52 research outputs found

    The neutral top-pion and the lepton flavor violating ZZ decays ZliljZ\to l_{i}l_{j}

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    Taking into account the constraints of the present experimental limit of the process μeγ\mu\to e\gamma on the free parameters of topcolor-assisted technicolor(TC2) models, we calculate the contributions of the neutral top-pion to the lepton flavor violating(LFV) ZZ decays ZliljZ\to l_{i}l_{j}. Our results show that the value of the branching ratio Br(Zτl)Br(Z\to \tau l) is larger than that of Br(Zμe)Br(Z\to \mu e) in all of the parameter space and there is Br(Zτμ)Br(Zτe)2×1014Br(Z\to \tau\mu)\approx Br(Z\to \tau e)\simeq 2\times 10^{-14} , which is far from the reach of present or future experiments.Comment: 12 pages and 3 figures. To be published in J. Phys.

    A New Switching Impulse Generator Based on Transformer Boosting and Insulated Gate Bipolar Transistor Trigger Control

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    To make the switching impulse (SI) generator more compact, portable and feasible in field tests, a new approach based on transformer boosting was developed. To address problems such as triggering synchronization and electromagnetic interference involved with the traditional spark gap, an insulated gate bipolar transistor (IGBT) module with drive circuit was employed as the impulse trigger. An optimization design for the component parameters of the primary winding side of the transformer was realized by numerical calculation and error correction. Experiment showed that the waveform parameters of SI and oscillating switching impulse (OSI) voltages generated by the new generator were consistent with the numerical calculation and the error correction. The generator was finally built on a removable high voltage transformer with small size. Thus the volume of the generator is significantly reduced. Experiments showed that the waveform parameters of SI and OSI voltages generated by the new generator were basically consistent with the numerical calculation and the error correction

    Top quark associated production of the neutral top-pion at high energy e+ee^{+}e^{-} colliders

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    In the context of topcolor-assisted technicolor (TC2) models, we calculate the associated production of the neutral top-pion πt0\pi_{t}^{0} with a pair of top quarks via the process e+ettˉπt0e^{+}e^{-}\longrightarrow t\bar{t}\pi_{t}^{0}. We find that the production cross section is larger than that of the process e+ettˉH e^{+}e^{-}\longrightarrow t\bar{t}H both in the standard model (SM) and in the minimal supersymmetric SM. With reasonable values of the parameters in TC2 models, the cross section can reach 20fb20fb. The neutral top-pion πt0\pi_{t}^{0} may be direct observed via this process.Comment: Latex files, 10 pages and 3 figure

    Non-universal gauge bosons ZZ^{\prime} and lepton flavor-violation tau decays

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    There are many models beyond the standard model predicting the existence of non-universal gauge bosons ZZ^{\prime}, which can give rise to very rich phenomena. We calculate the contributions of the non-universal gauge bosons ZZ^{\prime}, predicted by topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models, to the lepton flavor-violation tau decays τliγ\tau\to l_{i}\gamma and τliljlk\tau\to l_{i}l_{j}l_{k}. We find that the branching ratio Br(τliljlk)B_{r}(\tau\longrightarrow l_{i}l_{j}l_{k}) is larger than that of the process τliγ\tau\longrightarrow l_{i}\gamma in all of the parameter space. Over a sizable region of the parameter space, we have Br(τliljlk)108B_{r}(\tau\longrightarrow l_{i}l_{j}l_{k})\sim 10^{-8}, which may be detected in the future experiments.Comment: Final version to appear in Phys. Lett. B. References added and typos correcte

    A study of starch resources with high-amylose content from five Chinese mutant banana species

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    Investigation on staple crop starch of new species has been becoming the research focus of scholars at present. Based on this, the physicochemical properties and microstructural characteristics of starches isolated from Chinese mutant Musa acuminata Colla acuminata and double balbisiana (MA), Musa double acuminata cv. Pisang Mas (MAM), Musa acuminata cv. Pisang Awak (MAA), and Musa Basjoo Siebold (MBS), and Musa double acuminata and balbisiana-Prata (MAP) were investigated. Results exhibited that all starches exhibited high content of amylose (34.04–42.59%). According to the particle size, they were divided into medium (MA, MAM) (14.54–17.71 μm) and large (MAA, MBS, MAP) (23.01–23.82 μm) group. The medium group with A-type crystallization showed higher peak viscosity (PV), final viscosity, gel fracturability and gel hardness. For large group with B-type crystallization, the compact particle morphology, higher degree of crystallinity, short range order, gelatinization enthalpy, pasting temperature, lower porosity, water absorption capacity (WAC) and oil absorption capacity were found. In addition, the medium group with higher PV and gel hardness could be used as food thickening or gelling agents. The large group with higher Rc, short-range order, lower porosity and WAC could be potential to become raw material for resistant starch. All results showed the amylose content, had significant effect on the microstructure and physicochemical properties of starch samples. Outcomes in this investigation might provide a basis of theoretical application for industrial food production

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Application of Pullulan and Chitosan Multilayer Coatings in Fresh Papayas

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    In this work, some multilayer coatings (two-layer, four-layer or six-layer) based on pullulan and chitosan for protecting papayas were prepared by the layer-by-layer technique. The papayas were coated by immersion and stored at 25 °C, 50% relative humidity or up to 14 days. Uncoated and monolayer-coated papayas were used as controls. The pullulan/chitosan coatings decreased the papaya weight loss, softening, color change (b*, ΔE), and pH, retarded the fall of titratable acidity and vitamin C, and maintained respiratory rate and soluble solid contents. Sensory quality evaluation demonstrated that pullulan/chitosan coatings effectively preserved papaya flavor and overall acceptance. In general, the four-layer coatings provided the best fruit preservation. In conclusion, multilayer pullulan/chitosan coatings are efficient in maintaining the post-harvest quality and prolonging the shelf life of fresh papaya
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