We study the problem of a diffusing particle confined in a large sphere in the n-dimensional space being absorbed into a small sphere at the center. We first non-dimensionalize the problem using the radius of large co...We study the problem of a diffusing particle confined in a large sphere in the n-dimensional space being absorbed into a small sphere at the center. We first non-dimensionalize the problem using the radius of large confining sphere as the spatial scale and the square of the spatial scale divided by the diffusion coefficient as the time scale. The non-dimensional normalized absorption rate is the product of the physical absorption rate and the time scale. We derive asymptotic expansions for the normalized absorption rate using the inverse iteration method. The small parameter in the asymptotic expansions is the ratio of the small sphere radius to the large sphere radius. In particular, we observe that, to the leading order, the normalized absorption rate is proportional to the (n - 2)-th power of the small parameter for .展开更多
The system analysis of specific absorption rate(SAR)in human body exposed to a base station antenna by using finite difference time domain techniques was presented in this research works.The objectives of ...The system analysis of specific absorption rate(SAR)in human body exposed to a base station antenna by using finite difference time domain techniques was presented in this research works.The objectives of this work are to evaluate the knowledge and awareness about SAR among human body and mobile base station.The paper investigates the electromagnetic wave absorption inside a human body.The human body has been identified using dataset based on 2D object considering different electrical parameters.The SAR convinced inside the human body model exposed to a radiating base station antenna(BSA)has been considered for multiple numbers of carrier frequencies and input power of 20 W/carrier at GSM 900 band.The distance(R)of human body from BSA is varied in the range of 0.1 m to 5.0 m.For the number of carrier frequency equal to one and R=0.1 m,the concentrated value of whole-body average SAR obtained by FDTD technique is found to be 0.68 W/kg which decreases either with increase of R or decrease of number of carrier frequencies.Safety distance for general public is found to be 1.5 m for number of carrier frequencies equal to one.The performance accuracy of this analysis meets the high level condition by comparing with the relevant system development in recent time.展开更多
Background Previous studies have suggested that nomogram can simplize complicated calculations of several varibles. A simple nomogram was constructed to estimate absorption rate coefficient (k a) by using the peak t...Background Previous studies have suggested that nomogram can simplize complicated calculations of several varibles. A simple nomogram was constructed to estimate absorption rate coefficient (k a) by using the peak time (t peak ) and the elimination rate coefficient (k e) of drugs administered orally Methods The nomogram was based on the plasma concentration-time (C-T) curve equation and the function relation between t peak , k a and k e A mathematical analysis was presented for the construction of single chart nomogram To check the degree of accuracy of the developed nomogram, we used it to analyze retrospective profiles of 46 drugs and compared the k a values obtained graphically and those calculated by numerically solving the descriptive equation In addition, we measured the carbocisteine concentration of 18 healthy volunteers by HPLC with fluorescence detection To analyze performance error, the measured carbocisteine concentrations were compared with predicted concentrations by the k a obtained from the nomograms along with the other pharmacokinetic parameters Results The estimated of k a values from nomograms were in very close proximity with the numerical values The performance error was as follows: median performance error (MDPE) and median absolute performance error (MDAPE) were 1 32% and 18 15%, respectively Conclusions The developed nomogram is accurate and reliable The size of performance error meets the demand of clinical pharmacokinetics Therefore, the nomograms can offer another convenient and easy method for rational individualized dosage regimens展开更多
In this work,characterization and kinetics of CO2 absorption in potassium carbonate(K_(2)CO_(3))solution promoted by diethylenetriamine(DETA)were investigated.Kinetics measurements were performed using a stirred cell ...In this work,characterization and kinetics of CO2 absorption in potassium carbonate(K_(2)CO_(3))solution promoted by diethylenetriamine(DETA)were investigated.Kinetics measurements were performed using a stirred cell reactor in the temperature range of 303.15–323.15 K and total concentration up to 2.5 kmol m3.The density,viscosity,physical solubility,CO_(2) diffusivity and absorption rate of CO_(2) in the solution were determined.The reaction kinetics between CO_(2) and K2CO3þDETA solution were examined.Pseudo-first order kinetic constants were also predicted by zwitterion mechanism.It was revealed that the addition of small amounts of DETA to K_(2)CO_(3) results in a significant enhancement in CO_(2) absorption rate.The reaction order and activation energy were found to be 1.6 and 35.6 kJ mol1,respectively.In terms of reaction rate constant,DETA showed a better performance compared to the other promoters such as MEA,EAE,proline,arginine,taurine,histidine and alanine.展开更多
In this issue,manuscripts have been published on a wide variety of topics,which demonstrates the large scope of Semiconductor Science&Information Devices.Even the authors are from diverse geographical areas!We con...In this issue,manuscripts have been published on a wide variety of topics,which demonstrates the large scope of Semiconductor Science&Information Devices.Even the authors are from diverse geographical areas!We continue to encourage such submissions on varied topics.In fact,much of the engineering today is multi-disciplinary involving close cooperation&collaboration among many fields&specializations.展开更多
Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop...Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop test with varying impact energy was conducted to reproduce the dynamic performance of MP1rockbolts under a wide range of seismic event magnitudes. The test results showed that the impact process could be subdivided into four distinct stages, i.e. mobilization, strain hardening, plastic flow(ductile), and rebound stage, of which strain hardening and plastic flow are the primary energy absorbing stages. As the impact energy per drop increases from 8.1 to 46.7 k J, the strain rate of the shank varies between 1.20 and 2.70 s^(-1), and the average impact load is between 240 and 270kN, which may be considered as constant. The MP1 rockbolt has a cumulative maximum energy absorption(CMEA) of 31.9–40.0 k J/m, with an average of 35.0 k J/m, and the elongation rate is 11.4%–14.7%, with an average of 12.7%, both of which are negatively correlated with the impact energy per drop. Regression analysis shows that energy absorption and shank elongation, as well as momentum input and impact duration,conform to the linear relationship. The complete dynamic capacity envelope of MP1 rockbolts is proposed, which reflects the dynamic bearing capacity, elongation, and distinct stages. This study is helpful to better understand the dynamic characteristics of energy-absorbing rockbolts and assist design engineers in robust reinforcement systems design to mitigate rockburst damage in seismically active underground excavations.展开更多
The antenna plays an essential role in the medical industry.The short-range 5th Generation(5G)communication can be used for seamless transmission,reception,patient monitoring,sensing and measuring various processes at...The antenna plays an essential role in the medical industry.The short-range 5th Generation(5G)communication can be used for seamless transmission,reception,patient monitoring,sensing and measuring various processes at high speeds.A passive Ultra Wide Band(UWB)antenna,used as a sensor in the mea-surement of Prothrombin Time(PT)i.e.,blood clot is being proposed.The inves-tigated micro-strip patch UWB antenna operating in the frequency range of 3.1 to 10.6 GHz consists of a circular patch with a diamond-shaped slot made of jeans substrate material with good sensing properties is accomplished by adjusting the copper thickness of the patch.Due to the turbidity in blood plasma,PT measure-ment is the repetitive approach to get accurate value.In order to solve this issue,an antenna is designed,fabricated and analysed to obtain the accurate PT mea-surements from blood plasma.The blood clotting is observed by electromagnetic emitted voltage converted into the frequency range of 5 to 10 GHz and voltage range of 0.66 to 0.87 mV.The circular UWB antenna is constructed employing jean’s substrate with a partial ground plane to improve the S-parameter,gain,bandwidth and performance characteristics.The proposed antenna with Specific Absorption Rate(SAR)value within the acceptable range can be used as a wear-able device in the human body,leveraging 5G technology.This antenna is well suited for various other applications like wireless sensors,wearable devices and short-range communication applications.展开更多
This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum(OAM)waves with Mode+2 at 3.5 GHz(3.4 to 3.6 GHz)of the sub-6 GHz fifth-generation(5G)New Radio(NR)band.Th...This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum(OAM)waves with Mode+2 at 3.5 GHz(3.4 to 3.6 GHz)of the sub-6 GHz fifth-generation(5G)New Radio(NR)band.The proposed antenna is based on a uniform circular array of eight microstrip patch antennas on a felt textile substrate.In contrast to previous works involving the use of rigid substrates to generate OAM waves,this work explored the use of flexible substrates to generate OAM waves for the first time.Other than that,the proposed antenna was simulated,analyzed,fabricated,and tested to confirm the generation of OAMMode+2.With the same design,OAM Mode−2 can be generated readily simply by mirror imaging the feed network.Note that the proposed antenna operated at the desired frequency of 3.5 GHz with an overall bandwidth of 400 MHz in free space.Moreover,mode purity analysis is carried out to verify the generation of OAM Mode+2,and the purity obtained was 41.78%at free space flat condition.Furthermore,the effect of antenna bending on the purity of the generated OAM mode is also investigated.Lastly,the influence of textile properties on OAM modes is examined to assist future researchers in choosing suitable fabrics to design flexible OAM-based antennas.After a comprehensive analysis considering different factors related to wearable applications,this paper demonstrates the feasibility of generating OAMwaves using textile antennas.Furthermore,as per the obtained Specific Absorption Rate(SAR),it is found that the proposed antenna is safe to be deployed.The findings of this work have a significant implication for body-centric communications.展开更多
This work is part of an experimental contribution approach to the study of the incorporation of glass sand from the grinding of recycled glass waste in cement mortars and its influence on the physical and mechanical b...This work is part of an experimental contribution approach to the study of the incorporation of glass sand from the grinding of recycled glass waste in cement mortars and its influence on the physical and mechanical behavior of semi-rich mortars without adjuvants. For this purpose, after a physical characterization of the sands, eight (08) formulations of mortars based on cement CEM II B/L 32.5R and fine sands (0/2) of glass at mass contents of 0%, 10%, 20%, 30%, 40%, 50%, 75% and 100% of the silty sand (0/2) were made respectively to three (03) types of fine glass sand (white, brown, green) with water dosages on cement (W/C) of 0.50, 0.45, 0.40. The results obtained show that the fine sands of recycled glass have a higher water absorption than the silty sand and the physical properties of the mortars prepared are affected by the increase in the glass content. The mechanical performances are obtained for the ratio W/C = 0.50 and the formulation of glass mortars for an optimal compressive strength superior to glass-free mortar requires a substitution of 10% for fine white glass sand, 20% for sand fine green glass and 75% for fine brown glass sand. The comparative study between these different compositions of fine glass sand mortars shows that the mechanical performances of fine brown glass sand are better than other glass sands but generally remain inferior to the control mortar based on natural silty sand.展开更多
A heuristic stochastic solution of the Pennes equation is developed in this paper by applying the self-organizing, self-similar behaviour of living structures. The stochastic solution has a probability distribution th...A heuristic stochastic solution of the Pennes equation is developed in this paper by applying the self-organizing, self-similar behaviour of living structures. The stochastic solution has a probability distribution that fits well with the dynamic changes in the living objects concerned and eliminates the problem of the deterministic behaviour of the Pennes approach. The solution employs the Weibull two-parametric distribution which offers satisfactory delivery of the rate of temperature change by time. Applying the method to malignant tumours obtains certain benefits, increasing the efficacy of the distortion of the cancerous cells and avoiding doing harm to the healthy cells. Due to the robust heterogeneity of these living systems, we used thermal and bioelectromagnetic effects to distinguish the malignant defects, selecting them from the healthy cells. On a selective basis, we propose an optimal protocol using the provided energy optimally such that molecular changes destroy the malignant cells without a noticeable effect on their healthy counterparts.展开更多
The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by H...The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by HN for medical diagnosis and treatment. Research issues including the wave frequency, power intensity, reflections and scattering, and penetration depths are of important considerations to be incorporated into the research study. In this study, computer simulation for the EM exposure to HN was studied for the purpose of determining the upper limits of the electric and magnetic field intensities, power consumption, reflections and transmissions, and the change in temperature resulting from the power absorption by human neurons. Both high frequency structural simulators (HFSS) from ANSYS software, and COMSOL multi-physics were used for the simulation of the EM transmissions and reflections, and the temperature profile within the cells, respectively. For the temperature profile estimation, the study considers an electrical source of 0.5 watt input power, 64 MHz. The EM simulation was looking into the uniformity of the fields within the sample cells. The size of the waveguide was set to be appropriate for a small animal model to be conducted in the future. The incident power was fully transmitted throughout the waveguide, and less than 1% reflections were observed from the simulation. The minimum reflected power near the sample under investigation was found to be with negligible reflected field strengths. The temperature profile resulting from the COMSOL simulation was found to be near 0.25 m°K, indicating no change in temperature on the neuro cells under the EM exposure. The paper details the simulation results for the EM response determined by HFSS, and temperature profile simulated by COMSOL.展开更多
Objective This study is to obtain precise data on iron physiological requirements in Chinese children using single stable isotope tracertechnique.Methods Thirty boys(10.6±0.2 years)and 27 girls(10.4±0.2 year...Objective This study is to obtain precise data on iron physiological requirements in Chinese children using single stable isotope tracertechnique.Methods Thirty boys(10.6±0.2 years)and 27 girls(10.4±0.2 years)were received oral 6 mg ^(57)Fe each day for 5 consecutive days.Venous blood samples were subsequently drawn to examine the change of total iron concentration and ^(57)Fe abundance at day 0,14,28,60,90,180,360,450,540,630,720.The iron physiological requirement was calculated by iron loss combined with iron circulation rate once ^(57)Fe abundance stabilized in human body.Results The iron physiological requirement was significantly lower in boys than those values in girls(16.88±7.12 vs.18.40±8.81μg/kg per day,P<0.05).Correspondingly,the values were calculated as 722.46±8.43μg/day for boys and 708.40±7.55μg/day for girls,respectively.Considering nearly 10%iron absorption rate,the estimated average iron physiological requirement was 6.0 mg/day in boys and 6.2 mg/day in girls.Conclusion This study indicate that iron physiological requirement could require more daily iron intake in girls as compare with the values in boys having the same body weight.These findings would be facilitate to the new revised dietary reference intakes.展开更多
Microwave-induced thermoacoustic imaging(MI-TAI)remains one of the focus of attention among biomedical imaging modalities over the last decade.However,the transmission and dis-tribution of microwave inside bio-tissues...Microwave-induced thermoacoustic imaging(MI-TAI)remains one of the focus of attention among biomedical imaging modalities over the last decade.However,the transmission and dis-tribution of microwave inside bio-tissues are complicated,thus result in severe artifacts.In this study,to reveal the underlying mechanisms of artifacts,we deeply investigate the distribution of specific absorption rate(SAR)inside tissue-mimicking phantoms with varied morphological features using both mathematical simulations and corresponding experiments.Our simulated results,which are confirmed by the associated experimental results,show that the SAR distri-bution highly depends on the geometries of the imaging targets and the polarizing features of the microwave.In addition,we propose the potential mechanisms including Mie-scattering,Fabry-Perot-feature,small curvature effect to interpret the diffraction effect in different scenarios,which may provide basic guidance to predict and distinguish the artifacts for TAI in both fundamental and clinical studies.展开更多
[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla...[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla Miq. seeds during different harvest periods were analyzed and compared. [Results] The results showed that the A. oxyphylla Miq. fruit picking period was closely related to the seed quality,and the seed maturity was highest 100 d after the flowering of A. oxyphylla Miq.,that is,the A. oxyphylla Miq. fruit skin turned from green to yellow( yellow-green),the peel had a small number of brown spots,it was spicy enough,the fruit dry/fresh weight ratio was greater than0. 34,the seed thousand kernel weight reached 11 g or more,and the dried seed moisture content was 13. 01%. Using the TTC method,the seed viability index was determined to be 85%,and in this case,it was the best time of harvesting seed. The water permeability of A. oxyphylla Miq. seed was poor,and the seed imbibition and water absorption time was long,about 72 h. The maximum water absorption rate was about23. 71% at the imbibition and water absorption stage,and it was inferred that the A. oxyphylla Miq. seeds were hard seeds. The germination time of A. oxyphylla Miq. seeds was long,the mature A. oxyphylla Miq. seeds began to germinate on the 12 th d,and the germination rate reached 75. 56% on the 50 th d. [Conclusions] This study determined the optimum harvest period of A. oxyphylla Miq. seeds,clarified the biological characteristics of slow seed water absorption and long germination cycle,and concluded that the seed coat was the main factor leading to slow seed water absorption and long seed germination cycle.展开更多
[Objectives]To optimize the drying technology and formation process of Naomai Xingshen Capsules.[Methods]The yield of paste powder and moisture content as evaluation indicators were taken as indicators,the relative de...[Objectives]To optimize the drying technology and formation process of Naomai Xingshen Capsules.[Methods]The yield of paste powder and moisture content as evaluation indicators were taken as indicators,the relative density of feed liquid,inlet air temperature and dosage of excipients were selected as investigation factors,the orthogonal experiment method was used to optimize the spray drying process.The moisture absorption rate and angle of repose were taken as evaluation indicators,the types of forming excipient were screened,and the critical relative humidity was determined.[Results]The optimum spray drying process was that the relative density of liquid medicine was 1.05(60℃),the air inlet temperature was 200℃,and the dosage of excipients was 2%.The effect of using dextrin as a forming excipient was better,and the relative humidity of the production environment should be controlled below 65%.[Conclusions]The optimized process is stable,feasible,scientific and reasonable,and can be used for large-scale industrial production.展开更多
The dynamics of accumulations of plant dry matter, nutrient uptake and N fertilizer recovery were studied with different water and N supply, using summer maize (Zea mays L. var. Shandan9) as an indicator crop. The tot...The dynamics of accumulations of plant dry matter, nutrient uptake and N fertilizer recovery were studied with different water and N supply, using summer maize (Zea mays L. var. Shandan9) as an indicator crop. The total dry matter (including roots) and N, P, K uptake amounts were continuously increased with plant growth, and their accumulations with time during plant-growing period were shaped in S curves that could be described by exponential regression equations. Differentiating the regression equations fitting the curves over time for first derivatives, the momentary rate was obtained of the dry matter and nutrient uptake. Results show that the dry matter and the nutrient uptake were not in the same rate at all time, but changed from one time to another. Usually, the rate increased rapidly at early stages, and gradually decreased after reaching their peak. Of N, P and K, the uptake rate of N and K was higher, and their increase and decrease were both fast while P was reversed. The time of the maximum absorptive rate appeared earlier for K, followed by N, and then by P. In any case, the maximum nutrient uptake rate appeared earlier than did the dry matter. The momentary N recovery rate was similar in trend to those of dry matter and N uptake, and its maximum recovery rate occurred almost at the same time as its maximum uptake rate. Supplemental irrigation raised the cumulative and momentary rates of N. Although water and N supplies increased dry matter and nutrient uptake rates, they did not alter their changing trends during the plant-growing period.展开更多
Although arbuscular mycorrhizal fungi(AMF)could play important roles in zinc(Zn)uptake in host plants,the effects of AMF on Zn uptake and transport in winter wheat during the whole growth stages remain unclear.A pot e...Although arbuscular mycorrhizal fungi(AMF)could play important roles in zinc(Zn)uptake in host plants,the effects of AMF on Zn uptake and transport in winter wheat during the whole growth stages remain unclear.A pot experiment was conducted to investigate the effects of Funneliformis mosseae(Fm)and Claroideoglomus etunicatum(Ce)on Zn absorption,transport,and accumulation in winter wheat growing in soils spiked with different Zn levels(0,2.5,and 25 mg kg^(-1)).The results showed that there was a significant correlation between mycorrhizal colonization rate and Zn absorption efficiency in winter wheat roots during the post-anthesis period,but there was no significant correlation during the pre-anthesis period.Arbuscular mycorrhizal fungi significantly increased Zn concentrations(0.56–1.58 times)in wheat grains under 0 mg kg^(-1)Zn level,but decreased Zn concentrations in wheat grains under 25 mg kg^(-1)Zn level.Additionally,at the filling and maturity stages,AMF increased Zn absorption rate and the contribution of root Zn uptake to grain Zn by 3–14 and 0.36–0.64 times,respectively,under 0 mg kg^(-1)Zn level and 0.21–1.02 and 0.27–0.37 times,respectively,under 2.5 mg kg^(-1)Zn level.However,AMF decreased root Zn absorption rate(0.32–0.61 times)and increased the contribution of Zn remobilization in vegetative tissues to grain Zn(1.69–2.01 times)under 25 mg kg^(-1)Zn level.This study would complement the mechanisms and effects of AMF on Zn absorption and transport in winter wheat and provide a potential method for the application of AMF to enrich wheat grain Zn.展开更多
Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% hi...Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH3), respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation: k2,AMP/C3 = 7.702×106 exp (-2248.03/T). A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.展开更多
The energy absorption characteristics of the lotus-type porous coppers at the strain rate of 10-3 s-1 to N2400 s 1 were systematically investigated. Depending on the relative density and loading rate, the energy absor...The energy absorption characteristics of the lotus-type porous coppers at the strain rate of 10-3 s-1 to N2400 s 1 were systematically investigated. Depending on the relative density and loading rate, the energy absorption capability of the tested samples varied from -20 to -85 MJ m-1, while the energy absorption efficiency fluctuated around N0.6. An energy absorption efficiency curve based approach was proposed for unambiguous identification of the plateau regime, which gave an extension of -0.50 strain range for the presently investigated porous coppers. With detailed observations of cell wall morphologies at various deformation stages, it was suggested that buckling of cell wails was the dominant mechanism mediat- ing the energy absorption in lotus-type porous coppers.展开更多
As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility ...As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility as energy absorbers is still in question, particularly when compression is in the direction perpendicular to the axial orientation of cylindrical pores. In this work, the energy absorption of lotus-type porous coppers in the perpendicular direction is investigated at strain rates from 0.001 s^(-1) to^2400 s^(-1). The energy absorption capacity and the energy absorption efficiency are calculated to be4–16 k J/kg and 0.32–0.7, respectively, slightly inferior to metal foams and the same porous solid compressed in the parallel direction due to the shortened extent of the plateau stress region. The deformation mechanism is examined experimentally in conjunction with finite element modeling. Both suggest that gradual squeeze and collapse of pores are the mechanisms accommodating the energy absorption. The deformation is generally evenly distributed over pore ligaments and independent of strain rate.展开更多
文摘We study the problem of a diffusing particle confined in a large sphere in the n-dimensional space being absorbed into a small sphere at the center. We first non-dimensionalize the problem using the radius of large confining sphere as the spatial scale and the square of the spatial scale divided by the diffusion coefficient as the time scale. The non-dimensional normalized absorption rate is the product of the physical absorption rate and the time scale. We derive asymptotic expansions for the normalized absorption rate using the inverse iteration method. The small parameter in the asymptotic expansions is the ratio of the small sphere radius to the large sphere radius. In particular, we observe that, to the leading order, the normalized absorption rate is proportional to the (n - 2)-th power of the small parameter for .
基金This work is collaborative research with the Department of Electronics&Communication Engineering,Acharya Institute of Technology,Bengaluru,India.And also this work is a collaborative research between Yangon Technological University and University of Oulu in Finland based on the enhancement of Telecommunication Engineering Education in YTU.This work is fully supported by the government research funds of 2020-2021 academic year which is the grant no of GB/D(4)2020/4.
文摘The system analysis of specific absorption rate(SAR)in human body exposed to a base station antenna by using finite difference time domain techniques was presented in this research works.The objectives of this work are to evaluate the knowledge and awareness about SAR among human body and mobile base station.The paper investigates the electromagnetic wave absorption inside a human body.The human body has been identified using dataset based on 2D object considering different electrical parameters.The SAR convinced inside the human body model exposed to a radiating base station antenna(BSA)has been considered for multiple numbers of carrier frequencies and input power of 20 W/carrier at GSM 900 band.The distance(R)of human body from BSA is varied in the range of 0.1 m to 5.0 m.For the number of carrier frequency equal to one and R=0.1 m,the concentrated value of whole-body average SAR obtained by FDTD technique is found to be 0.68 W/kg which decreases either with increase of R or decrease of number of carrier frequencies.Safety distance for general public is found to be 1.5 m for number of carrier frequencies equal to one.The performance accuracy of this analysis meets the high level condition by comparing with the relevant system development in recent time.
文摘Background Previous studies have suggested that nomogram can simplize complicated calculations of several varibles. A simple nomogram was constructed to estimate absorption rate coefficient (k a) by using the peak time (t peak ) and the elimination rate coefficient (k e) of drugs administered orally Methods The nomogram was based on the plasma concentration-time (C-T) curve equation and the function relation between t peak , k a and k e A mathematical analysis was presented for the construction of single chart nomogram To check the degree of accuracy of the developed nomogram, we used it to analyze retrospective profiles of 46 drugs and compared the k a values obtained graphically and those calculated by numerically solving the descriptive equation In addition, we measured the carbocisteine concentration of 18 healthy volunteers by HPLC with fluorescence detection To analyze performance error, the measured carbocisteine concentrations were compared with predicted concentrations by the k a obtained from the nomograms along with the other pharmacokinetic parameters Results The estimated of k a values from nomograms were in very close proximity with the numerical values The performance error was as follows: median performance error (MDPE) and median absolute performance error (MDAPE) were 1 32% and 18 15%, respectively Conclusions The developed nomogram is accurate and reliable The size of performance error meets the demand of clinical pharmacokinetics Therefore, the nomograms can offer another convenient and easy method for rational individualized dosage regimens
文摘In this work,characterization and kinetics of CO2 absorption in potassium carbonate(K_(2)CO_(3))solution promoted by diethylenetriamine(DETA)were investigated.Kinetics measurements were performed using a stirred cell reactor in the temperature range of 303.15–323.15 K and total concentration up to 2.5 kmol m3.The density,viscosity,physical solubility,CO_(2) diffusivity and absorption rate of CO_(2) in the solution were determined.The reaction kinetics between CO_(2) and K2CO3þDETA solution were examined.Pseudo-first order kinetic constants were also predicted by zwitterion mechanism.It was revealed that the addition of small amounts of DETA to K_(2)CO_(3) results in a significant enhancement in CO_(2) absorption rate.The reaction order and activation energy were found to be 1.6 and 35.6 kJ mol1,respectively.In terms of reaction rate constant,DETA showed a better performance compared to the other promoters such as MEA,EAE,proline,arginine,taurine,histidine and alanine.
文摘In this issue,manuscripts have been published on a wide variety of topics,which demonstrates the large scope of Semiconductor Science&Information Devices.Even the authors are from diverse geographical areas!We continue to encourage such submissions on varied topics.In fact,much of the engineering today is multi-disciplinary involving close cooperation&collaboration among many fields&specializations.
基金CCTEG Coal Mining Research Institute(No.TDKC-2022-MS-01)the National Natural Science Foundation of China(No.52274123)the Mining Education Australia(MEA),Collaborative Research Grant Scheme(No.RS-59041).
文摘Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop test with varying impact energy was conducted to reproduce the dynamic performance of MP1rockbolts under a wide range of seismic event magnitudes. The test results showed that the impact process could be subdivided into four distinct stages, i.e. mobilization, strain hardening, plastic flow(ductile), and rebound stage, of which strain hardening and plastic flow are the primary energy absorbing stages. As the impact energy per drop increases from 8.1 to 46.7 k J, the strain rate of the shank varies between 1.20 and 2.70 s^(-1), and the average impact load is between 240 and 270kN, which may be considered as constant. The MP1 rockbolt has a cumulative maximum energy absorption(CMEA) of 31.9–40.0 k J/m, with an average of 35.0 k J/m, and the elongation rate is 11.4%–14.7%, with an average of 12.7%, both of which are negatively correlated with the impact energy per drop. Regression analysis shows that energy absorption and shank elongation, as well as momentum input and impact duration,conform to the linear relationship. The complete dynamic capacity envelope of MP1 rockbolts is proposed, which reflects the dynamic bearing capacity, elongation, and distinct stages. This study is helpful to better understand the dynamic characteristics of energy-absorbing rockbolts and assist design engineers in robust reinforcement systems design to mitigate rockburst damage in seismically active underground excavations.
文摘The antenna plays an essential role in the medical industry.The short-range 5th Generation(5G)communication can be used for seamless transmission,reception,patient monitoring,sensing and measuring various processes at high speeds.A passive Ultra Wide Band(UWB)antenna,used as a sensor in the mea-surement of Prothrombin Time(PT)i.e.,blood clot is being proposed.The inves-tigated micro-strip patch UWB antenna operating in the frequency range of 3.1 to 10.6 GHz consists of a circular patch with a diamond-shaped slot made of jeans substrate material with good sensing properties is accomplished by adjusting the copper thickness of the patch.Due to the turbidity in blood plasma,PT measure-ment is the repetitive approach to get accurate value.In order to solve this issue,an antenna is designed,fabricated and analysed to obtain the accurate PT mea-surements from blood plasma.The blood clotting is observed by electromagnetic emitted voltage converted into the frequency range of 5 to 10 GHz and voltage range of 0.66 to 0.87 mV.The circular UWB antenna is constructed employing jean’s substrate with a partial ground plane to improve the S-parameter,gain,bandwidth and performance characteristics.The proposed antenna with Specific Absorption Rate(SAR)value within the acceptable range can be used as a wear-able device in the human body,leveraging 5G technology.This antenna is well suited for various other applications like wireless sensors,wearable devices and short-range communication applications.
基金This work was supported by Ministry of Higher Education through the Fundamental Research Grant Scheme(FRGS)under a grant number of FRGS/1/2020/ICT09/UNIMAP/02/2.
文摘This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum(OAM)waves with Mode+2 at 3.5 GHz(3.4 to 3.6 GHz)of the sub-6 GHz fifth-generation(5G)New Radio(NR)band.The proposed antenna is based on a uniform circular array of eight microstrip patch antennas on a felt textile substrate.In contrast to previous works involving the use of rigid substrates to generate OAM waves,this work explored the use of flexible substrates to generate OAM waves for the first time.Other than that,the proposed antenna was simulated,analyzed,fabricated,and tested to confirm the generation of OAMMode+2.With the same design,OAM Mode−2 can be generated readily simply by mirror imaging the feed network.Note that the proposed antenna operated at the desired frequency of 3.5 GHz with an overall bandwidth of 400 MHz in free space.Moreover,mode purity analysis is carried out to verify the generation of OAM Mode+2,and the purity obtained was 41.78%at free space flat condition.Furthermore,the effect of antenna bending on the purity of the generated OAM mode is also investigated.Lastly,the influence of textile properties on OAM modes is examined to assist future researchers in choosing suitable fabrics to design flexible OAM-based antennas.After a comprehensive analysis considering different factors related to wearable applications,this paper demonstrates the feasibility of generating OAMwaves using textile antennas.Furthermore,as per the obtained Specific Absorption Rate(SAR),it is found that the proposed antenna is safe to be deployed.The findings of this work have a significant implication for body-centric communications.
文摘This work is part of an experimental contribution approach to the study of the incorporation of glass sand from the grinding of recycled glass waste in cement mortars and its influence on the physical and mechanical behavior of semi-rich mortars without adjuvants. For this purpose, after a physical characterization of the sands, eight (08) formulations of mortars based on cement CEM II B/L 32.5R and fine sands (0/2) of glass at mass contents of 0%, 10%, 20%, 30%, 40%, 50%, 75% and 100% of the silty sand (0/2) were made respectively to three (03) types of fine glass sand (white, brown, green) with water dosages on cement (W/C) of 0.50, 0.45, 0.40. The results obtained show that the fine sands of recycled glass have a higher water absorption than the silty sand and the physical properties of the mortars prepared are affected by the increase in the glass content. The mechanical performances are obtained for the ratio W/C = 0.50 and the formulation of glass mortars for an optimal compressive strength superior to glass-free mortar requires a substitution of 10% for fine white glass sand, 20% for sand fine green glass and 75% for fine brown glass sand. The comparative study between these different compositions of fine glass sand mortars shows that the mechanical performances of fine brown glass sand are better than other glass sands but generally remain inferior to the control mortar based on natural silty sand.
文摘A heuristic stochastic solution of the Pennes equation is developed in this paper by applying the self-organizing, self-similar behaviour of living structures. The stochastic solution has a probability distribution that fits well with the dynamic changes in the living objects concerned and eliminates the problem of the deterministic behaviour of the Pennes approach. The solution employs the Weibull two-parametric distribution which offers satisfactory delivery of the rate of temperature change by time. Applying the method to malignant tumours obtains certain benefits, increasing the efficacy of the distortion of the cancerous cells and avoiding doing harm to the healthy cells. Due to the robust heterogeneity of these living systems, we used thermal and bioelectromagnetic effects to distinguish the malignant defects, selecting them from the healthy cells. On a selective basis, we propose an optimal protocol using the provided energy optimally such that molecular changes destroy the malignant cells without a noticeable effect on their healthy counterparts.
文摘The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by HN for medical diagnosis and treatment. Research issues including the wave frequency, power intensity, reflections and scattering, and penetration depths are of important considerations to be incorporated into the research study. In this study, computer simulation for the EM exposure to HN was studied for the purpose of determining the upper limits of the electric and magnetic field intensities, power consumption, reflections and transmissions, and the change in temperature resulting from the power absorption by human neurons. Both high frequency structural simulators (HFSS) from ANSYS software, and COMSOL multi-physics were used for the simulation of the EM transmissions and reflections, and the temperature profile within the cells, respectively. For the temperature profile estimation, the study considers an electrical source of 0.5 watt input power, 64 MHz. The EM simulation was looking into the uniformity of the fields within the sample cells. The size of the waveguide was set to be appropriate for a small animal model to be conducted in the future. The incident power was fully transmitted throughout the waveguide, and less than 1% reflections were observed from the simulation. The minimum reflected power near the sample under investigation was found to be with negligible reflected field strengths. The temperature profile resulting from the COMSOL simulation was found to be near 0.25 m°K, indicating no change in temperature on the neuro cells under the EM exposure. The paper details the simulation results for the EM response determined by HFSS, and temperature profile simulated by COMSOL.
基金supported by the National Natural Science Foundation of China [grant number 81330066]
文摘Objective This study is to obtain precise data on iron physiological requirements in Chinese children using single stable isotope tracertechnique.Methods Thirty boys(10.6±0.2 years)and 27 girls(10.4±0.2 years)were received oral 6 mg ^(57)Fe each day for 5 consecutive days.Venous blood samples were subsequently drawn to examine the change of total iron concentration and ^(57)Fe abundance at day 0,14,28,60,90,180,360,450,540,630,720.The iron physiological requirement was calculated by iron loss combined with iron circulation rate once ^(57)Fe abundance stabilized in human body.Results The iron physiological requirement was significantly lower in boys than those values in girls(16.88±7.12 vs.18.40±8.81μg/kg per day,P<0.05).Correspondingly,the values were calculated as 722.46±8.43μg/day for boys and 708.40±7.55μg/day for girls,respectively.Considering nearly 10%iron absorption rate,the estimated average iron physiological requirement was 6.0 mg/day in boys and 6.2 mg/day in girls.Conclusion This study indicate that iron physiological requirement could require more daily iron intake in girls as compare with the values in boys having the same body weight.These findings would be facilitate to the new revised dietary reference intakes.
基金This study was supported by the National Natural Science Foundation of China(Nos.62022037,61775028,81571722,61528401 and 61921002)Guangdong province(2019ZT08Y191)+1 种基金Shenzhen Science and Technology Program(KQTD20190929172743294)Startup grant from Southern University of Science and Technology.
文摘Microwave-induced thermoacoustic imaging(MI-TAI)remains one of the focus of attention among biomedical imaging modalities over the last decade.However,the transmission and dis-tribution of microwave inside bio-tissues are complicated,thus result in severe artifacts.In this study,to reveal the underlying mechanisms of artifacts,we deeply investigate the distribution of specific absorption rate(SAR)inside tissue-mimicking phantoms with varied morphological features using both mathematical simulations and corresponding experiments.Our simulated results,which are confirmed by the associated experimental results,show that the SAR distri-bution highly depends on the geometries of the imaging targets and the polarizing features of the microwave.In addition,we propose the potential mechanisms including Mie-scattering,Fabry-Perot-feature,small curvature effect to interpret the diffraction effect in different scenarios,which may provide basic guidance to predict and distinguish the artifacts for TAI in both fundamental and clinical studies.
基金Supported by the Fundamental Research Funds for Environment and Plant Protection Institute,Chinese Academy of Tropical Agricultural Sciences(16300420170291630042017008)
文摘[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla Miq. seeds during different harvest periods were analyzed and compared. [Results] The results showed that the A. oxyphylla Miq. fruit picking period was closely related to the seed quality,and the seed maturity was highest 100 d after the flowering of A. oxyphylla Miq.,that is,the A. oxyphylla Miq. fruit skin turned from green to yellow( yellow-green),the peel had a small number of brown spots,it was spicy enough,the fruit dry/fresh weight ratio was greater than0. 34,the seed thousand kernel weight reached 11 g or more,and the dried seed moisture content was 13. 01%. Using the TTC method,the seed viability index was determined to be 85%,and in this case,it was the best time of harvesting seed. The water permeability of A. oxyphylla Miq. seed was poor,and the seed imbibition and water absorption time was long,about 72 h. The maximum water absorption rate was about23. 71% at the imbibition and water absorption stage,and it was inferred that the A. oxyphylla Miq. seeds were hard seeds. The germination time of A. oxyphylla Miq. seeds was long,the mature A. oxyphylla Miq. seeds began to germinate on the 12 th d,and the germination rate reached 75. 56% on the 50 th d. [Conclusions] This study determined the optimum harvest period of A. oxyphylla Miq. seeds,clarified the biological characteristics of slow seed water absorption and long germination cycle,and concluded that the seed coat was the main factor leading to slow seed water absorption and long seed germination cycle.
基金Medical Research Project of Zhongshan City Health and Family Planning Bureau,Guangdong Province(2015J050).
文摘[Objectives]To optimize the drying technology and formation process of Naomai Xingshen Capsules.[Methods]The yield of paste powder and moisture content as evaluation indicators were taken as indicators,the relative density of feed liquid,inlet air temperature and dosage of excipients were selected as investigation factors,the orthogonal experiment method was used to optimize the spray drying process.The moisture absorption rate and angle of repose were taken as evaluation indicators,the types of forming excipient were screened,and the critical relative humidity was determined.[Results]The optimum spray drying process was that the relative density of liquid medicine was 1.05(60℃),the air inlet temperature was 200℃,and the dosage of excipients was 2%.The effect of using dextrin as a forming excipient was better,and the relative humidity of the production environment should be controlled below 65%.[Conclusions]The optimized process is stable,feasible,scientific and reasonable,and can be used for large-scale industrial production.
基金the projects(49890330,30230230,30070429 , 40201028) the Nat ional Natural Science Foundation of China(NSFC)+2 种基金 the project(G1999011707)the National Key Basic Research Support Funds(NKBRSF)the opportunity of thanking the NSFC and the NKBRSF for their kindness of supporting such projects.
文摘The dynamics of accumulations of plant dry matter, nutrient uptake and N fertilizer recovery were studied with different water and N supply, using summer maize (Zea mays L. var. Shandan9) as an indicator crop. The total dry matter (including roots) and N, P, K uptake amounts were continuously increased with plant growth, and their accumulations with time during plant-growing period were shaped in S curves that could be described by exponential regression equations. Differentiating the regression equations fitting the curves over time for first derivatives, the momentary rate was obtained of the dry matter and nutrient uptake. Results show that the dry matter and the nutrient uptake were not in the same rate at all time, but changed from one time to another. Usually, the rate increased rapidly at early stages, and gradually decreased after reaching their peak. Of N, P and K, the uptake rate of N and K was higher, and their increase and decrease were both fast while P was reversed. The time of the maximum absorptive rate appeared earlier for K, followed by N, and then by P. In any case, the maximum nutrient uptake rate appeared earlier than did the dry matter. The momentary N recovery rate was similar in trend to those of dry matter and N uptake, and its maximum recovery rate occurred almost at the same time as its maximum uptake rate. Supplemental irrigation raised the cumulative and momentary rates of N. Although water and N supplies increased dry matter and nutrient uptake rates, they did not alter their changing trends during the plant-growing period.
基金The financial support from the Natural Science Basic Research Program of Shaanxi,China(No.2023-JC-ZD17)the National Natural Science Foundation of China(Nos.42077345 and 41571456)the Project of Innovative Experimental Plan for College Students of Northwest A&F University,China(No.202310712128)。
文摘Although arbuscular mycorrhizal fungi(AMF)could play important roles in zinc(Zn)uptake in host plants,the effects of AMF on Zn uptake and transport in winter wheat during the whole growth stages remain unclear.A pot experiment was conducted to investigate the effects of Funneliformis mosseae(Fm)and Claroideoglomus etunicatum(Ce)on Zn absorption,transport,and accumulation in winter wheat growing in soils spiked with different Zn levels(0,2.5,and 25 mg kg^(-1)).The results showed that there was a significant correlation between mycorrhizal colonization rate and Zn absorption efficiency in winter wheat roots during the post-anthesis period,but there was no significant correlation during the pre-anthesis period.Arbuscular mycorrhizal fungi significantly increased Zn concentrations(0.56–1.58 times)in wheat grains under 0 mg kg^(-1)Zn level,but decreased Zn concentrations in wheat grains under 25 mg kg^(-1)Zn level.Additionally,at the filling and maturity stages,AMF increased Zn absorption rate and the contribution of root Zn uptake to grain Zn by 3–14 and 0.36–0.64 times,respectively,under 0 mg kg^(-1)Zn level and 0.21–1.02 and 0.27–0.37 times,respectively,under 2.5 mg kg^(-1)Zn level.However,AMF decreased root Zn absorption rate(0.32–0.61 times)and increased the contribution of Zn remobilization in vegetative tissues to grain Zn(1.69–2.01 times)under 25 mg kg^(-1)Zn level.This study would complement the mechanisms and effects of AMF on Zn absorption and transport in winter wheat and provide a potential method for the application of AMF to enrich wheat grain Zn.
基金financially supported by the Brain Korea 21 Project in 2012the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.2006CCD11P011A -21-3-010)
文摘Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH3), respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation: k2,AMP/C3 = 7.702×106 exp (-2248.03/T). A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.
基金financial support from the National Natural Science Foundation of China (Grant No. 50904004)
文摘The energy absorption characteristics of the lotus-type porous coppers at the strain rate of 10-3 s-1 to N2400 s 1 were systematically investigated. Depending on the relative density and loading rate, the energy absorption capability of the tested samples varied from -20 to -85 MJ m-1, while the energy absorption efficiency fluctuated around N0.6. An energy absorption efficiency curve based approach was proposed for unambiguous identification of the plateau regime, which gave an extension of -0.50 strain range for the presently investigated porous coppers. With detailed observations of cell wall morphologies at various deformation stages, it was suggested that buckling of cell wails was the dominant mechanism mediat- ing the energy absorption in lotus-type porous coppers.
基金financial support from the National Natural Science Foundation of China (Grant No. 50904004)
文摘As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility as energy absorbers is still in question, particularly when compression is in the direction perpendicular to the axial orientation of cylindrical pores. In this work, the energy absorption of lotus-type porous coppers in the perpendicular direction is investigated at strain rates from 0.001 s^(-1) to^2400 s^(-1). The energy absorption capacity and the energy absorption efficiency are calculated to be4–16 k J/kg and 0.32–0.7, respectively, slightly inferior to metal foams and the same porous solid compressed in the parallel direction due to the shortened extent of the plateau stress region. The deformation mechanism is examined experimentally in conjunction with finite element modeling. Both suggest that gradual squeeze and collapse of pores are the mechanisms accommodating the energy absorption. The deformation is generally evenly distributed over pore ligaments and independent of strain rate.