机械零件可靠性统计量计算的三种基本方法

在以应力和强度均呈正态分布的前提假设条件下 ,归纳提出了计算机械零件可靠性统计量的三个基本方法——代数法、矩法和变异系数法 ,比较了三种方法的计算精度 。

论假设检验与置信区间的联系

论述了假设检验与置信区间的联系,然后说明可用求置信区间的方法法来解决假设检验问题,这样可避开概率论与数理统计教科书[1,2]中新立体系来解决假设检验问题的冗长的论述,从而体现理论教学中“必需、够用”的原则。

General Quantum Interference Principle and Duality Computer

In this article, we propose a general principle of quantum interference for quantum system, and based on this we propose a new type of computing machine, the duality computer, that may outperform in principle both classical computer and the quantum computer. According to the general principle of quantum interference, the very essence of quantum interference is the interference of the sub-waves of the quantum system itself A quantum system considered here can be any quantum system： a single microscopic particle, a composite quantum system such as an atom or a molecule, or a loose collection of a few quantum objects such as two independent photons. In the duality computer, the wave of the duality computer is split into several sub-waves and they pass through different routes, where different computing gate operations are performed. These sub-waves are then re-combined to interfere to give the computational results. The quantum computer, however, has only used the particle nature of quantum object. In a duality computer, it may be possible to find a marked item from an unsorted database using only a single query, and all NP-complete problems may have polynomial algorithms. Two proof-of-the-principle designs of the duality computer are presented： the giant molecule scheme and the nonlinear quantum optics scheme. We also propose thought experiment to check the related fundamental issues, the measurement efficiency of a partial wave function.

Holographic Gas as Dark Energy

We investigate the statistical nature of holographic gas, which may represent the quasi-particle excitations of a strongly correlated gravitational system. We find that the holographic entropy can be obtained by modifying degeneracy. We calculate thermodynamical quantities and investigate stability of the holographic gas. When applying to cosmology, we find that the holographic gas behaves as holographic dark energy, and the parameter c in holographic dark energy can be calculated from our model. Our model of holographic gas generally predicts c 〈 1, implying that the fate of our universe is phantom-like.

Estimates of potential new production in the Java-Sumatra upwelling system

The Java-Sumatra upwelling is one of the most important upwelling systems in the Indian Ocean, with maximum upwelling intensity in July through August. To estimate the nitrate supplied by upwelling, we developed a three-dimensional hydrodynamic model to calculate the mean vertical speed and determine the depth of upwelling. We used in-situ vertical nitrate profiles to assess nitrate concentration in the upwelled waters, and calculated the nitrate supply as the product of nitrate concentration and vertical transport obtained from the numerical model. The calculated result represents potential new production generated in the upwelling region. We found that on the event time scale (monthly) of Java-Sumatra upwelling, water brought to the surface originated from locations 100-m deep, giving a nitrate supply of 93.77×10 3mol/s and potential new production of 1.02×10 14gC/a.

Views on Piracy： Threats to International Peace

The study was conducted to ascertain the views on piracy among marine engineering students and marine officers who had encountered piracy on international waters thereby suggesting threats to international peace. The respondents of the study were 50, specifically distributed to thirty （30） onboard marine engineering students enrolled for the current school year 2014-2015 and twenty （20） marine officers who had experienced piracy at Somalia and other places. The researchers employed quantitative-qualitative research method design. The questionnaire on ＂Piracy at Sea＂ was validated by experts in research, statistics, qualitative research, and maritime international conventions. To test the reliability, this same instrument was pilot-tested among marine officers and students who had been on board international ships. Qualitative data were captured through interviews by using open-ended questions. Frequency count, percentage, and rank were used in this study for descriptive-quantitative statistics. The data were analyzed using appropriate statistics through computer-processed software （SPSS）. Qualitative analysis was employed to determine the views of the respondents on piracy so that mitigation measures were elicited for protection of life at sea leading towards international peace among identified HRAs （high-risk areas）. Results revealed that seafarers were familiar of piracy. They were aware that piracy usually happens in areas like Somalia water sand other threatening territories. To combat piracy, the participants have pointed out the role of the international community in their concerted effort to help seafarers safeguard their lives specifically during these hard times. Somalia also needs to effectively check their organization by whether or not strict implementation of the Anti Piracy Law was being observed. Full knowledge of piracy, techniques for avoiding it, and surviving pirate attacks are necessary among seafarers. Satellite system called shiplock allows shipping companies to monitor location of ships particularly useful during pirate attacks, hijacks, or ship theft. They also install non-lethal electrical fences around a ship＇s perimeter to protect them during these times. IMO regulations require ships to send distress signals and warnings covertly in case of pirate attacks.

Evaluation of photon beam dose calculation accuracy of treatment planning systems using in vivo dosimetry

Objective The treatment planning system currently represents one of the basics of radiation therapy,because it is the only method to estimate patient dose delivery fast forward and accurately represent estimated tumor location of the tumor with the possibility of estimating densities in the tissue surrounding the tumor to overcome dose calculation defects but radial estimated the patient.Despite the flaws associated with the systems and calculates the dose of your programs in all programs currently existing in the world.Than necessary,to the existence of a review of the accuracy of accounts and how to confirm the radiation dose to the patient programs.Methods A total of 35 cancer patients were considered for this study,with 245 field measurements made with low-and high-energy diode detectors for brain and prostate cases.The treatments for all patients were planned using Eclipse Treatment Planning System version 13.6.Results Of the 105 field measurements made for the prostate cancer patients,16 included discrepancies outside the ±5% action level.Of the 145 measurements taken of the brain cases,there were four outside the ±5% action level.The results indicated a higher degree of accuracy.The study revealed that,for the prostate measurements,the higher discrepancy in the doses for the particular fields(exceeding the action level) may have been due to the isocenter being very close to the jaws and multi-leaf collimator of the linear accelerator machine.As a result,scatter from the jaws and the multi-leaf collimator could have contributed to the high dose delivered to the diode;hence,a probable higher discrepancy of the dose in more brain cases due highest quality of VMAT technique and fixation system.Conclusion A greater percentage of the observed discrepancies were well within the set tolerance level.However,it is recommended that the positioning of the diode on the patient's skin and the angular sensitivity of the diodes be reconsidered.It is also recommended that a more accurate calculation of expected diode values be performed,especially for fields that pass through the table.These efforts would achieve action levels of ±5%.

Energy optimization of representative barrier algorithms

Too high energy consumption is widely recognized to be a critical problem in large-scale parallel computing systems.The LogP-based energy-saving model and the frequency scaling method were proposed to reduce energy consumption analytically and systematically for other two representative barrier algorithms:tournament barrier and central counter barrier.Furthermore,energy optimization methods of these two barrier algorithms were implemented on parallel computing platform.The experimental results validate the effectiveness of the energy optimization methods.67.12% and 70.95% energy savings are obtained respectively for tournament barrier and central counter barrier on platforms with 2048 processes with 1.55%?8.80% performance loss.Furthermore,LogP-based energy-saving analytical model for these two barrier algorithms is highly accurate as the predicted energy savings are within 9.67% of the results obtained by simulation.

Bone marrow-sparing intensity-modulated radiotherapy for postoperative treatment of cervical cancer

Objective： The aim of this study was to compare bone marrow-sparing intensity-modulated radiotherapy （IMRT） with IMRT without entering pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods： For a cohort of 10 patients, bone marrow-sparing IMRT and routine IMRT planning were designed. The prescribed dose was 45 Gy/1.8 Gy/25f, 95% of the planning target volume received this dose. Doses were computed with a commercially available treatment planning system （TPS） using convolution/superimposition （CS） algorithm. Plans were compared according to dose-volume histogram （DVH） analysis in terms of planning target volume （PTV） homogeneity and conformity indices （HI and CI） as well as organs at risk （OARs） dose and volume parameters. Results： Bone marrow-sparing IMRT had an vantages over routine IMRT in terms of CI, but inferior to the latter for HI. Compared with routine IMRT, V5, Vl0, V20, V30, V40 of pelvic bone marrow of bone marrow-sparing IMRT reduced by 1.81%, 8.61%, 31.81%, 29.50%, 28.29%, respectively. No statistically significant differences were observed between bone marrow-sparing IMRT and routine IMRT in terms of small bowel, bladder and rectum. Conclusion： For patients with cervical cancer after hysterectomy, bone marrowsparing IMRT reduced the pelvic bone marrow volume irradiated at all dose levels and might be conducive to preventing the occurrence of acute bone marrow toxicity.

Effects of source opacity and expansion on two-pion Bose-Einstein correlations

We examine two-pion Bose-Einstein correlations for partially coherent particle-emitting sources within quantum statistical formal- ism, where the sources are treated as classical currents with chaotic and coherent components. The two-pion correlation functions of the partially coherent sources contain a phase which is sensitive to the asymmetry of the source emission function. We investigate the influence of source opacity and expansion in high energy heavy ion collisions on the phase by Monte Carlo calculations. We find that these two physical effects shift the phase from zero. The Gaussian-formula fit results to the simulated two-pion correlation functions indicate that the opaque and expansion effects lead to a smaller interferometry radius Rout and a larger 2 parameter.

Statistical analyses of protein folding rates from the view of quantum transition

Understanding protein folding rate is the primary key to unlock the fundamental physics underlying protein structure and its folding mechanism.Especially,the temperature dependence of the folding rate remains unsolved in the literature.Starting from the assumption that protein folding is an event of quantum transition between molecular conformations,we calculated the folding rate for all two-state proteins in a database and studied their temperature dependencies.The non-Arrhenius temperature relation for 16 proteins,whose experimental data had previously been available,was successfully interpreted by comparing the Arrhenius plot with the first-principle calculation.A statistical formula for the prediction of two-state protein folding rate was proposed based on quantum folding theory.The statistical comparisons of the folding rates for 65 two-state proteins were carried out,and the theoretical vs.experimental correlation coefficient was 0.73.Moreover,the maximum and the minimum folding rates given by the theory were consistent with the experimental results.