze culture between northern Anhui and the surrounding areas.

BACKGROUND The contents of silver, tin, boron, molybdenum, and lead in geological samples are extremely important for studying the metallogenic regularity and for geochemical prospecting. Current analytical methods rarely determine silver, tin, boron, molybdenum, and lead simultaneously. OBJECTIVES To establish a method to simultaneously determine silver, tin, boron, molybdenum and lead in geological samples. METHODS To eliminate the matrix interference, first-class standard materials (rock, soil and water sediments) were used for linear fitting of the synthetic silicate standard materials curve. By setting analytical line conversion values, different analytical line can be used for samples with different contents. RESULTS The detection limits of silver, tin, boron, molybdenum, and lead were 0.0077μg/g, 0.19μg/g, 0.68μg/g, 0.058μg/g, 0.49μg/g, respectively. The precisions of the method were 3.23%-9.39%. The measured value of national first class standard materials including soil, water sediments and rock by this method was in accordance with standard values, with an absolute value of △logC < 0.10. The qualified rates of actual sample were 92%-98%, and the qualified rate of the inspection sample was 100%. CONCLUSIONS This method is easy to apply and can be used to analyze samples rapidly. It can also be used to avoid contamination during sample dilution. Compared with traditional atomic emission spectrometry that uses a single analytical spectrum line, this method can be used to obtain a value which is closer to the standard value of national standard materials. The detection limit of this method is much lower than the standard value of the specification of testing quality management for geological laboratories.

Objective To investigate the effects and mechanisms of long-chain non-coding RNA CRNDE on the proliferation and migration of HepG2 cells. Methods The CRNDE over-expression vector was constructed and packed into lentivirus. Then, HepG2 cells was infected by the lentivirus containing LV5/NC and LV5/CRNDE vectors. After treatment with 2.5 μg/mL puromycin for 4-5 weeks, real-time PCR was used to detect the expression level of CRNDE in the two groups. CCK8 and cell scratch assay was used to detect the changes of proliferation and migration ability of each group. Meanwhile, real-time PCR and Western blot were used to detect the mRNA and protein expression of E-cadherin, N-cadherin, Bax and Bcl-2 in each group. Results Compared with LV5/NC group, the expression of CRNDE in LV5/CRNDE group significantly increased(P＜0.01). The proliferation and migration of LV5/CRNDE group cells were also significantly increased (P＜0.01, P＜0.01). At the same time, the expression of E-cadherin and Bax in LV5/CRNDE group significantly decreased(P＜0.01, P＜0.01), while the expression of N-cadherin and Bcl-2 significantly increased(P＜0.01, P＜0.01). Conclusions CRNDE may stimulate proliferation and migration of HepG2 cells by promoting the expression of N-cadherin/Bcl-2 and inhibiting the expression of E-cadherin and Bax.

A novel kind of lattice-distributed ESTM-fabrics (ES-L) and random-distributed ESTM-fabrics (ES-R) were developed by using polyethersulfone (PES) and U3160 according to ex-situ toughening technology. ESTM-fabrics reinforced 3266 moderate temperature curing epoxy resin composites (ESTM-fabric/3266) were prepared through RTM process. Impact resistance and residual strength of ESTM-fabric/3266 were studied and the ex-situ toughening mechanism was analyzed by fluorescence microscope and SEM. The untoughened U3160 fabrics reinforced 3266 moderate temperature curing epoxy resin composites were studied to compare performance of composites as well. The result of low velocity impact testing shows that the toughened ESTM-fabric/3266 composites exhibit the higher delamination damage threshold load, the lower projected delaminated areas, the slower damage development, compared to U3160/3266 composites without toughener PES (ES-U).The major failure mode is intralaminar crack (transverse matrix cracking), debonding between fibre and matrix in fiber-bundle regions as well as local ply breakage along with ply-matrix debonding.The ES-L allows an increase of 37% in CAI compared to ES-U. Microstructural observation of damage zone reveals that ES-R composite has a homogeneous distribution of phase inversion in the interlaminar regions while ES-L composite exhibits a hard phase composing of the 3266 epoxy resin continuous matrix and a soft phase composing of the nodular structure of BMI in the 3266 epoxy resin continuous matrix. The excellent impact resistance and damage tolerance of ES-L composite are due to synergistic effects of hard phase and soft phase, which can release the stress concentration,give the extra strain energy dissipated and subsequently terminate crack via crack blunting mechanism.

The conductive mechanism of graphene/rubber nanocomposites was introduced.Advances in the synthesis and properties of graphene and its derivatives, modifications of graphene, along with its hybrid fillers, as well as fabrication of related rubber conducting nanocomposites were reviewed.Many factors affecting the electrical properties, such as fabrication method, vulcanization, temperature, pressure, frequency and media etc. were also summarized.It was pointed out that the further research should be focused on multi-component graphene/rubber nanocomposites and its double percolation phenomenon.

Based on the type of DZLY180 gear reducer,aiming at the particularity of the tooth profile of point- line meshing gear,the curve equation of the tooth profile of point- line meshing gear is applied to calculate some coordinates on the tooth profile curve after modification. The cubic spline curves are used to fit the data,and 3D Software Solidworks is used to fit the tooth profile curve of point- line meshing gear. Then the three- dimensional modeling is carried out,the interference- free assembly of the gear is completed. The simulation results show that,the overall interference- free assembly in the meshing process of the point- line meshing gear is realized by the method.

The experiment aimed to investigate the influence of rosemary extract on oxidative stress in weaned piglets. A total of 144 'Duroc x Landrace x Yorkshire' ternary hybrid piglets weighing about 8.0 kg and weaned at 26 days of age were randomly divided into four groups, with six replicates in each group and six piglets (half in male and female) in each replicate. The piglets in the control group were fed with a basal diet, and experimental groups (200, 400, 600 mg/kg RE group) added an additional 200, 400, and 600 mg/kg rosemary extract (RE) to the basal diet, respectively. The test lasted for 24 d. The results showed that compared with the control group, the addition of 200 mg/kg RE could significantly increase the average daily gain and average daily feed intake of weaned piglets (P<0.05), and significantly reduce the feed to gain ratio (P<0.05). On the 10th day, compared with the control group, the serum GSH-Px and SOD activity of weaned piglets in the experimental groups were significantly increased (P<0.05), CAT activity in serum of weaned piglets in 600 mg/kg RE group was significantly increased (P<0.05), and the content of MDA in the 600 mg/kg RE group was decreased significantly (P<0.05). On the 10th day, the serum levels of IGF-I and Ghrelin in weaned piglets in the 200 mg/kg RE group were significantly increased (P<0.05), and the GH levels in the serum of weaned piglets in 400 mg/kg RE group were significantly increased (P<0.05). On the 24th day, the serum levels of IGF-I and GH in the weaned piglets in the 200 mg/kg group were significantly increased (P<0.05), and the serum levels of IGF-I in the weaned piglets in the 600 mg/kg group were significantly increased (P<0.05). The study indicates that the addition of RE to the diet can alleviate the oxidative stress caused by early weaning of piglets, promote the growth and development of weaned piglets, and enhance the antioxidant ability of piglets, and the suitable amount of addition is 200 mg/kg. [ABSTRACT FROM AUTHOR]

When point-line meshing gear is used in an automobile gearbox,it has the effect of reducing transmission series,increasing transmission ratio,enhancing strength,reducing noise,reducing volume and weight reduction etc. The parameter choosing transmission ratio distribution,calculating example and improved tooth number distribution of point-line meshing gears in an automobile gearbox are described. Several gearboxes are produced,and the noise is lower than involute gearbox,after using more than twenty months,the gearboxes run well and without tooth breaking and pitting.

[Objectives] To compare metabolic differences between diapausing (Dpre) and non-diapausing Trichogramma dendrolimi prepupae (NDpre) in order to better understand the diapause mechanism of this species. [Methods] Liquid Chromatography-Mass Spectrometry (LC-MS) was used for metabonomic analysis. PCA, PLS-DA and OPLS-DA were used for model analysis and statistical tests. Differences in metabolites between treatment groups were compared using the P-value in t-tests, VIP-values and fold change. Significant enrichment pathways of differential metabolites were screened using KEGG enrichment analysis. [Results] A total of 1 072 differential metabolites were identified. Among these, 674 significantly increased, and 398 significantly decreased, during diapause. These were mainly phospholipids, lysophosphatides, amino acids and their derivatives, and carbohydrates. KEGG pathway enrichment analysis indicated that there were significant changes in the synthesis and metabolism of various amino acids, and in the tricarboxylic acid cycle pathway, indicating significant changes in, and mutual transformation of, energy-storing substances that improve cold tolerance during diapause. [Conclusions] A preliminarily investigation of metabolic differences between diapausing and non-diapausing T. dendrolimi prepupae sheds light on the metabolic regulation mechanisms and pathways regulating diapause in this species. [ABSTRACT FROM AUTHOR]

Aimed at disadvantages on most existing coverage control algorithms for directional sensor networks,such as finite orientations,the restrained degree of optimization,the deficient applicability of these algorithms etc.,a coverage control strategy（CCS） was presented,which was strictly deduced from some mathematic properties.A distributed algo-rithm generated from the CCS could be extensively used in different kinds of networks with different sensing models.Simulation results and performance analysis illustrate that the CCS can efficiently enhance the coverage of networks and show the certain superiority comparing to existing algorithms of the same kind.

An energy-efficient data sampling and transmission method in wireless multimedia sensor networks was proposed.Node’s sensing direction could be adjusted with the help of Voronoi diagram which enhances network coverage level.And energy consumption on sampling was reduced on the basis of periodical sleeping as well as different sampling granularities.Moreover,the transmission overhead was further brought down by means of color block matching.Simulation results show that this method obtains satisfactory performance on prolonging networks lifetime.

A multi-path transmission method for multimedia sensor networks was proposed.By considering the transmission time,residual energy as well as transmission rate of the wireless links,three classes of paths are established with the help of metadata packets.Network congestion rate is reduced as well by adjusting time intervals of sampling.Experiments results show that this method is well performed on packet loss,real-time transmission as well as congestion control.

A distance-assistant node coverage identification model was proposed which adopts distance information be-tween the node and its neighbors to identify nodes coverage without using any location information.Theory analysis and simulation results are presented to evaluate the proposed DANCI model.It is shown that in randomly deployed sensor networks,the maximum error between DANCI model and location information-aware strategy is 6.396 0%,and the nodes coverage accuracy improves significantly compared to neighbor number-based scheme and nearest neighbor-based scheme.

Owed to the obvious characters of energy-constraint and dynamic topology, issues including confidentiality, integrality, authentication and no sufficient memory for abundance of key information, needed to be effectively solved in key management technique, especially in wireless sensor networks （abbreviation for WSN） applications. Aimed at some limitations like these on current research work, a key distribution scheme based on logic grid of WSN was proposed, which used the layer-cluster topologic structure. The complete process was described, involving resolution of coefficient matrix, keys’ initialization and specific realization. Compared with some other schemes, such as SPIN protocol and logic key tree methods, simulation results show its advantages on security, memory performance and energy- consumption, etc..

A novel request scheduling algorithm was proposed for the OCS （online charging system） server. The basic idea is that one of the requests from all classes of service queues is scheduled with some priority probability which is based on the system queue-length, the request arrival rate, and the pre-assigned delay differentiation parameter. The experimental results show that, in considering request service delays, this proposed algorithm always outperforms some other traditional PDD （proportional delay differentiation） scheduling ones and the performance advantages are relatively greater when request service delays increase and vary greatly from each other. Furthermore, it can efficiently meet 6 QoS （quality of service） requirements proposed in content-based billing.

According to the characteristics of subjectivity,fuzziness and randomicity in subjective trust,the model of trust evaluation based on membership cloud theory was proposed by introducing the theory of membership cloud. The trust cloud and trust grade cloud were described quantificationally,the process of calculation,synthesis and comprehen-sive operation for the trust evaluation cloud was presented,and the evaluation of trust grade was also presented. The re-sults of experiments show that the trust evaluation model proposed is valid.

A novel dynamic scheduling algorithm P2CAS2M2（proxy caching algorithm based on segment popularity for mobile streaming media）based on segment popularity for mobile streaming media was proposed.Proxy caching admis-sion and replacement algorithm based on the object segment popularity for mobile streaming media was implemented.The principle was obeyed that the data cached for each mobile streaming media object were in proportion to their popu-larity at the proxy server.The cache window size was updated periodically according to the average access time of the clients.Simulation results show that this algorithm is more adaptive than A2LS（adaptive and lazy segmentation algorithm） for the variety of the proxy server cache.It can gain more average number of cached mobile streaming media objects and less delayed requested ratio while byte-hit ratio of P2CAS2M2 is close to or exceeds A2LS under the circumstance of the same proxy cache space.

In order to study the relationship between wellbore size and wellbore stability in Changqing oilfield block, uniaxial compressive strength experiments were carried out on rock samples with different pore sizes, and the relationship between pore sizes and compressive strengths of rocks was obtained. The mathematical models of wellbore collapse pressure and fracture pressure considering the effect of wellbore size were established, and the equivalent density of the collapse pressure and the equivalent density of the fracture pressure were calculated. The experimental analysis shows that the compressive strength increases with the decrease of the wellbore size, with the decrease of corresponding collapse pressure and increase of the fracture pressure, and the safe density window range of the drilling fluid expands accordingly. The study has certain guiding significance for safe drilling on small boreholes. [ABSTRACT FROM AUTHOR]

Aimed at some security properties on key management for multicast such as forward confidentiality,backward confidentiality,resisting conspiracy-analysis,expansibility and robustness,and furthermore the obvious character of en-ergy-constraint,a new key management scheme based on threshold mechanism ＆ key relation table was proposed,which mapped keys’ value onto the three-dimensional curves and surfaces.Although computing complexity increases within a little scale,the performance optimization of memory complexity as well as communication complexity were proposed.

Since the 1980s, China has experienced a long-term imbalance in the sex ratio, manifested by a far greater number of males than females. In the face of the sex ratio imbalance, how do parents make choice when it comes to the educational level of their children? This paper finds that the sex ratio imbalance decreases the educational attainment of males in rural areas and in households with parents of low educational level, both in an absolute sense and compared with that of females, while the educational attainment of males in urban areas and in households with parents of high educational level rises, and the educational attainment of females is unaffected. This implies that the sex ratio imbalance widens the gap between the human capital of males with higher and lower socioeconomic status. Since educational decisions are usually made several years before marriage, this paper further explores how parents predict future supply and demand in the marriage market. The findings are that parents tend to underestimate the extent of the shortage of marriageable women when their children are about to marry, implying that current levels of human capital may deviate from the consensual levels. [ABSTRACT FROM AUTHOR]

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The selenium, copper, indium and gallium were comprehensively recovered from the CIGS Scrap by the process which includes sulfatizing roasting, water leaching, copper extraction, indium extraction, gallium neutralization precipitation and alkali leaching. The crude selenium, cathode copper, refined indium and metallic gallium were obtained in the process. The experimental conditions were studied. And then the selenium volatilization rate is 99.5% in the Selenium Distillation process under the optimum conditions. The extractions of copper and indium in the solvent extraction are 98.4% and 99.9%, respectively. The leaching rate of gallium can reach 99.5% in the process of gallium neutralization precipitation-alkali leaching. [ABSTRACT FROM AUTHOR]

Based on the framework of Simon's bounded rationality and satisficing rule, this paper investigates the traffic assignment problem in parallel network under boundedly rational user equilibrium (BRUE) condition. By introducing the concept of aspiration level, we first develop a novel model for the problem. The user heterogeneity is then considered according to aspiration level and preference to different routes. Properties and conditions required for the existence of BRUE are derived. The analytical results show that the user aspiration levels on the preferred route are no lower than that on the sub-preferred route. We also find that the BRUE condition can be reduced to the UE condition under certain conditions. Furthermore, the numerical result shows that the total travel times by various BRUE flow patterns are always no lower than that by UE flow pattern. [ABSTRACT FROM AUTHOR]

A bi-objective programming model with spatial equity constraints for the location of P&R facilities on networks is proposed. The objectives are to minimize the passenger flow volume while minimize the construction cost of P&R facilities. The concept of passenger flow volume per cost is defined. Then, this two-objective problem is converted into the single objective problem with a parameter by the linearly weighted method. Furthermore, some properties of the model solution are analyzed. The monotonicity, the upper and lower bounds of passenger flow volume per cost are also given. Finally, the model is applied into the transportation network of Anaheim City. This study can provide decision-making tools for scientifically planning P&R facility system from a cost-benefit perspective. It also can be applied to the P&R facility location for the urban transportation planning government in the real world. [ABSTRACT FROM AUTHOR]

Agricultural biodiversity is a key part of the ecosystem biodiversity, but it receives little concern. The monoculture, environmental pollution and habitat fragmentation caused by agricultural activities have threatened agricultural biodiversity over the past 50 years. To optimize agricultural management measures for crop production and environmental protection, we reviewed the effects of agricultural activities, including cultivation patterns, plastic mulching, chemical additions and the cultivation of transgenic crops, on agricultural biodiversity. The results showed that chemical pesticides and fertilizers had the most serious influence and the effects of transgenic crops varied with other factors like the specific transgene inserted in crops. The environmental risk of transgenic crops should be assessed widely through case-by-case methods, particularly its potential impacts on agricultural biodiversity. It is important to consider the protection of agricultural biodiversity before taking certain agricultural practices, which could improve agricultural production and simultaneously reduce the environmental impacts. [ABSTRACT FROM AUTHOR]

In this study, the differences of morphology of stem and roots, dry weight and physiological property of corn varieties with different lodging-resistance capability were studied systematically to reveal the mechanism of corn lodging and provide theory basis for high yield with lodging-resistant corn cultivation and breeding. On 28th August,2012,there was a" Bolaven" typhoon attacked middle west part of Jilin Province, and lots of aces corn fell over. Research group went to survey the characters and rate of lodging in the 11 mian corn varieties( Liangyu99, Liangyu88, Liangyu66, Nonghua101, Dika516, Jidan50, Xianyu335, Zhengdan958, Limin33, Yinhe32 and Yinhe33) after the typhoon. The lodging of maize was investigated and the morphology, dry matter and physiological characteristics of stalk and root were measured, and the variances of different variety and effects of lodging on yield were analysed. The field investigation showed that most of corn varieties except 'Liangyu99' were in the lodging and the rate of lodging was almost 100%. The stalk below the ear in 'Liangyu99' had the following features the lower coefficient of ear-height, the shorter internode, the bigger diameter, the higher ratio of dry weight to the length, and the stalk strength from 1st to 3rd internode above base were the highest and the number of brace root was the most in all maize varieties. In the aspect of physiological characteristics, the content of soluble sugar, ligin, Si and Zn of all internodes below the ear in' Liangyu99' and' Zhengdan958' were higher significantly than others, and those of' Yinhe32' and' Yinhe33' were the lowest. There was significant difference in the Ca and Mg content of all varieties, and the content of cellulose, N, K of 'Yinhe32' and' Yinhe33' were lower than others. The yield of' Liangyu99, was far lower than yield of' Xianyu335' and' Zhengdan958'. The yield of' Zhengdan958' was not sensitive to lodging in the filling stage. 'Liangyu99' showed great characters of both over ground and under ground which make it show great capability of lodging resistance when facing the natural hazard, while the yield only lie in the middle level. When choosing the corn varieties with lodging resistance, both morphological and physiology indexes should be taken into consideration synthetically, and rational close planting and fertilization should be applied to decrease the risk of lodging and guarantee the yield potential. [ABSTRACT FROM AUTHOR]