In this work, ZnO nanorod arrays grown by an electrochemical deposition method are investigated. The crucial parameters of length, diameter, and density of the nanorods are optimized over the synthesize process and na...In this work, ZnO nanorod arrays grown by an electrochemical deposition method are investigated. The crucial parameters of length, diameter, and density of the nanorods are optimized over the synthesize process and nanorods growth time. Crystalline structure, morphologies, and optical properties of ZnO nanorod arrays are studied by different techniques such as x-ray diffraction, scanning electron microscope, atomic force microscope, and UV-visible transmission spectra. The ZnO nanorod arrays are employed in an inverted bulk heterojunction organic solar cell of Poly （3-hexylthiophene）：[6- 6] Phenyl-（6） butyric acid methyl ester to introduce more surface contact between the electron transporter layer and the active layer. Our results show that the deposition time is a very important factor to achieve the aligned and uniform ZnO nanorods with suitable surface density which is required for effective infiltration of active area into the ZnO nanorod spacing and make a maximum interfacial surface contact for electron collection, as overgrowing causes nanorods to be too dense and thick and results in high resistance and lower visible light transmittance. By optimizing the thickness of the active layer on top of ZnO nanorods, an improved efficiency of 3.17% with a high FF beyond 60% was achieved.展开更多
A novel distribute feedback (DFB) laser which gave two different wavelengths under two distinct work conditions was fabricated. The laser consists of two Bragg gratings with different periods corresponding to waveleng...A novel distribute feedback (DFB) laser which gave two different wavelengths under two distinct work conditions was fabricated. The laser consists of two Bragg gratings with different periods corresponding to wavelength spacing of 20 nm in an identical active area. When driving current was injected into one of the different sections separately, two different wavelengths at 1542.4 and 1562.5 nm were realized. The side mode suppression ratio (SMSR) of 45 dB or more both for the two Bragg wavelengths were achieved. The fabricating process of the laser was just the samp as that of traditional DFB laser diode. This device can be potentially used in coarse wavelength division multiplexer (CWDM) as a promising light source and the technology idea can be used to enlarge the transmission capacity in metro area network (MAN).展开更多
Changes in activated areas of the brain during ankle active dorsiflexion and ankle active plantar flexion were observed in six healthy subjects using functional magnetic resonance imaging. Excited areas of ankle activ...Changes in activated areas of the brain during ankle active dorsiflexion and ankle active plantar flexion were observed in six healthy subjects using functional magnetic resonance imaging. Excited areas of ankle active dorsiflexion involved the bilateral primary motor area and the primary somatosensory area, as well as the bilateral supplementary sensory area, the primary visual area, the right second visual area, and the vermis of cerebellum. Excited areas of ankle active plantar flexion included the ipsilateral supplementary motor area, the limbic system, and the contralateral corpus striatum. Fine movements of the cerebral cortex control the function of the ankle dorsiflexion to a larger extent than ankle plate flexion, and the function of ankle plate flexion is more controlled by the subcortical area.展开更多
In order to clear the activated area in electrostatic accelerator facilities,four accelerator facilities were selected and typical neutron emission experiments were performed.Neutron flux during operation and induced ...In order to clear the activated area in electrostatic accelerator facilities,four accelerator facilities were selected and typical neutron emission experiments were performed.Neutron flux during operation and induced activity caused by charged particles on the accelerator and its surrounding area after irradiation were measured.Also the monitored neutron flux and calculated value by Monte Carlo calculation using PHITS code were compared.It was confirmed that the results between calculated data and measured data showed the good agreement with each other.Finally,it was concluded that we have to take care the activation of beam line and target.But,it is not necessary to treat accelerator tank,surrounding materials,and building concrete as radioactive materials in case of decommissioning.展开更多
OBJECTIVES： An animal experiment clarified that insertion of an orthodontic apparatus activated the trigeminal neurons of the medulla oblongata. Orthodontic tooth movement is known to be associated with the sympathet...OBJECTIVES： An animal experiment clarified that insertion of an orthodontic apparatus activated the trigeminal neurons of the medulla oblongata. Orthodontic tooth movement is known to be associated with the sympathetic nervous system and controlled by the nucleus of the hypothalamus. However, the transmission of both has not been demonstrated in humans. The purpose of this study were to examine the activated cerebral areas using brain functional magnetic resonance imaging（MRI）, when orthodontic tooth separators were inserted, and to confirm the possibility of the transmission route from the medulla oblongata to the hypothalamus.METHODS： Two types of alternative orthodontic tooth separators（brass contact gauge and floss） were inserted into the right upper premolars of 10 healthy volunteers. Brain functional T2＊-weighted images and anatomical T1-weighted images were taken.RESULTS： The blood oxygenation level dependent（BOLD） signals following insertion of a brass contact gauge and floss significantly increased in the somatosensory association cortex and hypothalamic area.CONCLUSION： Our findings suggest the possibility of a transmission route from the medulla oblongata to the hypothalamus.展开更多
BACKGROUND ： Functional magnetic resonance imaging （fMRI） studies have disclosed the changes of the motor function in the motor cortex of ipsilateral and contralateral hemispheres of tumor, which have special signi...BACKGROUND ： Functional magnetic resonance imaging （fMRI） studies have disclosed the changes of the motor function in the motor cortex of ipsilateral and contralateral hemispheres of tumor, which have special significance for making the surgical planning and most greatly minimizing the postoperative functional damages. OBJECTIVE： To analyze the association between the manifestation characteristics of hand functional area and motor dysfunction using fMRI in patients with space-occupying lesions of tumor in motor cortex. DESIGN ： A case-controlled observation SETTING： Department of Radiology, Second Affiliated Hospital, Shantou University Medical College .PARTICIPANTS： Twenty-three patients （13 males and 10 females） with space-occupying lesions of central sulcus area, aged 21-53 years with a mean age of （47±1） years were selected from the Second Affiliated Hospital of Shantou University Medical College. All the patients were diagnosed by MR scanning as space-occupying lesions of motor area, and pathologically confirmed that the lesions involved central sulcus and central Iobule; Lesions occurred in left and right hemispheres in 13 and 10 cases respectively. The tumor types were astrocytoma （n =8）, metastatic tumours （n =7）, meningiomas （n =5） and oligodendroglioma （n =3）. The muscle strength was normal in 11 cases （grade 5） and obviously decreased in 12 cases （grade 2-3 in 3 cases and grade 4 in 9 cases）; muscle strengths of both upper and lower limbs were decreased in 7 cases, and only that of upper limbs was decreased in 5 cases. Informed consents were obtained from all the subjects. Meanwhile, 9 healthy physical examinees （5 males and 4 females） of 20-56 years old with an average of （34±1） years were taken as controls. All the patients and healthy subjects were right-handed. METHODS： All the enrolled subjects were examined with MR scanning and functional imaging. Twenty cases whose clinical symptoms were mild in the patient group and 9 healthy volunteers adopted simple active finger-tapping movements, and for the 3 cases whose clinical symptoms were severe in the patient group, the simple passive finger-tapping movements were used. The manifestations in the activated brain areas were analyzed in the patients with brain tumor of different muscle strength and the controls. The motor deficit and activation of contralateral primary motor cortex （M1） in simple finger-tapping movements were observed in the patient group. MAIN OUTCOME MEASURES： （1） Brain areas activated by finger-tapping movements in each group： （2） Activated volumes in hemisphere by finger-tapping movements between groups. RESULTS： The contralateral M1 area could not be activated in 1 case in the patient group,, all the other 22 patients and 9 healthy subjects were involved in the analysis of results. （1） In the control group, unilateral finger tapping movement activated the contralateral primary motor cortex （M1）, bilateral SMA and bilateral PMC. The activation volume was the largest in contralateral primary motor cortex （M1）, smaller in the SMA, and the smallest in PMC. The finger tapping movement in healthy subjects could activate contralateral primary motor cortex （M1）, bilateral SMA and bilateral PMC, which had no obvious differences from the manifestations of brain functional area activated by active finger tapping. There was no significant difference in the volume of activated functional areas between right and left hands. In the patient group, the central sulcos around the tumor in the activated M1 area displaced towards dorsal or ventral side, also extended. The distance of displacement in the functional area was determined as compared with the contralateral central sulcus, and the results suggested the M1 displacement, including that there were 10 cases with the M1 displacement larger than 10 mm in the patients with motor deficit, which were obviously more than in those without motor deficit （n =1, P 〈 0.01）, and the activated volume in contralateral M1 area was obvious smaller in the patients with motor deficit than in those without motor deficit （P 〈 0.01）. （2） The M1 activation and changes were observed in contralateral hemisphere in the patient group, and the activated volume was obviously larger than that in the control group （P 〈 0.01）. The activated volumes of M1 and PMC in ipsilateral hemisphere were obviously larger than those in the control group （P 〈 0.05）, but that of SMA had no obvious difference between the two groups （P 〉 0.05）. CONCLUSION： fMRI can be used to observe the activation of the brain motor functional areas of patient with space-occupying lesions in motor area, and evaluate the state of their motor function. The larger the distance of displacement of M1 compressed by tumor, the more obviously the muscle strength decreases in the patients.展开更多
Totally three articles focusing on functional magnetic resonance imaging features of brain function in the activated brain regions of stroke patients undergoing acupuncture on the healthy limbs and healthy controls un...Totally three articles focusing on functional magnetic resonance imaging features of brain function in the activated brain regions of stroke patients undergoing acupuncture on the healthy limbs and healthy controls undergoing acupuncture on the lower extremities are published in three issues. We hope that our readers find these papers useful to their research.展开更多
In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction（ASR）, and to identify the mechanism of suppressing ASR by this powders, ...In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction（ASR）, and to identify the mechanism of suppressing ASR by this powders, mortar and paste containing reactive sandstone powders of four replacement levels ranging from 10wt% to 40wt% and four specific surfaces areas ranging from 210 m^2/kg to 860 m^2/kg were studied. The experimental results showed that incorporation of 40wt% reactive sandstone powders could suppress ASR effectively except for mortar containing reactive sandstone powders with specific surface area of 610 m^2/kg, which disagreed with the most results reported that the higher reactive powder specific surface area, the smaller ASR expansion. By means of fl ame photometry, Fourier transform infrared spectroscopy（FT-IR） and thermo gravimetric analysis（TG）, the mechanism of reactive sandstone powders on reducing or suppressing ASR was soluble alkalis type of reactive sandstone powders and the competition of liberating and bonding alkali of cement paste containing reactive sandstone powders,when the ability of alkali bonding was greater than the ability of alkali liberation, ASR caused by reactive sandstone was supressed effectively.展开更多
Nickel-rich LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(NCM,1-x-y≥0.6)is known as a promising cathode material for lithium-ion batteries since its superiority of high voltage and large capacity.However,polycrystalline Ni-rich NCMs...Nickel-rich LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(NCM,1-x-y≥0.6)is known as a promising cathode material for lithium-ion batteries since its superiority of high voltage and large capacity.However,polycrystalline Ni-rich NCMs suffer from poor cycle stability,limiting its further application.Herein,single crystal and polycrystalline LiNi_(0.84)Co_(0.07)Mn_(0.09)O_(2)cathode materials are compared to figure out the relation of the morphology and the electrochemical storage performance.According to the Li^(+)diffusion coefficient,the lower capacity of single crystal samples is mainly ascribed to the limited Li+diffusion in the large bulk.In situ XRD illustrates that the polycrystalline and single crystal NCMs show a virtually identical manner and magnitude in lattice contraction and expansion during cycling.Also,the electrochemically active surface area(ECSA)measurement is employed in lithium-ion battery study for the first time,and these two cathodes show huge discrepancy in the ECSA after the initial cycle.These results suggest that the single crystal sample exhibits reduced cracking,surface side reaction,and Ni/Li mixing but suffers the lower Li^(+)diffusion kinetics.This work offers a view of how the morphology of Ni-rich NCM effects the electrochemical performance,which is instructive for developing a promising strategy to achieve good rate performance and excellent cycling stability.展开更多
Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,t...Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.展开更多
[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water res...[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows： conventional ridge tillage, loosening the cm in spring （deep loosening in spring）, and depth of 30 cm in autumn （deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn）. Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure.展开更多
A novel C/Pb composite has been successfully prepared by electmless plating to reduce the hydrogenevolution and achieve the high reversibility of the anode of lead-carbon battery （LCB）. The depositedlead on the surf...A novel C/Pb composite has been successfully prepared by electmless plating to reduce the hydrogenevolution and achieve the high reversibility of the anode of lead-carbon battery （LCB）. The depositedlead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Becauselead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogenevolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead.Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge-discharge reversibility, which is attributed to the good connection between carbon additives and leadthat has been stuck on the surface of C/Pb composite during the preparation process. The addition of CIPb composite maintains a solid anode structure with high specific surface area and power volume, andthereby, it plays a significant role in the highly reversible lead-carbon anode.展开更多
A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon （HSAAC） under certain conditions. The physical and chemical per- formances of the novel...A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon （HSAAC） under certain conditions. The physical and chemical per- formances of the novel carbon-sulfur nano-composite were characterized by scanning electron microscopy （SEM）, Brunauer-Emmett-Teller （BET） and X-ray diffraction （XRD）. The electrochemical performances of nano-composite were characterized by charge-discharge characteristic, cyclic voltammetry and electrochemical impendence spectroscopy （EIS）. The experimental results indicate that the electrochemical capability of nano- composite material was superior to that of traditional S-containing composite material. The cathode made by carbon-sulfur nano-composite material shows a good cycle ability and a high specific charge-discharge capacity. The HSAAC shows a vital role in adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for a sulfur cathode and prevents the shuttle behavior of the lithium-sulfur battery.展开更多
A systematic study on ″ring phenomena″ frequently occurring before great earthquakes has made in this paper, which has analyzed the features of ring distributions before 16 great earthquakes and part of large ear...A systematic study on ″ring phenomena″ frequently occurring before great earthquakes has made in this paper, which has analyzed the features of ring distributions before 16 great earthquakes and part of large earthquakes in China and its boundary areas, and discussed their features of generality, regularity and predictive meaning. The results have showed that moderate earthquakes or larger earthquakes distribute around the epicenter like a ring from decades to hundred years before the great earthquakes of magnitude more than 7, which is a general phenomenon of great earthquakes without an exception. The active ring generally occurs in the areas from hundreds to thousands of kilometers from the epicenter(according to the magnitude). The seismicity in the ring has three basic stages with different features. in the first stage, seismicity remains at low level and the earthquakes distribute scatteredly, while the source area of the future great earthquake remains quiet; in the second stage, the seismicity strengthens, whose frequency, intensity, concentrated degree, released rate of strain and ratio of distributed area etc. increase, while the quiet area decreases or disappears; in the third stage, the seismicity is weaker than in the former stage, and the quiet area appears again. The source area surrounded by the active ring might have three periods of activity(called as early term, medium term and late term foreshocks activity). The length of the quiet area undergoes the process from large to small, then to large. Therefore, we can estimate the occurring place, magnitude and seismogenic stage of great earthquake according to the area,length and the seismicity in the active ring, which is valuable to make a long term prediction of great earthquakes. At last, we had a preliminary discussion on the mechanism of active ring formation.展开更多
Carbon-sulfur nano-composite cathodes for lithium rechargeable batteries were investigated by electrochemical impedance spectroscopy (EIS). The novel carbon-sulfur nano-composite material was synthesized by heating su...Carbon-sulfur nano-composite cathodes for lithium rechargeable batteries were investigated by electrochemical impedance spectroscopy (EIS). The novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon (HSAAC) in certain conditions. Equivalent circuits were used to fit the spectra at different discharge states. The variations of impedance spectra, charge-transfer resistance and double layer capacitance were discussed. The changes of EIS with potential were analyzed based on a plausible electrical equivalent circuit model, and some parameters were measured and analyzed about electrochemical performance and state of charge and discharge of the electrode. The good accuracy in fitting values of the model to the experimental data indicates that the mathematical model gives out a satisfying description upon the mechanism of high rate of capacity fade in lithium-sulfur battery.展开更多
The chemical compositions of the sludge after treatment are tested by fully chemical analysis techniques. Its crystalline phase structure changes of the sludge calcined at different temperature are characterized by XR...The chemical compositions of the sludge after treatment are tested by fully chemical analysis techniques. Its crystalline phase structure changes of the sludge calcined at different temperature are characterized by XRD method. Nitrogen gas isothermal adsorption method （77 K） is applied to measure the influences of ammonium bicarbonate on specific surface area and pore structure of activated alumina synthesized from waste aluminum sludge. The result shows that the amount of Al2O3 in the sludge accounts for more than 94%, and Na2Owt% in a 0.1-0.2% range. By calcining raw sludge at 600℃, monophase γ-Al2O3 is obtained. And this can satisfy the performance requirements of activated alumina adsorbent. The specific surface area of the specimen with NH4HCO3 added has expanded from 179 to 249 m^2/g and the pore volume from 0.25 to 1.11 cm^3/g as well as the average pore diameter from 5.6 to 17.8 nm. All these show that NH4HCO3 is an effective pore-expansion agent to remarkably improve the structure and performance of activated alumina synthesized from waste aluminum sludge.展开更多
In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, us...In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO2 activation and Potassium hydroxide（KOH） activation. CO2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO2 concentration range of10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N2 and CO2 adsorption at 77 and 273 K, respectively.Central composite design was used to evaluate the combined effects of temperature and concentration of CO2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm3/g and surface area of 1400 m2/g had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO2 and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO2 activated carbons remained remarkably stable after50 cycles with low temperature（160°C） regeneration.展开更多
Rigorous assessment of heterogeneous electrocatalysts for electrochemical water splitting has been a critical issue mainly due to insufficient standard protocols to measure and report experimental data.In this perspec...Rigorous assessment of heterogeneous electrocatalysts for electrochemical water splitting has been a critical issue mainly due to insufficient standard protocols to measure and report experimental data.In this perspective,we highlight some common pitfalls when measuring and reporting electrocatalytic data,which should be avoided to ensure the accuracy and reproducibility and to advance the water splitting field.We advocate to prevent the introduction of artefacts from the counter and reference electrodes,as well as the impurities in the electrolyte when conducting electrocatalyst activity measurements.In addition,we encourage the use of the electrochemically active surface area(ECSA)-normalized current densities to represent the intrinsic activity of the reported catalysts for a better comparison with previously known materials.Suitable ECSA measurement methods should be employed based on the nature of catalysts.Recommendations made in this perspective will hopefully assist in identifying advanced catalysts for water splitting research.展开更多
文摘In this work, ZnO nanorod arrays grown by an electrochemical deposition method are investigated. The crucial parameters of length, diameter, and density of the nanorods are optimized over the synthesize process and nanorods growth time. Crystalline structure, morphologies, and optical properties of ZnO nanorod arrays are studied by different techniques such as x-ray diffraction, scanning electron microscope, atomic force microscope, and UV-visible transmission spectra. The ZnO nanorod arrays are employed in an inverted bulk heterojunction organic solar cell of Poly （3-hexylthiophene）：[6- 6] Phenyl-（6） butyric acid methyl ester to introduce more surface contact between the electron transporter layer and the active layer. Our results show that the deposition time is a very important factor to achieve the aligned and uniform ZnO nanorods with suitable surface density which is required for effective infiltration of active area into the ZnO nanorod spacing and make a maximum interfacial surface contact for electron collection, as overgrowing causes nanorods to be too dense and thick and results in high resistance and lower visible light transmittance. By optimizing the thickness of the active layer on top of ZnO nanorods, an improved efficiency of 3.17% with a high FF beyond 60% was achieved.
基金This work was supported by National "973" Project of China (No. G20000683-1)the National Natural Science Foundation of China (No. 90401025)the National "863" Program of China (No. 2002AA312150).
文摘A novel distribute feedback (DFB) laser which gave two different wavelengths under two distinct work conditions was fabricated. The laser consists of two Bragg gratings with different periods corresponding to wavelength spacing of 20 nm in an identical active area. When driving current was injected into one of the different sections separately, two different wavelengths at 1542.4 and 1562.5 nm were realized. The side mode suppression ratio (SMSR) of 45 dB or more both for the two Bragg wavelengths were achieved. The fabricating process of the laser was just the samp as that of traditional DFB laser diode. This device can be potentially used in coarse wavelength division multiplexer (CWDM) as a promising light source and the technology idea can be used to enlarge the transmission capacity in metro area network (MAN).
基金supported by the Science and Technology Innovation Nursery Foundation of Chinese PLA General Hospital, No. 09KMM41
文摘Changes in activated areas of the brain during ankle active dorsiflexion and ankle active plantar flexion were observed in six healthy subjects using functional magnetic resonance imaging. Excited areas of ankle active dorsiflexion involved the bilateral primary motor area and the primary somatosensory area, as well as the bilateral supplementary sensory area, the primary visual area, the right second visual area, and the vermis of cerebellum. Excited areas of ankle active plantar flexion included the ipsilateral supplementary motor area, the limbic system, and the contralateral corpus striatum. Fine movements of the cerebral cortex control the function of the ankle dorsiflexion to a larger extent than ankle plate flexion, and the function of ankle plate flexion is more controlled by the subcortical area.
文摘In order to clear the activated area in electrostatic accelerator facilities,four accelerator facilities were selected and typical neutron emission experiments were performed.Neutron flux during operation and induced activity caused by charged particles on the accelerator and its surrounding area after irradiation were measured.Also the monitored neutron flux and calculated value by Monte Carlo calculation using PHITS code were compared.It was confirmed that the results between calculated data and measured data showed the good agreement with each other.Finally,it was concluded that we have to take care the activation of beam line and target.But,it is not necessary to treat accelerator tank,surrounding materials,and building concrete as radioactive materials in case of decommissioning.
基金partially supported by a Grant-in-Aid for Scientific Research(C)(26462862)from the Japan Society for the Promotion of Science
文摘OBJECTIVES： An animal experiment clarified that insertion of an orthodontic apparatus activated the trigeminal neurons of the medulla oblongata. Orthodontic tooth movement is known to be associated with the sympathetic nervous system and controlled by the nucleus of the hypothalamus. However, the transmission of both has not been demonstrated in humans. The purpose of this study were to examine the activated cerebral areas using brain functional magnetic resonance imaging（MRI）, when orthodontic tooth separators were inserted, and to confirm the possibility of the transmission route from the medulla oblongata to the hypothalamus.METHODS： Two types of alternative orthodontic tooth separators（brass contact gauge and floss） were inserted into the right upper premolars of 10 healthy volunteers. Brain functional T2＊-weighted images and anatomical T1-weighted images were taken.RESULTS： The blood oxygenation level dependent（BOLD） signals following insertion of a brass contact gauge and floss significantly increased in the somatosensory association cortex and hypothalamic area.CONCLUSION： Our findings suggest the possibility of a transmission route from the medulla oblongata to the hypothalamus.
基金a grant from theMedical Scientific ResearchFoundation of GuangdongProvince, No. A2003526
文摘BACKGROUND ： Functional magnetic resonance imaging （fMRI） studies have disclosed the changes of the motor function in the motor cortex of ipsilateral and contralateral hemispheres of tumor, which have special significance for making the surgical planning and most greatly minimizing the postoperative functional damages. OBJECTIVE： To analyze the association between the manifestation characteristics of hand functional area and motor dysfunction using fMRI in patients with space-occupying lesions of tumor in motor cortex. DESIGN ： A case-controlled observation SETTING： Department of Radiology, Second Affiliated Hospital, Shantou University Medical College .PARTICIPANTS： Twenty-three patients （13 males and 10 females） with space-occupying lesions of central sulcus area, aged 21-53 years with a mean age of （47±1） years were selected from the Second Affiliated Hospital of Shantou University Medical College. All the patients were diagnosed by MR scanning as space-occupying lesions of motor area, and pathologically confirmed that the lesions involved central sulcus and central Iobule; Lesions occurred in left and right hemispheres in 13 and 10 cases respectively. The tumor types were astrocytoma （n =8）, metastatic tumours （n =7）, meningiomas （n =5） and oligodendroglioma （n =3）. The muscle strength was normal in 11 cases （grade 5） and obviously decreased in 12 cases （grade 2-3 in 3 cases and grade 4 in 9 cases）; muscle strengths of both upper and lower limbs were decreased in 7 cases, and only that of upper limbs was decreased in 5 cases. Informed consents were obtained from all the subjects. Meanwhile, 9 healthy physical examinees （5 males and 4 females） of 20-56 years old with an average of （34±1） years were taken as controls. All the patients and healthy subjects were right-handed. METHODS： All the enrolled subjects were examined with MR scanning and functional imaging. Twenty cases whose clinical symptoms were mild in the patient group and 9 healthy volunteers adopted simple active finger-tapping movements, and for the 3 cases whose clinical symptoms were severe in the patient group, the simple passive finger-tapping movements were used. The manifestations in the activated brain areas were analyzed in the patients with brain tumor of different muscle strength and the controls. The motor deficit and activation of contralateral primary motor cortex （M1） in simple finger-tapping movements were observed in the patient group. MAIN OUTCOME MEASURES： （1） Brain areas activated by finger-tapping movements in each group： （2） Activated volumes in hemisphere by finger-tapping movements between groups. RESULTS： The contralateral M1 area could not be activated in 1 case in the patient group,, all the other 22 patients and 9 healthy subjects were involved in the analysis of results. （1） In the control group, unilateral finger tapping movement activated the contralateral primary motor cortex （M1）, bilateral SMA and bilateral PMC. The activation volume was the largest in contralateral primary motor cortex （M1）, smaller in the SMA, and the smallest in PMC. The finger tapping movement in healthy subjects could activate contralateral primary motor cortex （M1）, bilateral SMA and bilateral PMC, which had no obvious differences from the manifestations of brain functional area activated by active finger tapping. There was no significant difference in the volume of activated functional areas between right and left hands. In the patient group, the central sulcos around the tumor in the activated M1 area displaced towards dorsal or ventral side, also extended. The distance of displacement in the functional area was determined as compared with the contralateral central sulcus, and the results suggested the M1 displacement, including that there were 10 cases with the M1 displacement larger than 10 mm in the patients with motor deficit, which were obviously more than in those without motor deficit （n =1, P 〈 0.01）, and the activated volume in contralateral M1 area was obvious smaller in the patients with motor deficit than in those without motor deficit （P 〈 0.01）. （2） The M1 activation and changes were observed in contralateral hemisphere in the patient group, and the activated volume was obviously larger than that in the control group （P 〈 0.01）. The activated volumes of M1 and PMC in ipsilateral hemisphere were obviously larger than those in the control group （P 〈 0.05）, but that of SMA had no obvious difference between the two groups （P 〉 0.05）. CONCLUSION： fMRI can be used to observe the activation of the brain motor functional areas of patient with space-occupying lesions in motor area, and evaluate the state of their motor function. The larger the distance of displacement of M1 compressed by tumor, the more obviously the muscle strength decreases in the patients.
文摘Totally three articles focusing on functional magnetic resonance imaging features of brain function in the activated brain regions of stroke patients undergoing acupuncture on the healthy limbs and healthy controls undergoing acupuncture on the lower extremities are published in three issues. We hope that our readers find these papers useful to their research.
基金Funded partly by the the National 973 Program of China(No.2013CB035901)the National Natural Science Foundation of China(No.51379163)
文摘In order to understand the effect of powders ground from reactive sandstone replacing cement on reducing or suppressing alkali-silica reaction（ASR）, and to identify the mechanism of suppressing ASR by this powders, mortar and paste containing reactive sandstone powders of four replacement levels ranging from 10wt% to 40wt% and four specific surfaces areas ranging from 210 m^2/kg to 860 m^2/kg were studied. The experimental results showed that incorporation of 40wt% reactive sandstone powders could suppress ASR effectively except for mortar containing reactive sandstone powders with specific surface area of 610 m^2/kg, which disagreed with the most results reported that the higher reactive powder specific surface area, the smaller ASR expansion. By means of fl ame photometry, Fourier transform infrared spectroscopy（FT-IR） and thermo gravimetric analysis（TG）, the mechanism of reactive sandstone powders on reducing or suppressing ASR was soluble alkalis type of reactive sandstone powders and the competition of liberating and bonding alkali of cement paste containing reactive sandstone powders,when the ability of alkali bonding was greater than the ability of alkali liberation, ASR caused by reactive sandstone was supressed effectively.
基金supported by the National Natural Science Foundation of China(Nos.51872157,52072208)Shenzhen Technical Plan Project(JCYJ20170817161753629)+1 种基金Fundamental Research Project of Shenzhen(No.JCYJ20190808153609561)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01N111).
文摘Nickel-rich LiNi_(1-x-y)Co_(x)Mn_(y)O_(2)(NCM,1-x-y≥0.6)is known as a promising cathode material for lithium-ion batteries since its superiority of high voltage and large capacity.However,polycrystalline Ni-rich NCMs suffer from poor cycle stability,limiting its further application.Herein,single crystal and polycrystalline LiNi_(0.84)Co_(0.07)Mn_(0.09)O_(2)cathode materials are compared to figure out the relation of the morphology and the electrochemical storage performance.According to the Li^(+)diffusion coefficient,the lower capacity of single crystal samples is mainly ascribed to the limited Li+diffusion in the large bulk.In situ XRD illustrates that the polycrystalline and single crystal NCMs show a virtually identical manner and magnitude in lattice contraction and expansion during cycling.Also,the electrochemically active surface area(ECSA)measurement is employed in lithium-ion battery study for the first time,and these two cathodes show huge discrepancy in the ECSA after the initial cycle.These results suggest that the single crystal sample exhibits reduced cracking,surface side reaction,and Ni/Li mixing but suffers the lower Li^(+)diffusion kinetics.This work offers a view of how the morphology of Ni-rich NCM effects the electrochemical performance,which is instructive for developing a promising strategy to achieve good rate performance and excellent cycling stability.
基金the financial support of the Training Program of the Major Research Plan of the National Natural Science Foundation of China(92061124)the National Natural Science Foundation of China(21975292,21978331,22068008,and 52101186)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2021A1515010167 and 2022A1515011196)the Guangzhou Key R&D Program/Plan Unveiled Flagship Project(20220602JBGS02)the Guangzhou Basic and Applied Basic Research Project(202201011449)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202220 and FC202216)。
文摘Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.
基金Supported by National Maize Industry Technology System(CARS-02-38)Science and Technology Development Project of Jilin Province(LFGC14308)Special Fund for Scientific Research in the Public Interest(201303125-03)
文摘[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows： conventional ridge tillage, loosening the cm in spring （deep loosening in spring）, and depth of 30 cm in autumn （deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn）. Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure.
基金the financial support provided by the National Natural Science Foundation of China (No.21573093)the National Key Research and Development Program (No.2017YFB0307501)Guangdong Innovative and Entrepreneurial Research Team Program (No.2013C092)
文摘A novel C/Pb composite has been successfully prepared by electmless plating to reduce the hydrogenevolution and achieve the high reversibility of the anode of lead-carbon battery （LCB）. The depositedlead on the surface of C/Pb composite was found to be uniform and adherent to carbon surface. Becauselead has been stuck on the surface of C/Pb composite, the embedded structure suppresses the hydrogenevolution of lead-carbon anode and strengthens the connection between carbon additive and sponge lead.Compared with the blank anode, the lead-carbon anode with C/Pb composite displays excellent charge-discharge reversibility, which is attributed to the good connection between carbon additives and leadthat has been stuck on the surface of C/Pb composite during the preparation process. The addition of CIPb composite maintains a solid anode structure with high specific surface area and power volume, andthereby, it plays a significant role in the highly reversible lead-carbon anode.
基金the Science and Technique Key Foundation of Guangdong Province(No.2003A1100101,2003C105006)
文摘A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon （HSAAC） under certain conditions. The physical and chemical per- formances of the novel carbon-sulfur nano-composite were characterized by scanning electron microscopy （SEM）, Brunauer-Emmett-Teller （BET） and X-ray diffraction （XRD）. The electrochemical performances of nano-composite were characterized by charge-discharge characteristic, cyclic voltammetry and electrochemical impendence spectroscopy （EIS）. The experimental results indicate that the electrochemical capability of nano- composite material was superior to that of traditional S-containing composite material. The cathode made by carbon-sulfur nano-composite material shows a good cycle ability and a high specific charge-discharge capacity. The HSAAC shows a vital role in adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for a sulfur cathode and prevents the shuttle behavior of the lithium-sulfur battery.
文摘A systematic study on ″ring phenomena″ frequently occurring before great earthquakes has made in this paper, which has analyzed the features of ring distributions before 16 great earthquakes and part of large earthquakes in China and its boundary areas, and discussed their features of generality, regularity and predictive meaning. The results have showed that moderate earthquakes or larger earthquakes distribute around the epicenter like a ring from decades to hundred years before the great earthquakes of magnitude more than 7, which is a general phenomenon of great earthquakes without an exception. The active ring generally occurs in the areas from hundreds to thousands of kilometers from the epicenter(according to the magnitude). The seismicity in the ring has three basic stages with different features. in the first stage, seismicity remains at low level and the earthquakes distribute scatteredly, while the source area of the future great earthquake remains quiet; in the second stage, the seismicity strengthens, whose frequency, intensity, concentrated degree, released rate of strain and ratio of distributed area etc. increase, while the quiet area decreases or disappears; in the third stage, the seismicity is weaker than in the former stage, and the quiet area appears again. The source area surrounded by the active ring might have three periods of activity(called as early term, medium term and late term foreshocks activity). The length of the quiet area undergoes the process from large to small, then to large. Therefore, we can estimate the occurring place, magnitude and seismogenic stage of great earthquake according to the area,length and the seismicity in the active ring, which is valuable to make a long term prediction of great earthquakes. At last, we had a preliminary discussion on the mechanism of active ring formation.
文摘Carbon-sulfur nano-composite cathodes for lithium rechargeable batteries were investigated by electrochemical impedance spectroscopy (EIS). The novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon (HSAAC) in certain conditions. Equivalent circuits were used to fit the spectra at different discharge states. The variations of impedance spectra, charge-transfer resistance and double layer capacitance were discussed. The changes of EIS with potential were analyzed based on a plausible electrical equivalent circuit model, and some parameters were measured and analyzed about electrochemical performance and state of charge and discharge of the electrode. The good accuracy in fitting values of the model to the experimental data indicates that the mathematical model gives out a satisfying description upon the mechanism of high rate of capacity fade in lithium-sulfur battery.
文摘The chemical compositions of the sludge after treatment are tested by fully chemical analysis techniques. Its crystalline phase structure changes of the sludge calcined at different temperature are characterized by XRD method. Nitrogen gas isothermal adsorption method （77 K） is applied to measure the influences of ammonium bicarbonate on specific surface area and pore structure of activated alumina synthesized from waste aluminum sludge. The result shows that the amount of Al2O3 in the sludge accounts for more than 94%, and Na2Owt% in a 0.1-0.2% range. By calcining raw sludge at 600℃, monophase γ-Al2O3 is obtained. And this can satisfy the performance requirements of activated alumina adsorbent. The specific surface area of the specimen with NH4HCO3 added has expanded from 179 to 249 m^2/g and the pore volume from 0.25 to 1.11 cm^3/g as well as the average pore diameter from 5.6 to 17.8 nm. All these show that NH4HCO3 is an effective pore-expansion agent to remarkably improve the structure and performance of activated alumina synthesized from waste aluminum sludge.
基金Funding for this research is provided by Natural Sciences and Engineering Research Council (NSERC) of Canada
文摘In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO2 activation and Potassium hydroxide（KOH） activation. CO2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO2 concentration range of10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N2 and CO2 adsorption at 77 and 273 K, respectively.Central composite design was used to evaluate the combined effects of temperature and concentration of CO2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm3/g and surface area of 1400 m2/g had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO2 and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO2 activated carbons remained remarkably stable after50 cycles with low temperature（160°C） regeneration.
基金the Fund of the Australian Renewable Energy Agency(ARENA)and the Fund of the Australian Research Council(No.FT170100224)。
文摘Rigorous assessment of heterogeneous electrocatalysts for electrochemical water splitting has been a critical issue mainly due to insufficient standard protocols to measure and report experimental data.In this perspective,we highlight some common pitfalls when measuring and reporting electrocatalytic data,which should be avoided to ensure the accuracy and reproducibility and to advance the water splitting field.We advocate to prevent the introduction of artefacts from the counter and reference electrodes,as well as the impurities in the electrolyte when conducting electrocatalyst activity measurements.In addition,we encourage the use of the electrochemically active surface area(ECSA)-normalized current densities to represent the intrinsic activity of the reported catalysts for a better comparison with previously known materials.Suitable ECSA measurement methods should be employed based on the nature of catalysts.Recommendations made in this perspective will hopefully assist in identifying advanced catalysts for water splitting research.
