Origin of the threshold voltage instability in SiO/sub 2//HfO/sub 2/ dual layer gate dielectrics

The magnitude of the V/sub T/ instability in conventional MOSFETs and MOS capacitors with SiO/sub 2//HfO/sub 2/ dual-layer gate dielectrics is shown to depend strongly on the details of the measurement sequence used. By applying time-resolved measurements (capacitance-time traces and charge-pumping measurements), it is demonstrated that this behavior is caused by the fast charging and discharging of preexisting defects near the SiO/sub 2//HfO/sub 2/ interface and in the bulk of the HfO/sub 2/ layer. Based on these results, a simple defect model is proposed that can explain the complex behavior of the V/sub T/ instability in terms of structural defects as follows. 1) A defect band in the HfO/sub 2/ layer is located in energy above the Si conduction band edge. 2) The defect band shifts rapidly in energy with respect to the Fermi level in the Si substrate as the gate bias is varied. 3) The rapid energy shifts allows for efficient charging and discharging of the defects near the SiO/sub 2//HfO/sub 2/ interface by tunneling.     

Renal R2 chemoreceptor activity is attenuated after back heating in the rat

The aim of the present study was to determine the afferent connections of the nucleus accumbens in snakes, in particular its catecholaminergic input. For that purpose, in vitro and in vivo applications of retrograde tracers in the nucleus accumbens of Elaphe guttata were combined with tyrosine hydroxylase (TH) immunohistochemistry. Both techniques revealed telencephalic inputs to the nucleus accumbens originating from the diagonal band of Broca, ventral pallidum, amygdaloid complex, and dorsal cortex. Major diencephalic inputs arise from the dorsomedial thalamic nucleus and the hypothalamus. In the brainstem, a few retrogradely labeled cells were observed in the raphe nucleus and the locus coeruleus. Considerably more cells were found in the midbrain tegmentum. Within the confines of the locus coeruleus and, in particular, the midbrain tegmentum, retrogradely labeled cells stained also for TH suggesting that those areas constitute the major catecholaminergic input to the nucleus accumbens of snakes. The experimental approach used in the present study, in particular the in vitro technique, seems to be very suited for studying the development of basal ganglia organization of reptiles in the near future.     

A clinical study in the treatment of acute bacterial infections with fleroxacin

The purpose of this clinical trial is to evaluate the efficacy and safety of fleroxacin and to compare with those of lomefloxacin. A randomized controlled study was carried out to treat sixty patients with urinary tract and respiratory tract bacterial infections, thirty in each group with one of the two drugs, and fifty cases were treated with fleroxacin in an open trial. Altogether there were one hundred and ten cases. Both fleroxacin and lomefloxacin were given orally, the dosage was 200 mg every 12 hours or 400 mg every 24 hours for 7-14 days. The clinical efficacy rate was 93.3%; the culturing rate in the fleroxacin group was 83.3%; the bacterial clearance rate was 92.3%, the incidence of adverse reactions was 9.4%, while in the lomefloxacin group they were 90.0%, 80.0%, 87.5% and 6.7% respectively, with no statistically significant difference between the two groups (P > 0.05). In the open and randomized trials, fleroxacin cured eighty cases of bacterial infections, the overall clinical efficacy rate was 90.0%, the culturing rate in the flero-xacin group was 83.8%, the bacterial clearance rate was 88.2% and the incidence of adverse reactions was 9.6%. It is shown that fleroxacin is an antibiotic of broad-spectrum, high efficacy and safety.     

Heading towards an advanced signalling system for multimedia,multiparty services in broadband ISDN

Introduction of the broadband integrated services digital network (B-ISDN) will enable network users to make use of advanced multimedia, multiparty services. With this aim in view, RACE II project R2044, MAGIC, is investigating long-term signalling requirements, architecture and protocols for B-ISDN. New service concepts are being developed in MAGIC which will provide more flexibility when compared to narrowband ISDN (N-ISDN). The service requirements and other signalling requirements, such as the separation between call and associated connections at the network-node interface, are used to determine the distribution of functions over the network. The signalling protocols which are used to exchange the signalling information are subsequently developed. These signalling protocols are simulated to prove the performance and the feasibility of call handling concepts     

Overexpression, purification, and characterization of SHPTP1, a Src homology 2-containing protein-tyrosine-phosphatase

A protein-tyrosine-phosphatase (PTPase; EC 3.1.3.48) containing two Src homology 2 (SH2) domains, SHPTP1, was previously identified in hematopoietic and epithelial cells. By placing the coding sequence of the PTPase behind a bacteriophage T7 promoter, we have overexpressed both the full-length enzyme and a truncated PTPase domain in Escherichia coli. In each case, the soluble enzyme was expressed at levels of 3-4% of total soluble E. coli protein. The recombinant proteins had molecular weights of 63,000 and 45,000 for the full-length protein and the truncated PTPase domain, respectively, as determined by SDS/PAGE. The recombinant enzymes dephosphorylated p-nitrophenyl phosphate, phosphotyrosine, and phosphotyrosyl peptides but not phosphoserine, phosphothreonine, or phosphoseryl peptides. The enzymes showed a strong dependence on pH and ionic strength for their activity, with pH optima of 5.5 and 6.3 for the full-length enzyme and the catalytic domain, respectively, and an optimal NaCl concentration of 250-300 mM. The recombinant PTPases had high Km values for p-nitrophenyl phosphate and exhibited non-Michaelis-Menten kinetics for phosphotyrosyl peptides.     

精轧油膜轴承密封失效机理的初步分析

对油膜轴承密封出现的进水、漏油现象作了大量的调查、测量和统计分析，找出了产生质量事故的根本原因，提出了解决措施。     

聚苯硫醚酰胺的合成与表征

用4-氯苯甲酰4′-氯苯胺和硫化钠为原料在常压下合成了聚苯硫醚酰胺,并对其进行了表征。结果表明所合成的产物为结晶性聚合物,并且有较高的热稳定性。     

济钢中板厂加快技术创新的对策

本文通过对中板厂近年来技术改造后工艺装置和技术水平的分析，并结合中国加入WTO后对中国钢铁企业面临全球化市场竞争严峻性的认识，提出了中板厂在实现高产生产模式后，应加快技术创新的步伐，尽快完成由高产向优质、多品种、低消耗的高效化生产模式转化的主导思想、措施及建议。