调制脉冲声测量系统的原理及应用

本文介绍的调制脉冲声测量系统是TDS和数字测量技术的进一步发展,其特点是简化了TEF系统的实现条件,解决了全频带的测量动态问题。本系统曾在上海音像公司录音棚中进行过测量,取得了一定的效果。     

工艺条件对薄片陶瓷材料凝胶流延成型的影响

利用有机单体的聚合原理，成功进行了陶瓷薄片材料的凝胶流延成型。讨论了工艺条件对成型的影响。使用惰性气氛保护克服了单体聚合反应中的氧气阻聚问题，浆料在一定温度和气氛条件下能够顺利完成聚合反应。所成型的坯体具有良好的强度和柔韧性，在1550℃经2h烧结，烧结样品显微结构均匀，没有发现晶粒异常长大现象，烧结体致密度达到97．7％。     

99Tcm-MDP scintigraphy in high-voltage electrical burn patients

In high-voltage electrical burn injuries (> 1000 V), it is difficult to identify the site and extent of non-viable deep tissue damage for debridement to avoid further tissue injury from wound infection and the risk of sepsis. This prospective study was designed to evaluate the usefulness of 99Tcm-methylene di-phosphonate (99Tcm-MDP) scintigraphy in detecting the extent of tissue injury and determining the level of amputation required for electrical burn patients. Over a 5 year period, 33 high-voltage electrical burn patients were studied. Blood flow and blood pool studies revealed absent perfusion in 37 limbs, all of which eventually were amputated. In addition to a routine three-phase bone scan, images were obtained at 30-60 min (early images) to evaluate whether soft tissue injury could be detected better at that time. For comparison of the detection rate from the early images and bone (delayed) images, 164 corresponding spot views of both images were reviewed. Eighty-three and 125 tissue necrotic lesions were demonstrated by the early images and bone images respectively. All of the 83 lesions found by the early images were more clearly identified by the bone images. All but one of the 125 lesions underwent surgical debridement or amputation. We concluded that the blood flow and blood pool images correlated well with the level of amputation required. The site and extent of tissue necrotic lesions can be clearly identified on 99Tcm-MDP bone scans. Because the early images were less sensitive in detecting tissue necrosis, we suggest that early imaging is not necessary.     

长脉冲激光沉积原位生成YBaCuO超导膜

用长脉冲激光(脉冲宽度150μs,波长1.06μm)辐照高温烧结的YBa_2Cu_3O_(7-x)靶,在6Pa的氧气压强下,巳在(100)YSZ单晶衬底上原位生成YBa_2Cu_(?)O_(7-x)超导膜。衬底置于750℃的加热器上,衬底与靶之间的距离5cm,用该法制得的薄膜光亮坚实,正常态呈金属性,零电阻温度为84.7K。用XRD和SEM对薄膜进行了分析研究。     

A new kind of compound solid-state quasi-optical power combiner

In this paper, a new kind of solid-state quasi-optical power combiner is presented. It consists of two or more singlecavity multiple-device power combiners and a Fabry-Perot cavity. The experimenal results using six Gunn diodes at X-band show that the total output power is higher than 400 mW, the total combining efficiency is as high as 83%, and the frequency stability is better than 10^?5.     

用γ分析方法研究滇池现代沉积年代

用γ分析方法对采自云南滇池沉积孔柱中的天然放射性核素２１０Ｐｂ、２２６Ｒａ和人工放射性核素１３７Ｃｓ、２４１Ａｍ的垂直剖面特征及相应沉积年代进行了研究。并且用２１０Ｐｂ法计算了近百年来该地沉积速率的变化和各采样层位的沉积年代。对计算结果用人工放射性核素１３７Ｃｓ和２４１Ａｍ时标法进行了验证。研究结果表明该地湖泊沉积演化过程受到较强的人类活动的影响。     

尼尔基水利枢纽质量 进度及投资控制与管理

尼尔基水利枢纽工程在实施过程中,业主以合同管理为纽带,通过对"质量、进度、投资"的控制与管理,顺利完成了工程建设目标.     

动情期家兔输卵管上皮及其分泌活动的电镜观察

本实验用透射电镜和扫描电镜观察了动情期家兔输卵管上皮。证实分泌细胞和纤毛细胞都有分泌功能，共分泌三种分泌物质。本文对这些分泌物质的分泌方式、分泌活动进行了研究和探讨。另外，发现上皮基膜下方始终有一层成纤维细胞形成的胞质膜伴行，据此，对血一输卵管腔屏障的构成亦进行了讨论。     

一种基于神经网络的模糊推理方法

对于Zadeh的模糊关系合成法则（简称CRI方法），选择一个适宜蕴涵关系矩阵是至关重要的。通常蕴涵关系矩阵的元素值是通过一个所构造的数学表达式计算的，或是由领域专家凭经验直接给出。然而，有时，特别是对于后一种情形，CRI法不能满足模糊推理最基本的一致性要求。文章构造了一个神经网络用于模糊推理，新方法不仅是CRI方法的推广，而且远比CRI方法易于满足推理的一致性要求。得益于神经网络的长处，新方法具有灵活性、可调性。文章给出了权值的具取值法。     

一种红外成像系统作用距离试验评估方法

进行红外成像系统作用距离考核试验时，由于外场试验中的目标特性及气象条件与指标提出对应的目标特性及气象条件有差别，因此需要进行必要的折算。提出一种基于信噪比准则的可行的红外成像系统作用距离试验评估方法。