Carbon nanotubes(CNTs)have garnered significant attention in the fields of science,engineering,and medicine due to their numerous advantages.The initial step towards harnessing the potential of CNTs involves their mac...Carbon nanotubes(CNTs)have garnered significant attention in the fields of science,engineering,and medicine due to their numerous advantages.The initial step towards harnessing the potential of CNTs involves their macroscopic assembly.The present study employed a gentle and direct self-assembly technique,wherein controlled growth of CNT sheaths occurred on the metal wire’s surface,followed by etching of the remaining metal to obtain the hollow tubes composed of CNTs.By controlling the growth time and temperature,it is possible to alter the thickness of the CNTs sheath.After immersing in a solution containing 1 g/L of CNTs at 60℃ for 24 h,the resulting CNTs layer achieved a thickness of up to 60μm.These hollow CNTs tubes with varying inner diameters were prepared through surface reinforcement using polymers and sacrificing metal wires,thereby exhibiting exceptional attributes such as robustness,flexibility,air tightness,and high adsorption capacity that effectively capture CO_(2) from the gas mixture.展开更多
Hematite(α-Fe_(2)O_(3))constitutes one of the most promising photoanode materials for oxygen evolution reaction(OER).Recent research on Fe_(2)O_(3) have found a fast OER rate dependence on surface hole density,sugges...Hematite(α-Fe_(2)O_(3))constitutes one of the most promising photoanode materials for oxygen evolution reaction(OER).Recent research on Fe_(2)O_(3) have found a fast OER rate dependence on surface hole density,suggesting a multisite reaction pathway.However,the effect of heteroatom in Fe_(2)O_(3) on the multisite mechanism is still poorly understood.Herein we synthesized Fe_(2)O_(3) on Ti substrates(Fe_(2)O_(3)/Ti)to study the oxygen intermediates of OER by light-dark electrochemical scans.We identified the Fe-OH species disappeared and Ti-OH intermediates appeared on Fe_(2)O_(3)/Ti when pH=11‒14,which significantly improved the OER performance of Fe_(2)O_(3)/Ti.Combined with the density functional theory calculations,we propose that Ti atom acts as cocatalyst site and captures proton from neighboring Fe-OH species under highly alkaline condition,thereby promoting the coupling of Fe=O and reducing the energy barrier of the non-electrochemical step.Our work provides a new insight into the role of heteroatom in OER multisite mechanism based on clarifying the reaction intermediates.展开更多
Recent genome studies indicate that tree shrew is in the order or a closest sister of primates,and thus may be one of the best animals to model human diseases.In this paper,we report on a social defeat model of depres...Recent genome studies indicate that tree shrew is in the order or a closest sister of primates,and thus may be one of the best animals to model human diseases.In this paper,we report on a social defeat model of depression in tree shrew(Tupaia belangeri chinensis).Two male tree shrews were housed in a pair-cage consisting of two independent cages separated by a wire mesh partition with a door connecting the two cages.After one week adaptation,the connecting door was opened and a brief fighting occurs between the two male tree shrews and this social conflict session consisted of 1 h direct conflict(fighting) and 23 h indirect influence(e.g.smell,visual cues) per day for 21 days.The defeated tree shrew was considered the subordinate.Compared with na?ve animals,subordinate tree shrews at the final week of social conflict session showed alterations in body weight,locomotion,avoidance behavior and urinary cortisol levels.Remarkably,these alterations persisted for over two weeks.We also report on a novel captive conditioning model of learning and memory in tree shrew.An automatic trapping cage was placed in a small closed room with a freely-moving tree shrew.For the first four trials,the tree shrew was not trapped when it entered the cage and ate the bait apple,but it was trapped and kept in the cage for 1 h on the fifth trial.Latency was defined as the time between release of the tree shrew and when it entered the captive cage.Latencies during the five trials indicated adaptation.A test trial 24 h later was used to measure whether the one-trial trapping during the fifth trial could form captive memory.Tree shrews showed much longer trapping latencies in the test trial than the adaptation trials.The N-methyl-d-aspartate(NMDA) receptor antagonist MK-801(0.2 mg/kg,i.p.),known to prevent the formation of memory,did not affect latencies in the adaptation trails,but did block captive memory as it led to much shorter trapping latencies compared to saline treatment in the test trial.These results demonstrate a chronic social defeat model of depression and a novel one-trial captive conditioning model for learning and memory in tree shrews,which are important for mechanism studies of depression,learning,memory,and preclinical evaluation for new antidepressants.展开更多
The pollination mechanisms of Platycladus orientalis (L.) Franco and Thuja occidentalis L. seem to be of the same type, as based on the morphological study of the change in pollination drop, during the process of poll...The pollination mechanisms of Platycladus orientalis (L.) Franco and Thuja occidentalis L. seem to be of the same type, as based on the morphological study of the change in pollination drop, during the process of pollination. Entering the pollination drop, the pollen may alter the surface of the drop or reduce the secretion of the ovule with concomitant increase of evaporation. It has been further noticed that the dynamiechange of the drop withdrawal rate was closely associated with the different kinds of pollen received. It seemsthat the withdrawal of the pollination drop may be induced by pollen from plants consanguineous to P. orientalis, almost as effective as from pollen of P. orientalis itself and comparatively more effective than the foreignpollen received from distant plant species. The drop withdrawal could he mainly induced by the pollen that causes the reduction of ovule secretion.展开更多
The design of a global positioning system (GPS) software receiver is introduced. This design uses the concept of software radio, and it consists of the following parts: front-end, acquisition, tracking, synchroniza...The design of a global positioning system (GPS) software receiver is introduced. This design uses the concept of software radio, and it consists of the following parts: front-end, acquisition, tracking, synchronization, navigation solution and some assisting modules. In the acquisition module, the acquisition algorithm based on circular correlation is utilized. The input data and the local code are converted into the frequency domain by means of the fast Fourier transform (FFT). After performing circular correlation, the initial phase of the C/A code can be obtained and the cartier frequency can be found in 1 kHz frequency resolution, which is too coarse to use for the tracking loop. In order to improve the frequency resolution, the fine frequency estimation through a phase relationship is then achieved, by which, the frequency resolution is improved dramatically. Experiments show that the inaccuracy of the carrier frequency can be estimated within a few hertz by the fine frequency estimation method, and the fine frequency attained can be directly used for the tracking loop.展开更多
Annealing study of the Al/GaSb system was performed by using a slow positron beam and the measurement of X-ray diffraction. The S parameter against positron energy data were fitted by a three layer model (Al/interfac...Annealing study of the Al/GaSb system was performed by using a slow positron beam and the measurement of X-ray diffraction. The S parameter against positron energy data were fitted by a three layer model (Al/interface/GaSb). It was found there was a ~5 nm interfacial at the region between the Al layer and bulk in the sample of as-deposited. After the 400 ℃ annealing, this interfacial region extends to over 40 nm and S parameter dramatically drops. This is possibly due to a new phase formation induced by the atoms'inter-diffusion at the interface. The annealing out of the open volume defects in the Al layer was revealed by the decrease of the S parameter and the increase of the effective diffusion length of the Al layer. Annealing behaviors of Sb and Lb of the GaSb bulk showed the annealing out of positron traps at 250 ℃. However,further annealing at 400 ℃ induces formation of positron traps, which are possibly another kind of VGarelated defect and the positron shallow trap GaSb anti-site. The results of the X-ray diffraction experiment verified the conclusion of obtained by using positron technology.展开更多
Objective: Laser capture microdisection has become indispensable to the analysis of the difference of gene expression between human bladder transitional cell and bladder transitional cell carcinoma (BTCC). However,...Objective: Laser capture microdisection has become indispensable to the analysis of the difference of gene expression between human bladder transitional cell and bladder transitional cell carcinoma (BTCC). However, to obtain sufficient RNA from laser-capture microdissected cells is quite difficult. The study was designed to determinc a feasible technical routine to isolate transitional cells from bladder membrane, separate carcinoma cclls from stromal cells and to amplify the RNA isolated from laser-capture microdissected cells. Methods: Bladder transitional cell were obtained from frozen sections of bladder membrane applying LCM, by the same token, BTCC cells from frozen sections of BTCC tissue. Then RNA was extracted and linearly amplified in vitro. The expression levels of β-actin in primary total RNA and amplified RNA were detected using RT-PCR. Results: That RNA integrity was good after LCM was confirmed by control experiment Ⅰ; By control experiment Ⅱ, the correlation between the number of LCM-shooting and RNA quantity undcr arranged conditions was preliminarily confirmed. About 0.5-2.5kb RNA fragments were obtained after RNA amplification and β-actin levels were integral. Conclusion: Laser capture microdissection combined with RNA linear amplification in vitro can be successfully applied to obtain pure objective cells for research. The integrity of the amplified RNA is good and can be employed in further research.展开更多
We present a design for an adaptive gain phase-locked loop (PLL) that features fast acquisition,low jitter,and wide tuning range. A dual-edge-triggered phase frequency detector (PFD) and a self-regulated voltage c...We present a design for an adaptive gain phase-locked loop (PLL) that features fast acquisition,low jitter,and wide tuning range. A dual-edge-triggered phase frequency detector (PFD) and a self-regulated voltage controlled oscillator (VCO) are employed in this design to realize the aforementioned properties. Measured results show that the experimental chip, implemented in a standard 0.5μm 5V CMOS logic process, has an acquisition time of about 150ns at 37% frequency variation and an output RMS jitter of 39ps at 640MHz.(dual-edge-triggered phase frequency detector)展开更多
Among the current technologies for post-combustion CO2 capture,amine-based chemical absorption appears to be the most technologically mature and commercially viable method.This review highlights the opportunities and ...Among the current technologies for post-combustion CO2 capture,amine-based chemical absorption appears to be the most technologically mature and commercially viable method.This review highlights the opportunities and challenges in post-combustion CO2 capture using amine-based chemical absorption technologies.In addition,this review provides current types and emerging trends for chemical solvents.The issues and performance of amine solvents are reviewed and addressed in terms of thermodynamics,kinetics,mass transfer,regeneration and solvent management.This review also looks at emerging and future trends in post-combustion CO2 capture using chemical solvents in the near to mid-term.展开更多
This paper presented a comparative study of monoethanolamine (MEA) and diethanolamine (DEA) for post- combustion CO2 capture (PCC) process with different process configurations to study the interaction effect be...This paper presented a comparative study of monoethanolamine (MEA) and diethanolamine (DEA) for post- combustion CO2 capture (PCC) process with different process configurations to study the interaction effect between solvent and process. The steady state process model of the conventional MEA-based PCC process was developed in Pro/II and was validated with the experimental data. Then ten different process configurations were simulated for both MEA and DEA. Their performances in energy consumption were compared in terms of reboiler duty and total equivalent work. The results show that DEA generally has better thermal performances than MEA for all these ten process configurations. Seven process configurations provide 0.38%-4.61% total energy saving compared with the conventional PCC process for MEA, and other two configurations are not favourable. For DEA, except one configuration, other process configurations have 0.27%-4.50% total energy saving. This work also analyzed the sensitivities of three key parameters (amine concentration, stripper pressure and lean solvent loading) in conventional process and five process modifications to show optimization strategy.展开更多
Guan-fu base A(GFA),a new antiarrhythmic alkaloid with a structure of C_(20)-diterpenoid could react rapidly and quantitatively with trifluoroacetic anhydride(TFAA) to produce GFA—TFAA of which the structure was iden...Guan-fu base A(GFA),a new antiarrhythmic alkaloid with a structure of C_(20)-diterpenoid could react rapidly and quantitatively with trifluoroacetic anhydride(TFAA) to produce GFA—TFAA of which the structure was identified by GC—MSD.There was a wide linear range of the GC-ECD method from 10 to 20000ng/ml(r=0.9984).The average recovery of GFA from the spiked plasma was 97.52%.The coefficients of variation of within-day and between-day were less than 7% and 9%,respectively.The method was used in the preclinical experiment of pharmacology of GFA and the results showed that GFA con- centrations in rabbits' plasma within 6 hours after the administration ranged from 0.338± 0.014 to 13.459±5.393μg/ml for dosage 10mg/kg,from 0.133±0.038 to 2.546±0.480 μg/ml for dosage 2mg/kg and from 45.25±10.34 to 535.86±24.36ng/ml for dosage 0.4 mg/kg.展开更多
Capture of CO2 by hydrate is one of the attractive technologies for reducing greenhouse effect.The primary challenges are the large energy consumption,low hydrate formation rate and separation efficiency.This work pre...Capture of CO2 by hydrate is one of the attractive technologies for reducing greenhouse effect.The primary challenges are the large energy consumption,low hydrate formation rate and separation efficiency.This work presents a new method for capture of CO2 from simulated flue gasCO2(16.60%,by mole) /N2 binary mixture by formation of cyclopentane(CP) hydrates at initial temperature of 8.1°C with the feed pressures from 2.49 to 3.95 MPa.The effect of cyclopentane and cyclopentane/water emulsion on the hydrate formation rate and CO2 separation efficiency was studied in a 1000 ml stirred reactor.The results showed the hydrate formation rate could be increased remarkably with cyclopentane/water emulsion.CO2 could be enriched to 43.97%(by mole) and 35.29%(by mole) from simulated flue gas with cyclopentane and cyclopentane/water(O/W) emulsion,respectively,by one stage hydrate separation under low feed pressure.CO2 separation factor with cyclopentane was 6.18,higher than that with cyclopentane/water emulsion(4.01) ,in the range of the feed pressure.The results demonstrated that cyclopentane/water emulsion is a good additive for efficient hydrate capture of CO2.展开更多
Iron oxide(Fe2O3) was doped onto fullerene[60](C(60)) to form a C(60)‐Fe2O3 composite using an easy and scalable impregnation method. The as‐prepared C(60)‐Fe2O3 samples were characterized by powder X‐ra...Iron oxide(Fe2O3) was doped onto fullerene[60](C(60)) to form a C(60)‐Fe2O3 composite using an easy and scalable impregnation method. The as‐prepared C(60)‐Fe2O3 samples were characterized by powder X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, high‐resolution transmission electron microscopy, UV‐vis absorption spectroscopy, Raman spec‐troscopy, and Fourier transform infrared spectroscopy. The photocatalytic activity of the C(60)‐Fe2O3 catalyst was evaluated by examining the degradation of methylene blue(MB), rhodamine B(RhB), methyl orange(MO), and phenol under visible light(λ 420 nm) in the presence of hydrogen per‐oxide. The results showed that the catalyst exhibited excellent catalytic properties over a wide pH range 3.06–10.34. Under optimal conditions, 98.9% discoloration and 71% mineralization of MB were achieved in 80 min. Leaching test results indicated that the leaching of iron from the catalyst was negligible and that the catalyst had a high photocatalytic activity after five reaction cycles. The catalyst was also efficient in the degradation of RhB, MO, and phenol. These findings could be at‐tributed to the synergetic effects of C(60) and Fe2O3. We used active species trapping experiments to determine the main active oxidant in the photocatalytic reaction process and found that hydroxyl radicals played a major role in the entire process.展开更多
The essential requirements of the end-effector of large space manipulator are capabilities of misalignment tolerance and soft capture.According to these requirements,an end-effector prototype combining the tendon-shea...The essential requirements of the end-effector of large space manipulator are capabilities of misalignment tolerance and soft capture.According to these requirements,an end-effector prototype combining the tendon-sheath transmission system with steel cable snaring mechanism was manufactured.An analysis method based on the coordinate transformation and the projection of key points of the mechanical interface was proposed,and it was a guideline of the end-effector design.Furthermore,the tendon-sheath transmission system was employed in the capture subassembly to reduce the inertia of the capture mechanism and enlarge the capture space.The capabilities of misalignment tolerance and soft capture were validated through the dynamic simulation in ADAMS software.The results of the capture simulation and experiment show that the end-effector has outstanding capabilities of misalignment tolerance and soft capture.The translation misalignments in radial directions are±100 mm,and angular misalignments about pitch and yaw are±15°.展开更多
Due to their negligible volatility,reasonable thermal stability,strong dissolubility,wide liquid range and tunability of structure and property,ionic liquids have been regarded as emerging candidate reagents for CO2 c...Due to their negligible volatility,reasonable thermal stability,strong dissolubility,wide liquid range and tunability of structure and property,ionic liquids have been regarded as emerging candidate reagents for CO2 cap-ture from industries gases.In this review,the research progresses in CO2 capture using conventional ionic liquids,functionalized ionic liquids,supported ionic-liquids membranes,polymerized ionic liquids and mixtures of ionic liquids with some molecular solvents were investigated and reviewed.Discussion of relevant research fields was presented and the future developments were suggested.展开更多
Most extant nonhuman primates occasionally prey on fast-moving, warm-blooded animals; however, Indriidae, Lepilemuridae, and Colobinae either scavenged for meat or did not eat meat at all. Here we report six cases of ...Most extant nonhuman primates occasionally prey on fast-moving, warm-blooded animals; however, Indriidae, Lepilemuridae, and Colobinae either scavenged for meat or did not eat meat at all. Here we report six cases of animal consumption by the snub-nosed monkey Rhinopithecus bieti in a wild, habituated group between 2004 and 2009 in Yunnan, China. At present, only males in an all-male unit within the study group were involved in active hunting. Such a male-biased activity may be related to the group structure and spatial spread of R. bieti. Two females were observed eating freshly killed birds. The findings confirmed that R. bieti engaged in scavenging and, when hunting, employed a cranio-cervical bite to kill their prey. Meat eating is likely a nutrient maximization feeding strategy in R. bieti, especially in males. A begging behavior occurred after successful prey capture. Although begging was observed, no sharing of the meat was seen. The present findings illuminate the dietary diversity of R. bieti and their ability to expand their dietary spectrum.展开更多
lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synt...lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synthesized by a low-temperature hydrothermal method using a tai-lored diquaternary ammonium surfactant as the structure-directing agent.Introducing Ni^2+cationsat the ion-exchange sites of the TS-1 NS framework significantly enhanced its photoactivity in aero-bic alcohol oxidation.The optimized Ni cation-functionalized TS-1 NS(Ni/TS-1 NS)provide impres-sive photoactivity,with a benzyl alcohol(BA)conversion of 78.9%and benzyl aldehyde(BAD)se-lectivity of 98.8%using O as the only oxidant under full light irradiation;this BAD yield is approx-imately six times greater than that obtained for bulk TS-1,and is maintained for five runs.The ex-cellent photoactivity of Ni/TS-1 NS is attributed to the significantly enlarged surface area of thetwo-dimensional morphology TS-1 NS,extra mesopores,and greatly improved charge separation.Compared with bulk TS-1,Ni/TS-1 NS has a much shorter charge transfer distance.Theas-introduced Ni species could capture the photoelectrons to further improve the charge separa-tion.This work opens the way to a class of highly selective,robust,and low-cost titanosilicate mo-lecular sieve-based photocatalysts with industrial potential for selective oxidative transformationsand pollutant degradation.展开更多
During sampling for spawning stock of the silver pomfret,Pampus argenteus in Kuwait waters,a few seriously deformed individuals were captured.These individuals had been attacked and wounded,but had healed and survived...During sampling for spawning stock of the silver pomfret,Pampus argenteus in Kuwait waters,a few seriously deformed individuals were captured.These individuals had been attacked and wounded,but had healed and survived.The fish body deformities are believed to be caused by predation attempts on silver pomfret by predators such as sharks,groupers,and croakers.展开更多
基金Project(ZCLTGS24B0101)supported by Zhejiang Provincial Natural Science Foundation of ChinaProject(Y202250501)supported by Scientific Research Fund of Zhejiang Provincial Education Department,ChinaProject supported by SRT Research Project of Jiaxing Nanhu University,China。
文摘Carbon nanotubes(CNTs)have garnered significant attention in the fields of science,engineering,and medicine due to their numerous advantages.The initial step towards harnessing the potential of CNTs involves their macroscopic assembly.The present study employed a gentle and direct self-assembly technique,wherein controlled growth of CNT sheaths occurred on the metal wire’s surface,followed by etching of the remaining metal to obtain the hollow tubes composed of CNTs.By controlling the growth time and temperature,it is possible to alter the thickness of the CNTs sheath.After immersing in a solution containing 1 g/L of CNTs at 60℃ for 24 h,the resulting CNTs layer achieved a thickness of up to 60μm.These hollow CNTs tubes with varying inner diameters were prepared through surface reinforcement using polymers and sacrificing metal wires,thereby exhibiting exceptional attributes such as robustness,flexibility,air tightness,and high adsorption capacity that effectively capture CO_(2) from the gas mixture.
文摘Hematite(α-Fe_(2)O_(3))constitutes one of the most promising photoanode materials for oxygen evolution reaction(OER).Recent research on Fe_(2)O_(3) have found a fast OER rate dependence on surface hole density,suggesting a multisite reaction pathway.However,the effect of heteroatom in Fe_(2)O_(3) on the multisite mechanism is still poorly understood.Herein we synthesized Fe_(2)O_(3) on Ti substrates(Fe_(2)O_(3)/Ti)to study the oxygen intermediates of OER by light-dark electrochemical scans.We identified the Fe-OH species disappeared and Ti-OH intermediates appeared on Fe_(2)O_(3)/Ti when pH=11‒14,which significantly improved the OER performance of Fe_(2)O_(3)/Ti.Combined with the density functional theory calculations,we propose that Ti atom acts as cocatalyst site and captures proton from neighboring Fe-OH species under highly alkaline condition,thereby promoting the coupling of Fe=O and reducing the energy barrier of the non-electrochemical step.Our work provides a new insight into the role of heteroatom in OER multisite mechanism based on clarifying the reaction intermediates.
基金supported by grants KSCX2-EW-R-12 and KSCX2-EW-J-23 from the Chinese Academy of Sciences
文摘Recent genome studies indicate that tree shrew is in the order or a closest sister of primates,and thus may be one of the best animals to model human diseases.In this paper,we report on a social defeat model of depression in tree shrew(Tupaia belangeri chinensis).Two male tree shrews were housed in a pair-cage consisting of two independent cages separated by a wire mesh partition with a door connecting the two cages.After one week adaptation,the connecting door was opened and a brief fighting occurs between the two male tree shrews and this social conflict session consisted of 1 h direct conflict(fighting) and 23 h indirect influence(e.g.smell,visual cues) per day for 21 days.The defeated tree shrew was considered the subordinate.Compared with na?ve animals,subordinate tree shrews at the final week of social conflict session showed alterations in body weight,locomotion,avoidance behavior and urinary cortisol levels.Remarkably,these alterations persisted for over two weeks.We also report on a novel captive conditioning model of learning and memory in tree shrew.An automatic trapping cage was placed in a small closed room with a freely-moving tree shrew.For the first four trials,the tree shrew was not trapped when it entered the cage and ate the bait apple,but it was trapped and kept in the cage for 1 h on the fifth trial.Latency was defined as the time between release of the tree shrew and when it entered the captive cage.Latencies during the five trials indicated adaptation.A test trial 24 h later was used to measure whether the one-trial trapping during the fifth trial could form captive memory.Tree shrews showed much longer trapping latencies in the test trial than the adaptation trials.The N-methyl-d-aspartate(NMDA) receptor antagonist MK-801(0.2 mg/kg,i.p.),known to prevent the formation of memory,did not affect latencies in the adaptation trails,but did block captive memory as it led to much shorter trapping latencies compared to saline treatment in the test trial.These results demonstrate a chronic social defeat model of depression and a novel one-trial captive conditioning model for learning and memory in tree shrews,which are important for mechanism studies of depression,learning,memory,and preclinical evaluation for new antidepressants.
文摘The pollination mechanisms of Platycladus orientalis (L.) Franco and Thuja occidentalis L. seem to be of the same type, as based on the morphological study of the change in pollination drop, during the process of pollination. Entering the pollination drop, the pollen may alter the surface of the drop or reduce the secretion of the ovule with concomitant increase of evaporation. It has been further noticed that the dynamiechange of the drop withdrawal rate was closely associated with the different kinds of pollen received. It seemsthat the withdrawal of the pollination drop may be induced by pollen from plants consanguineous to P. orientalis, almost as effective as from pollen of P. orientalis itself and comparatively more effective than the foreignpollen received from distant plant species. The drop withdrawal could he mainly induced by the pollen that causes the reduction of ovule secretion.
基金Program for New Century Excellent Talents in Universi-ty(No.NCET-06-0462)Excellent Young Teacher Foundation of SoutheastUniversity(No.4022001002).
文摘The design of a global positioning system (GPS) software receiver is introduced. This design uses the concept of software radio, and it consists of the following parts: front-end, acquisition, tracking, synchronization, navigation solution and some assisting modules. In the acquisition module, the acquisition algorithm based on circular correlation is utilized. The input data and the local code are converted into the frequency domain by means of the fast Fourier transform (FFT). After performing circular correlation, the initial phase of the C/A code can be obtained and the cartier frequency can be found in 1 kHz frequency resolution, which is too coarse to use for the tracking loop. In order to improve the frequency resolution, the fine frequency estimation through a phase relationship is then achieved, by which, the frequency resolution is improved dramatically. Experiments show that the inaccuracy of the carrier frequency can be estimated within a few hertz by the fine frequency estimation method, and the fine frequency attained can be directly used for the tracking loop.
基金This work was supported by the CERG, RGC, HKSAR (projects 7134/99P and 7107/02P)the National Science Foundation of China (No.10425072).
文摘Annealing study of the Al/GaSb system was performed by using a slow positron beam and the measurement of X-ray diffraction. The S parameter against positron energy data were fitted by a three layer model (Al/interface/GaSb). It was found there was a ~5 nm interfacial at the region between the Al layer and bulk in the sample of as-deposited. After the 400 ℃ annealing, this interfacial region extends to over 40 nm and S parameter dramatically drops. This is possibly due to a new phase formation induced by the atoms'inter-diffusion at the interface. The annealing out of the open volume defects in the Al layer was revealed by the decrease of the S parameter and the increase of the effective diffusion length of the Al layer. Annealing behaviors of Sb and Lb of the GaSb bulk showed the annealing out of positron traps at 250 ℃. However,further annealing at 400 ℃ induces formation of positron traps, which are possibly another kind of VGarelated defect and the positron shallow trap GaSb anti-site. The results of the X-ray diffraction experiment verified the conclusion of obtained by using positron technology.
文摘Objective: Laser capture microdisection has become indispensable to the analysis of the difference of gene expression between human bladder transitional cell and bladder transitional cell carcinoma (BTCC). However, to obtain sufficient RNA from laser-capture microdissected cells is quite difficult. The study was designed to determinc a feasible technical routine to isolate transitional cells from bladder membrane, separate carcinoma cclls from stromal cells and to amplify the RNA isolated from laser-capture microdissected cells. Methods: Bladder transitional cell were obtained from frozen sections of bladder membrane applying LCM, by the same token, BTCC cells from frozen sections of BTCC tissue. Then RNA was extracted and linearly amplified in vitro. The expression levels of β-actin in primary total RNA and amplified RNA were detected using RT-PCR. Results: That RNA integrity was good after LCM was confirmed by control experiment Ⅰ; By control experiment Ⅱ, the correlation between the number of LCM-shooting and RNA quantity undcr arranged conditions was preliminarily confirmed. About 0.5-2.5kb RNA fragments were obtained after RNA amplification and β-actin levels were integral. Conclusion: Laser capture microdissection combined with RNA linear amplification in vitro can be successfully applied to obtain pure objective cells for research. The integrity of the amplified RNA is good and can be employed in further research.
文摘We present a design for an adaptive gain phase-locked loop (PLL) that features fast acquisition,low jitter,and wide tuning range. A dual-edge-triggered phase frequency detector (PFD) and a self-regulated voltage controlled oscillator (VCO) are employed in this design to realize the aforementioned properties. Measured results show that the experimental chip, implemented in a standard 0.5μm 5V CMOS logic process, has an acquisition time of about 150ns at 37% frequency variation and an output RMS jitter of 39ps at 640MHz.(dual-edge-triggered phase frequency detector)
基金Supported by the National Natural Science Foundation of China(21276068,U1362112and 21376067,21476064)the National Key Technology R&D Program(2012BAC26B01)+4 种基金Innovative Research Team Development Plan of the Ministry of Education of the People's Republic of China(IRT1238)Specialized Research Fund for the Doctoral Program of Higher Education(20130161110025)Technology Development contract(Shanyan 12-34)Innovative Research Program for Graduate Student of Hunan Province,China(CX2013B158)Key project of international®ional scientific and technological cooperation of Hunan Provincial science and technology plan(2014WK2037)
文摘Among the current technologies for post-combustion CO2 capture,amine-based chemical absorption appears to be the most technologically mature and commercially viable method.This review highlights the opportunities and challenges in post-combustion CO2 capture using amine-based chemical absorption technologies.In addition,this review provides current types and emerging trends for chemical solvents.The issues and performance of amine solvents are reviewed and addressed in terms of thermodynamics,kinetics,mass transfer,regeneration and solvent management.This review also looks at emerging and future trends in post-combustion CO2 capture using chemical solvents in the near to mid-term.
文摘This paper presented a comparative study of monoethanolamine (MEA) and diethanolamine (DEA) for post- combustion CO2 capture (PCC) process with different process configurations to study the interaction effect between solvent and process. The steady state process model of the conventional MEA-based PCC process was developed in Pro/II and was validated with the experimental data. Then ten different process configurations were simulated for both MEA and DEA. Their performances in energy consumption were compared in terms of reboiler duty and total equivalent work. The results show that DEA generally has better thermal performances than MEA for all these ten process configurations. Seven process configurations provide 0.38%-4.61% total energy saving compared with the conventional PCC process for MEA, and other two configurations are not favourable. For DEA, except one configuration, other process configurations have 0.27%-4.50% total energy saving. This work also analyzed the sensitivities of three key parameters (amine concentration, stripper pressure and lean solvent loading) in conventional process and five process modifications to show optimization strategy.
文摘Guan-fu base A(GFA),a new antiarrhythmic alkaloid with a structure of C_(20)-diterpenoid could react rapidly and quantitatively with trifluoroacetic anhydride(TFAA) to produce GFA—TFAA of which the structure was identified by GC—MSD.There was a wide linear range of the GC-ECD method from 10 to 20000ng/ml(r=0.9984).The average recovery of GFA from the spiked plasma was 97.52%.The coefficients of variation of within-day and between-day were less than 7% and 9%,respectively.The method was used in the preclinical experiment of pharmacology of GFA and the results showed that GFA con- centrations in rabbits' plasma within 6 hours after the administration ranged from 0.338± 0.014 to 13.459±5.393μg/ml for dosage 10mg/kg,from 0.133±0.038 to 2.546±0.480 μg/ml for dosage 2mg/kg and from 45.25±10.34 to 535.86±24.36ng/ml for dosage 0.4 mg/kg.
基金Supported by the National High Technology Research and Development Program of China(2007AA03Z229) the National Natural Science Foundation of China(20876019)
文摘Capture of CO2 by hydrate is one of the attractive technologies for reducing greenhouse effect.The primary challenges are the large energy consumption,low hydrate formation rate and separation efficiency.This work presents a new method for capture of CO2 from simulated flue gasCO2(16.60%,by mole) /N2 binary mixture by formation of cyclopentane(CP) hydrates at initial temperature of 8.1°C with the feed pressures from 2.49 to 3.95 MPa.The effect of cyclopentane and cyclopentane/water emulsion on the hydrate formation rate and CO2 separation efficiency was studied in a 1000 ml stirred reactor.The results showed the hydrate formation rate could be increased remarkably with cyclopentane/water emulsion.CO2 could be enriched to 43.97%(by mole) and 35.29%(by mole) from simulated flue gas with cyclopentane and cyclopentane/water(O/W) emulsion,respectively,by one stage hydrate separation under low feed pressure.CO2 separation factor with cyclopentane was 6.18,higher than that with cyclopentane/water emulsion(4.01) ,in the range of the feed pressure.The results demonstrated that cyclopentane/water emulsion is a good additive for efficient hydrate capture of CO2.
基金supported by the National Natural Science Foundation of China (21347006, 21576175, 51478285, 51403148)the Opening Project of Key Laboratory of Jiangsu Province environmental science and engineering of Suzhou University of Science and Technology (zd131205)Collabora‐tive Innovation Center of Technology and Material of Water Treatment and Suzhou Key Lab of Separation and Purification Materials & Technologies (SZS201512)~~
文摘Iron oxide(Fe2O3) was doped onto fullerene[60](C(60)) to form a C(60)‐Fe2O3 composite using an easy and scalable impregnation method. The as‐prepared C(60)‐Fe2O3 samples were characterized by powder X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, high‐resolution transmission electron microscopy, UV‐vis absorption spectroscopy, Raman spec‐troscopy, and Fourier transform infrared spectroscopy. The photocatalytic activity of the C(60)‐Fe2O3 catalyst was evaluated by examining the degradation of methylene blue(MB), rhodamine B(RhB), methyl orange(MO), and phenol under visible light(λ 420 nm) in the presence of hydrogen per‐oxide. The results showed that the catalyst exhibited excellent catalytic properties over a wide pH range 3.06–10.34. Under optimal conditions, 98.9% discoloration and 71% mineralization of MB were achieved in 80 min. Leaching test results indicated that the leaching of iron from the catalyst was negligible and that the catalyst had a high photocatalytic activity after five reaction cycles. The catalyst was also efficient in the degradation of RhB, MO, and phenol. These findings could be at‐tributed to the synergetic effects of C(60) and Fe2O3. We used active species trapping experiments to determine the main active oxidant in the photocatalytic reaction process and found that hydroxyl radicals played a major role in the entire process.
基金Project(2006AA04Z228) supported by National Hi-tech Research and Development Program of China
文摘The essential requirements of the end-effector of large space manipulator are capabilities of misalignment tolerance and soft capture.According to these requirements,an end-effector prototype combining the tendon-sheath transmission system with steel cable snaring mechanism was manufactured.An analysis method based on the coordinate transformation and the projection of key points of the mechanical interface was proposed,and it was a guideline of the end-effector design.Furthermore,the tendon-sheath transmission system was employed in the capture subassembly to reduce the inertia of the capture mechanism and enlarge the capture space.The capabilities of misalignment tolerance and soft capture were validated through the dynamic simulation in ADAMS software.The results of the capture simulation and experiment show that the end-effector has outstanding capabilities of misalignment tolerance and soft capture.The translation misalignments in radial directions are±100 mm,and angular misalignments about pitch and yaw are±15°.
基金Supported by the Key Program of National Natural Science Foundation of China (21036007)the National High Technology Research and Development Program of China (2011AA050606)
文摘Due to their negligible volatility,reasonable thermal stability,strong dissolubility,wide liquid range and tunability of structure and property,ionic liquids have been regarded as emerging candidate reagents for CO2 cap-ture from industries gases.In this review,the research progresses in CO2 capture using conventional ionic liquids,functionalized ionic liquids,supported ionic-liquids membranes,polymerized ionic liquids and mixtures of ionic liquids with some molecular solvents were investigated and reviewed.Discussion of relevant research fields was presented and the future developments were suggested.
基金granted by the key project of NSFC (No.30630016)the 973 Program (2007CB411600)+1 种基金the project of NSFC (No.30970442) China Program of TNC
文摘Most extant nonhuman primates occasionally prey on fast-moving, warm-blooded animals; however, Indriidae, Lepilemuridae, and Colobinae either scavenged for meat or did not eat meat at all. Here we report six cases of animal consumption by the snub-nosed monkey Rhinopithecus bieti in a wild, habituated group between 2004 and 2009 in Yunnan, China. At present, only males in an all-male unit within the study group were involved in active hunting. Such a male-biased activity may be related to the group structure and spatial spread of R. bieti. Two females were observed eating freshly killed birds. The findings confirmed that R. bieti engaged in scavenging and, when hunting, employed a cranio-cervical bite to kill their prey. Meat eating is likely a nutrient maximization feeding strategy in R. bieti, especially in males. A begging behavior occurred after successful prey capture. Although begging was observed, no sharing of the meat was seen. The present findings illuminate the dietary diversity of R. bieti and their ability to expand their dietary spectrum.
文摘lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synthesized by a low-temperature hydrothermal method using a tai-lored diquaternary ammonium surfactant as the structure-directing agent.Introducing Ni^2+cationsat the ion-exchange sites of the TS-1 NS framework significantly enhanced its photoactivity in aero-bic alcohol oxidation.The optimized Ni cation-functionalized TS-1 NS(Ni/TS-1 NS)provide impres-sive photoactivity,with a benzyl alcohol(BA)conversion of 78.9%and benzyl aldehyde(BAD)se-lectivity of 98.8%using O as the only oxidant under full light irradiation;this BAD yield is approx-imately six times greater than that obtained for bulk TS-1,and is maintained for five runs.The ex-cellent photoactivity of Ni/TS-1 NS is attributed to the significantly enlarged surface area of thetwo-dimensional morphology TS-1 NS,extra mesopores,and greatly improved charge separation.Compared with bulk TS-1,Ni/TS-1 NS has a much shorter charge transfer distance.Theas-introduced Ni species could capture the photoelectrons to further improve the charge separa-tion.This work opens the way to a class of highly selective,robust,and low-cost titanosilicate mo-lecular sieve-based photocatalysts with industrial potential for selective oxidative transformationsand pollutant degradation.
文摘During sampling for spawning stock of the silver pomfret,Pampus argenteus in Kuwait waters,a few seriously deformed individuals were captured.These individuals had been attacked and wounded,but had healed and survived.The fish body deformities are believed to be caused by predation attempts on silver pomfret by predators such as sharks,groupers,and croakers.