压电行波马达的孤极反馈频率跟踪技术

提出利用定子陶瓷的孤极反馈来完成行波马达的闭环控制，减少了频率漂移所引起的速度波动问题。     

A statistical description of stimulated Brillouin scattering beamcombination efficiency

The mutual coherence between two stimulated Brillouin signals produced by undepleted pump beams that are partially overlapped is studied. The mutual coherence of the stimulated-Brillouin-scattered beams determines the efficiency with which the two beams can be combined. The statistical properties of the mutual coherence are calculated. The mechanism for coupling of two stimulated-Brillouin-scattering outputs is four-wave mixing. Mutual coherence is found to depend on the pump beam's pulse duration, the medium's phonon lifetime, and the degree of overlap between the laser pump beams     

Associations between ADHD and psychoactive substance use disorders. Findings from a longitudinal study of high-risk siblings of ADHD children

This article investigates the relationship between attention-deficit/hyperactivity disorder (ADHD) and psychoactive substance use disorders (PSUD) in siblings of ADHD and normal-control probands and addresses issues of psychiatric comorbidity and gender. Using DSM-III-R structured diagnostic interviews and blind raters, the authors conducted a 4-year follow-up of siblings. ADHD and male gender predicted higher rates and an earlier onset of PSUD after adjusting for high-risk status, other psychiatric disorders, and age. Risk was particularly high if the siblings had ADHD plus conduct disorder. This study's findings confirms the authors' prior report high-lighting the importance of drug and alcohol prevention and cessation programs aimed at ADHD youth and their siblings, particularly those with comorbid conduct disorder.     

Aberrant cervical thymus: a case report and review of literature

This article illustrates a case of an aberrant cervical thymus presented as a neck mass. This is a case of a 4-month-old boy presenting with a right submandibular mass whose preoperative diagnosis was lymphangioma or neoplastic lesion. The mass was successfully removed and the histopathological examination showed normal thymic tissue with no diagnostic abnormality. This paper reviews the embryological background of aberrant cervical thymus, the varying clinical presentations with an emphasis on differential diagnosis, clinical work-up, and surgical treatment.     

甲酸甲酯与三聚甲醛偶联合成乙醇酸甲酯 Ⅱ.硫酸/金属羰基化合物对收率的影响

研究了硫酸／金属羰基化合物对甲酸甲酯与三聚甲醛偶联合成乙醇酸甲酯反应的催化作用，结果乙醇酸甲酯和甲氧基乙酸甲酯的收率均有提高；用甲醇分解偶联反应母液，进一步提高了产品收率，优选出较佳的配比，用１０ｍｌ硫酸、３．１２ｇＡｇ２ＳＯ４（Ｉ）所形成的硫酸／金属羰基化合物作催化剂，与４５ｍｌ甲酸甲酯和１２ｇ三聚甲醛进行偶联反应，在甲醇分解偶联反应母液后，得到乙醇酸甲酯和甲氧基乙酸甲酯的摩收率分别为５９．８２％和３４．３９％，超过国外研究结果。     

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本文研究了四川盆地的陆盆发展史,指出在燕山期有一个以自贡-乐山地区为中心的沉积古隆起,它对四川盆地上三叠统的油气生成、储层物性及油气的运移、聚集都有明显的控制作用。所以,在燕山期古隆起斜坡带是寻找上三叠统油气藏的有利地区。     

平键联接两个工艺问题的分析及解决

对平键联接中键槽尺寸的选取以及高精度深内孔键槽的加工进行工艺分析，提出解决措施。     

Communication between Chinese and non-Chinese scientists in the discovery of high-Tc superconductor: I. The formal perspective

As the first part of a two-phase study, 240 documents highly cited in a self-created Chinese database and inScience Citation Index for the period of 1987–89 were examined to delineate the formal structure of communication in superconductivity research. Noteworthy similarities, e.g., analogous cited cores, identical publication sources, and comparable intellectual structures of cocitation data, were found in formal communication between Chinese and non-Chinese scientists. However, differences were also located in citedness, timeliness, and direction of communication.     

Characterization of Grain Boundaries in Superplastically Deformed Y-TZP Ceramics

The effects of compressive deformation on the grain boundary characteristics of fine-grained Y-TZP have been investigated using surface spectroscopy, impedance analysis, and transmission electron microscopy. After sintering at low temperature (1150°C), the grain boundaries are covered by an ultrathin (1nm) yttrium-rich amorphous film. After deformation at 1200°–1300°C under low stress, some grain boundaries are no longer covered by the amorphous film. Yttrium segregation seems to occur only at wetted grain boundaries. Evidence has been found that the extent of dewetting increases with increasing applied stress.     

制度创新与中国电信业的改革发展

制度确定了一个社会的激励结构,是决定长期经济绩效的基本因素,一个政体所获得的有效制度,要为创立和实施有效的产权制度创立激励。由于没有降低成本的动力和采用业务交叉补贴造成信息不充分带来的“政府失灵”,国有垄断制度的全社会收益呈现边际递减,低效率结果是不可回避的,这就是中国电信业发展的制度障碍。中国电信业下一步改革,就外部市场竞争而言,应该实施运营商重组、投融资体制改革、加快立法、放松资费管制、建立普遍服务基金等;就内部治理结构来说,重点要强化机制创新、培育与企业改革相适应的企业文化。中国电信机制创新包括快速市场反应机制、激励约束机制、内部压力传递机制三大机制的创新。它们之间相互联系、相互作用,共同构成了电信经营机制,推动电信经营模式从内部导向向市场导向转变,将市场的种种挑战和机会通过市场营销体系有效地传递到组织内部各个团队和每一个员工,从而使中国电信快速调整、优化资源配置,保证中国电信总体战略的有效贯彻,最终实现战略目标。