Flow and Velocity Distribution in Meandering Compound Channels

An investigation of flow and velocity distribution in meandering compound channels with over bank flow is described. Equations concerning the three-dimensional variation of longitudinal, transverse, and vertical velocity in the main channel and floodplain of compound section in terms of channel parameters are presented. The flow and velocity distributions in meandering compound channels are strongly governed by interaction between flow in the main channel and that in the floodplain. The proposed equations take adequate care of the interaction affect. Results from the formulations, simulating the three-dimensional velocity field in the main channel and in the floodplain of meandering compound channels are compared with their respective experimental channel data obtained from a series of symmetrical and unsymmetrical test channels with smooth and rough sections. The aspect ratio of the test channels varies from two to five. The equations are found to be in good agreement with the experimental data. The formulations are verified against the natural river and other meandering compound channel data. The power laws used for simulating the three-dimensional velocity structure are found to be quite adequate.     

Effects of Foam Claddings for Structure Protection against Blast Loads

A load-cladding-structure (LCS) model is developed to investigate the protective effects of foam claddings on the main structure subjected to blast loads. The properties of the blast load and the foam cladding as well as the main structure are all considered in the analytical model. Two nondimensional parameters are introduced to describe the relations between the foam cladding and the main structure. Parametric study by characterizing the pressure-impulse diagrams for structures with and without foam cladding is carried out. Based on the LCS model and the pressure-impulse diagram analysis, the maximum allowable intensity of the blast load can be predicted for a given cladding protected structure. Equally, the foam cladding can be appropriately designed to protect a particular structure against a certain range blast load. It is found that the blast resisting capacity of the structure system may be greatly enhanced if the foam cladding is properly designed. The maximum allowable external blast load depends on the properties of the particular foam cladding and the specific main structure.     

Side Outflow from Supercritical Channel Flow

Side flow on a flood plain from a side outlet of the main channel is investigated both theoretically and experimentally for supercritical main flow. The side outlet as a model simulates a failure of a river bank in a prototype. The discharge ratios of the side outflow to that of the main channel flow, the water depth, and the velocity at the side outlet are obtained. The theoretical discharge ratio is a function of the Froude number of the main channel flow. The theoretical spreading angle of the side flow and the theoretical relationship between the velocities and the distance from an upstream point of the side outlet are also compared and predicted. All the theoretical results are found to be in good agreement with the experimental data.     

二矿区主斜坡道延伸施工工艺研究

二矿区主斜坡道长度已超过十公里,因700m中段建设需要,主斜坡道需进一步延伸至610m水平。由于主斜坡道深度大,地压活动明显,部分区域岩石条件较差,独头掌子掘进通风条件差,施工难度较大。本文通过现场实际调研和分析,提出将主斜坡道与24行主井联络道进行贯通然后施工空压机站硐室解决通风困难问题,提出18行出毛方案以解决深部开采工程的毛石长距离拉运问题等措施,保证了主斜坡道延伸工程顺利的进行。     

Current trends in the therapy of bleeding duodenal ulcer

A distinction is drawn between two main groups of patients with continuous and massive haemorrhage respectively in bleeding duodenal ulcer, and the criteria upon which this distinction is based are described. The two main types of surgery proposed for the treatment of this complication of duodenal ulcer (vagotomy and gastric resection) are examined. The conclusion is drawn that vagotomy (truncular with drainage, or superselective with or without drainage) is to be preferred to gastric resection in the light of personal experience, and with particular reference to operative mortality and the recurrence of haemorrhage and ulcers.     

Factors influencing the machinability of sintered steels

The machinability of powder metallurgy materials is considered to be poor. The main factors that deteriorate the machining of PM parts are introduced in this work. They are those which participate in different ranges and modes in the formation of a sintered body with required mechanical and other characteristics. The effect of base iron powders, alloying systems, and alloying elements, as well as the effect of processing routes, especially solid-state sintering, are mentioned. The characteristic heterogeneous microstructures are presented. The effect of porosity in terms of interrupted and deformation cutting theories is discussed and demonstrated. The main measures to improve machinability of PM materials are described.     

高磁感取向硅钢中的抑制剂

结合高磁感取向硅钢的生产工艺和技术发展趋势,对板坯高温、中温和低温加热工艺中的抑制剂进行了论述和分析。MnS和AlN是高温加热工艺的主要抑制剂。对于中温加热工艺则主要利用AlN为主要抑制剂,Cu2S和MnS作为辅助抑制剂。低温板坯加热工艺中所采用的抑制剂主要为AlN,其工艺手段就是在发生二次再结晶之前进行渗氮处理。Nb(C,N)有可能成为低温板坯加热工艺一种新型抑制剂。     

Screening for cutaneous carcinoma]

Skin carcinoma is the most frequent of all cancers. The main risk factor is represented by solar exposition and, so, individuals with special risk are xeroderma pigmento sum (enzymatic defect of DNA repair), light phototype person, sun-seekers, outdoor-workers and patients treated with high doses of PUVA. X-rays, mineral oils, tar and arsenic are also known skin carcinogens. HPV can also participate to skin carcinogenis alone or associated with UV particularly in immunosupressed sujets. Subjects with predisposition for skin carcinoma can be pointed out and cautioned. Detection of preepitheliomatous lesions is easy; actinic keratosis are the main signs.     

Atraumatic cardiac arrest in apparently healthy young women

It was as long ago as 1908 when the first study of epileptic psychosis appeared from Japan. Major literatures since that time with regard to psychoses in patients with epilepsy in Japan are reviewed. The history of epileptic psychoses could be divided into five eras according to the main interests in that period: (i) dawn of the history of epileptic psychoses; (ii) the early era; (iii) the era of periodic psychoses; (iv) the middle era; and (v) the present era. The main topics in each era are described and re-evaluated herein.     

Stimulation of alpha1A-adrenoceptors in Rat-1 cells inhibits extracellular signal-regulated kinase by activating p38 mitogen-activated protein kinase

We report a patient with cholangiocellular carcinoma with tumor thrombi in the main portal trunk who has survived for 9.5 years after hepatic resection. A 57-year-old woman underwent an extended left lobectomy, and resection of the caudate lobe plus the main portal trunk for a liver tumor that had a portal tumor thrombus in the main portal trunk. The portal vein was reconstructed with an autologous vein graft obtained from the external iliac vein. Histological examination of the resected specimen revealed moderately differentiated tubular adenocarcinoma compatible with cholangiocellular carcinoma. Factors contributing to the patient's long-term survival are discussed. Aggressive surgical resection can be effective even for such an advanced case of cholangiocellular carcinoma.     

定径机轧辊机架弧齿锥齿轮传动性能及牌坊振动特性分析

定径机轧辊机架弧齿锥齿轮传动特性和机架牌坊的振动特性是影响轧制精度的主要因素,分析研究了影响弧齿锥齿轮传动特性的内外因素,从而指导定径机轧辊机架的传动设计;用有限元软件Abaqus对轧辊机架进行模态分析,提取其前六阶固有振型和主、从动轴轴承座处某节点的位移图。通过分析,可以在实际应用中有效避免使牌坊长期处于共振频率下工作,从而避免结构的破坏。     

Prophylaxis in orthopaedic implant surgery--should we use a glycopeptide?

Multicenter trials are important for answering questions that require large numbers of subjects. Such trials require standardized implementation of behavioral change programs across diverse populations, regions, and staff. Researchers involved with the Trial of Nonpharmacologic Interventions in the Elderly conducted a 17-week pilot study of their most complex intervention (combined weight and sodium reduction) before actual start-up of the main study. This allowed staff to rehearse implementing the program and to identify and address intervention and standardization issues. Registered dietitians in 4 US communities recruited 28 participants for the pilot study, using eligibility criteria similar to those for the main trial. Participant evaluations reflected high satisfaction with the program materials and overall approach. Minor protocol changes suggested by results of the pilot study were made easily in time for start-up of the main study. Reductions in weight and sodium intake were less than targeted but were sufficient to suggest that the intervention would be effective under optimal conditions. This partial achievement of goals in the pilot study underscored the need to allow for a learning curve, for without it standardization and outcomes of the main study would be compromised.     

燃气负荷影响因素的初步研究与预测应用

燃气负荷影响因素的研究工作应根据不同的预测对象、不同的预测目的、不同的预测需求,选择合适的预测方法,对主要的影响因素进行取舍,将主要影响因素的不确定部分最大限度地转化成确定因素。利用未来一段时间燃气负荷可能出现的状况及概率分布进行评估和预测,并以直观可视的形式为管理人员提供决策依据。     

乳山西涝口矿区地质特征及找矿探讨

西涝口矿区位于胶莱盆地北缘。出露地层主要有古元古界荆山群、中生界莱阳群地层,岩浆岩以燕山期活动为主。区内与金矿成矿关系密切的构造复杂多样,地表矿化蚀变随处可见,使找矿工作较难开展,通过总结该区矿床地质特征,把与金成矿关系密切的构造划分为层间滑动构造带及其上盘张性裂隙构造带2种主要类型,理清了找矿思路,对今后工作方向进行了探讨。     

Modern trends in the development of ladle metallurgy and the problem of nonmetallic inclusions in steel

The main trends in the development of the ladle treatment of steel have been analyzed. The most complex problem is shown to be the formation of nonmetallic inclusions having a certain type and a low concentration. The main parameters of the ladle treatment of steel that control the type and amount of nonmentallic inclusions in ready products are analyzed using the data of industrial heats, laboratory experiments, and physicochemical simulation and computation. The principles of control of steel purity in nonmetallic inclusions are formulated, and the main trends in the development of the concepts of nonmetallic inclusions are determined.     

钢渣吸附剂在废水处理中的应用

钢渣是炼钢过程中的副产品,具有较大的比表面积和复杂的化学组成。钢渣处理废水的作用机理主要是吸附作用和沉淀作用,影响钢渣吸附性能的主要因素有反应温度、pH值、钢渣的颗粒粒度和反应时间。钢渣可以处理含铬、砷、镍、铜等废水,应用前景广阔。钢渣吸附剂的工业化关键需要解决钢渣吸附剂的造粒问题。     

声纳化渣技术的原理与应用

介绍了声纳化渣技术的基本原理和主要设备，对该技术在３０ｔ转炉上的实际应用效果进行了扼要叙述，并提出了该系统存在的问题，可供有关人员在推广或改进该项技术时参考。     

方坯连铸机漏钢原因分析及改进措施

统计了武钢一炼钢厂方坯连铸机2006年的漏钢情况,分析了粘结漏钢和角部纵裂漏钢的特点及机理,并找出了产生粘结漏钢和角部纵裂漏钢的主要原因是保护渣的性能、结晶器的精度、钢水的过热度、拉速及浸入式水口的对中等.采取了相应的措施后铸机的漏钢率有了明显的降低.     

Determinants of side chain conformational preferences in protein structures

A discriminatory function based on a statistical analysis of atomic contacts in protein structures is used for selecting side chain rotamers given a peptide main chain. The function allows us to rank different possible side chain conformations on the basis of contacts between side chain atoms and atoms in the environment. We compare the differences in constructing side chain conformations using contacts with only the local main chain, using the entire main chain, and by building pairs of side chains simultaneously with local main chain information. Using only the local main chain allows us to construct side chains with approximately 75% of the chi1 angles within 30 degrees of the experimental value, and an average side chain atom r.m.s.d. of 1.72 A in a set of 10 proteins. The results of constructing side chains for the 10 proteins are compared with the results of other side chain building methods previously published. The comparison shows similar accuracies. An advantage of the present method is that it can be used to select a small number of likely side chain conformations for each residue, thus permitting limited combinatorial searches for building multiple protein side chains simultaneously.     

Examination of the compaction properties of a 1:1 acetaminophen:microcrystalline cellulose mixture using precompression and main compression

The compaction properties of a 1:1 acetaminophen and microcrystalline cellulose (MCC) mixture have been studied using a compaction simulator to make tablets by single compression and by a combination of precompression and main compression. The tensile strengths of the tablets and the energies involved in the compressions were determined. The tensile strengths of the tablets increased with increases in single compression pressure from 80 to 400 MPa and as the total applied pressure increased from 80 MPa up to around 400 MPa when combinations of precompression and main compression pressures were used. The tablet porosity decreased with increase in main compression pressure while the tablet tensile strengths increased. At minimum tablet porosity, further increase in main compression pressure could no longer result in increase in tablet strengths. Tablets compressed with combinations of precompression and main compression were stronger (2.15 +/- 0.02 to 3.99 +/- 0.1 MPa) than those produced with single compression (0.73 +/- 0.01 to 3.09 +/- 0.05 MPa). The total gross energies of compression increased with an increase in pressure of both the precompression and main compression. The elastic energies during main compression increased with an increase in precompression pressure as the tablet exhibited greater elastic deformation and reduced plasticity on second compression. The increase in elastic energies during main compression may also be because elastic energy is recoverable and is independent of precompression. As the precompression pressure increased, the minimum tablet porosity was attained; hence, the plastic energy during main compression became smaller while the elastic energy increased. Thus, a combination of low precompression and main compression pressures of 160/80 MPa or 80/160 MPa are more advantageous in the tableting of the 1:1 acetaminophen:MCC than a high single compression pressure of 320 or 400 MPa.