Fluctuations (or drifts) in switching voltages such as programming set/reset voltages and threshold voltage pose serious obstacles to the reliable operation of electrical phase change memory devices. Using a phase cha...
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Fluctuations (or drifts) in switching voltages such as programming set/reset voltages and threshold voltage pose serious obstacles to the reliable operation of electrical phase change memory devices. Using a phase change memory device having a GeSb2Te4 phase change material and TiN electrode, these fluctuations are demonstrated to result from device resistances varying with programming cycles. Fluctuating resistances appear to stem primarily from large contact resistances at the interface between the phase change material and the TiN electrode and from inhomogeneous phase distribution across the GeSb2Te4 layer due to unsuccessful heat confinement near the interface with TiN. Oxidation of a TiN electrode surface (via thermal annealing at 350 degrees C under an atmospheric gas mixture of 97.9 vol % N-2 and 2.1 vol % O-2) is very effective in the reduction of fluctuations in device resistances and switching voltages hence the resulting increase in the programming cycles by two orders of magnitude. From a high resolution transmission electron microscopy, the oxidized surface was shown to consist of a titanium oxide layer primarily with Ti2O3 crystallites which is presumed to yield enhanced stability of the device by the following two effects. Firstly, Ge, Sb, and Te atoms would have stronger bonds to oxygen atoms than to nitrogen atoms by about 0.5 eV, thereby producing more robust interface. Accordingly, the magnitude of contact resistance and its variation are reduced significantly so as to have little influence on the device resistances and their fluctuations. Secondly, thermally and electrically more resistive nature of the oxide layer would tend to yield, by enhanced generation and confinement of Joule heat, more uniform temperature distribution across the phase change material layer, rendering possibly a more homogeneous single phase material hence steadier sheet resistances with programming cycles. (c) 2006 American Institute of Physics.
Objective To compare the hypertensive disorders of pregnancy (HDP) risk between vaginal and intramuscular (IM) progesterone in programmed frozen-thawed embryo transfer (FET) *** This was a retrospective cohort study a...
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Objective To compare the hypertensive disorders of pregnancy (HDP) risk between vaginal and intramuscular (IM) progesterone in programmed frozen-thawed embryo transfer (FET) *** This was a retrospective cohort study at a tertiary hospital, and only women who achieved ongoing pregnancy after programmed FET between January 2018 and June 2022 were included. Women with chronic hypertension before pregnancy or with history of gestational hypertension or pre-eclampsia in previous pregnancies were excluded. All women were divided into IM progesterone or vaginal progesterone groups according to the route of progesterone supplementation. Follow-up information on obstetric complications and neonatal outcomes were obtained by telephonic interviews. The primary outcome was HDP. Association between routes of progesterone supplementation and HDP was assessed by subgroup analysis and multivariable logistic *** A total of 5891 programmed FET cycles (3196 IM progesterone cycles and 2695 vaginal progesterone cycles) were included in the analysis. The prevalence of HDP in the IM progesterone group was significantly lower than that of the vaginal progesterone group (6.54% vs 9.17%, P < 0.001). Therein, the prevalence of gestational hypertension (3.57% vs 4.94%, P = 0.009) and pre-eclampsia (2.97% vs 4.23%, P = 0.009) in the IM progesterone group were all significantly lower as compared to the vaginal progesterone group. According to subgroup analysis, IM progesterone was associated with lower HDP risk in all subgroups. The logistic regression analysis showed that the IM progesterone cycles were associated with lower risk of HDP compared to vaginal progesterone cycles (adjusted odds ratio 0.66, 95% CI: 0.54-0.80, P < 0.001).Conclusion Among women undergoing programmed FET cycles, progesterone supplementation with IM progesterone was associated with reduced HDP risk compared to vaginal progesterone.
This diploma thesis maps pupils understanding about a functional principle of using commands along with testing conditions (IF, IF - THEN, REPEAT - UNTIL, etc.) when creating algorithms. The main aim of the thesis is ...
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This diploma thesis maps pupils understanding about a functional principle of using commands along with testing conditions (IF, IF - THEN, REPEAT - UNTIL, etc.) when creating algorithms. The main aim of the thesis is to design and implement a set of lessons and a teaching approach based on a theory about learning of algorithmic concepts at primary education for pupils (aged in 9-11) with the intention of verifying a functionality of designed teaching procedures and their possible impacts on pupils understanding. Data was collected through continuous monitoring of pupils behavioural characteristics, progress and solution of chosen tasks, video recordings of task solving within the suggested unplugged activities, using a virtual tool *** for monitoring of a pupils progress, audio recordings of interview with pupils, and photographs capturing a creation of own blocks of commands set up by a transcription from pupils mother language into a machine language (programming language) have all been used for a verification process of the designed teaching approach. By combining the acquired data sets, adjustments of these procedures have been made in order to eliminate the most frequent problems that pupils have encountered during teaching. The case study findings revealed that it is important for...
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