Eight new Leptographium species associated with tree-infesting bark beetles in China

Leptographium spp. are anamorphs of Grosmannia residing in the order Ophiostomatales. These fungi are typically associated with bark-beetles and are common causal agents of sapstain in lumber and some are important tree pathogens. In this study, Leptographium spp. associated with bark beetles collected during a survey in Jilin and Yunnan provinces of China, were identified. Identifications were achieved using comparisons of morphological characters and DNA sequence data for the ITS2-partial LSU rDNA region, as well as the β-tubulin and EF-1α gene regions. Eight unknown species of Leptographium are recognised and described from conifer and hardwood hosts, associated with beetles including Ips subelongatus, Tomicus yunnanensis, Hylurgops minor, Polygraphus verrucifrons and a Pissodes sp. Six of the new species are morphologically and phylogenetically related to species known to occur in Asia such as G. yunnanense, L. bhutanense, L. bistatum and L. sinoprocerum. The remaining two taxa are related to those in a group containing G. americana and L. abietinum, found in North America. This study also provides the first report of L. pineti on Pinus kesiya in China

Electrical performance and reliability characterization of a SiC MOSFET power module with embedded decoupling capacitors

Integration of decoupling capacitors in SiC MOSFET modules is an advanced solution to mitigate the effect of parasitic inductance induced by module assembly interconnects. In this paper, the switching transient behavior is reported for a 1.2kV SiC MOSFET module with embedded DC-link capacitors. It shows faster switching transition and less overshoot voltage compared to a module using an identical package but without capacitors. Active power cycling and passive temperature cycling are carried out for package reliability characterization and comparisons are made with commercial Si and SiC power modules. Scanning acoustic microscopy images and thermal structure functions are presented to quantify the effects of package degradation. The results demonstrate that the SiC modules with embedded capacitors have similar reliability performance to commercial modules and that the reliability is not adversely affected by the presence of the decoupling capacitors

Modifications to PM-assisted Synchronous Reluctance Machine to Achieve Rare-Earth Free Heavy-duty Traction

Automotive applications require electrical machines designed for high torque density, wide speed range, and low cost. NdFeB magnets can achieve a high torque density and wide speed range, and however, they have a high cost. Therefore, this article explores the capability of rare-earth-free (REF) design through a PM-assisted synchronous reluctance (PM-SynRel) motor. A PM-SynRel design with NdFeB has been used in this study where the NdFeB magnets have been replaced with ferrite magnets. Then, several modifications on the rotor have been made to ensure mechanical safety. Thermal analysis has been conducted last to evaluate the temperatures in the different machine parts to avoid exceeding the required limits. Finally, a prototype has been made and tested to validate the simulation results

Comparison of thermal and reliability performance between a SiC MOSFET module with embedded decoupling capacitors and commercial Si IGBT power modules

This paper characterizes thermal and reliability performance of a SiC MOSFET power module with embedded decoupling capacitors and without anti-parallel diodes. Active and passive temperature cycling, supported by transient thermal impedance characterisation and scanning acoustic microscopy, are used to evaluate key degradation mechanisms. The forward voltage drop of the body diode is used as a thermo-sensitive electrical parameter to estimate the junction temperature and the thermal structure function is analysed to elucidate the degradation in the heat flow path inside the module. Comparisons are made with commercial Si IGBT power modules

Parascedosporium and its relatives: phylogeny and ecological trends

The genus Scedosporium and its relatives comprising microascalean anamorphs with slimy conidia were studied. Graphium and Parascedosporium also belong to this complex, while teleomorphs are found in Pseudallescheria, Petriella, Petriellopsis, and Lophotrichus. Species complexes were clearly resolved by rDNA ITS sequencing. Significantly different ecological trends were observed between resolved species aggregates. The Pseudallescheria and Scedosporium prolificans clades were the only lineages with a marked opportunistic potential to mammals, while Petriella species were associated primarily with soil enriched by, e.g. dung. A consistent association with bark beetles was observed in the Graphium clade. The ex-type strain of Rhinocladium lesnei, CBS 108.10 was incorrectly implicated by Vuillemin (1910) in a case of human mycetoma; its sequence was identical to that of the ex-type strain of Parascedosporium tectonae, CBS 127.84

Airgap Length Analysis of a 350kW PM-Assisted Syn-Rel Machine for Heavy Duty EV Traction

Synchronous reluctance (Syn-Rel) machines with embedded permanent magnets (PMs) are research hotspots in variable speed motor drives due to their robust rotor structure and wide constant power speed range (CPSR). In this paper, the potential of PM-assisted Syn-Rel machine to be next generation heavy duty traction motor solution has been investigated, with special attention put on one key geometric parameter, i.e., airgap length. Careful machine design and optimization has been conducted based on geometric parametrization including airgap length variation, for 15000rpm peak speed and 350kW peak power output. In low speed operations, the influence of airgap length on different torque components has been analyzed in detail based on the frozen permeability method. In field weakening region, the variation trend of several key parameters such as output power, torque ripple, and power losses have been investigated along with airgap length. It is found that with high electric and magnetic loading, reducing the electromagnetic airgap length is not always beneficial. There exists a suitable airgap length value to comprehensively balance torque/power density, cooling capability, efficiency and reliability. Numerical FEA and experimental tests of the prototype are combined to verify the conclusions

Strategic Adaptations by Foreign Retailers in Chinese Market: The Case of Walmart China

沃爾瑪前十幾年已經被稱為美國流行文化的主要部份之一。經過五十年的發展，沃爾瑪公司成為全球年度銷售最高的大型零售企業，同時也成為全球最大私人雇主。沃爾瑪公司所進行的供應鏈創新讓他普遍被認為整個零售業的推動引擎之一。沃爾瑪公司的成功歸回到山姆沃爾頓，沃爾瑪公司的創辦人。他不但透過十分努力以及主張不斷的成長的企圖心而且也因為勇敢地應用前所未有的運作創新而創造沃爾瑪的文化以及策略良好基礎。 在美國市場沃爾瑪早就被稱為整個產業的冠軍而且很顯然也得到顧客認同：每週平均有兩一名顧客來沃爾瑪購物。雖然如此，不過沃爾瑪仍希望能夠在美國持續成長他銷售額。它目前規劃兩個發展方向為：第一美國大都市，第二為虛擬商店。 與此同時，沃爾瑪也繼續擴張它海外業務。中國大陸也被指定為沃爾瑪關鍵市場。不過來自美國的沃爾瑪在進入中國大陸市場過程中也遭遇不少牽涉到文化差異或營業環境大不同的成長障礙。本文目的為描述沃爾瑪在中國大陸有進行哪一些策略以及營業模式調整，讓它更恰好滿足中國消費者所產生的需求。The name Walmart has become iconic decades ago in United States. Walmart is world’s biggest retailer and private employer that in the course of its 50 year life has been pushing the pace of innovation in American retail industry. At the base of Walmart’s success there are ideas of restless growth and constant experiments that Sam Walton, company’s founder, has always stood by. In America, Walmart won almost everything that was there to win: the 200 mil-lion customers that visit Walmart each week is a viable proof of that. Still Walmart, always hungry for growth, is now trying to expand to the big American cities and online retail. Simultaneously, Walmart is transferring its values and know-how to foreign markets. One of them is China, the most populous country in the world that due to the ambitious growth over past 35 years allowed its citizens to taste the flavor of con-sumerism for the first time in the modern history. Nevertheless the cultural distance and economic differences between America and China are massive obstacle that for-eign retailers need to overcome to become successful in China. Walmart has been try-ing to find a way to convince Chinese consumers for 17-year now. This thesis attempts to describe the measures Walmart has undertaken in the process of adjusting its strategy and business model in Chinese market

Barcoding and microcoding using "identiprimers" with Leptographium species

Leptographium species provide an ideal model to test the applications of a PCR microcoding system for differentiating species of other genera of ascomycetes. Leptographium species are closely related and share similar gross morphology. Probes designed for a PhyloChip for Leptographium have been transferred and tested as primers for PCR diagnostic against Leptographium species. The primers were combined with complementary universal primers to identify known and suspected undescribed species of Leptographium. The primer set was optimized for 56 species, including the three varieties of L. wageneri, then blind-tested against 10 random DNA samples. The protocols established in this study successfully identified species from the blind test as well as eight previously undescribed isolates of Leptographium. The undescribed isolates were identified as new species of Leptographium with the aid of the microcoding PCR identification system established in this study. The primers that were positive for each undescribed isolate were used to determine close relatives of these species and some of their biological characteristics. The transfer of oligonucleotides from a micro-array platform to a PCR diagnostic was successful, and the identification system is robust for both known and unknown species of Leptographium. © 2010 by The Mycological Society of America.Articl

Comparison of thermal and reliability performance between a SiC MOSFET module with embedded decoupling capacitors and commercial Si IGBT power modules

This paper characterizes thermal and reliability performance of a SiC MOSFET power module with embedded decoupling capacitors and without anti-parallel diodes. Active and passive temperature cycling, supported by transient thermal impedance characterisation and scanning acoustic microscopy, are used to evaluate key degradation mechanisms. The forward voltage drop of the body diode is used as a thermo-sensitive electrical parameter to estimate the junction temperature and the thermal structure function is analysed to elucidate the degradation in the heat flow path inside the module. Comparisons are made with commercial Si IGBT power modules

Characterisation of synnematous bark beetle-associated fungi from China, including Graphium carbonarium sp. nov.

Ophiostomatoid fungi on trees are typically bark beetle associates that cause sapstain in timber and some are pathogens. Very little is known regarding the ophiostomatoid fungi associated with bark beetles in China and the aim of this study was to identify a collection of these fungi with synnematous anamorphs. Micromorphology and DNA sequences of the internal transcribed spacer regions (ITS) of the ribosomal DNA and the partial β-tubulin gene were used for identifications. The isolates could be divided in six morphological groups. DNA sequence comparisons with published data confirmed that these groups represented six species, four in the Ophiostomatales (Sordariomycetidae) and two in the Microascales (Hypocreomycetidae). The majority of these were isolated from conifer hosts. Ophiostoma quercus, O. setosum, Pesotum fragrans (Ophiostomatales) and Graphium pseudormiticum (Microascales) were found on Tsuga dumosa infested by a Pissodes sp. In addition, O. quercus and P. fragrans were found associated with Tomicus yunnanensis on Pinus yunnanensis, P. fragrans with a Pissodes sp. on P. armandi, and O. piceae with Ips subelongatus on Larix olgensis. Only two species, O. quercus and a new species in the Graphium penicilliodes complex, described here as Graphium carbonarium sp. nov., were isolated from Pissodes galleries on Salix babylonica. These results include several new fungus-host and fungus-insect associations, and G. pseudormiticum is reported here for the first time from China.National Research Foundation (NRF), Department of Science and Technology (DST), members of the Tree Protection Co-operative program (TPCP), Ministry of Science and Technology (MOST) of China for financial support (2007DFA31190