Optimization model of a structural simulation design for a CICC

The engineering design of a Cable-In-Conduit Conductor (CICC) is complicated. A model for the optimal design of a CICC based on conductor stability, AC loss and strain is proposed. The model considers the critical current density as a function of applied strain. A mathematical programming method that minimizes the AC loss of the CICC is established to yield an optimal design for the CICC structure. The optimized structure and related performance agree well with the engineering design values used for the KSTAR project.     

Magnetic properties of surface soils across the southern Tarim Basin and their relationship with climate and source materials

The magnetic susceptibility (χ) of surface soils on the Chinese Loess Plateau (CLP) has strong positive correlation with mean annual precipitation.It is widely accepted that ultrafine magnetite/maghemite grains produced during pedogenesis are responsible for the enhancement of χ,and loess χ on the CLP has been widely used as a proxy for the intensity of the East Asian summer monsoon.However,few works have investigated mechanisms for the enhancement of χ in the case of surface aeolian sediments in westerly-dominated inland China,north of the Tibetan Plateau.Here detailed rock magnetism and grain size studies of 49 surface samples taken across the southern Tarim Basin for different rainfall/temperature/altitude conditions are presented.The results show that samples taken from desert have the lowest χ values and that χ of loessic sand and loess samples decreases with increasing altitude.In addition,the rock magnetism studies suggest that the magnetic properties of surface soils across the southern Tarim Basin are mainly controlled by the concentration of coarse aeolian ferrimagnetic minerals.The contribution of ultrafine pedogenically produced magnetic grains to χ is very limited.     

Study on temperature characteristics of organic light-emitting diodes based on tris-（8-hydroxylquinoline）-aluminum

Both single-layer and double-layer organic light-emitting devices based on tris-（8-hydroxylquino- line）-aluminum （AIq3） as emitter are fabricated by thermal vacuum deposition. The electroluminescent characteristica of these devices at various temperatures are measured, and the temperature characteristics of device performance are studied. The effect of temperature on device current conduction regime is analyzed in detail. The results show that the current-voltage （I-V） characteristics of devices are in good agreement with the theoretical prediction of trapped charge limited current （TCLC）. In addition, both the charge carrier mobility and charge carrier concentration in the organic layer increase with the rise of temperature, which results in the monotonous increase of AIq3 device current. The current conduction mechanisms of two devices at different temperatures are identical, but the exponent m in current-voltage equation changes randomly with temperature. The device luminance increases slightly and the efficiency decreases monotonously due to the aging of AIq3 luminescent properties caused by high temperature. A tiny blue shift can be observed in the electroluminescent （EL） spectra as the temperature increases, and the reduction of device monochromaticity is caused by the intrinsic characteristics of organic semiconductor energy levels.     

农业中壳聚糖的功能与应用研究

简述了壳聚糖在农业上的功能和作为种子处理剂、饲料添加剂、植物病害诱抗剂、降解性地膜、肥料和土壤改良剂、农药、食物保鲜剂等在农业方面的应用情况及发展前景.     

Improved and excellent CO sensing properties of Cu-doped TiO<Subscript>2</Subscript> nanofibers

Cu-doped TiO2 nanofibers with an average diameter of about 80 nm are synthesized through an electrospinning method. Both anatase and rutile crystallographic structures are found in the fibers based on XRD results. Compared with pure TiO2 nanofibers, the Cu-doped TiO2 nanofibers exhibit improved CO sensing properties at 300°C. The sensitivity of Cu-doped TiO2 nanofibers is up to 3 when the sensor is exposed to 5 ppm CO, and the response and recovery times are about 4 and 8 s, respectively. Good selectivity i...     

Red organic light emitting device with improved performance using a novel fluorescent dye codoped with phosphor-sensitizer

Efficient red organic light-emitting device consisted of a compound fluorescent-phosphor-sensitized emission layer was fabricated. A novel red fluorescent dye, 3-(dicyanomethylene)-5,5-dimethyl-1-(4-dimethylamino-styryl) cyclohexene (DCDDC), and a green phosphorescent dye, fac tris(2-phenylpyridine) iridium [Ir(ppy)3] were codoped into a host material 4,4’-N,N’-dicarbazolebiphenyl (CBP). By adjusting the component ratio of doping system, a series of devices with different concentration proportion of Ir(ppy)3:DCDDC were constructed. The results demonstrated that the device with 0.2 wt% DCDDC had a maximum power efficiency (η_p) of 2.12 lm/W at a current density of 0.1 mA/cm², which was about 38% higher than that of conventional fluorescent device. When at a current density of 4 mA/cm2 (100 cd/m²) and 52 mA/cm² (1000 cd/m²), the η_p percentage was about 160% and 143% higher than that of conventional device, respectively. A stable red light emission at a peak of 615 nm with Commissions Internationale de l’Eclairage coordinates near the region of (0.56, 0.42) in a wide bias range was also obtained. The improved performances were attributed to the efficient multiple-stage energy transfer from the host to the guest and the suppression of loss mechanism.     

Methoxy n-fatty acids in surface soils from the Gongga and Kunlun Mountains: Ecological implications

GC-MS characteristics of surface soil samples from the eastern and northern Tibetan Plateau provide tentative identification of 8(–14)-Methoxy hexadecanoic acid (iME-16:0) and 9(–17)-methoxy octadecanoic acid (iME-18:0). Sixty surface soil samples were collected from the eastern slope of Gongga Mountain, at elevations ranging from ~1230 to 4500 m (eastern Tibetan Plateau), and from the northern slope of West Kunlun Mountains, ranging from ~1300 to 5500 m (northern Tibetan Plateau). This study also analyzed the methoxy n-fatty acids (MFAs) of Gongga Mountain tree leaves from six common living species, at the elevation of 2900–4200 m. MFAs dominate these samples, with more centrally located methoxy groups eluting earlier than those with methoxy groups located closer to the end of the main carbon chain. MFAs occur prominently in most of the Gongga Mountain soil samples (and from six tree samples) from dominantly coniferous and deciduous broadleaved forests. Other than in two narrow vegetation zones between 4000–4350 m and 2900–3300 m, no MFAs were found in 19 Kunlun Mountains soil samples from areas covered mainly with montane desert and alpine desert steppe vegetation. Based on the inventory of plants and soils from which MFAs have been isolated, we conclude that the MFAs most probably originate from specific woody plants. If we can exclude some particular grasses as sources, MFAs may be specific woody plants-derived biomarkers; thus they would serve as an important additional proxy for comprehensive and precise ecological reconstructions.     

Polaron-pair-dependent equivalent circuit parameters of organic solar cells based on CuPc and C<Subscript>60</Subscript>

We present the current-voltage characteristics of organic solar cells based on single and double heterojunction of copper phthalocyanine (CuPc) and C60 by introducing a constant JP instead of photo-current density Jph to represent the density of polaron-pairs generated from excitons at D/A interface. A diode Dext models polaron-pair dissociation, and a diode Drec stands for loss due to polaron-pair recombination. The photovoltaic response under AM 1.5 solar illumination at an intensity of 100 mW/cm2 is para...     

Influences of fluorine auxochrome in fluorene molecular electroluminescent material on optoelectronic property

The UV-Vis absorption and photoluminescence （PL） spectra of 2,3-bis（9,9-dihexyl-9H-fluoren-2-yl） quinoxaline （Py）, 2,3-bis（9,9-dihexyl-9H-fluoren-2-yl）-6,7-difluoroquinoxaline （F2Py） and 2,3-bis（9,9- dihexyl-9H-fluoren-2-yl）-5,6,7,8-tetrafluoroquinoxaline （F4Py）, which are fluorene molecular derivatives with conjugated structure, were investigated. For further investigation of the influences of fluorine suxochrome in fluorene molecular electroluminescent material on optoelectronic property, the electroluminescence （EL） characteristics of materials were studied by double-layer organic light-emitting diodes （OLEDs） using N,N＇-Di-[（1-naphthalenyl）-N,N＇-diphenyl]-（1,1＇-biphenyl）-4,4＇-diamine （NPB） as a hole transporting layer （HTL） with the conventional vacuum deposition method. The results showed that the absorption and PL spectra of materials in film state red shifted with fluorine substituenta increased in molecule configuration. The performance of OLEDs is as follows： at a bias voltage of 5 V, Py emitted a blue-green light at 508 nm with the Commission Internationale d＇Eclairage （ClE） coordinates of （0.23, 0.43） and full width at half maximum （FWHM） of 100 nm. The device had a turn-on voltage （defined as the drive voltage at the luminance of 1 cd/m^2） of 4.8 V, a luminance of 129 cd/m^2 with a current density of 59 mA/cm^2 at 10 V, and a maximum luminous efficiency of 0.18 lm/W at 5.4 V. F2Py and F4Py emitted a green light peaking at 544 nm and a yellow light at 570 nm at 5 V, with the CIE coordinates of （0.38, 0.56） and （0.44, 0.49）, and FWHM of 103 and 117 nm, respectively. The F2Py and F4Py devices had a turn-on voltage of 4 and 2 V, a luminance of 557 and 3300 cd/m^2 with a current density of 100 and 880 mA/cm^2 at 10 V, and a maximum luminous efficiency of 0.22 lm/W at 7.6 V and 0.53 lm/W at 2 V, respectively.