This paper has proved that the Diophantine equation x3+1=38y2 has only integer solutions(x,y)=(-1, 0),(31,±28).
A formal definition of proposition formulae was provided by context-free grammar,and the conversion from proposition formulae to polynomials was solved automatically. Using Wu′s Method, the paper presented another solution to the problem of theorem reasoning. In addition, a method for producing logical deduction was introduced.
A new method based on numeric computation for automated geometric theorem proving and discovering is shown. And a dynamic searching system of geometric theorem has been implemented,which can solve elementary geometric problems efficiently, including some non-constructive problems.
Based on the smaller information granularity security, granule technology was presented in this paper, and the information content security architecture model was also given. The model-based prototype system exampled with protecting WORD documents was implemented.
This paper studies the resource sharing in Tele-learning systems.A community P2P learning resource sharing model is proposed and the resource sharing will be restricted in certain communities. The metadata of digital learning resources is stated by LOM standard. By means of distributed metadata management in structured pure P2P topology, the distributed storage and bandwidth can be taken full advantage. The constitution of community, the publication and retrieval of learning resources are specified in this paper as well as implement of the model.
There are plenty of local copies of pages of remote web sites on local databases on most of web search engine sites. It is necessary to pull remote web pages periodically to refresh local copies of these pages on database in order to keep copies and source pages consistent，and which takes plenty of time and resources.The article proposes serveral policies to synchronize copy and source pages , proposes a Poission model of source page change, define freshness and fresh time, studies on these policies and compares their effectiveness.It is shown that the proposed policies improve the freshness of web pages significantly.
Uniform Ag nano-particles was synthesized within nanoscale pores of oxidized porous silicon (OPS) by a simple solution immersion-thermal decomposition approach，forming the compound structure of Ag/OPS/silicon. Ag films deposited on OPS were characterized by X-ray diffraction, and SEM showed the existence of silver nano-particles.
In this paper, we defined lowering and raising operator of single photon's two polarization states, and used the theory of linear transformation of operator in Fock space to study BS, PBS, wave plate and H transformation. We obtained their representation of operator .On the base of this; we studied some quantum information experiment, e.g. Teleportation, from a new aspect. Using the new representation, we can analyze the probability of photons output states .To do this, we try to find a new method to devise experiments much efficiently.
This paper advances a novel measurement of wave-height — differential algorithm.Compared with electric level method, the differential algorithm has its advantages. This article details its principle,algorithm and demonstrates it with a living example.
Syntheses of three novel heteroretinoids were reported. Novel heteroretinoids were 5-(5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-3-pyrazole carboxylic acid, 2-Methyl -5-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-furan-3-carboxylic acid, 1-Butyl -2-methyl-5-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-1H-pyrrole-3-carboxylic acid.The results of biological test indicated that these compounds possessed some growth inhibition effects in leukemia cells.
Genomic DNA was isolated from the musculature of Macrobrachium nipponensis to establish a reproducible and stable PCR technical system. The ingredients and programs of amplified reactions were optimized respectively. The results showed that the profiles of PCR products could be improved obviously by using the 25 μL solution of 10×Buffer 2.5 μL, Mg+2 1.5 mmol/L, 4×dNTP 0.2 mmol/L, 1 U Taq DNA polymerase, 0.4 μmol/L of each primer and 200~300 ng of DNA template as well as the programs of 5 min at 95 ℃, 35 cycles of 1 min at 95 ℃, 50 s at 56 ℃, 1 min at 72 ℃ and finally, 10 min at 72 ℃. The optimized conditions could result in satisfactory specificity and reproducibility in amplifying 18S rRNA,COI,ND5 gene fragments, and consequently provide a useful means for the research of genetic diversity, molecular marker and germplasm identification in Macrobrachium nipponensis.
Amino acids composition and activities of four digestive enzymes including pepsin, tryptase, amylase, cellulase were determined in the eggs of freshwater prawn, Macrobrachium nipponense. These eggs were sampled from different embryonic development stages. The results indicated that digestive enzymes activities and amino acids correlated closely with the stages of embryonic development. Activities of pepsin, tryptase and amylase were relatively high during the whole embryonic development stages. Activities of pepsin, tryptase and amylase were high in early and late developmental stages, but relatively low during middle stages. Cellulose activity was low and showed no obvious change during different embryonic development stages. During protozoea stage, activities of pepsin, tryptase and amylase increased obviously. The content of dissolvable protein and amino acid had a decreased trend. It had relevance to the activities of related enzymes. However, content of the dissolvable protein and amino acid during gastrula stage were higher than that of during blastula stage. Among all the amino acids determined, content of Glu was the highest, the highest essential amino acid (EAA) content was Leu. There was little difference between the ratios of content of single EAA to total EAA during different stages of embryonic development of M. nipponense.
The purpose of this paper was to compare two methods of acquiring free sperms from spermatophores of Chinese mitten-handed crab (Eriocheir sinensis). Under the condition of pH 7.4 and different reaction temperatures (27 ℃,32 ℃,37 ℃,42 ℃and 47 ℃, respectively), trypsinase concentrations (0.05 %, 0.10 %, 0.15 %, 0.20 % and 0.25 %, respectively) and reaction times(5 min，10 min，15 min，20 min and 25 min, respectively), the best reaction condition of trypsinase digestion method (TDM) was studied by orthogonal tests and the sperm amounts which got from each gram of spermatophores was used as a criterion. According to the results of orthogonal tests, we found that enzymatic reaction time was the primary factor, and the reaction temperature and the trypsinase concentration also functioned. The maximum effect of trypsinase digesting works at temperature 37 ℃, trypsinase concentration 0.20 % and time 5 min. By using TDM the amounts of free sperms acquired from each gram of spermatophore were 7.41×108 which was significantly higher than that using HM which was only 3.33×108 and the sperm mortality rate was 4.75 % by using TDM which was significantly lower than that using HM which was 27.00 %. Furthermore, the acrosome reaction ability was detected by artificially-induced methodology and the reaction rates were 62.3 % (TDM) and 64.5 % (HM), and there was no significant difference between them. These results suggest that TDM is more effective than HM in acquiring free sperms.
15α-hydroxylation of 13-ethyl-estr-4-ene-3,17-dione using immobilized Penicillium raistrickii entrapped in calcium alginate gel was studied. The conversion conditions, which affected hydroxylation such as substrate concentration, the time to add substrate, conversion duration, were investigated. The results show that, the immobilized Penicillium raistrickii can be utilized repeatedly five times with no obvious decline of hydroxylation ability.
The effects of Puararia flavonoids(PF) on bovine vascular endothelial cells(VEC) in vitro injured by advanced glycation end products(AGEs) were investigated. When VEC was incubated with AGEs(4 g/L) for 48 hours, the growth of VEC was enhanced, the contents of lactate dehydrogenase(LDH) and malondialdehyde(MDA) and lipofuscin(LPF) were markedly increased(P<0.01), the contents of nitric oxide(NO-2/ NO-3) and glutatuhione(GSH) were reduced. Treatment with PF caused a reduction in LDH and MDA and LPF, the contents of GSH and NO-2/ NO-3 were increased. The results suggest AGEs has direct effects on VEC, perhaps oxidative stress participates in this process. PF can protect cultured VEC from being injured by AGEs, thereby exert favorable effect against the occurrence and development of chronic vascular complications in diabetic mellitus.
Gene expression of VHA-c was detected in Arabidopsis silique, flower, leaf, bolt, root. However, the expression level of VHA-c3 was much higher in leaves than in the other tissues. Analysis of the putative promoter of VHA-c3 was carried out in tobacoo leave system. A series of the promoter mutants were constructed in which various extents of VHA-c3 promoter were placed upstream of the GUS gene in vector pC1305.1. The expression of GUS was analyzed by Agrobacterium-mediated transient expression system.It was found that a 2 812 bp promoter region has high gene expression capacity. And there is a high potential key cis-element for leaf-specific expression between 2812-2 234 bp region.
The ash contents and caloric values of different aboveground organs for three dominant tree species and four dominant shrub species in the east subtropical evergreen broad-leaved forest in Tiantong National Forest Park(TNFP), Zhejiang Province were studied in the paper. The results showed that the gross caloric values （GCV）and the ash-free caloric values（AFCV） of various aboveground organs are different among dominant species, the GCV and AFCV of three dominant tree species can be ranked in a decreasing order as Schima superba> Castanopsis carlesii > C. fargesii, and their GCV and AFCV during mature trees are the biggest among the different developmental phases. Meanwhile the GCV and AFCV of the three tree species during the saplings and seedlings are higher than those of shrub species too. GCV and AFCV of the same organ in different aboveground layers decreased from tree species to shrub species, therefore it suggested that the caloric values are closely related to the light gradient within the community. For the same species, the caloric values altered greatly among different organs, the GCV and AFCV of leaves are higher than those of branch and bark. The paper also showed that the gross caloric values are affected obviously by the ash contents.
A four-season investigation was conducted on the soil animals in the litter layers and soil layers depth of 0-15 cm of Castanopsis fargesii forest at Tiantong, Zhejiang province during September, 2003 and July, 2004. The litter layer includes fresh litter layer (L), fermentation layer (F) and humus layer (H).Soil animals amount to a total of 32, 657 in number, including macrofauna, mesofauna and wet types, falling into 10 classes and 27 groups respectively. For soil macrofauna, the dominant groups are Coleoptera, Hymenoptera and Blattoptera, while for mesofauna, they are Acarina and Collembola and for wet type ones, Nematoda. The results of the investigation indicate that: (1) the group numbers and density are all greater in the litter than in the soil depth of 0-15 cm; (2) the vertical distribution of soil animals in the litter differs from that in the soil, the group numbers in the former tend to increase gradually from top to bottom,with those in bottom humus layer the largest; altogether 18 groups are found in it;large numbers of individuals are seen in the middle fermentation layer and in the bottom humus layer, with those in the former greater, both accounting for 77.04 % of the total; (3) the DG index (density-group index) reveals a seasonal change of soil animal community diversity as autumn ＞spring＞winter＞summer; (4) the vertical distribution of dominant groups varies with seasons in a regular manner, thus influencing the seasonal change of the vertical distribution of the entire community.
The investigation of nutrient contents of 39 common species was carried out in Tiantong National Forest Park. The results reveal that the leaf N contents of evergreen-broad leaved trees range from 1.059% to 2.896%，P contents range from 0.069% to 0.126%， the leaf N contents of deciduous-broad leaved trees range from 1.868% to 3.254%, and P contents range from 0.092% to 0.186%. The leaf N contents of coniferous tree Pinus massoniana is 1.874% (N), and the P contents of 0.078％. Average nutrient contents in all organs are different， average nutrient contents in stem and root are lower, and the leave are highest among organs. N and P contents are closely correlated in different organs. Deciduous broad-leaved species have consistently higher leaf N and P than evergreen broad-leaved species, but there are no significant differences in stems, branches and roots. The nutrient contents of trees are higher than shrubs among evergreen broad-leaved species. According to nutrient contents,the common and dominant species in different succession stages can be classified into three groups,nanmely, the rapid growth strategy group, the nutrient retention strategy group and the other group.In addition, there is a correlated relationship between N and P contents in different organs and the correlation cofficient is in the order: leaf>stem>branch>root.The positive relationship between N and P for the need of different organs is also observed.
Smooth cordgrass(Spartina alterniflora)is one of the most notorious invader plants and was listed in the alien invader species of China in 2003. The area of smooth cordgrass in Shanghai was about 3592 hm2. However, few information was available about its vegetative dispersal ability in the nature. In the present study, we surveyed the distribution in Shanghai and estimated the vegetative dispersal ability in Eastern End of Chongming Island, Shanghai. Strong vegetative growth was observed in individuals and patches of smooth cordgrass. After 9 months＇growth, smooth cordgrass individuals could develope 86 to 222 ramets per genet. The largest dispersal distance was 226 cm for individual smooth cordgrass. Mean dispersal distance of smooth cordgrass patches was 107 cm and the largest was 263 cm. At last, some strategies based on the observations had been proposed to control the rapid spreading of this species.
Based on system dynamics model, the water resources carrying capacity of Chongming Island in Shanghai city was discussed. Six scenes of water diversion (local surface water quantity, present water diversion quantity, 10% largest water diversion quantity, 20% largest water diversion quantity, 30% largest water diversion quantity and 50% largest water diversion quantity) as well as four scenes of water resource policies (present water policy, water conservation and recycling policy, industrial structure adjustment policy and integrate policy) were analyzed. The water resources carrying capacity of Chongming Island in different years was simulated, and the population, GDP and COD at different scenes were predicated. Compared with longterm plan of Chongming Island, the water resources carrying capacity indicators were calculated. Finally, the strategy which can promote coordinated development of society, economy and environment was obtained.
中国综合性科技类核心期刊(北大核心)
