In this work, five methods for measuring the thickness of ultra-thin gate oxide layers in MOS structures were compared experimentally on n+ poly-SiO2-p-Si structures. Three methods are based on electrical capacitance-voltage (C-V) and current-voltage (I-V) data and the other two methods are HRTEM and optical measurement. MOS capacitors with oxide thickness in the range 17-55 Å have been used in this study. We found that thickness extracted using QM C-V and HRTEM agree within 1.0 Å over the whole thickness range when a dielectric constant of 3.9 was used. Comparison between thickness extracted using quantum interference (QI) I-V technique and optical measurement were also within 1.0 Å for thickness 31-47 Å. However, optical oxide thickness was consistently lower than the TEM thickness by about 2 Å over the thickness range under consideration. Both optical measurement and QM C-V modeling yield the same thickness as the nominal oxide thickness increases (>50 Å) 相似文献
Spinal cord injury (SCI) causes significant mortality and morbidity. Currently, no FDA-approved pharmacotherapy is available for treating SCI. Previously, low doses of estrogen (17β-estradiol, E2) were shown to improve the post-injury outcome in a rat SCI model. However, the range of associated side effects makes advocating its therapeutic use difficult. Therefore, this study aimed at investigating the therapeutic efficacy of Premarin (PRM) in SCI. PRM is an FDA-approved E2 (10%) formulation, which is used for hormone replacement therapy with minimal risk of serious side effects. The effects of PRM on SCI were examined by magnetic resonance imaging, immunofluorescent staining, and western blot analysis in a rat model. SCI animals treated with vehicle alone, PRM, E2 receptor antagonist (ICI), or PRM + ICI were graded in a blinded way for locomotor function by using the Basso–Beattie–Bresnahan (BBB) locomotor scale. PRM treatment for 7 days decreased post-SCI lesion volume and attenuated neuronal cell death, inflammation, and axonal damage. PRM also altered the balance of pro- and anti-apoptotic proteins in favor of cell survival and improved angiogenesis and microvascular growth. Increased expression of estrogen receptors (ERs) ERα and ERβ following PRM treatment and their inhibition by ER inhibitor indicated that the neuroprotection associated with PRM treatment might be E2-receptor mediated. The attenuation of glial activation with decreased inflammation and cell death, and increased angiogenesis by PRM led to improved functional outcome as determined by the BBB locomotor scale. These results suggest that PRM treatment has significant therapeutic implications for the improvement of post-SCI outcome. 相似文献
Wireless Sensor Network (WSN) consists of randomly distributed sensor nodes which can collect, process, route and transmit data from their respective environment. Most of the research on WSN is oriented towards optimizing utilization of finite resources of Sensor Nodes to increase the overall network operative time. Recent literature on WSNs reveals that hierarchical routing unequal clustering methodologies are gaining popularity due to energy efficiency, load balancing and scalability. In literature, numerous surveys on clustering methodologies are available which address different equal clustering methods. The unequal clustering protocols, which have their own attributes viz. balance load distribution, hot spot mitigation and energy efficiency, are comparatively less explored. This motivated us to undertake the present study on the taxonomy, comparison and simulation analysis of different methodologies pertaining to less explored unequal clustering protocols. Our base metrics for comparison of different unequal clustering protocols are scalability, energy efficiency & load balancing capability of the resulting network. A comprehensive discussion has also been presented to highlight the various advantages and disadvantages of different unequal clustering protocols. Further, we have summarized the study of unequal clustering protocols in the tabular form.
BACKGROUND: The role of surgery in patients with pulmonary metastatic germ cell tumors has been evolving since the 1970s. To evaluate the results of pulmonary resection, we reviewed our 28-year experience. METHODS: Between July 1967 and May 1995, 157 patients with testicular germ cell tumors underwent pulmonary resections for suspected metastases. Their clinical and pathological data were reviewed. Kaplan-Meier and Cox regression models were used to analyze prognostic factors for survival after resection of metastatic disease. RESULTS: All patients were male with median age of 27 years (range 15-65). Complete resection was accomplished in 155 (99%) patients. Viable carcinoma was present in 44% (70) of the patients. Forty-one (26%) patients had metastases to other sites after pulmonary metastasectomy. The overall actuarial survival 5 years after pulmonary resection was 68% for the entire group and 82% for patients diagnosed after 1985. On multivariate analysis, the adverse prognostic factors were metastases to nonpulmonary visceral sites (p = 0.0069) and the presence of viable carcinoma in the resected specimen (p < 0.0001). CONCLUSIONS: With current chemotherapy regimens, almost 85% of the patients with testicular germ cell tumors undergoing complete resection of their pulmonary metastases can be expected to achieve long-term survival. 相似文献
Growing advances in VLSI technology have led to an increased level of complexity in current hardware systems. Late detection of design errors typically results in higher costs due to the associated time delay as well as loss of production. Thus it is important that hardware designs be free of errors. Formal verification has become an increasingly important technique towards establishing the correctness of hardware designs. In this article we survey the research that has been done in this area, with an emphasis on more recent trends. We present a classification framework for the various methods, based on the forms of the specification, the implementation, and the proff method. This framework enables us to better highlight the relationships and interactions between seemingly different approaches. 相似文献
Wireless Personal Communications - A meandered tag antenna is proposed for dual band operation in UHF (Ultra High Frequency) range at f1?=?866 MHz and... 相似文献
Predictive analysis aims at detecting concurrency errors during runtime by monitoring a concrete execution trace of a concurrent
program. In recent years, various models based on the happens-before causality relations have been proposed for predictive
analysis. However, these models often rely on only the observed runtime events and typically do not utilize the program source
code. Furthermore, the enumerative algorithms they use for verifying safety properties in the predicted traces often suffer
from the interleaving explosion problem. In this paper, we introduce a precise predictive model based on both the program
source code and the observed execution events, and propose a symbolic algorithm to check whether a safety property holds in
all feasible permutations of events of the given trace. Rather than explicitly enumerating and checking the interleavings,
our method conducts the search using a novel encoding and symbolic reasoning with a satisfiability modulo theory solver. We
also propose a technique to bound the number of context switches allowed in the interleavings during the symbolic search,
to further improve the scalability of the algorithm. 相似文献
This paper was recently published in the January edition of Industrial Environmental Management and is a modified version of an article published previously in Circuit World Vol.9 No. 4, 2003. The work was carried out as a CRAFT Project (ROCWAT-Thematic Priority F5 (Project number EEVK1-2001-30014). Part of the process involves dissemination to as wide an audience as possible through appropriate journals. 相似文献
Poly(ethylene terephthalate) (PET) recycling has been carried out by various methods, e.g., mechanical recycling, chemical recycling and energy recovery method. In this study, chemical recycling of PET was carried out by aminolysis using ethanolamine and converted into bis(2-hydroxyethyl) terephthalamide (BHETA). The reaction was performed by varying the PET:ethanolamine ratio, reaction time and catalyst used for waste medical grade bottles of PET. Yield of about 81 % was obtained for PET:ethanolamine ratio of 1:4 (w/w), with 3 h reaction time, at 160 °C with zinc acetate as a catalyst. BHETA was characterized with FTIR, 1H NMR, and DSC analysis. BHETA was further reacted with heptanoic acid at a molar ratio of 1:2.5. The product obtained was used as a plasticizer for PVC at 5, 10, 15 and 20 parts per hundred (phr) concentration. Thermal and mechanical tests were carried out and the result obtained was compared with the virgin PVC without plasticizer and with conventional plasticizer of PVC, i.e., dioctyl phthalate at 15 phr concentration since new plasticizer showed excellent properties at 15 phr concentration. This newly synthesized plasticizer was completely fused with PVC and in tensile testing helped in increasing the elongation, which was an indication of the plasticization effect shown by this developed material. Glass transition temperature also decreased with an incorporation of the new plasticizer as compared to virgin PVC. 相似文献