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1.
Cylindrical or “bubble” domains and their propagation are briefly described. The physical properties required for materials used in bubble domain memories are listed and the presently known materials are compared with reference to those properties. Materials are also compared with respect to ease of preparation. The crystal growth techniques used to prepare bubble domain materials are described in detail with emphasis on the growth of rare earth iron garnets. Limitations on bubble domain materials imposed by crystal defects are discussed.  相似文献   

2.
磁铁精矿冷固球团直接还原新工艺的研究   总被引:1,自引:0,他引:1  
章庆和 《钢铁》1997,32(10):1-3,11
介绍了磁铁精矿采用有机粘结剂进行冷固结,得到冷固球团,然后直接进行还原生产金属化球团的新工艺,试验表明,此工艺可得到性能优良的冷固球团及金属化率≥95%的金属化球团,文章还对其各工艺条件及影响因素进行了阐述。  相似文献   

3.
The group sequential tests (GST) are appropriate for performing interim analyses in clinical trials. Various GST are reviewed and compared in this paper in terms of the expected sample size, the maximum sample size, and other practical aspects. Also discussed are the p-values of the significant differences for GST. Common problems and difficulties of using GST in practice are examined. One problem is difficulties associated with the delayed data accumulated after a trial is terminated at an interim test. The GST with O'Brien-Fleming type of boundaries are found to be safe in dealing with delayed observations. Possible approaches for performing futility analyses are illustrated with examples. It is recommended that futility analysis with GST be built into the design of large clinical trials.  相似文献   

4.
An increased number of adults with mental retardation are living in the community and seeking health care from family physicians. When mentally retarded patients are enrolled in a medical practice, guardianship status should be determined, but these patients should be involved in their own care to as great an extent possible. Since a verbal history may be difficult to obtain, a systematic, thorough physical examination is important. Certain Illnesses, such as hepatitis B, recurrent aspiration syndrome, leukemia and atlantoaxial instability, are much more common in adults with Down syndrome then in adults with mental retardation from other causes. Seizures and mental illness are equally common in all mentally retarded adults. The behavior management and pharmacologic therapy of patients with mental retardation are best handled in close association with caregivers, as well as psychiatrists and neurologists who are familiar with the special needs of this population.  相似文献   

5.
杨雄  史文义  刘莉 《包钢科技》2011,37(6):37-39
利用MMS-200型热模拟试验机研究了不同冷却速度对高强度结构钢组织结构的影响,用热膨胀法建立了动态条件下的连续冷却转变曲线(CCT),结果表明:冷却速度在1~2℃/s时,相变组织为多边形铁素体+少量珠光体组织;随着冷却速度的升高,珠光体逐渐消失,相变组织为多边形铁素体+少量粒状贝氏体;当冷速大于15℃/s时,相变组织主要为板条状贝氏体;大于25℃/s时,组织逐渐演变为板条马氏体。  相似文献   

6.
The synthesis of suramin analogues bearing a 2-phenyl-benzimidazole moiety is described. Aminoarene sulfonic acids 2a-e are acylated with 3,4-dinitrobenzoyl chloride 3 yielding the amides 4a-e which are hydrogenated to the corresponding diamines 5a-e. These are treated with 3-nitrobenzaldehyde, yielding the azomethines 7a-e and their isomers 8a-e and 9a-e. Key step in the synthesis of the target compounds 12a-e is the oxidation of the azomethines with oxygen to the benzimidazoles 10a-e. These are hydrogenated to the amines 11a-e reacting with phosgene to yield the symmetric ureas 12a-e. Results of the anti-HIV, cytostatic, and antiangiogenic screening are presented.  相似文献   

7.
Chemical dynamics in proteins are discussed, with bacteriorhodopsin serving as a model system. Ultrafast time-resolved methods used to probe the chemical dynamics of retinal photoisomerization in bacteriorhodopsin are discussed, along with future prospects for ultrafast time-resolved crystallography. The photoisomerization of retinal in bacteriorhodopsin is far more selective and efficient than in solution, the origins of which are discussed in the context of a three-state model for the photoisomerization reaction coordinate. The chemical dynamics are complex, with the excited-state relaxation exhibiting a multiexponential decay with well-defined rate constants. Possible origins for the two major components are also discussed.  相似文献   

8.
The following are things I have learned, routines my nurses have brought to me, or that we have developed together during 11-years existence with amyotropic lateral sclerosis (ALS) eight of which have been burdened by ALS induced quadriplegia and ventilator dependence. Items are listed, not in order of importance, which may vary from individual to individual, but alphabetically. Some are unique. Some commonplace. All are useful and many are of surprising value. Deviations from common understanding or practice are marked with an asterisk, and practices that can afford significant economies are double asterisked. This is written in an attempt to share with others in the profession lessons I have learned from personal experience--the hard way.  相似文献   

9.
A newly developed hydraulic joint for pipe jacking is described and compared with conventional compression rings. It is shown that with the hydraulic joint, thrust eccentricities are largely reduced, resulting in a much more uniform stress profile at the pipe ends and hence a considerably reduced pipe damage potential. Higher jacking forces can be applied (fewer or no intermediate jacking stations are necessary), longer pipes can be used (fewer joints are necessary), smaller radii of curvature are feasible (fewer or no intermediate jacking pits are necessary) and frictional forces are reduced. The measurement of joint displacements and joint liquid pressures permits an effective real-time monitoring of the jacking process. 30 of the 40 pipelines with a total length of 8.2?km completed so far had curved alignments. The smallest radius of curvature was 86?m using 3?m long pipes with an internal diameter of 1.2?m. Practical experiences gained with the hydraulic joint are summarized.  相似文献   

10.
It is argued that a general practitioner's ability to make accurate ratings of psychological distress is partly determined by the rate at which patients emit cues that are indicative of such distress. This study addresses the behaviours of doctors which influence the rates at which patients emit such cues. Consultations were videotaped involving six General Practice Vocational Trainees, three of them poor, and three of them able identifiers of emotional illness. Consultations were selected so that each trainee was rated interviewing 4 patients with low GHQ scores, and 4 patients with high scores. Behaviours are described which lead to increased cue emission and which are also practised more frequently by able identifiers, while other behaviours reduce cue emission and are practised less frequently by them. Another set of behaviours is no more frequent among the able identifiers, but when practised by able identifiers is associated with increased cue emission by the patients, and when practised by poor identifiers with unaltered or decreased cue emission. Interviews that are 'patient-led' are associated with increased rates of cue emission, while those that are 'doctor-led' are associated with lower rates. The implications of these findings for training doctors working in general medical settings are discussed.  相似文献   

11.
To understand and model damage generated during impact by a penetrator of ultrahigh strength concrete targets, edge-on impact tests are performed with Ductal concrete, which is unreinforced or reinforced with short fibers. Two edge-on impact configurations are designed with a dynamic confinement system. The first configuration uses aluminum projectiles and allows us to study the dynamic fragmentation that spreads out within the tile without any confined damage close to the impact point. The fragmentation process is composed of numerous oriented millimetric cracks. In the second configuration, steel projectiles are used with a higher impact velocity. Damaged zones are visualized by using an ultrahigh speed camera and a sarcophagus configuration designed to prevent the fragments from moving. Postmortem studies of impacted tiles enabled us to observe an intense fragmentation of the targets and confined damage close to the impact point when steel projectiles were used. Simulations are performed with an anisotropic damage model coupled with a concrete plasticity model. Orientation and crack density are compared with postmortem observations.  相似文献   

12.
张涛 《冶金动力》2014,(9):23-24
从15万m3高压橡胶膜密封煤气柜的特点出发,与同容积的稀油密封圆形煤气柜进行技术经济分析比较,分析两种柜型的优缺点,指出两种柜型的适用范围。  相似文献   

13.
Analytical equations for friction correction factors for center-pivot laterals without end guns are developed. This work illustrates a discrepancy when earlier equations are applied to center-pivots with small numbers of outlets. Earlier equations were also limited to center-pivots with constant outlet spacing. Equations presented in the current work are developed for center-pivots with constant outlet spacing and also for center-pivots with constant outlet discharge. When the equations developed in the current work are applied to center-pivots with a large number of outlets, the results are in good agreement with previous work for center-pivot laterals with an infinite number of outlets. When applied to a smaller number of outlets the equations presented here provide a more precise estimate of the friction correction factor. Using the current equations, the friction correction factor for center-pivots with constant outlet spacing was found to be very similar to the friction correction factor for center-pivots with constant outlet discharge. Useful simple equations are also presented for calculating the discharge of each outlet or for calculating the spacing between outlets.  相似文献   

14.
Structural and functional disturbances closely associated with mitochondrial insufficiency are found in the nervous system elements, skeletal and smooth muscles, myocardium, kidneys, liver, gastrointestinal tract, endocrine glands, systems of hematopoiesis and immunity. Nosological and syndromic forms of mitochondrial pathology associated with mitochondrial or nuclear DNA mutations are characterized. The disease variants with symptomatic (may be secondary) or with presumable mitochondrial pathology are analyzed. For the pathologist the most reliable diagnostic criteria are skeletal muscle changes, and the "ragged red fibres" phenomenon first of all. The comparisons of the clinicobiochemical and morphological data are of the decisive importance.  相似文献   

15.
Myoclonus may be observed in children with mild or severe epileptic syndromes. Both types are seen at characteristic ages, together with other factors: aetiology, family history, hereditary pattern, effect on psychomotor development and EEG-EMG findings. In children with progressive or degenerative encephalopathies and myoclonus, better known as progressive myoclonic epilepsy, there are also specific clinical data, together with biological and genetic markers which permit identification. The most specific clinical characteristics of each of these clinical pictures are described, as are the complementary tests which permit confirmation of these diagnoses.  相似文献   

16.
Contrary to Brown, Keenan, and Pott's (1986) conclusions, Lord's (1980) report of self-image memory inferiority is defended as reliable and consistent with previous studies of paired associate mental imagery that have concerned memory for imaginary rather than actual events. When instructions state that all images are to be of actual events or consistent with general world knowledge, those images of the self are recalled no differently than are images of others; when instructions imply that all images are to be of imaginary events, self-images are recalled worse than other-images are. These differences between self- and other-images are associated with differences in the interactiveness of actions that are invented for the self versus another person. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

17.
Two patient with familial cavernous angiomatosis presenting with long lasting variable epilepsy with a poor therapeutic response and variable neurologic impairments are presented here. One of the numerous cavernous angiomas was resected in one case. This last patient remains asymptomatic. Familial cerebral cavernous angiomas are often numerous and disseminated in the brain, therefore clinical manifestations are very polymorphous. Moreover the course of these lesions is variable. Therefore MRI should be performed to every patient presenting with poorly understood neurological symptoms, focal or generalized epileptic seizures or absence in order to look for potentially imputable brain lesions. A reliable genetic marker might be helpful for diagnosis of this disease with a variable penetrance and autosomal dominant inheritance. Then a neurosurgical treatment should be carefully discussed if lesions are accessible and medications are poorly efficient with recurrent neurologic impairments or epilepsy.  相似文献   

18.
The difficult legal, ethical, and professional issues confronting psychologists who work with people with dual diagnoses are discussed here. Applicable constitutional principles are outlined in the context of discussing the right to institutional services and to refuse treatment, statutes that go beyond constitutional protections are described, issues that people with dual diagnoses face in the criminal and civil justice systems are highlighted, and some recommendations that psychologists should consider when providing services to this population are offered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
Different ligands with high molecular masses are immobilized on compact, porous separation units and used for affinity chromatography. In subsequent experiments different enzymes are immobilized and used for converting substrates with low and high molecular masses. Disk or tube with immobilized concanavalin A (ConA) are used as model systems for lectin affinity chromatography. The enzyme glucose oxidase is used as a standard protein to test the ConA units. Subsequently glycoproteins from plasma membranes of rat liver are separated, using units with immobilized ConA. The enzyme dipeptidyl peptidase i.v., which is used as a model protein in the experiments, is enriched about 40-fold in a single step, with a yield of over 90%. The results are only slightly better than those obtained with ConA when it is immobilized on bulk supports. The important improvement lies in the reduction of separation time to only 1 h. Experiments concerning the isolation of monoclonal antibodies against clotting factor VIII (FVIII) are carried out on disks, combining anion-exchange chromatography and protein A affinity chromatography as a model for multidimensional chromatography. Both IgG (bound to the protein A disk) and accompanying proteins (bound to the anion-exchange disk) from mouse ascites fluid are retarded and eluted separately. With the immobilized enzymes invertase and glucose oxidase (GOX) the corresponding substrates with low molecular masses, saccharose and glucose, are converted. It is shown that the amount of immobilized enzyme and the concentration of the substrate are responsible for the extent of the conversion, whereas the flow-rates used in the experiments have no effect at all. The influence of immobilization chemistry was investigated with GOX. Indirect immobilization with ConA as spacer proved to be the best alternative. With trypsin, immobilized on a disk, substrates with high molecular masses are digested in flow-through. For optimal digestion the proteins have to be denatured in the buffer for sodium dodecyl sulfate-polyacrlyamide gel electrophoresis prior to application. In contrast to the conversion of substrates with low molecular masses, flow-rates play an important part in conversion of substrates with high molecular masses. With lower flow-rates a higher degree of digestion is achieved.  相似文献   

20.
Exciton calculations on symmetric and asymmetric Fenna-Matthews-Olson (FMO) trimers, combined with absorption difference anisotropy measurements on FMO trimers from the green bacterium Chlorobium tepidum, suggest that real samples exhibit sufficient diagonal energy disorder so that their laser-excited exciton states are noticeably localized. Our observed anisotropies are clearly inconsistent with 21-pigment exciton simulations based on a threefold-symmetric FMO protein. They are more consistent with a 7-pigment model that assumes that the laser-prepared states are localized within a subunit of the trimer. Differential diagonal energy shifts of 50 cm(-1) between symmetry-related pigments in different subunits are large enough to cause sharp localization in the stationary states; these shifts are commensurate with the approximately 95 cm(-1) inhomogeneous linewidth of the lowest exciton levels. Experimental anisotropies (and by implication steady-state linear and circular dichroism) likely arise from statistical averaging over states with widely contrasting values of these observables, in consequence of their sensitivity to diagonal energy disorder.  相似文献   

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