基于线素法的回转体零件CAD／CAM集成系统（R－MCADAM）的开发研究

Ｒ－ＭＣＡＤＡＭ系统采用形体组合法实现零件数据输入和绘图，用框架结构存储零件几何及工艺信息，以线素数据文件作为ＣＡＤ与ＣＡＭ之间的集成接口，利用工艺规则菜单以人机交互方式生成工艺文件，与刀位轨迹文件结合后，自动编制数控加工程序。

裂隙网络非达西渗流REV及非达西系数张量研究

裂隙网络渗流理论最初建立在裂隙渗流服从立方定律的基础上,而裂隙中非达西渗流更为广泛存在,因此,裂隙网络非达西渗流特性研究更具工程应用前景。本文首先对基于单裂隙立方定律的线素法模型进行改进,用以实现裂隙网络非达西渗流的计算,进而将其应用于实测裂隙数据生成的裂隙网络非达西渗流特性的研究。研究结果表明:根据改进线素法模型和Forchheimer定律计算得到的等效渗透系数张量与线素法模型和达西定律计算得到的具有一致性。对于同一裂隙网络而言,等效非达西系数张量确定的渗流REV要比等效渗透系数张量确定的大,且等效渗透系数张量与等效非达西系数张量的主轴方向一致,但两者之间的长轴互相垂直。

Synergistic effect of pinellia total alkaloids and uncaria total alkaloids on anticonvulsant action in mice and rats

Aim To investigate the synergistic effect of the combination of pinellia total alkaloid （PTA） and uncaria total alkaloid （UTA）, and explore the mechanism of anticonvulsant action. Methods Anticonvulsant and toxic effect profiles of combinations of PTA with UTA, alone and at three fixed ratios of 1：4, 1 ：1, 4：1, were evaluated in maximal electroshock （MES）-induced seizures and acute toxicity test in mice. Respective ED50 and LD50 were calculated with Bliss＇s method. Their synergistic effect were evaluated by isobolographic analysis and allowed the determination of benefit indices （BI） for respective combinations. The model of convulsive rats kindled by penicillin topically injected into cortex was used to investigated the content of Glu, Asp, Gly and GABA in hippocampus using high performance liquid chromatography （HPLC）. Results Combinations of PTA and UTA at the ratio of 4：1 were synergistic in MES test and antagonistic in acute toxicity test, showing the best profile for combinations of PTA with UTA. In contrast, the ratios of 1 ：4 and 1 ： 1, despite synergistic in MES test, were additive in acute toxicity test. The 4：1 combination and two drugs alone significantly decreased Glu level and increased GABA level in the hippocampus, but the GABA level in the 4：1 combination group was higher than that in the two drugs alone groups. They did not have significant influence on the levels of ASp and Gly. Conclusion Combinations of PTA and UTA at 4：1 ratio demonstrated synergistic effect in anticonvulsant action and antagonistic effect in toxicity. The anticonvulsant mechanism might be related to decreasing the excitability of Glutamatergic neurons and increasing the inhibition of GABAergic neurons.

Comparison of inversion of Chlorophyll concentration in the Bohai Bay based on GOCI Data

Bohai bay has poor water circulation capacity and low self-purification capacity,and a large number of land-sourced pollutants are accepted every year.The estimation of chlorophyll concentration based on remote sensing plays an important role in the study of marine red tide and the monitoring of water quality in the Bohai Bay.So it is necessary to select the best algorithm by comparing the performance of each algorithm.Choosing the best algorithm is helpful to improve the precision of chlorophyll concentration.Based on the in-situ measurement data of the Bohai Bay and the GOCI remote sensing reflectance data,the retrieval models of chlorophyll concentration were established in this paper by using the methods of fluorescence line height(FLH),OC3,blue-green band ratio and NIR-red band ratio.The above algorithms were evaluated by comparing the simulation results and the verification results.The results showed that there are obvious differences in the accuracy of different retrieval methods.The fitting and retrieval effect of FLH is the best and NIR-red band ratio is the worst,and the OC3is similar to the blue-green band ratio method.

Avidin chase reduces side effects of radioimmunotherapy in nude mice bearing human colon carcinoma

AIM: To evaluate the influence of avidin chase on the side effects of radioimmunotherapy (RIT) in nude mice bearing human colon carcinoma and therapeutic outcome.METHODS: Purified anti-CEA monoclonal antibody (McAb)was biotinylated with NHS-biotin, and then radiolabeled with 188Re by the direct method. 188Re-labeledbiotinylated anti-CEA McAb (188Re-CEA McAb-Bt) was intravenously injected followed by intravenous injection of avidin after 24 h. SPECT imaging and biodistribution study were performed at 28-48 h after the injection of 188Re-CEA McAb-Bt. Three groups of nude mice subcutaneously grafted with human colon carcinoma were treated 7 d after the graft. Mice in the avidin chase group received intravenous injection of 188Re-CEA McAb-Bt (11.1 MBq/20 μg) followed by intravenous injection of cold avidin (80 μg) after 24 h. Mice in the control group (treated group without avidin chase) only received the injection of 188Re-CEA McAb-Bt (11.1 MBq/20 μg), another control group (non-treated group) only received 0.1 mL normal saline solution. Toxicity was evaluated on the basis of change of body weight and peripheral WBC counts, and therapy effects were determined by variation in tumor volume. Histological analysis of tumors was also performed.RESULTS: Avidin chase markedly accelerated the clearance of 188Re-CEA McAb-Bt from the blood and normal tissues. The tumor uptakes of 188Re-CEA Mc Ab-Bt at 28 h were 5.90 and 6.42% ID/g, respectively, in chase group and in non-chase group, while the tumor-to-background (T/NT) ratios were 3.19 and 0.56, respectively. The tumor uptake was slightly decreased by avidin chase, but the T/NT ratios were increased. In treated groups the growth rate of body weight and the number of WBC decreased after injection of 188Re-CEA McAb-Bt, and the WBC counts recovered earlier in the group with avidin chase than in the group without avidin chase. Compared to the nontreated group, treated groups with and without avidin chase showed significant anti-tumor effects.CONCLUSION: Avidin chase can effectively reduce the side effects of RIT, and improve therapeutic efficacy.

The distribution and variation of elements in sediments off the Huanghe (Yellow) River mouth

Surface sediment samples collected off the Huanghe （Yellow） River mouth during the period 2007-2009 were analyzed for major and trace element concentrations. Concentrations of 16 elements were measured using X-ray fluorescence spectrometry. Results demonstrate that sediment grain size is the dominant factor controlling the spatial variations of elemental concentrations. Correlation and cluster analyses allowed classification of the study area into four geochemical regions： Regions Ⅰ and Ⅲare characterized by high concentrations ofAl2O3, Fe2O3, MgO, Na2O, K2O, Cr, Cu, Mn, Ni, Pb, V, and Zn, and contain fine-grained sediments with mean grain size （Mz）〈22 μm; and; Regions Ⅱ and Ⅳcontain mostly coarse-grained sediments, and are characterized by high concentrations of SiO2, Na2O, and Zr. The sediment entering the sea from the Huanghe River and its tributaries is enriched in Ca. Thus, the Ca/Al ratio was used as an indicator of the proportion of sediments in the study area that originated from the Huanghe River. Ca/Al ratios decrease from Regions Ⅰ and Ⅱ（located in the nearshore zone of the Huanghe River delta） to Regions Ⅲand Ⅳ（distributed in the offshore zone of the northern Huanghe River delta, southern and southeastern Laizhou Bay area）.

Application of gap element to nonlinear mechanics analysis of drillstring

This paper presents a nonlinear finite element method to resolve the problem of the nonlinear contact between the drillstring and hole wall by using a Multi-directional Contact Gap Element (MCGE) contacting at appropriate positions in each beam element. The method was successfully applied to the Daqing Oil Field GP1 well. It was shown that the drillstring's contact resistance at any well depth could be obtained by calculations and that as the error in the calculation of the hole top load is below 10%, the calculation result can provide theoretical basis for the design and operation of drillstrings.

An Image Encryption Approach Using a Shuffling Map

A new image encryption approach is proposed.First,a sort transformation based on nonlinear chaoticalgorithm is used to shuffle the positions of image pixels.Then the states of hyper-chaos are used to change the greyvalues of the shuffled image according to the changed chaotic values of the same position between the above nonlinearchaotic sequence and the sorted chaotic sequence.The experimental results demonstrate that the image encryptionscheme based on a shuffling map shows advantages of large key space and high-level security.Compared with someencryption algorithms,the suggested encryption scheme is more secure.

Analysis of Linear Triangular Elements for Convection-diffusion Problems by Streamline Diffusion Finite Element Methods

This paper is devoted to studying the superconvergence of streamline diffusion finite element methods for convection-diffusion problems. In [8], under the condition that ε ≤ h^2 the optimal finite element error estimate was obtained in L^2-norm. In the present paper, however, the same error estimate result is gained under the weaker condition that ε≤h.

Fast forward modeling of muon transmission tomography based on model voxelization ray energy loss projection

To solve the problems associated with low resolution and high computational effort infinite time,this paper proposes a fast forward modeling method for muon energy loss transmission tomography based on a model voxelization energy loss projection algorithm.First,the energy loss equation for muon transmission tomography is derived from the Bethe–Bloch formula,and the imaging region is then dissected into several units using the model voxelization method.Thereafter,the three-dimensional(3-D)imaging model is discretized into parallel and equally spaced two-dimensional(2-D)slices using the model layering method to realize a dimensional reduction of the 3-D volume data and accelerate the forward calculation speed.Subsequently,the muon energy loss transmission tomography equation is discretized using the ray energy loss projection method to establish a set of energy loss equations for the muon penetration voxel model.Finally,the muon energy loss values at the outgoing point are obtained by solving the projection coefficient matrix of the ray length-weighted model,achieving a significant reduction in the number of muons and improving the computational efficiency.A comparison of our results with the simulation results based on the Monte Carlo method verifies the accuracy and effectiveness of the algorithm proposed in this paper.The metallic mineral identification tests show that the proposed algorithm can quickly identify high-density metallic minerals.The muon energy loss response can accurately identify the boundary of the anomalies and their spatial distribution characteristics.

Geochemical characteristics of illite clay rocks from the Shihezi Formation in the Hanxing mining area and its sedimentary environment

We studied the geochemical characteristics of illite clay rocks and their importance from the 5hihezi Formation of Late Permian in the Hanxing mining area by means of ICP-M5 and sequential X-ray fluorescence spectrometry. The results show that the amount of SiO2 is between 53.37% and 61.58% （by weight） and that of Al2O3 22.40% and 31.31% （by weight）. The ratio of SiO2/Al2O3 lies between 1.71 and 2.75. The amount of K2O ranges from 1.11% to 2.56% （by weight）. The amounts of Fe and Ti are higher than the theoretical values in illite clay rock would indicate. The amounts of some trace elements, such as Ga, As, Ba, Cu, Th and U are higher than their Clark values, while that of another 23 trace elements are found to be dose to their Clark values. The amounts of REE range from 22.59 to 570.54 μg/g, with an average of 163.23μg/g. The ratios of LREE/HREE range from 5.41 to 21.82, with an average of 8.87. These characteristics show that LREE are much richer in content than HREE. The REE distribution patterns of our samples were characterized by clearly negative Ce and Eu anomalies. We analyzed the sedimentary environment of the Hanxing mining area in Late Permian by the characteristic element ratio method. The ratios of Mn/Fe range from 0 to 0.0168, which are lower than those in a marine sedimentary environment. The ratios of Sr/Ba （0.20-0.41） are less than 1. These are all indications that the sediments of the Hanxing mining area in Late Permian form largely a continental sedimentary environment. The sedimentary water is freshwater, a conclusion reached on the basis of the ratios of Th/U （2.66-6.62） and of Ca/（Ca ＋ Fe） （0.01-0.059）; the average ratio of Fe2＋/Fe3＋ is 4.8. The sedimentary water condition is weakly acidic and weakly oxidative-weakly reductive, a conclusion reached on the basis of ratios of Fe2＋/Fe3＋ （4.8） and of Ceanom （-0.08）.

A Comparison between Neutron Activation Analysis and X-Ray Fluorescence Methods in Analyzing the Granite Samples

This study focused on the performance of where elements analysing techniques were used to detect the elements in granite stones. These techniques are NAA （neutron activation analysis） and XRF （X-ray fluorescence）. They were applied to detect the elements in samples which had been chosen from different areas of Pulua Penang in Malaysia collected by geophysics group which helped to describe and identify the elements found in the granite stone that were used in the study procedures to control the analytical results. The integration of both methods has enabled the researcher to determine 40 elements in the samples. The numbers of elements detected by XRF analysis method are 12 elements （Ar, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn）; while, the elements detected by NAA method have three folds of elements with XRF analysis method were 35 elements （Na, AI, Si, K, Ca, Sc,Ti, Mn, Fe, Co, Ga, Ce, As, Br, Rb, Zr, Sb, I, Cs, Ba, La, Nd, Sm, Eu,Tb, Dy, Yb, Lu, Hf, Ta, W, Au, Pa and Np）. Seven common elements were detected in both techniques： K, Sc, Ti, V, Mn, Fe and Co. Si has a higher concentration in NAA technique which is 331.8 ppm. Sc has a lower concentration in XRF technique which is 0.25 ppm. Nd has a lower concentration in NAA technique which is 3.09 - 10-5 ppm. Finally, it is found that the NAA is better to detect the elements than XRF.

Base force element method (BFEM) on complementary energy principle for linear elasticity problem

Using the concept of base forces as state variables,a new finite element method-the base force element method (BFEM) on complementary energy principle for linear elasticity problems is presented.Firstly,an explicit expression of compliance matrix for an element is derived through base forces by dyadic vectors.Then,the explicit control equations of finite element method of complementary energy principle are derived using Lagrange multiplier method.Thereafter,the base forces element procedure for linear elasticity is developed.Finally,several examples are analyzed to illustrate the reliability and accuracy of the formulation and the procedure.

Stability of proteins with multi-state unfolding behavior

A new model used to calculate the free energy change of protein unfolding is presented. In this model, proteins are considered to be composed of structural elements. The unfolding of a structural element obeys a two-state mechanism and the free energy change of the element can be obtained by a linear extrapolation method. If a protein consists of the same structural elements, its unfolding will displays a two-state process, and only the average structural element free energy change 〈△G0 element（H2O）〉 can be measured. If protein consists of completely different structural elements, its unfolding will show a multi-state behavior. When a protein consists of n structural elements its unfolding will shows a （n＋1）-state behavior. A least-squares fitting can be used to analyze the contribution of each structural element to the protein and the free energy change of each structural element can be obtained by using linear extrapolation to zero denaturant concentration, not to the start of each transition. The measured △Gn protein（H2O） is the sum of the free energy change for each structural element. Using this new model, we can not only analyze the stability of various proteins with similar structure and similar molecular weight, which undergo multi-state unfolding processes, but also compare the stability of proteins with different structures and molecular weights using the average structural element free energy change 〈△G0 element（H2O）〉. Although this method cannot completely provide the exact free energy of proteins, it is better than current methods.

Influence of Ice on Soil Elemental Characterization via Portable X-Ray Fluorescence Spectrometry

Field portable X-ray fluorescence （PXRF） spectrometry has become an increasingly popular technique for in-situ elemental characterization of soils. The technique is fast, portable, and accurate, requiring minimal sample preparation and no consumables. However, soil moisture 〉 20% has been known to cause fluorescence denudation and error in elemental reporting and few studies have evaluated the presence of soil moisture in solid form as ice. Gelisols （USDA Soil Taxonomy）, permafrost-affected soils, cover a large amount of the land surface in the northern and southern hemispheres. Thus, the applicability of PXRF in those areas requires further investigation. PXRF was used to scan the elemental composition （Ba, Ca, Cr, Fe, K, Mn, Pb, Rb, Sr, Ti, Zn, and Zr） of 13 pedons in central and northern Alaska, USA. Four types of scans were completed： 1） in-situ frozen soil, 2） re-frozen soil in the laboratory, 3） melted soil/water mixture in the laboratory, and 4） moisture-corrected soil. All were then compared to oven dry soil scans. Results showed that the majority of PXRF readings from in-situ, re-frozen, and melted samples were significantly underestimated, compared to the readings on oven dry samples, owing to the interference expected by moisture. However, when the moisture contents were divided into 〉 40% and 〈 40〈 groups, the PXRF readings under different scanning conditions performed better in the group with 〈 40% moisture contents. Most elements of the scans on the melted samples with 〈 40% moisture contents acceptably compared to those of the dry samples, with R2 values ranging from 0.446 （Mn） to 0.930 （St）. However, underestimation of the melted samples was still quite apparent. Moisture-corrected sample PXRF readings provided the best correlation to those of the dry, ground samples as indicated by higher R2 values, lower root mean square errors （RMSEs）, and slopes closer to 1 in linear regression equations. However, the in-situ （frozen） sample scans did not differ appreciably from the melted sample scans in their correlations to dry sample scans in terms of R2 values （0.81 vs. 0.88）, RMSEs （1.06 vs. 0.85）, and slopes （0.88 vs. 0.92）. Notably, all of those relationships improved for the group with moisture contents 〈 40%.