Nitrogen and phosphorus co-doped activated carbon induces high density Cu^(+)active center for acetylene hydrochlorination

This work aims to solve the problems of low reaction activity of Cu-based catalysts and agglomeration of active centers in acetylene hydrochlorination.Cu-based catalysts supported by NAP co-doped activated carbon(AC)with different content(mCu-xNP/AC)were manufactured and applied in the acetylene hydrochlorination reaction.It was found that the doping of carriers N and P induced the transformation of Cu^(2+)to Cu^(+),and the catalytic activity was markedly improved.Under the optimal reaction temperature of 220℃,the gas hourly space velocity(GHSV)of C_(2)H_(2)was 90 h^(-1)and V_(HCl):V_(C_(2)H_(2))was 1.15.The initial activity of the 5%Cu-30 NP/AC catalyst reached 95.59%.Through some characterization methods showed the addition of N and P improved the dispersion of Cu in carbon,which increased the ratio of Cu^+/Cu^(2+).The measurement results confirmed that the chemisorption capacity of mCu-xNP/AC for C_(2)H_(2)decreased slightly,and the chemisorption capacity for HCl increased significantly,which was the reason for the increased activity of the catalyst.The conclusion provides a reference for the development of acetylene hydrochlorination Cu catalyst.

Study on Interaction between Lanthanum and Phosphor in Purity Steel

Using SEM and EDS some particles containing La and P were discovered in low oxygen and sulfur purity steel with lanthanum. In these particles low melting point elements such as As and Sb also were detected. According to the result of simulative calculation of segregation, it is shown that La and P enrich so strongly in the process of solidification that their concentrations can satisfy thermodynamic condition to forme LaP compound or meet the requirements to forme eutectic phase in the last stage of solidification. Therefore, the particles are concluded as LaP compound or eutectics, which exist on grain boundary mainly.

Long-Term Impact of Soil Management on Microbial Biomass C, N and P in Rice-Based Cropping System

A 12-year field experiment was conducted to investigate the effect of different tillage methods and fertil- ization systems on microbial biomass C, N and P of a gray fluvo-aguic soil in rice-based cropping system. Five fertilization treatments were designed under conventional tillage (CT) or no tillage (NT) system: no fertilizer (CK); chemical fertilizer only (CF); combining chemical fertilizer with pig manure (PM); combining chemical fertilizer with crop straw (CS) and fallow (F). The results showed that biomass C, N and P were enriched in the surface layer of no-tilled soil, whereas they distributed relatively evenly in the tilled soil, which might result from enrichment of crop residue, organic manure and mineral fertilizer, and surficial development of root systems under NT. Under the cultivation system, NT had slightly greater biomass C, N and P at 0～5 cm depth, significantly less biomass C, N and P at 5～15 cm depth, less microbial biomass C, N and equivalent biomass P at 15 ～30 cm depth as compared to CT, indicating that tillage was beneficial for the multiplica tion of organisms in the plowed layer of soil. Under the fallow system, biomass C, N and P in the surface layer were significantly greater for NT than CT while their differences between the two tillage methods were negligible in the deeper layers. In the surface layer, biomass C, N and P in the soils amended with organic manure combined with mineral fertilizers were significantly greater than those of the treatments only with mineral fertilizers and the control. Soils without fertilizer had the least biomass nutrient contents among the five fertilization treatments. Obviously, the long-term application of organic manure could maintain the higher activity of microorganisms in soils. The amounts of biomass C, N and P in the fallowed soils varied with the tillage methods; they were much greater under NT than under CT, especially in the surface layer, suggesting that the frequent plowing could decrease the content of organic matter in the surface layer of the fallowed soil.

Changes of Soil Microbial Biomass C and P During Wheat Growth After Application of Fertilizers

A pot experiment was carried out with a clay loam in a green house. The results showed that soil microbial biomass C increased with the application of organic manure at the beginning of the experiment and then gradually decreased with declining of the temperature. The soil biomass C increased at the tillering stage when the temperature gradually increased, and rose to the highest value at the anthesis stage, being about 554.9-794.4 mg C kg-1. The application of organic manure resulted in the highest increase in biomass C among the fertilization treatments while that of ammonium sulphate gave the lowest. At the harvest time the soil biomass C decreased to the presowing level. Like the soil biomass C the amount of biomass P was increased by the incorporation of organic manure and was the highest among the treatments, with the values of the check and ammonium sulphate treatments being the lowest. Meanwhile, the changing patterns of the C/P ratio of soil microbial biomass at stages of wheat growth are also described.

Nutrient cycling characteristics of Quercus acutissima and Pinus massoniana mixed forest in the Three Gorge Reservoir area, China

The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest which is the most common forest type in the Three Gorge Reservoir areas in China, were systematically analyzed. The results showed that N, P and K accumulated in the plant pool and in the litter pool, while total N, P, and K were deficient in the soil pool and in the forest systems. Contents of N in the soil of depth 20—40 cm were the key factor limiting growth of trees. The biological outside cycling coefficients were 878, 725 and 117 times of inside cycling coefficients of N, P and K, respectively. 3392, 1026 and 1588 kg of N, P and K return to the litter pool from branches, leaves and throughfall per year, but, 1431, 132 and 1048 kg of N, P and K return to the soil from litter pool per year respectively. It is clear that 58% of N, 87% of P, and 34% of K are lost by surface runoff per year. 549%, 130%, and 834% of N, P and K withdraw from leaves to branches, 499%, 199% and 730% of N, P and K withdraw from branches to trunks per year, respectively.

Spatial patterns of leaf nitrogen and phosphorus stoichiometry across southeast to central Tibet

Leaf N and P stoichiometry in terrestrial ecosystems has been widely investigated in recent years owing to the importance of these elements in improving the predicted vegetation responses to global changes.The vertical distribution of leaf N and P stoichiometry has attracted increasing attention because of the dramatic changes in environmental factors at regional scales.However,the characteristics of leaf N and P stoichiometry in the southeast Qinghai–Tibet plateau(SET)are not clear,although this area is sensitive to global change.Here,we analyzed the leaf N and P concentrations in dominant plant species on natural altitudinal gradients on the Duoxiongla(DXL),Sejila(SJL),Mila(ML),and Gangbala(GBL)mountains across the SET all the way to central Tibet.Our results showed that the leaf N concentrations were comparable among the regions,whereas the leaf P concentrations dramatically decreased from SET to central Tibet(CT).The leaf N concentrations were 23.6,21.3,20.8,and 22.4 g kg^(-1),and the leaf P concentrations were 2.40,2.49,1.94,and 1.59 g kg^(-1) on the SJL,DXL,ML and GBL mountains,respectively.The leaf N/P ratios on the DXL,SJL,ML,and GBL mountains were 8.81,10.3,11.2,and 14.2,respectively.Considering the increasing trend of the leaf N/P ratio from southeast Qinghai–Tibet plateau to central Tibet,N limitation might widely exist in well vegetated ecosystems in the Qinghai–Tibet plateau.

Regulation of neural stem/progenitor cell functions by P2X and P2Y receptors

Neural stem/progenitor cells：Radial glial cells constitute multipotent cells in the ventricular zone,lining the wall of the lateral ventricle of the embryonic brain.They have the capacity to give rise to cells belonging to all three major linages（neurons,astrocytes and oligodendrocytes）of the nervous system（Tang and Illes,2017）.

IR AND EPR STUDIES OF THE NUCLEAR ALKYLATION OF TOLUENE AND ETHYLENE ON THE MODIFIED Mg—AND P—ZSM—5 CATALYST

The surface intermediate (C_2H_5^+ and CH_3C_6H_5^+) and the reactive pathway of nuclear alkylation of toluene with ethylene to para—ethyl toluene over Mg salt and phosphorus acid modified ZSM—5 zeolites have been studied by 1R and EPR methods.

Correlation of cognitive function with acetylcholinesterase activity and P300 event-related potential of patients with type 2 diabetes mellitus

BACKGROUND： At present, central cholinergic neuron system is regarded the most major structural basis of cognitive function. Changes in structure of cholinergic neuron system of brain and receptor expression after brain injury can cause cognitive impairment. OBJECTIVE＂ To comparatively observe the intelligence quotient （IQ）, latent period and wave amplitude of P300 event-related potential and the difference of activity of acetylcholinesterase （ACHE） in blood and cerebrospinal fluid between patients with type 2 diabetes mellitus and with non-diabetes mellitus, and analyze the correlation of IQ of cognitive impairment patients with diabetes mellitus with AChE activity, latent period and wave amplitude of P300 event-related potential in cerebrospinal fluid. DESIGN： Correlation analysis of contrast observation SETTING： Department of Endocrinology, Affiliated Hospital of Binzhou Medical College PARTICIPANTS： Totally 32 patients with type 2 diabetes mellitus who received the treatment in the Department of Endocrinology, Affiliated Hospital of Binzhou Medical College between April 2004 and April 2005 were recruited, serving as diabetes mellitus group. They, including 19 male and 13 female, aged 49 to 73 years, with disease course of 4 to 11 years, all met the diagnostic criteria of diabetes mellitus revised by World Health Organization in 1999. Another 30 patients with non-diabetes mellitus who homeochronously underwent lumbar anesthesia in the Department of Surgery and Department of Gynecology were recruited, serving as non-diabetes mellitus group. The 30 patients included 18 male and 12 female, and their age ranged from 46 to 71 years. Informed consents of detected items were obtained from the involved patients. METHODS： ① Evaluation,on IQ： The IQ of involved subjects was evaluated with Chinese Version of the Wechsler Adult Intelligence Scale revised by Gong Yao-xian （WAIS-RC）. WAIS-RC included 6 verbal subscales and 5 performance subscales. The test scores of the 11 subscales integrated into the scores of the whole scale, and the scores on the WAIS-RC included verbal IQ （VlQ）, performance IQ （PIQ） and full scale IQ （FIQ）. FIQ ≤79 scores indicated low IQ and FIQ≤69 indicated intelligence impairment. ② Detection of P300 wave： P300 wave was detected with evoked potential instrument （MYTOPRO, Italian）, and data of latent period and amplitude of P300 event-related potential were automatically shown by computer. ③ Detection of AChE activity in blood and cerebrospinal fluid： Activity of AChE of blood and cerebrospinal fluid was measured with biochemical methods by using CORNING-560 autoanalyzer.④Correlation analysis： Correlation of FIQ with AChE of cerebrospinal fluid and P300 wave of patients with type 2 diabetes mellitus was analyzed, t test was used in intergroup comparison and linear correlation analysis for relevant treatment. MAIN OUTCOME MEASURES： ① Comparison of IQ, latent period and wave amplitude of P300 wave as well as the activity of AChE between two groups. ② Analysis on the correlation of FIQ of patients with type 2 diabetes mellitus with AChE of cerebrospinal fluid and P300 wave. RESULTS： Thirty-two patients with diabetes mellitus and 30 non-diabetes mellitus participated in the result analysis. ①Comparison of IQ, latent period and wave amplitude of P300 wave as well as the activity of AChE between two groups： The scores of VIP, PIQ and FIQ of patients with type 2 diabetes mellitus were （97.4±10.4）. （92.6±8.4） and （95.2±9.7） scores, respectively; and those of patients with non-diabetes mellitus were （104.7±9.6）, （102.5±8.5）and（102.7±8.9） scores, respectively, and P 〈 0.05-0.01 was set in intergroup comparison. The latent period of P300 wave at points Fz , Cz and Pz of patients with type 2 diabetes mellitus was （370.8±41.8）.（371.5±39.1）and （375.1±43.1） ms, respectively, and that of patients with non-diabetes mellitus was （ 332.1 ±28.3 ）, （335.7 ±29.4）and （339.7 ±27.3） ms, respectively, and P 〈 0.01 was set in intergroup comparison; Wave amplitude of P300 of patients with type 2 diabetes mellitus was （8.6±4.1）,（8.6±4.0） and （7.7±4.0） μV, respectively and that of patients with non-diabetes mellitus was （11.9±4.1）,（11.5±4.4） and （10.9±5.0） μV, respectively , and P 〈 0.05-0.01 was set in intergroup comparison; The level of AChE in blood and cerebrospinal fluid of patients with type 2 diabetes mellitus was （235.61 ±50.34）and （17.89±4.46） μkat/L, respectively, which was significantly higher than that of patients with non-diabetes mellitus [（205.03±44.15）and （14.63±0.48） μkat /L, respectively], and P 〈 0.05-0.01 was set in the intergroup comparison. ② Correlation of FIQ value of patients with type 2 diabetes mellitus with AChE of cerebrospinal fluid and P300 wave： The value of FIQ was significantly negatively correlated with the AChE activity of cerebrospinal fluid （r=-0.588 1, P 〈 0.01 ）, significantly negatively correlated with the latent period at points Fz. C and Pz of P300 wave （r= -0.700 5, -0.689 4, -0.688 5, P 〈 0.01 ）, and significantly positively correlated with the amplitude at points Fz . Cz and Pz of P300 wave（r= 0.607 4,0.616 1,0.592 0,P 〈 0.01 ）. CONCLUSION： ① Cognitive impairment of patients with type 2 diabetes mellitus might be related to the increase of activity of AChE in cerebrospinal fluid. ②Combined application of examination of P300 wave and evaluation of IQ is more useful in deciding the state of cognitive function of patients with type 2 diabetes mellitus.

Mechanism of Competition between Nutlin3 and p53 for Binding with Mdm2

The tumour suppressor p53 is a transcription factor that regulates multiple biological functions including metabolism, DNA repair, cell cycle arrest, apoptosis and senescence. About half of human cancers show a normal TP53 gene and aberrant overexpression of Mdm2. This fact promotes a promising cancer therapeutic strategy by inhibiting the interactions between p53 and Mdm2. Various inhibitors have been designed to achieve this novel approach for cancer therapy. However, the detailed competition mechanism between these inhibitors and the p53 molecule in their binding process to Mdm2 is still unclear. We investigate this competition mechanism between Nutlin3 and p53 using molecular dynamics simulations. It is found that Nutlin3 binds faster than the p53 molecule to Mdm2 to prevent p53 binding to Mdm2 when Nutlin3 and p53 have equal distance from Mdm2. Nutlin3 can also bind to the p53-Mdm2 complex to disturb and weaken the interactions between p53 and Mdm2. Consequently, p53 cannot bind to Mdm2 and its tumour suppression function is reactivated. These results provide the detailed competition mechanism between Nutlin3 and p53 in their binding to Mdm2. Because the binding site of most other inhibitors to Mdm2 is the same as Nutlin3, therefore this competition mechanism can extend to most inhibitors which target the p53-Mdm2 interaction.

The expression of Cyclin A and p21^(cip1)in fibroblast of hypertrophic scar

Objective To study the relation of the mRNA and protein expression of CyclinA and p21cip1 in different stages hypertrophic scar fibroblast (FB) with its cell cycle,so as to provide theoretical evidence for intervention therapy of

Deciphering nitrogen concentrations in Metasequoia glyptostroboides : a novel approach using RGB images and machine learning

Recent advances in spectral sensing techniques and machine learning(ML)methods have enabled the estimation of plant physiochemical traits.Nitrogen(N)is a primary limiting factor for terrestrial forest growth,but traditional methods for N determination are labor-intensive,time-consuming,and destructive.In this study,we present a rapid,non-destructive method to predict leaf N concentration(LNC)in Metasequoia glyptostroboides plantations under N and phosphorus(P)fertilization using ML techniques and unmanned aerial vehicle(UAV)-based RGB(red,green,blue)images.Nine spectral vegetation indices(VIs)were extracted from the RGB images.The spectral reflectance and VIs were used as input features to construct models for estimating LNC based on support vector machine,ran-dom forest(RF),and multiple linear regression,gradient boosting regression and classification and regression trees(CART).The results show that RF is the best fitting model for estimating LNC with a coefficient of determination(R2)of 0.73.Using this model,we evaluated the effects of N and P treatments on LNC and found a significant increase with N and a decrease with P.Height,diameter at breast height(DBH),and crown width of all M.glyptostroboides were analyzed by Pearson correlation with the predicted LNC.DBH was significantly correlated with LNC under N treat-ment.Our results highlight the potential of combining UAV RGB images with an ML algorithm as an efficient,scalable,and cost-effective method for LNC quantification.Future research can extend this approach to different tree species and different plant traits,paving the way for large-scale,time-efficient plant growth monitoring.

Effects of metal lead on growth and mycorrhizae of an invasive plant species (Solidago canadensis L.)

It is less known whether and how soil metal lead （Pb） impacts the invasion of exotic plants. A greenhouse experiment was conducted to estimate the effects of lead on the growth and mycorrhizae of an invasive species （Solidago canadensis L.） in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that allowed arbuscular mycorrhizal （AM） fungal hyphae rather than plant roots to grow into the TEST compartments. Three Pb levels （control, 300, and 600 mg/kg soil） were used in this study to simulate ambient soil and two pollution sites where S. canadensis grows. Mycorrhizal inoculum comprised five indigenous arbuscular mycorrhizal fungal species （ Glomus mosseae, Glomus versiform, Glomus diaphanum, Glomus geosporum, and Glomus etunicatum）. The ^15N isotope tracer was used to quantify the mycorrhizally mediated nitrogen acquisition of plants. The results showed that S. canadensis was highly dependent on mycorrhizae. The Pb additions significantly decreased biomass and arbuscular mycorrhizal colonization （root length colonized, RLC%） but did not affect spore numbers, N （including total N and ^15N） and P uptake. The facilitating efficiency of mycorrhizae on nutrient acquisition was promoted by Pb treatments. The Pb was mostly sequestered in belowground of plant （root and rhizome）. The results suggest that the high efficiency of mycorrhizae on nutrient uptake might give S. canadensis a great advantage over native species in Pb polluted soils.

Fertilization Affects Biomass Production of Suaeda salsa and Soil Organic Carbon Pool in East Coastal Region of China

Land use practice significantly affects soil properties. Soil is a major sink for atmospheric carbon, and soil organic carbon （SOC） is considered as an essential indicator of soil quality. The objective of this study was to assess the effects of N and P applied to Suaeda salsa on biomass production, SOC concentration, labile organic carbon （LOC） concentration, SOC pool and carbon management index （CMI） as well as the effect of the land use practice on soil quality of coastal tidal lands in east coastal region of China. The study provided relevant references for coastal exploitation, tidal land management and related study in other countries and regions. The field experiment was laid out in a randomized complete block design, consisting of four N-fertilization rates （0 （NO）, 60 （N1）, 120 （N2） and 180 kg ha-1 （N3））, three P-fertilization rates （0 （P0）, 70 （P1） and 105 kg ha-~ （P2）） and bare land without vegetation. N and P applied to S. salsa on coastal tidal lands significantly affected biomass production （above-ground biomass and roots）, bulk density （Pb）, available N and P, SOC, LOC, SOC pool and CMI. Using statistical analysis, significantly interactions in N and P were observed for biomass production and the dominant factor for S. salsa production was N in continuous 2-yr experiments. There were no significant interactions between N and P for SOC concentration, LOC concentration and SOC pool. However, significant interaction was obtained for CMI at the 0-20 cm depth and N played a dominant role in the variation of CMI. There were significant improvements for soil measured attributes and parameters, which suggested that increasing the rates of N and P significantly decreased Pb at the 0-20 cm depth and increased available N and P, SOC, LOC, SOC pool as well as CMI at both the 0-20 and 20-40 cm depth, respectively. By correlation analysis, there were significantly positive correlations between biomass （above- ground biomass and roots） and SOC as well as LOC in 2010 and 2011 across all soil depth, respectively. The treatment with N at 180 kg ha-~ and P at 105 kg ha-1 was superior to the other treatments. The results from the 2-yr continuous experiments indicated that, in short-term, there were a few accumulation of SOC and LOC concentrations by means of N and P application to S. salsa, whereas in the long run, S. salsa with N and P application was recommended for coastal tidal lands because of its great potential of carbon sequestration, improvements of soil nutrition status and promotion of soil quality.

Ecological stoichiometry and biomass response of Agropyron michnoi Roshev.under simulated N deposition in a sandy grassland,China

Sandy grassland in northern China is a fragile ecosystem with poor soil fertility.Exploring how plant species regulate growth and nutrient absorption under the background of nitrogen(N)deposition is crucial for the management of the sandy grassland ecosystem.We carried out a field experiment with six N levels in the Hulunbuir Sandy Land of China from 2014 to 2016 and explored the Agropyron michnoi Roshev.responses of both aboveground and belowground biomasses and carbon(C),N and phosphorus(P)concentrations in the plant tissues and soil.With increasing N addition,both aboveground and belowground biomasses and C,N and P concentrations in the plant tissues increased and exhibited a single-peak curve.C:N and C:P ratios of the plant tissues first decreased but then increased,while the trend for N:P ratio was opposite.The peak values of aboveground biomass,belowground biomass and C concentration in the plant tissues occurred at the level of 20 g N/(m2•a),while those of N and P concentrations in the plant tissues occurred at the level of 15 g N/(m2•a).The maximum growth percentages of aboveground and belowground biomasses were 324.2%and 75.9%,respectively,and the root to shoot ratio(RSR)decreased with the addition of N.N and P concentrations in the plant tissues were ranked in the order of leaves>roots>stems,while C concentration was ranked as roots>leaves>stems.The increase in N concentration in the plant tissues was the largest(from 34%to 162%),followed by the increase in P(from 10%to 33%)and C(from 8%to 24%)concentrations.The aboveground biomass was positively and linearly correlated with leaf C,N and P,and soil C and N concentrations,while the belowground biomass was positively and linearly correlated with leaf N and soil C concentrations.These results showed that the accumulation of N and P in the leaves caused the increase in the aboveground biomass,while the accumulation of leaf N resulted in the increase in the belowground biomass.N deposition can alter the allocation of C,N and P stoichiometry in the plant tissues and has a high potential for increasing plant biomass,which is conducive to the restoration of sandy grassland.

Replanting of broadleaved trees alters internal nutrient cycles of native and exotic pines in subtropical plantations of China

Background:The replanting of broadleaved trees in pure coniferous plantations is widely implemented,as mixed plantations are generally more stable and functional.However,the effect of interspecific interactions between broadleaved and coniferous trees on internal nutrient cycles of conifers remains unclear.Methods:We selected pure coniferous plantations of a native(Pinus massoniana)and an exotic(P.elliottii)pine species and their corresponding mixed plantations with broadleaved trees(Schima superba)in subtropical China,and measured the nitrogen(N)and phosphorus(P)contents in the rhizosphere soils,fine roots,twigs,needles and needle litter of pines.We calculated the root capture,needle resorption and translocation of N and P by pines to determine the mobility of nutrients in trees.Results:Although the N and P in the rhizosphere soils increased due to the replanting of broadleaved trees,the N and P contents in the aboveground tissues of the two pine species did not increase in mixed plantations.Mixed planting had a negative effect on the N and P capture of native pine and a positive effect on that of exotic pine.The N and P resorption efficiencies increased in native pine but were unchanged in exotic pine after the replanting of S.superba.Native pine preferentially employed an aboveground nutrient resorption strategy,whereas exotic pine tended to adopt a belowground nutrient capture strategy after replanting.Translocation of N and P in trees was detected,which reflected the trade-offs between root nutrient capture and needle nutrient resorption.Conclusions:The effect of mixed planting varied between the species of native and exotic pines,and the internal nutrient cycles of both pine species might be dominated by interspecific interaction effects on nutrients rather than soil nutrients.Our study highlights the importance of selecting suitable broadleaved species for replanting in coniferous plantations.

Investigation on the Mechanical Properties at Room Temperature of Q and P Steel Sheet With Ultrahigh Strength

Quenching and Partitioning (Q&P) steel is a new type ultrahigh strength steel with transformation induced plasticity (TRIP) effect. Uniaxial tensile experiments of the Q&P steel at room temperature were carried out to investigate the effects of sampling angle and strain rate on its mechanical properties. Experimental results show that the flow stress-strain curve, the hardening component n, the anisotropy coefficient through thickness r and the elongation of the Q&P steel are not sensitive to the sampling angle. However, the hardening component n and the elongation of the Q&P steel decrease with increasing the strain rate. Due to the Q&P steel with TRIP effect, when the strain rate greater, the deformation work will transform to the internal energy of specimen, and the TRIP effect of the Q&P steel will be inhibited, which results in less transformed retained austenite. X ray diffraction experiments were performed to verify it.

An Intelligent Early Warning Method of Press-Assembly Quality Based on Outlier Data Detection and Linear Regression

Focusing on controlling the press-assembly quality of high-precision servo mechanism,an intelligent early warning method based on outlier data detection and linear regression is proposed.Linear regression is used to deal with the relationship between assembly quality and press-assembly process,then the mathematical model of displacement-force in press-assembly process is established and a qualified press-assembly force range is defined for assembly quality control.To preprocess the raw dataset of displacement-force in the press-assembly process,an improved local outlier factor based on area density and P weight(LAOPW)is designed to eliminate the outliers which will result in inaccuracy of the mathematical model.A weighted distance based on information entropy is used to measure distance,and the reachable distance is replaced with P weight.Experiments show that the detection efficiency of the algorithm is improved by 5.6 ms compared with the traditional local outlier factor(LOF)algorithm,and the detection accuracy is improved by about 2%compared with the local outlier factor based on area density(LAOF)algorithm.The application of LAOPW algorithm and the linear regression model shows that it can effectively carry out intelligent early warning of press-assembly quality of high precision servo mechanism.

Effect of land use on microbial biomass－C, －N and －P in red soils

Eleven red soils varying in land use and fertility status were used to examine the effect of land use on microbial biomass C, N and P. Microbial biomass C in the red soils ranged from about 68 mg C/kg to 225 mg C/kg, which is generally lower than that reported from other types of soil, probably because of low organic matter and high acidity in the red soils. Land use had considerable effects on the amounts of soil C mic . The C mic was the lowest in eroded fallow land, followed by woodland, tea garden, citrus grove and fallow grassland, and the highest in vegetable and paddy fields. There was significant correlation between C mic and organic matter content, suggesting that the influence of land use on C mic is mainly related to the input and accumulation of organic matter. Microbial biomass N in the soils ranged from 12.1 Nmg/kg to 31.7 Nmg/kg and was also affected by land use. The change of N mic with land use was similar to that of C mic . The microbial C/N ratio ranged from 5.2 to 9.9 and averaged 7.6. The N mic was significantly correlated with soil total N and available N. Microbial biomass P in the soils ranged from 4.5 mg P/kg to 52.3 mg P/kg. The microbial C/P ratio was in the range of 4-23. The P mic was relatively less affected by land use due to differences in fertilization practices for various land use systems.