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61.
研究了诱发电位(EP)信号潜伏期变化的检测与估计问题.传统的时域平均EP信号检测方法不能跟踪潜伏期的时变特性,基于相关计算的EP信号检测方法在存在外界周期性干扰的条件下是很不可靠的.本文提出一种自适应相位谱时间延迟估计方法,用于在低信噪比和低信扰比条件下检测和估计诱发电位信号潜伏期的变化.实验和计算机模拟表明,在信噪比和信扰比均低至-5dB时,本文方法仍能有效地跟踪EP信号潜伏期的变化,给出正确的估计结果.这种方法也可以用于时实EP信号的分析和处理.  相似文献   
62.
讨论了舌鳞状细胞癌平阳霉素单一化疗前后的病理组织学对照及化疗后肿瘤局部出现明显的临床愈合现象对手术治疗效果、生存率、生存质量的影响。治疗方法采用肌注或静脉滴注,动脉插管灌注PYM,每日10mg,效果显著。手术前瘤体明显缩小、消失,手术后病理组织学发现肿瘤细胞数量减少,残留细胞退变并被大量淋巴、巨噬细胞及炎性细胞包围,似疤痕化,确保原发灶完整干净切除。  相似文献   
63.
The changes in the environmental features of the Yellow Sea during the last 25 years of the 20th century were studied using a set of seasonally monitored data along a transect (at 36°N) maintained by the State Oceanic Administration of China. The data included the ocean temperature (T), salinity (S) and biogenic elements, such as dissolved oxygen (DO), phosphorus (PO4-P), silicon (SiO3-Si) and dissolved inorganic nitrogen (DIN).The seasonal (summer and winter) values and the annual mean of these elements showed significant changes during the monitored period. Time series of T, S, DIN and N:P ratios exhibited positive trends, while those of DO, P and Si exhibited negative trends. During this period, the annual mean of T and DIN in the Yellow Sea increased by 1.7 °C and 2.95 μmol L−1, respectively, while those of DO, P and Si decreased by 59.1, 0.1 and 3.93 μmol L−1, respectively. In the 1980s, particularly in between 1985 and 1989, concentrations of P and Si dropped to near the ecological threshold for growth of diatoms. The N:P ratio increased from 4 in 1984 to over 16 in 2000. The climate trend coefficients, Rxt, for these time series are all above 0.43 with significance levels of 95%, except for salinity. The increases in T were consistent with the recent climate warming in northern China and the adjacent seas, i.e. the Bohai Sea and the East China Sea. The reduction of DO was probably attributable to the increase in T and decrease in primary production in these regions. The positive trend of DIN was mainly attributable to precipitation and partly to Changjiang River discharge. The negative concentration trends of P and Si were due to the decreases in their concentrations in seawater that flowed to the Yellow Sea from the Bohai Sea. As a result, N:P ratios greatly increased in the seawater of the Yellow Sea.Moreover, some important responses of the Yellow Sea ecosystems to the changes in physical variables and chemical biogenic elements were obviously displayed. These responses include strengthening nutrient limitation, decreasing chlorophyll a, primary production and phytoplankton abundance, succession of dominant phytoplankton species from diatoms to non-diatoms, changes in fish community structure and species diversity.  相似文献   
64.
Bacterial abundance and production were measured monthly for one year along cross-shore transects in 3 sub-Antarctic fjords of the Kerguelen Archipelago (seven stations each). Mean values of the 3 most coastal (inside) and most offshore (outside) stations were used to describe the relationship between temperature, phytoplankton biomass, bacterial abundance and bacterial production over a one year annual cycle. The entire sampling protocol was repeated twice during each cruise: once at noon and once at midnight. Over the whole sampling period, the temperature ranged from 2.1 to 7.4 °C, while chlorophyll a concentrations varied by a factor of 10, and bacterial abundance and production varied by factors of 12 and 30, respectively. Within one day, all of these parameters sometimes varied by a factor of 4 between noon and midnight. A clear seasonality was observed for all of the parameters. However, while variations of phytoplankton and bacterial production paralleled those of temperature, bacterial abundance was low in midsummer and maximum in autumn. While no general pattern could be observed from the total data set, spatial gradients could interfere strongly with temporal changes.  相似文献   
65.
结合澳大利亚新南威尔士州道路交通规则2008年修订内容,提出了在制订和实施道路交通法规过程中应注重人性化与处罚有机结合的策略。  相似文献   
66.
无迹卡尔曼滤波可以在状态估计中滤去噪声干扰,已经被广泛应用于动力定位系统中.针对复杂海洋情况下动力定位系统需要准确、及时地估计当前时刻的状态而无迹卡尔曼滤波无法跟踪状态突变的问题,为此文章提出了一种自适应无迹卡尔曼滤波.通过及时判断状态值突变并适当调整后验均方差矩阵,可有效地跟踪船舶状态并减小实际位置与定点位置的偏差.仿真实验证明了算法的有效性.  相似文献   
67.
在松花江大桥承台大体积混凝土的施工过程中,通过对绝热升温等所造成的和布置降温管后混凝土内部中心温度的计算,发现施工中易出现温度裂缝问题,为此从混凝土组成、配合比、降温管及施工后的养护等方面采取控制措施,实践证明效果良好,同时也降低了成本,获得较好的经济效益,值得在以后的施工中加以推广和借鉴。  相似文献   
68.
目的 探讨多囊卵巢综合征 (PCOS)妇女用克罗米酚 (CC)促排卵治疗无效的原因 ,以预测其疗效。方法  41例PCOS患者均计算BMI ,行F G毛发评分 ,服CC前后测血清生殖激素水平 ,B超了解卵巢形态并监测排卵。结果 与CC治疗有反应组相比 ,无反应组的F G毛发评分、基础A、fT增高 ,卵泡数增多 ,卵巢体积及髓质面积增大 ,卵泡晚期FSH、LH、E2 降低 (P均 <0 0 5) ;相关回归显示平均卵泡数与T、A ,平均髓质面积与A呈正相关。结论 多毛患者对CC治疗的反应性降低。H P O轴功能状态可影响CC疗效 ;一定的激素水平和卵巢超声表现提示CC抵抗 ;卵巢超声形态与T、A间存在正相关  相似文献   
69.
为探讨腰椎间盘突出症的不同病理分型和自身体液免疫状态之间的相互关系,采用速率散色比浊法和免疫组化法对28 例腰椎间盘突出症患者血清、脑脊液和髓核组织中IgG、IgM 进行测定。结果表明:①脑脊液中IgG、IgM 含量增高对腰椎间盘突出症有一定诊断价值;②外周血中IgG、IgM 的增高有助于区分腰椎间盘突出症的破裂型和游离型,可明确经皮髓核摘除术中的禁忌症;③突出的髓核组织中有免疫球蛋白沉积,可引起自身免疫反应性炎症,这是腰椎间盘退变、突出和腰腿痛的原因之一  相似文献   
70.
作者观察1例尸检,2例活检的心肌组织,发现围产期心肌病的组织学改变为灶状肌溶性坏死,病灶呈全心分布,以左室内侧密集且趋向融合,间质未见炎性渗出反应。取右室心肌活检电镜观察,可见心肌细胞有两种变化:一为肌原纤维的灶状溶解脱失,一为肌纤维内絮斑状电子密度物质沉积。闰盘呈各种变异及间隙加宽。作者未发现心肌细胞质内有任何其他沉积物,电镜下也未见任何异常的微丝聚集及高电子密度团块。通过观察,作者同意本病属多因素综合症的说法,其病变可能为机体免疫状态发生变化所导致的变应性心肌病。  相似文献   
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