LaB6 Work Function and Structural Stability under High Pressure

The work functions of the （110） and （10（3） surfaces of LaB6 are determined from ambient pressure to 39.1 GPa. The work function of the （110） surface slowly decreases but that of the （100） surface remains at a relatively constant value. To determine the reason for this difference, the electron density distribution （EDD） is determined from high-pressure single-crystal x-ray diffraction data by the maximum entropy method. The EDD results show that the chemical bond properties in LaB6 play a key role also investigated by single-crystal x-ray diffraction. In observed from ambient pressure to 39.1 GPa. The structural stability of LaB6 under high pressure is this study, no structural or electronic phase transition is

Mathematic Model and Analytic Solution for a Cylinder Subject to Exponential Function

Hollow cylinders are widely used in spacecraft, rockets, weapons, metallurgy, materials, and mechanical manufacturing industries, and so on, hydraulic bulging roll cylinder and hydraulic press work all belong to hollow cylinders. However, up till now, the solution of the cylinder subjected to the pressures in the three-dimensional space is still at the stage of the analytical solution to the normal pressure or the approximate solution to the variable pressure by numerical method. The analytical solution to the variable pressure of the cylinder has not yet made any breakthrough in theory and can not meet accurate theoretical analysis and calculation requirements of the cylindrical in Engineering. In view of their importance, the precision calculation and theoretical analysis are required to investigate on engineering. A stress function which meets both the biharmonic equations and boundary conditions is constructed in the three-dimensional space. Furthermore, the analytic solution of a hollow cylinder subjected to exponential function distributed variable pressure on its inner and outer surfaces is deduced. By controlling the pressure subject to exponential function distributed variable pressure in the hydraulic bulging roller without any rolling load, using a static tester to record the strain supported hydraulic bulging roll, and comparing with the theoretical calculation, the experimental test result has a higher degree of agreement with the theoretical calculation. Simultaneously, the famous Lam6 solution can be deduced when given the unlimited length of cylinder along the axis. The analytic solution paves the way for the mathematic building and solution of hollow cylinder with randomly uneven pressure.

MATHEMATIC MODEL AND ANALYTIC SOLUTION FOR CYLINDER SUBJECT TO UNEVEN PRESSURES

According to the inverse solution of elasticity mechanics, a stress function is constructed which meets the space biharmonic equation, this stress functions is about cubic function pressure on the inner and outer surfaces of cylinder. When borderline condition that is predigested according to the Saint-Venant＇s theory is joined, an equation suit is constructed which meets both the biharmonic equations and the boundary conditions. Furthermore, its analytic solution is deduced with Matlab. When this theory is applied to hydraulic bulging rollers, the experimental results inosculate with the theoretic calculation. Simultaneously, the limit along the axis invariable direction is given and the famous Lame solution can be induced from this limit. The above work paves the way for mathematic model building of hollow cylinder and for the analytic solution of hollow cvlinder with randomly uneven pressure.

Effects of renal artery stenting on renal function and blood pressure in patients with atherosclerotic renovascular disease

Objective To study the effects of percutaneous renal artery intervention on renal function and blood pressure in patients with renal artery stenosis. Methods Eighty-seven patients with severe uni- or bi-lateral renal artery stenosis (luminal diameter narrowing ≥70%) and clinical hypertension received renal artery stenting between January 2002 and December 2002. The changes in blood pressure and serum creatinine level and creatinine clearance (CCr) 48 hours after intervention and during 6 months of follow-up were assessed.Results Renal stenting was performed in 98 stenotic arteries of 87 patients,and the procedural success rate was 100%. Serum creatinine level was slightly elevated from (176±21) μmol/L to (179±11) μmol/L ( P =0.15) 48 hours after the procedure,but significantly decreased to (149±15) μmol/L at 6 months ( P <0.001). CCr was also greatly improved [(37±11) ml/min before versus (51±8) ml/min at 6 months,P <0.001]. During follow-up,61% of the patients experienced a normal renal function. Despite conventional medical treatment,systolic and diastolic blood pressures were also significantly decreased after stenting [(163±23)/(96±13) mm Hg before versus (148±12)/(79±15) mm Hg at 6 months,all P <0.001],and hypertension was well controlled in 67% of the patients at 6 months’ follow-up.Conclusion Renal artery stenting has a high success rate and is effective in improving renal function and blood pressure for patients with severe renal artery stenosis.

Numerical analysis of elastic coated solids in line contact

A line contact model of elastic coated solids is presented based on the influence coefficients(ICs) of surface displacement and stresses of coating-substrate system and the traditional contact model. The ICs of displacement and stresses are obtained from their corresponding frequency response functions(FRF) by using a conversion method based on fast Fourier transformation(FFT). The contact pressure and the stress field in the subsurface are obtained by employing conjugate gradient method(CGM) and discrete convolution fast Fourier transformation(DC-FFT). Comparison of the contact pressure and subsurface stresses obtained by the numerical method with the exact analytical solutions for Hertz contact is conducted, and the results show that the numerical solution has a very high accuracy and verify the validity of the contact model. The effect of the stiffness and thickness of coatings is further numerically studied. The result shows that the effects on contact pressure and contact width are opposite for hard and soft coatings and are intensified with the increase of coating thickness; the locations of crack initiation and propagation are different for soft and hard coatings; the risk of cracks and delaminations of coatings can be brought down by improving the lubrication condition or optimizing the non-dimensional parameter h/bh. This research offers a tool to numerically analyze the problem of elastic coated solids in line contact and make the blindness and randomness of trial-type coating design less.

THE EFFECT OF ISOPTIN SR ON BLOOD PRESSURE,HEART FUNCTION AND HYPERTROPHY OF LEFT VENTRICLEOF HYPERTENSIVE PATIENTS

Isoptin SR was used in 65 essential hypertensive patients.240mg Isoptin SR(German Knoll Pharmaceutical company) Per day was used in group A(35 cases)for 6 weeks,and in guoup B(30 cases)for 24 weeks,BP in group a and B decreased obviously in the first and second week after treament.

Effects of tube system and data correction for fluctuating pressure test in wind tunnel

The accuracy of fluctuating pressure test in wind tunnel is affected by the tube system. By employing contradistinctive experimental method, systematic study was conducted to investigate the effects of the tube system on fluctuating pressure. The analyzed tube system parameters include tube length, inside diameter, curvature, deflection angle, thickness, material, restrictor length,restrictor inside diameter, and restrictor place. It is found that all the tube system parameters mentioned above except tube curvature have non-negligible effects on fluctuating pressure. Based on the research results, test methods were presented for the fluctuating pressure measurement in low-speed wind tunnel, which can obviously improve the data accuracy but not lose test efficiency. The effectiveness of the method is verified by the wind tunnel test.

A New Empirical Method for Constructing Capillary Pressure Curves from Conventional Logs in Low-Permeability Sandstones

Pore structure reflected from capillary pressure curves plays an important role in low-permeability formation evaluation. It is a common way to construct capillary pressure curves by Nuclear Magnetic Resonance（NMR） log. However, the method＇s efficiency will be severely affected if there is no NMR log data or it cannot reflect pore structure well. Therefore, on the basis of J function and diagenetic facies classification, a new empirical model for constructing capillary pressure curves from conventional logs is proposed here as a solution to the problem. This model includes porosity and the relative value of natural gamma rays as independent variables and the saturation of mercury injection as a dependent variable. According to the 51 core experimental data sets of three diagenetic facies from the bottom of the Upper Triassic in the western Ordos Basin, China, the model＇s parameters in each diagenetic facies are calibrated. Both self-checking and extrapolation tests show a positive effect, which demonstrates the high reliability of the proposed capillary pressure curve construction model. Based on the constructed capillary pressure curves, NMR T_2 spectra under fully brine-saturated conditions are mapped by a piecewise power function. A field study is then presented. Agreement can be seen between the mapped NMR T_2 spectra and the MRIL-Plog data in the location of the major peak, right boundary, distribution characteristics and T_2 logarithmic mean value. In addition, the capillary pressure curve construction model proposed in this paper is not affected by special log data or formation condition. It is of great importance in evaluating pore structure, predicting oil production and identifying oil layers through NMR log data in low-permeability sandstones.

Comparison on Traditional and Machinery Decoctions for Da-cheng-qi Decoction Based on Chemical Ingredients, Pharmacological Functions, and Clinical Trials

Objective Patients and doctors often have questions about the equivalence of traditional and machinery decoctions. In this article, using Da-cheng-qi Decoction（DCQD） as a model of formula, traditional decoction（TD）, machinery decoction under high pressure（MDHP）, and machinery decoction under normal pressure（MDNP） were compared. Methods For chemical components, HPLC fingerprints were established and evaluated using AHP combined with CRITIC weighing method; For animals＇ effects, the experiments of small intestinal propulsion were conducted; For clinical effects, a randomized clinical trial（RCT） was designed and performed. Results Although there were some differences between TD and MDNP in chemical ingredients, there was no significant difference in animal experiments and clinical trials（P 〉 0.05）. Conclusion The traditional and machinery decoctions of DCQD could be used bioequivalently.