预应力薄腹梁质量事故的分析及鉴定

阐述了某工程由于施工原因，导致预应力混凝土工字形屋面梁强度不足的预制构件的检验鉴定过程和方法。采用回弹法推定混凝土实际强度；通过静载试验测试构件的实际挠度、抗裂和承载能力。分析了导致混凝土强度不足的原因。     

冷却水循环用离心泵汽蚀的原因与防止方法探讨

通过对冷却水循环用离心泵产生汽蚀的因素进行分析，提出了防止汽蚀产生的技术措施，经生产应用效果良好。     

秦皇岛装船原油管道能耗指标测算

针对秦皇岛原油装船线装船量急剧下降的情况，从分析油电消耗着手，推导出油电指标的测算公式，探讨成本与装船计划的关系。确定了维持成本运行的最低年装船量，并提出了相应降低能耗的措施。     

Inflammation-related changes in cyclic AMP and cyclic GMP in bovine mastitis

Cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) cocentrations in milk and plasma samples from healthy and mastitic cows were determined by radioi-immunoassay and compared with prostaglandins (PGE2, PGF2 and thromboxane B2 [TXB2]), phospholipids and other relevant parameters in milk and blood. The concentrations of cAMP were about five times higher in plasma (p<0.01) than in milk, whereas the cGMP concentration in milk was three times higher (p<0.01) than that in plasma in both healthy and diseased animals. In mastitic milk, the cAMP and cGMP concentrations were 19% and 65% and in blood plasma 13% and 84% higher respectively than in healthy animals. In milk, cyclic nucleotide concentrations correlated with the markedly elevated cell count and also with the prostaglandin concentration and pH. In blood, cAMP correlated positively with phospholipids and cGMP with reduced glutathione (GSH). These changes are considered to be important in the disease process and, in particular, the increase in cGMP deserves further study.     

Effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells from rats exposed to chronic hypoxia

AIM: To investigate the effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells (PASMCs) from rats exposed to chronic hypoxia. METHODS: (1) Wistar rats were randomly divided into control group (group A) and chronic hypoxia group (group B). Then group B received hypoxia 8 hours per day for 4 consecutive weeks. (2) Single PASMC was obtained via acute enzyme separation method. (3) Conventional whole-cell patch clamp technique was used to record resting membrane potential (Em) and ion currents of voltage-gated potassium channel. The changes of ion currents of voltage-gated potassium channel before and after applying cGMP (1 mmol/L), an agonist of protein kinase G (PKG), and cGMP plus H-8 (1 mmol/L), an inhibitor of PKG were compared between two groups. RESULTS: The Em of group B were significantly lower than that of group A. The ion currents of voltage-gated potassium channel in group A and group B were all significantly inhibited by cGMP [control group: from (118.0±5.0) pA/pF to (89.9±16.5) pA/pF, n=6, P＜0.05;chronic hypoxia group: from (81.0±5.0) pA/pF to (56.8±9.1) pA/pF, n=6, P＜0.05]and these effects were reversed by H-8 [control group: from (119.2±10.3) pA/pF to (117.8±9.1) pA/pF, n=6, P＞0.05;chronic hypoxia group: from (96.8±6.2)　pA/pF to (98.0±2.2)　pA/pF, n=6, P＞0.05]. CONCLUSIONS: The currents of voltage-gated potassium channel was inhibited by chronic hypoxic. The inhibitory effect of cGMP on currents of voltage-gated potassium channel in PASMCs from both normal and chronic hypoxic rats may be probably through the phosphorylation of voltage-gated potassium channel.     

无缝烟夹不同针尖处理对烤后烟叶孔径的影响

为优化无缝烟夹装置设计,充分发挥无缝烟夹装烟方式的优势,对不同直径、不同形状针尖及不同方向的无缝烟夹烤后烟叶的针孔面积进行了比较研究。结果表明:不同直径烟针相比,3 mm直径无缝烟夹烤后针孔面积小于5 mm直径无缝烟夹;无缝烟夹在3 mm直径条件下,扁形针尖平行处理烤后针孔面积最小;在5 mm直径条件下,圆形针尖平行处理烤后针孔面积最小。     

多径衰落信道下OFDM系统的符号同步方法研究

由于在正交频分复用（OFDM）的系统中存在符号时间同步误差，为了消除这种误差，提出了工作在多径衰落信道的符号时间频移（STO）估计方法，即基于CP的符号时间偏移估计和基于训练符号的符号时间偏移估计，通过仿真对基于循环序列（CP）估计技术的最大似然法（ML）和基于训练符号的最小均方差异法（Classen）两类性能比较分析，在无载波频移条件下，ML算法精确度更高，当存在载波频移时，Classen算法精确度更高。     

青核桃去皮过程的受力分析

青核桃在去皮方面不断进取的同时,存在着共同的问题是去掉的青皮被打成泥状,对核桃和环境都造成再次污染。为此,将通过模拟青核桃去皮过程的受力进行试验,分别从青核桃的尺寸、加载方向及加载速度等可能影响青核桃去皮过程的因素进行分析研究,为使青皮脱掉后不会被打成泥状,而是呈块状脱出奠定实验基础。     

The influences of ambient temperature and crude protein levels on performance and serum biochemical parameters in broilers

This study was undertaken to investigate the effects of ambient temperature, crude protein levels and their interaction on performance and serum biochemical parameters of broiler chickens. A total of 216 Arbor Acre broiler chickens (108 males and 108 females) were used in a 2 × 3 factorial arrangement and randomly reared at two temperatures (normal temperature: 23 °C; daily cyclic high temperature: 28–32 °C) and fed on three diets with different crude protein levels (153.3, 183.3 or 213.3 g/kg, with constant essential amino acids) from 28 to 42 days of age. Daily cyclic high ambient temperature decreased final body weight, average daily weight gain, average daily feed intake and serum total protein contents (p < 0.001, p < 0.001, p < 0.001, p = 0.008 respectively), but increased feed/gain, mortality, respiratory rate, rectal temperature, serum uric acid contents and serum creatine kinase activity (p = 0.008, p = 0.003, p < 0.0001, p < 0.0001, p < 0.0001, p = 0.003 respectively), irrespective of crude protein levels. At the ambient temperature, reducing crude protein levels resulted in an increase in feed/gain (p < 0.001), but a decrease in serum total protein and uric acid contents. Only serum creatine kinase activity in broiler chickens was interacted by daily cyclic high ambient temperature and dietary crude protein levels (p = 0.003). These results indicated that daily cyclic high ambient temperature had a great effect on performance and serum biochemical parameters in broiler chickens, whereas dietary crude protein levels affected them partially.     

A MIMD PARALLEL ALGORITHM TO SOLVE TRIDIAGONAL TOEPLITZ LINEAR EQUATIONS

The rank one updating formula and the parallel eliminating algorithm for linear recurrence systems ane combined fo form a MTMD parallel algorithm fo solve tridiagonal Toeplitz Cinear equations. This algorithm has a simple strictire and requires onlty a few storages as well as in-terprocessor communications. There is no special demand on the number of processors in the parallel system. The speedup can come dose to p12 comparing with the LU decomposition method (p is the number of processors). It is worth pointing out that it is proposed algcmthn that considels and organizes the parallel arithmetic in the first order linear ricurrence systems with constant coefficients.