《四世同堂》中的常二爷形象分析

在老舍的作品《四世同堂》中,常二爷的人物形象十分鲜活生动。他身上体现出了当时中国普通大众的思想和性格,尤其是他善于自我欺骗的软弱特质更是令人痛心疾首。此外,对常二爷的描写还体现出了传统古典小说的创作技巧,全方位地突显了常二爷的个性特征,使得整部小说的情节走向更加写实,直击痛点,给读者留下了深刻的印象。

基于常压蒸馏产物的掺稀介质优选实验评价

针对常规掺稀工艺存在的稀油缺口问题,本文提出了选择炼化工业中的常压蒸馏产物作为掺稀介质的思路。通过常顶、常一、常二的轻质油与塔河稠油的降黏效果评价实验以及掺混体系兼容性评价实验,认为常二轻质油可以作为掺稀介质。降黏实验结果表明,稀稠比为0.47∶1时,稠油黏度可降低到2000mPa·s。相溶性实验结果表明,常二轻质油作为掺稀介质,且稀稠比不超过2.5∶1时,掺混体系的兼容性和稳定性可以满足集输要求。

Metal cation crosslinking of Ti O_2-alginate hybrid gels

In order to improve the substrate diffusion properties and stability of an immobilized enzyme alginate microgels modified with TiO2 nanoparticles were employed as the enzyme immobilizing support.Ionotropic gelation was applied for the preparation of hybrid gels while Ca2＋ Ce3＋ Ni2＋Cu2＋and Fe3＋were employed as the crosslinkers.Papain was selected as the model enzyme. UV-Vis spectroscopy was employed to investigate the activity of papain to evaluate kinetics and stability.Analysis results show that the highest affinity the lowest Michaelis-Menten constant Km =11.0 mg/mL and the highest stability are obtained when using Cu2＋as the crosslinker.The effect of the mass ratio of TiO2 to papain on the stability and leakage of papain is also investigated and the results show that 10∶1 TiO2∶papain is optimal because the proper use of TiO2 can reduce enzyme leakage and ensure enzyme stability.Preparing Cu/alginate/TiO2 hybrid gels via ionotropic gelation can provide a satisfactory diffusion capability and enzyme stability.

Fast estimation of Michaelis-Menten constant of arylesterase with a pair of medium concentrations of substrate

Objective: To investigate the reliability for fast estimation of Michaelis-Menten constant (Km) with calibrated specific activity at only two medium concentrations of substrate by both simulation and experimentation with arylesterase (ArE)as model. Methods: Initial rates were simulated by randomly inserting uniform absolute error, and the experimental initial rates of ArE were determined by measuring the increaser of product absorbance. Calibrated specific activities at two substrate concentrations were obtained by regression analysis, and Km was calculated according to Michaelis-Menten equation. Results: By simulation with calibrated specific activities at two medium substrate concentrations, Km could be calculated according to Michaelis-Menten equation with reasonable precision and accuracy. By experimentation with substrates of 2-naphthyl acetate, phenyl acetate, and p-nitrophenyl acetate, there were no differences between the mean and SD of Km of ArE for either substrate by this linear kinetic method and the Lineweaver-Burk plot. Conclusion: This linear kinetic method was reliable for fast estimation of the Km of some specified enzyme on its substrate of lower solubility or lower sensitivity for quantification by common methods.

Cryotherapy in the management of premalignant and malignant conditions of the esophagus

Endoscopic cryotherapy is a relatively new thermal ablative modality used for the treatment of neoplastic lesions of the esophagus. It relies on cycles of rapid cooling and thawing to induce tissue destruction with a cryogen(liquid nitrogen or carbon dioxide) leading to intra and extra-cellular damage. Surgical treatment was once considered the standard therapeutic intervention for neoplastic diseases of the esophagus and is associated with considerable rates of morbidity and mortality. Several trials that evaluated cryotherapy in Barrett's esophagus(BE) associated neoplasia showed reasonable efficacy rates and safety profile. Cryotherapy has also found applications in the treatment of esophageal cancer, both for curative and palliative intent. Cryotherapy has also shown promising results as salvage therapy in cases refractory to radiofrequency ablation treatment. Cryoballoon focal ablation using liquid nitrogen is a novel mode of cryogen delivery which has been used for the treatment of BE with dysplasia and squamous cell carcinoma. Most common side effects of cryotherapy reported in the literature include mild chest discomfort, esophageal strictures and bleeding. In conclusion, cryotherapy is an effective and safe method for the treatment of esophageal neoplastic processes, ranging from early stages of low grade dysplasia to esophageal cancer.

Mutation of RET proto-oncogene in Hirschsprung's disease and intestinal neuronal dysplasia

AIM： To investigate the genetic relationship between Hirschsprung＇s disease （HD） and intestinal neuronal dysplasia （IND） in Chinese population.METHODS： Peripheral blood samples were obtained from 30 HD patients, 20 IND patients, 18 HD/IND combined patients and 20 normal individuals as control. Genomic DNA was extracted according to standard procedure. Exons 11,13,15,i7 of RET proto-oncogene were amplified by polymerase chain reaction （PCR）. The mutations of RET proto-oncogene were analyzed by single strand conformational polymorphism （SSCP） and sequencing of the positive amplified products was performed.RESULTS： Eight germline sequence variants were detected. In HD patients, 2 missense mutations in exon 11 at nucleotide 15165 G→A （G667S）, 2 frameshifc mutations in exon 13 at nucleotide 18974 （18974insG）, 1 missense mutation in exon 13 at nucleotide 18919 A→G （K756E） and 1 silent mutation in exon 15 at nucleotide 20692 G→A（Q916Q） were detected. In HD/IND combined patients, 1 missense mutation in exon 11 at nucleotide 15165 G→A and 1 silent mutation in exon 13 at nucleotide 18888 T→G （L745L） were detected. No mutation was found in IND patients and controls.CONCLUSION： Mutation of RET proto-oncogene is involved in the etiopathogenesis of HD. The frequency of REr proto-oncogene mutation is quite different between IND and HD in Chinese population, IND is a distinct clinical entity genetically different from HD.

Kinetic Rate Constant of Liquid Drainage from Colloidal Gas Aphrons

A kinetic model fitted by the empirical equation has been proposed to describe the liquid drainage behavior. Rate constants （kd） of liquid drainage equation could be obtained from the above empirical equation. In this paper, the stability of the colloidal gas aphrons （CGAs）, the effect of concentrations of sodium dodecyl benzene sulphate （SDBS）, dodecyl trimethylammonium bromide （HTAB） and polyoxyethylene sorbitol anhydride monolaurate（Tween-20）, temperature, stirring speed, stirring time, and various kinds of salts on the kd of liquid drainage are further investigated. The results show that the Arrhenius equation can be successfully used to describe the relation between kd arid absolute temperature （T）, and concentrations of surfactants, stirring speed, stirring time and salinities also have great effect on the kd. At last, the CGAs drainage mechanism is explained from analysis of the rate of liquid drainage as a function of time.

Second Order Parallel Tensors on Quasi-constant Curvature Manifolds

The author establishes in this paper the following results: (1) In a quasiconstant curvature manifold M a parallel tensor of type is constant multiple of the metric tensor. (2) On a quasi_constant curvature manifold there is no nonzero parallel 2_form. Unless the Ricci principal curvature corresponding to the generator of M is equal to zero.

Ectopic papilla of Vater in the pylorus

The major papilla of Vater is usually located in the second portion of the duodenum, to the posterior medial wall. Sometimes the mouth of the biliary duct is located in other areas. Drainage of the common bile duct into the pylorus is extremely rare. A 73-year old man, with a history of duodenal ulcer, was admitted to hospital with the diagnosis of cholangitis. Dilatation of the extrahepatic biliary duct was observed by abdominal ultrasonography, and endoscopic retrograde cholangiopancreatography （ERCP） was performed. No area suggesting the presence of the papilla of Vater was found within the second duodenal portion. Finally the major papilla was located in the theoretical pyloric duct. Cholangiography was performed and choledocholithiasis was found in the biliary tree. The patient underwent dilatation of the papilla with a balloon tyre and removal of a 7 mm stone using a Dormia basket, which solved the problem without further complications. This anomaly increased the difficulty of performing therapeutic interventions during ERCR This alteration in anatomy may increase the risk of complications during papillotomy, with a theoretically higher risk of perforation. Dilatation using a balloon was the chosen therapeutic technique both in our case and in the literature, due to its low rate of complications.

Adsorption of Aqueous Solution of O-Xylene on Modified Halloysite Adsorbents

In this study, the adsorption of o-xylene was investigated using modified halloysite adsorbents. The modification of the halloysite adsorbents depended on thermal processing, treated sulphuric acid（Vl） and sodium hydroxide, water solution of ammonium chloride as well as hexadecylotrimethyloammonium bromide. Adsorption rate constants of the pseudo-second order models were compared for experiment carried in the batch system. Langmuir and Freundlich to fit the adsorption equilibrium experimental data. pseudo-first and models were able

Analytical Dielectric Spectrum Formula Based on Representative Frequencies

According to experimental data available for the complex refractive index of particular dielectrics, a dielectric spectrum formula is proposed by the least square fitting technique combined with selected natural frequencies. From the dielectric spectrum formula, the spectra of optical and dielectric constants can be obtained in the whole frequency region. Three dielectrics, water, ethanol, and toluene, are taken as examples. In the region where the ex- perimental data are available, the spectra of the optical constants calculated by the formula are in good agreement with the real refractive spectrum obtained by Kramers-Kronig （K-K） transform and the experimental imaginary refractive spectrum. In the region where no ex- perimental data are available, the extrapolation of our formula can make predictions. The merits of the present treatment are that we are able to get the uniform spectrum formula, without splitting into different frequency sections, and the analytical form of the dielectric spectra will be useful in the theoretical description of solvation dynamics.

Bcklund Transformations and Explicit Solutions of (2+1)-Dimensional Barotropic and Quasi-Geostrophic Potential Vorticity Equation

By the Backlund transformation method, an important （2＋1）-dimensional nonlinear barotropie and quasigeostrophic potential vorticity （BQGPV） equation is investigated. Some simple special Backlund transformation theorems are proposed and used to get explicit solutions of the BQGPV equation. Furthermore, all solutions of a second order linear ordinary differential equation including an arbitrary function can be used to construct explicit solutions of the （2＋1）-dimensional BQGPV equation. Some figures are also given out to describe these solutions.

Outlier Detection Method based on Hybrid Rough - Negative Algorithm

This paper discusses on the detection of outliers by hybridizing Rough_Outlier Algorithm with Negative Association Rules. An optimization algorithm named Binary Particle Swarm Optimization is used to improve the computation of Non_Reduct in order to detect outliers.By using Binary PSO algorithm, the rules generated from Rough_Outliers algorithm is optimized, giving significant outliers object detected. The detection ofoutliers process is then enhanced by hybridizing it with Negative Association Rules. Frequent and Infrequent item sets from outlier rules are generated. Results show that the hybrid Rough_Negative algorithm is able to uncover meaningful knowledge of outliers from the frequent and infrequent item sets. These knowledge can then be used by experts in their field of domain for better decision making.

Approximation of Derivative for a Singularly Perturbed Second-Order ODE of Robin Type with Discontinuous Convection Coefficient and Source Term

In this paper, a singularly perturbed Robin type boundary value problem for second-order ordinary differential equation with discontinuous convection coefficient and source term is considered. A robust-layer-resolving numerical method is proposed. An e-uniform global error estimate for the numerical solution and also to the numerical derivative are established. Numerical results are presented, which are in agreement with the theoretical predictions.

Fast forward modeling of gravity anomalies for two-dimensional bodies of arbitrary shape and density distribution

A fast and high precision spatial domain algorithm is presented for forward modeling of two-dimensional(2D)body gravity anomalies of arbitrary shape and density distribution.The new algorithm takes advantage of the convolution properties of the expression for 2D gravity anomalies,uses a rectangular cell as a grid subdivision unit,and then 2D bodies with irregular cross-sections are approximated by a combination of 2D bodies with a rectangular cross section.The closed-form expression is used to calculate the gravitational anomalies of the combination of 2D bodies with a rectangular cross section.To improve computing effi ciency,the new algorithm uses a fast algorithm for the implementation of the Toeplitz matrix and vector multiplication.The synthetic 2D models with rectangular and circular cross-sections and constant and variable densities are designed to evaluate the computational accuracy and speed of the new algorithm.The experiment results show that the computation costs less than 6 s for a grid subdivision with 10000×10000 elements.Compared to the traditional forward modeling methods,the proposed method significantly improved computational effi ciency while guaranteeing computational accuracy.

Mechanism of stibnite volatilization at high temperature

The volatilization of stibnite(Sb2S3) in nitrogen from 700 to 1000 °C was investigated by using thermogravimetric analysis. The results indicate that in inert atmosphere, stibnite can be volatilized most efficiently as Sb2S3(g) at a linear rate below850 °C, with activation energy of 137.18 k J/mol, and the reaction rate constant can be expressed as k=206901exp(-16.5/T). Stibnite can be decomposed into Sb and sulfur at temperature above 850 °C in a nitrogen atmosphere. However, in the presence of oxygen,stibnite is oxidized into Sb and SO2 gas at high temperature. Otherwise, Sb is oxidized quickly into antimony oxides such as Sb2O3 and Sb O2, while Sb2O3 can be volatilized efficiently at high temperature.

Numerical Study of Unsteady Behavior of Partial Cavitation on Two Dimensional Hydrofoils

This paper deals with time dependent performance characteristics of cavitating hydrofoils, the flow around which has been simulated using pressure-based finite volume method. A bubble dynamics cavitation model was used to investigate the unsteady behavior of cavitating flow and describe the generation and evaporation of vapor phase. For choosing the turbulence model and mesh size a non cavitating study was conducted. Three turbulence models such as Spalart-Allmaras, Shear Stress Turbulence （SST） κ-ω model, Re-Normalization Group （RNG） κ-ε model with enhanced wall treatment are used to capture the turbulent boundary layer along the hydrofoil surface. The cavitating study presents an unsteady behavior of the partial cavity attached to the foil at different time steps for σ = 0.8 and σ = 0.4. Moreover, this study is focused on cavitation inception, the shape and general behavior of sheet cavitation, lift and drag forces for different cavitation numbers.

A New Loop Algebra and Corresponding Computing Formula of Constant γ in Quadratic-Form Identity

A new loop algebra containing four arbitrary constants is presented, -whose commutation operation is concise, and the corresponding computing formula of constant γ in the quadratic-form identity is obtained in this paper, which can be reduced to computing formula of constant γ in the trace identity. As application, a new Liouville integrable hierarchy, which can be reduced to AKNS hierarchy is derived.

Wave Functions for Time-Dependent Morse Potentials

The one dimensional Schrodinger equation associated with a time-dependent Morse potentials is studied. We use the invariant operator method （Lewis and Riesenfeld） to obtain approximate solution of the Schrodinger equation in terms of solution of second order ordinary differential equation describes the amplitude of the Morse potentials.

Transformation of Flue-Gas-Desulfurization Gypsum to α-Hemihydrated Gypsum in Salt Solution at Atmospheric Pressure

Direct phase transformation of flue gas desulfurization gypsum in hot salt solution at atmospheric pres-sure was investigated.The effects of temperature,salt species,salt concentration,solids content,pH and modifier were examined.The crystals obtained under different conditions and solubility of calcium sulfate in contact with solid gypsum were also determined.α-Calcium sulfate hemihydrate crystals of stubby columnar shape and regular pentahedral sides were obtained under the following conditions：salt concentration 20%-30%,operation tempera-ture 95-100 °C,solids mass content in the slurry 10%-30% and neutral pH.Thermodynamic analysis revealed that phase transformation of calcium sulfate dihydrate to α-calcium sulfate hemihydrate occurs because of the difference in solubilities between the two solid gypsum phases in this system.