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Fabrication of ultrafine Nd-Fe-B powder by a modified reduction-diffusion process

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Rare Metals 2006年第Z2期25卷 223-226页

作者： jang T.S. LEE D.H. CHOI C.j. SEO w.S. LEE Y.H. Department of Electronic Materials Engineering Sunmoon University Korea Powder Materials Research Center Korea Institute of Machinery and Materials Korea Advanced Materials Analysis & Evaluation Center Korea Institute of Ceramic Engineering and Technology Korea

In order to obtain ultrafine Nd-Fe-B powder, a spray-dried precursor was treated by reduction-diffusion (R/D) process. And, unlike the conventional R/D process, calcium reduction that is a crucial step for the formation of Nd2Fe14B was performed without conglomerating the precursor with Ca powder. By adopting this modified process, it is possible to synthesize the hard magnetic Nd2Fe14B at the reaction temperature as low as 850 ℃. The average size of Nd2Fe14B particles that are uniformly distributed in the optimally treated powder was were enclosed with thin layers of Nd-rich phase. Typical magnetic properties of such powder without eliminating impurity CaO were iHc=～5.9 kOe, Br=～5.5 kG, and (BH)max=～6 MGOe.

关键词： NdFeB powder spray drying reduction-diffusion process Nd2Fe14B magnetic powder

Iridium oxide fabrication and application: A review

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journal of Energy Chemistry 2020年第7期29卷 152-172,I0005页

作者： Hansaem jang jaeyoung Lee Electrochemical Reaction&Technology Laboratory(ERTL) School of Earth Sciences and Environmental EngineeringGwangju Institute of Science and Technology(GIST)Gwangju 61005Republic of Korea Ertl Center for Electrochemistry and Catalysis GRIGISTGwangju 61005Republic of Korea

Despite the scarcity and cost of iridium oxide,it is still the material of choice in numerous fields of science and applications,including capacitors,electrochromism,sensors,and various oxidation electrocatalysis(e.g.,chlorine evolution reaction,detoxification,and oxygen evolution reaction).Such versatility is attributed to the distinct features of iridium oxides,such as their activity,biocompatibility,conductivity,and *** features and properties of iridium oxides are strongly dependent on the fabrication *** this review,methodologies relating to the synthesis and fabrication of solid-state iridium oxides have been thoroughly collected and *** and crystallization techniques for iridium oxides are also *** the end of the review,the effects of utilizing a certain fabrication method on the characteristics of the iridium oxide product are recapitulated,together with the recommended application of the product in various fields.

关键词： Iridium oxide Iridium dioxide Electrode Electrocatalyst Electrochromism pH sensor Oxygen evolution reaction

The role of host refuge and strong Allee effects in a host-parasitoid system

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International journal of Biomathematics 2023年第5期16卷 111-135页

作者： Xiaochuan Hu Sophia R.-j.jang Vinli Inc. DallasTX75206USA Department of Mathematics and Statistics Teras Tech University LubbockTX 79409USA

we propose and study a discrete host-parasitoid model of difference equations with a spatial host refuge where hosts in the refuge patch are free from parasitism but undergo a demographic strong Allee *** the growth rate of hosts in the non-refuge patch is less than one,a host Allee threshold is derived below which both populations become *** is proven that both populations can persist indefinitely if the host growth rate in the non-refuge patch exceeds one and the maximum reproductive number of parasitoids is greater than *** simulations reveal that the host refuge can either stabilize or destabilize the host-parasitoid interactions,depending on other model parameters.A large number of parasitoid turnover from a parasitized host may be detrimental to the parasitoids due to Allee effects in the hosts within the refuge ***,it is demonstrated numerically that if the host growth rate is not small,the population level of parasitoids may suddenly drop to a small value as some parameters are varied.

关键词： Host refuge strong Allee effect stabilizing and destabilizing Beverton-Holt growth rate Allee threshold maximum reproductive number

Asymptotic dynamics of a modified discrete Leslie-Gower competition system

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International journal of Biomathematics 2017年第6期10卷 1-23页

作者： Yunshyong Chow Sophia R.-j. jang Institute of Mathematics Academia Sinica Taipei 10617 Taiwan Department of Mathematics and StatisticsTexas Tech University Lubbock TX 79409-1042 USA

we propose a modified discrete-time Leslie-Gower competition system of two popula- tions to study competition outcomes. Depending on the magnitude of a particular model parameter that measures intraspecific competition between individuals within the same population, either one or both populations may be subject to Allee effects. The resulting system can have up to four coexisting steady states. Using the theory of planar compet- itive maps, it is shown that the model has only equilibrium dynamics. The competition outcomes then depend not only on the parameter regimes but may also depend on the initial population distributions.

关键词： Competition saddle points Allee effects.

Schottky barrier modulation of bottom contact SnO_(2) thin-film transistors via chloride-based combustion synthesis

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journal of Materials Science & Technology 2023年第17期148卷 199-208页

作者： Bongho jang junhee Lee Hongki Kang jaewon jang Hyuk-jun Kwon Department of Electrical Engineering and Computer Science DGISTDaegu 42988South Korea School of Electronic and Electrical Engineering Kyungpook National UniversityDaegu 41566South Korea School of Electronics Engineering Kyungpook National UniversityDaegu 41566South Korea Convergence Research Advanced Centre for Olfaction DGISTDaegu 42988South Korea

The enhanced carrier flow at the interface between Au and SnO_(2)semiconductors,which initially form Schottky contacts,is realized using chloride-based combustion ***-based combustion sys-tems can achieve chlorine(Cl)doping effects as well as conversion to crystalline SnO_(2)films at clearly lower temperatures(∼250℃)than conventional *** to the Cl doping effect,the high carrier concentration can induce thin potential barriers at the metal/semiconductor(MS)junctions,resulting in carrier injection by *** a result,compared to conventional SnO_(2)thin-film transistors,the de-vices fabricated by combustion synthesis exhibit significantly improved electrical performance with field-effect mobility of 6.52 cm 2/Vs(∼13 times),subthreshold swing of 0.74 V/dec,and on/offratio of∼10^(7)below 300℃.Furthermore,because of the enhanced tunneling carriers induced by the narrowed barrier width,the Schottky barriers are significantly reduced from 0.83 to 0.29 eV(65%decrease)at 250℃and from 0.42 to 0.17 eV(60%decrease)at 400℃.Therefore,chloride-based combustion synthesis can con-tribute to developing SnO_(2)-based electronics and flexible devices by achieving both high-quality oxide films and improved current flow at the MS interface with low-temperature annealing.

关键词： SnO_(2) Combustion Sol-gel Schottky contact Thin-film transistors

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陶瓷部件的浆料打印快速成型(英文)

硅酸盐学报 2001年第4期29卷 344-349页

作者：王树海 jang j H Schulze w A Pilgrim S M 山东工业陶瓷研究设计院山东淄博255031 NYS College of Ceramics

采用Sanders公司的四打印头快速成型机进行了陶瓷部件的浆料打印成型实验 ,实际测试了所用四打印头快速成型机的打印工作条件 ,考察了石蜡和挥发性介质两种浆料技术路线 ,并采用石蜡为介质制备了钛酸钡陶瓷浆料 ,研究了其流变性能 .实... 详细信息

采用Sanders公司的四打印头快速成型机进行了陶瓷部件的浆料打印成型实验 ,实际测试了所用四打印头快速成型机的打印工作条件 ,考察了石蜡和挥发性介质两种浆料技术路线 ,并采用石蜡为介质制备了钛酸钡陶瓷浆料 ,研究了其流变性能 .实验表明 ,虽然偶联剂的加入可以降低石蜡介质浆料的粘度 ,但是粘度足够低的可打印浆料的固相含量太低 [约 3 % (involume)以下 ] ,打印成型后不能完全烧结 ,因此 ,要通过打印成型出可完全烧结的陶瓷部件便只能采用挥发性液体作为浆料介质。

关键词：陶瓷部件浆料打印成型烧结四打印头快速成型机

Cooperative hunting in a discrete predator-prey system

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International journal of Biomathematics 2020年第7期13卷 133-158页

作者： Yunshyong Chow Sophia R-j.jang Hua-Ming wang Institute of Mathematics Academia Sinica Taipei 10617Taiwan Department of Mathematics and Statistics Texas Tech University LubbockTX 79409USA Department of Statistics Anhui Normal University Wuhu 241003AnhuiP.R.China

we propose and investigate a discrete-time predator-prey system with cooperative hunting in the predator *** model is constructed from the classical Nicholson-Bailey host-parasitoid system with density dependent growth rate.A sufficient condition based on the model parameters for which both populations can coexist is derived,namely that the predator’s maximal reproductive number exceeds *** study existence of interior steady states and their stability in certain parameter *** is shown that the system behaves asymptotically similar to the model with no cooperative hunting if the degree of cooperation is *** cooperative hunting,however,may promote persistence of the predator for which the predator would otherwise go extinct if there were no cooperation.

关键词： Cooperative hunting discrete predator-prey system predator persistence Neimark-Sacker bifurcation

Perilesional reorganization of motor function in stroke patients

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Neural Regeneration Research 2010年第21期5卷 1668-1672页

作者： Sung Ho jang Department of Physical Medicine and Rehabilitation College of Medicine Yeungnam University

Perilesional reorganization is an important recovery mechanism for stroke patients because it yields good motor outcomes. However, perilesional reorganization remains poorly understood. The scientific basis for stroke rehabilitation can be established when detailed mechanisms of recovery are clarified. In addition, studies at the subcortical level remain in the early stages. Therefore, the present study suggested that additional investigations should focus on perilesional reorganization at the subcortical level, identifying the critical period for this mechanism and determining treatment strategies and modalities to facilitate development. The present study reviews literature focused on perilesional reorganization in stroke patients with regard to demonstration, clinical characteristics, and rehabilitative aspects, as well as previous studies of perilesional reorganization at cortical and subcortical levels.

关键词： stroke motor recovery functional MRI diffusion tensor imaging brain plasticity reorganization

Unusual long-term motor recovery in a patient with corona radiata infarct

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Neural Regeneration Research 2010年第17期5卷 1353-1356页

作者： Sung Ho jang Department of Physical Medicine and Rehabilitation College of MedicineYeungnam UniversityDaegu 705-717Republic of Korea

The majority of motor recovery following stroke occurs within 6 months after *** present study examined a patient with a corona radiata infarct,who exhibited an unusual long-term recovery（24 months after onset）.The patient was a 64-year-old female,who presented with severe paralysis of the left extremities resulting from a corona radiate *** recovery from the weakness progressed slowly over a 24-month period following onset,even at 6-12 months after *** tensor tractography at 2 weeks from onset showed disruption of the corticospinal tract of the affected hemisphere resulting from the ***,at 12 and 24 months after onset,the corticospinal tract was elongated to the cortex level,as shown by diffusion tensor tractography.A 2-week transcranial magnetic stimulation showed no motor-evoked potential for the affected hemisphere,but a motor-evoked potential of the corticospinal tract was observed at12 and 24 *** results suggest that motor function recovery in cerebral infarct patients can occur at least up to 24 months after stroke onset.

关键词： stroke motor recovery cerebral infarct diffusion tensor tractography transcranial magnetic stimulation diffusion tensor imaging