The effect of iron concentration on the microstructural and structural properties of ZnO for electrolysis and photodetector applications was investigated.The thin layers of un-doped and doped ZnO with different percen...The effect of iron concentration on the microstructural and structural properties of ZnO for electrolysis and photodetector applications was investigated.The thin layers of un-doped and doped ZnO with different percentages of Fe(2,4,and 6 wt.%)were deposited by spin-coating on glass substrates.Sample characterization was done by X-ray diffraction(XRD),atomic force microscopy(AFM),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),UV−Vis absorption spectra and X-ray photoelectron spectroscopy(XPS).Structural measurements by XRD showed that all the layers were composed of polycrystallines with a hexagonal Wurtzite structure.Two new peaks were also discovered after the doping process belonging to the Fe_(2)O_(4)(400)and(440)crystal phase.Morphological analysis showed that the surface roughness values of ZnO layers ranged between 8 and 45 nm.XPS studies confirmed the presence of Fe in 3+states in ZnO layers.An average transmittance of 90%was measured by UV−Vis in the wavelength range of 200−900 nm.The values of the energy gap(Eg)decreased with an increase in the concentration of Fe.AFM topography results confirmed that ZnO-based thin layers had a relatively uniform surface.The efficiency of these samples has been confirmed for their use in many electrical applications,including photodetectors and electrolysis of contaminated solutions.展开更多
Coconut(Cocos nucifera L.)is a key tropical economic tree valued for its fruit flavor,particularly 2-acetyl-1-pyrroline(2AP),a vital aroma metabolite.To enhance high-aromatic coconut breeding efforts,it is essential t...Coconut(Cocos nucifera L.)is a key tropical economic tree valued for its fruit flavor,particularly 2-acetyl-1-pyrroline(2AP),a vital aroma metabolite.To enhance high-aromatic coconut breeding efforts,it is essential to deeply understand the hereditary factors governing the production of 2AP.In this study,a genome-wide association analysis identifies 32 loci that exhibit significant associations with 2AP content based on single nucleotide polymorphism(SNP)variations from 168 aromatic coconut germplasm resources.Transcriptome analysis then pinpoints 22 candidate genes near significant loci involved in 2AP metabolism.Proteins encoded by these genes are involved in amino acid metabolism,glycolysis,and secondary metabolism.Among these,Asparagine synthetase coding gene ASN1,Gamma-glutamylcysteine synthetase coding gene GSH1,and UbiA prenyltransferase coding gene UBIA are enriched in the linkage region constructed by significant locus Chr04_61490504.In particular,the SNP mutation of CnASN1 leads to amino acid changes in the functional region of the coding protein,potentially resulting in differences in 2AP content among haplotype populations.Identifying variations in related candidate genes,particularly the gene CnASN1,provides molecular markers closely associated with 2AP synthesis for coconut breeding and offers further insights into the metabolic mechanisms of 2AP.展开更多
Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distor...Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired.In this paper,a compact Ultra-Wideband(UWB)V-shaped monopole antenna is presented.UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape.The proposed V-shaped is designed by incorporating a rectangle,and an inverted isosceles triangle using FR4 substrate.The size of the antenna is 25 mm×26 mm×1.6 mm.The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial,Scientific,and Medical(ISM),Worldwide Interoperability for Microwave Access(WiMAX),(IEEE 802.11/HIPERLAN band,5G sub 6 GHz)which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission(FCC)with a maximum gain of 3.83 dB.The antenna is designed in Ansys HFSS.Results for key performance parameters of the antenna are presented.The measured results are in good agreement with the simulated results.Due to flat gain,uniform group delay,omni directional radiation pattern characteristics and well-matched impedance,the proposed antenna is suitable for WiMAX,ISM and heterogeneous wireless systems.展开更多
In this paper,a low cost,highly efficient and low profile monopole antenna for ultra-wideband(UWB)applications is presented.A new inverted triangular-shape structure possessing meander lines is designed to achieve a w...In this paper,a low cost,highly efficient and low profile monopole antenna for ultra-wideband(UWB)applications is presented.A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency.To design the proposed structure,three steps are utilized to achieve an UWB response.The bandwidth of the proposed antenna is improved with changing meander lines parameters,miniaturization of the ground width and optimization of the feeding line.The measured and simulated frequency band ranges from 3.2 to 12 GHz,while the radiation patterns are measured at 4,5.3,6 and 8 GHz frequency bands.The overall volume of the proposed antenna is 26×25×1.6 mm^(3);whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.3 and 0.025,correspondingly.The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98%for the entire wideband.Design modelling of proposed antenna is performed in ANSYS HFSS 13 software.A decent consistency between the simulated and measured results is accomplished which shows that the proposed antenna is a potential candidate for the UWB applications.展开更多
The recent surge of mobile subscribers and user data traffic has accelerated the telecommunication sector towards the adoption of the fifth-generation (5G) mobile networks. Cloud radio access network (CRAN) is a promi...The recent surge of mobile subscribers and user data traffic has accelerated the telecommunication sector towards the adoption of the fifth-generation (5G) mobile networks. Cloud radio access network (CRAN) is a prominent framework in the 5G mobile network to meet the above requirements by deploying low-cost and intelligent multiple distributed antennas known as remote radio heads (RRHs). However, achieving the optimal resource allocation (RA) in CRAN using the traditional approach is still challenging due to the complex structure. In this paper, we introduce the convolutional neural network-based deep Q-network (CNN-DQN) to balance the energy consumption and guarantee the user quality of service (QoS) demand in downlink CRAN. We first formulate the Markov decision process (MDP) for energy efficiency (EE) and build up a 3-layer CNN to capture the environment feature as an input state space. We then use DQN to turn on/off the RRHs dynamically based on the user QoS demand and energy consumption in the CRAN. Finally, we solve the RA problem based on the user constraint and transmit power to guarantee the user QoS demand and maximize the EE with a minimum number of active RRHs. In the end, we conduct the simulation to compare our proposed scheme with nature DQN and the traditional approach.展开更多
Background:The purpose of this study is to examine volatility spillover effects between stock market and foreign exchange market in selected Asian countries;Pakistan,India,Sri Lanka,China,Hong Kong and Japan.This stud...Background:The purpose of this study is to examine volatility spillover effects between stock market and foreign exchange market in selected Asian countries;Pakistan,India,Sri Lanka,China,Hong Kong and Japan.This study considered daily data from 4th January,1999 to 1st January,2014.Methods:This study opted EGARCH(Exponential Generalized Auto Regressive Conditional Heteroskedasticity)model for the purpose of analyzing asymmetric volatility spillover effects between stock and foreign exchange market.Results:The EGARCH analyses reveal bidirectional asymmetric volatility spillover between stock market and foreign exchange market of Pakistan,China,Hong Kong and Sri Lanka.The results reveal unidirectional transmission of volatility from stock market to foreign exchange market of India.The analysis reveals no evidence of volatility transmission between the two markets in reference to Japan.Conclusions:The result of this study provide valuable insights to economic policy makers for financial stability perspective and to investors regarding decision making in international portfolio and currency risk strategies.展开更多
This paper presents a compact multi-band rectifier with an improved impedance matching bandwidth.It uses a combination of–matching network(MN)at Port-1,with a parallel connection of three cell branch MN at Port-2.The...This paper presents a compact multi-band rectifier with an improved impedance matching bandwidth.It uses a combination of–matching network(MN)at Port-1,with a parallel connection of three cell branch MN at Port-2.The proposed impedance matching network(IMN)is adopted to reduce circuit complexity,to improve circuit performance,and power conversion efficiency(PCE)of the rectifier at low input power.The fabricated rectifier prototype operates at 0.92,1.82,2.1,2.46 and 2.65 GHz covering GSM/900,GSM/1800,UMTS2100,and Wi-Fi/2.45–LTE2600.The size of the compact rectifier on the PCB board is 0.13λ_(g)×0.1λ_(g).The fabricated rectifier achieved an RF-to DC(radio frequency direct current)PCE of 31.8%,24%,22.7%,and 15%,and 14.1%for−20 dBm at the five respective measured operating frequencies.The circuit attains a peak RF-to-DC PCE of 82.3%for an input power of 3 dBm at 0.92 GHz.The proposed rectifier realizes an ambient output dc voltage of 454 mV for multi-tone input signals from the two ports.The rectifier drives a bq25504-674 power management module(PMM)to achieve 1.21 V from the two-port connection.The rectifier has the ability to exploit both frequency domain through the multi-band operation with good impedance bandwidth and a spatial domain using dual-port configuration.Hence,it is a potential candidate for various applications in radio frequency energy harvesting(RFEH)system.展开更多
Bacterial endophytes are beneficial to their hosts as they can fix nitrogen in the soil and make it available to the host.Endophytic bacteria also secrete plant growth-promoting hormones to support their host plants u...Bacterial endophytes are beneficial to their hosts as they can fix nitrogen in the soil and make it available to the host.Endophytic bacteria also secrete plant growth-promoting hormones to support their host plants under normal as well as stress conditions.The current study aimed to isolate endophytic bacteria from different parts of Calotropis procera,i.e.,roots,stem and leaves of Calotropis procera(Ait.)W.T.Aiton.Plants were collected from the Lundkhwar,district Mardan.A total of 12 bacterial strains,i.e.,six from roots,three from the stem and three from the leaves were isolated.The strains were screened for their growth-promoting activity in rice plants because rice shows a quick and easy response to the bioactive compounds present in the culture filtrate(CF)of the potent endophytic strains.The rice plants were cultivated in pots containing 30 mL of 0.8%w/v water-agar medium.The pots were placed in a growth chamber,operated at 28±0.3℃ for 14 h(day);and 25±0.3℃ for 10 h(night),at 70%relative-humidity.Among the isolated strains,R1,S1,S3,L1,R5 and R6 showed visible growth promotion in rice plants.The biochemical analysis revealed that the strains were able to produce indole acetic acid(IAA)and flavonoids in higher quantities.Moreover,the strains also produced bioactive compounds that inhibited the growth of Escherichia coli and Aspergillus flavus using the well diffusion method.From the results,it was concluded that these strains can secrete potent compounds that can promote the host plant growth and inhibit the growth of pathogenic microorganisms and,therefore,can be used as bio-fertilizer and bio-control agents.展开更多
This paper proposed the design of a dual-port rectifier with multifrequency operations.The RF rectifier is achieved using a combination of L-section inductive impedance matching network(IMN)at Port-1 with a multiple s...This paper proposed the design of a dual-port rectifier with multifrequency operations.The RF rectifier is achieved using a combination of L-section inductive impedance matching network(IMN)at Port-1 with a multiple stubs impedance transformer at Port-2.The fabricated prototype can harvest RF signal from GSM/900,GSM/1800,UMTS/2100,Wi-Fi/2.45 and LTE/2600 frequency bands at(0.94,1.80,2.10,2.46,and 2.63 GHz),respectively.The rectifier occupies a small portion of a PCB board at 0.20λg×0.15λg.The proposed circuit realized a measured peak RF-to-dc(radio frequency direct current)power conversion efficiency(PCE)of(21%,22.76%,25.33%,21.57%,and 22.14%)for an input power of−20 dBm.The RF harvester attains a measured peak RF-to-dc PCE of 72.70%and an output dc voltage of 154 mV for an input power of 3 dBm at 2.46 GHz.Measurement of the proposed rectifier in the ambiance gives a peak dc output voltage of 376.1 mV from the five signal tones.Similarly,a low-powered bq25504-674 evaluation module(EVM)is integrated with the rectifier.The module boost and drive the rectifier output dc voltage to 945 mV.The performance of the proposed rectifier in the ambiance environment makes it a suitable module for low-powered RF applications.展开更多
Using a sample of 280 firms listed on the Pakistan Stock Exchange,we empirically investigate factors that determine corporate cash holdings in different periods from 2005 to 2014.We divide the sample into three sub-pe...Using a sample of 280 firms listed on the Pakistan Stock Exchange,we empirically investigate factors that determine corporate cash holdings in different periods from 2005 to 2014.We divide the sample into three sub-periods—pre-crisis,crisis,and post-crisis—and apply a panel data model to estimate the results.The results suggest that financial crises affect firms’cash holdings policies.Further,findings show that financial crisis has influenced the relationship of size and leverage with cash holdings.In particular,cash flow,liquidity,and tangibility are major determinants of cash holdings in the sub-periods.We present important implications for corporate managers,academicians,and policymakers.展开更多
基金the support received from the Researchers Supporting Project(No.RSP2024R404),King Saud University,Riyadh,Saudi Arabia。
文摘The effect of iron concentration on the microstructural and structural properties of ZnO for electrolysis and photodetector applications was investigated.The thin layers of un-doped and doped ZnO with different percentages of Fe(2,4,and 6 wt.%)were deposited by spin-coating on glass substrates.Sample characterization was done by X-ray diffraction(XRD),atomic force microscopy(AFM),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),UV−Vis absorption spectra and X-ray photoelectron spectroscopy(XPS).Structural measurements by XRD showed that all the layers were composed of polycrystallines with a hexagonal Wurtzite structure.Two new peaks were also discovered after the doping process belonging to the Fe_(2)O_(4)(400)and(440)crystal phase.Morphological analysis showed that the surface roughness values of ZnO layers ranged between 8 and 45 nm.XPS studies confirmed the presence of Fe in 3+states in ZnO layers.An average transmittance of 90%was measured by UV−Vis in the wavelength range of 200−900 nm.The values of the energy gap(Eg)decreased with an increase in the concentration of Fe.AFM topography results confirmed that ZnO-based thin layers had a relatively uniform surface.The efficiency of these samples has been confirmed for their use in many electrical applications,including photodetectors and electrolysis of contaminated solutions.
基金supported by the Major Science and Technology Project of Hainan Province(ZDKJ2021012)National Natural Science Foundation of China(32071805)the National Key Research and Development Program of China(2023YFD2200700)。
文摘Coconut(Cocos nucifera L.)is a key tropical economic tree valued for its fruit flavor,particularly 2-acetyl-1-pyrroline(2AP),a vital aroma metabolite.To enhance high-aromatic coconut breeding efforts,it is essential to deeply understand the hereditary factors governing the production of 2AP.In this study,a genome-wide association analysis identifies 32 loci that exhibit significant associations with 2AP content based on single nucleotide polymorphism(SNP)variations from 168 aromatic coconut germplasm resources.Transcriptome analysis then pinpoints 22 candidate genes near significant loci involved in 2AP metabolism.Proteins encoded by these genes are involved in amino acid metabolism,glycolysis,and secondary metabolism.Among these,Asparagine synthetase coding gene ASN1,Gamma-glutamylcysteine synthetase coding gene GSH1,and UbiA prenyltransferase coding gene UBIA are enriched in the linkage region constructed by significant locus Chr04_61490504.In particular,the SNP mutation of CnASN1 leads to amino acid changes in the functional region of the coding protein,potentially resulting in differences in 2AP content among haplotype populations.Identifying variations in related candidate genes,particularly the gene CnASN1,provides molecular markers closely associated with 2AP synthesis for coconut breeding and offers further insights into the metabolic mechanisms of 2AP.
基金This work was supported by the Research Program through the National Research Foundation of Korea,NRF-2019R1A2C1005920,S.K.
文摘Due to rapid growth in wireless communication technology,higher bandwidth requirement for advance telecommunication systems,capable of operating on two or higher bands with higher channel capacities and minimum distortion losses is desired.In this paper,a compact Ultra-Wideband(UWB)V-shaped monopole antenna is presented.UWB response is achieved by modifying the ground plane with Chichen Itzia inspired rectangular staircase shape.The proposed V-shaped is designed by incorporating a rectangle,and an inverted isosceles triangle using FR4 substrate.The size of the antenna is 25 mm×26 mm×1.6 mm.The proposed V-shaped monopole antenna produces bandwidth response of 3 GHz Industrial,Scientific,and Medical(ISM),Worldwide Interoperability for Microwave Access(WiMAX),(IEEE 802.11/HIPERLAN band,5G sub 6 GHz)which with an additional square cut amplified the bandwidth response up to 8 GHz ranging from 3.1 GHz to 10.6 GHz attaining UWB defined by Federal Communications Commission(FCC)with a maximum gain of 3.83 dB.The antenna is designed in Ansys HFSS.Results for key performance parameters of the antenna are presented.The measured results are in good agreement with the simulated results.Due to flat gain,uniform group delay,omni directional radiation pattern characteristics and well-matched impedance,the proposed antenna is suitable for WiMAX,ISM and heterogeneous wireless systems.
基金the Research Program through the National Research Foundation of Korea,NRF-2019R1A2C1005920,S.K.
文摘In this paper,a low cost,highly efficient and low profile monopole antenna for ultra-wideband(UWB)applications is presented.A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency.To design the proposed structure,three steps are utilized to achieve an UWB response.The bandwidth of the proposed antenna is improved with changing meander lines parameters,miniaturization of the ground width and optimization of the feeding line.The measured and simulated frequency band ranges from 3.2 to 12 GHz,while the radiation patterns are measured at 4,5.3,6 and 8 GHz frequency bands.The overall volume of the proposed antenna is 26×25×1.6 mm^(3);whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.3 and 0.025,correspondingly.The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98%for the entire wideband.Design modelling of proposed antenna is performed in ANSYS HFSS 13 software.A decent consistency between the simulated and measured results is accomplished which shows that the proposed antenna is a potential candidate for the UWB applications.
基金supported by the Universiti Tunku Abdul Rahman (UTAR) Malaysia under UTARRF (IPSR/RMC/UTARRF/2021-C1/T05)
文摘The recent surge of mobile subscribers and user data traffic has accelerated the telecommunication sector towards the adoption of the fifth-generation (5G) mobile networks. Cloud radio access network (CRAN) is a prominent framework in the 5G mobile network to meet the above requirements by deploying low-cost and intelligent multiple distributed antennas known as remote radio heads (RRHs). However, achieving the optimal resource allocation (RA) in CRAN using the traditional approach is still challenging due to the complex structure. In this paper, we introduce the convolutional neural network-based deep Q-network (CNN-DQN) to balance the energy consumption and guarantee the user quality of service (QoS) demand in downlink CRAN. We first formulate the Markov decision process (MDP) for energy efficiency (EE) and build up a 3-layer CNN to capture the environment feature as an input state space. We then use DQN to turn on/off the RRHs dynamically based on the user QoS demand and energy consumption in the CRAN. Finally, we solve the RA problem based on the user constraint and transmit power to guarantee the user QoS demand and maximize the EE with a minimum number of active RRHs. In the end, we conduct the simulation to compare our proposed scheme with nature DQN and the traditional approach.
文摘Background:The purpose of this study is to examine volatility spillover effects between stock market and foreign exchange market in selected Asian countries;Pakistan,India,Sri Lanka,China,Hong Kong and Japan.This study considered daily data from 4th January,1999 to 1st January,2014.Methods:This study opted EGARCH(Exponential Generalized Auto Regressive Conditional Heteroskedasticity)model for the purpose of analyzing asymmetric volatility spillover effects between stock and foreign exchange market.Results:The EGARCH analyses reveal bidirectional asymmetric volatility spillover between stock market and foreign exchange market of Pakistan,China,Hong Kong and Sri Lanka.The results reveal unidirectional transmission of volatility from stock market to foreign exchange market of India.The analysis reveals no evidence of volatility transmission between the two markets in reference to Japan.Conclusions:The result of this study provide valuable insights to economic policy makers for financial stability perspective and to investors regarding decision making in international portfolio and currency risk strategies.
基金supported by TM R&D Malaysia under project number MMUE/190001.
文摘This paper presents a compact multi-band rectifier with an improved impedance matching bandwidth.It uses a combination of–matching network(MN)at Port-1,with a parallel connection of three cell branch MN at Port-2.The proposed impedance matching network(IMN)is adopted to reduce circuit complexity,to improve circuit performance,and power conversion efficiency(PCE)of the rectifier at low input power.The fabricated rectifier prototype operates at 0.92,1.82,2.1,2.46 and 2.65 GHz covering GSM/900,GSM/1800,UMTS2100,and Wi-Fi/2.45–LTE2600.The size of the compact rectifier on the PCB board is 0.13λ_(g)×0.1λ_(g).The fabricated rectifier achieved an RF-to DC(radio frequency direct current)PCE of 31.8%,24%,22.7%,and 15%,and 14.1%for−20 dBm at the five respective measured operating frequencies.The circuit attains a peak RF-to-DC PCE of 82.3%for an input power of 3 dBm at 0.92 GHz.The proposed rectifier realizes an ambient output dc voltage of 454 mV for multi-tone input signals from the two ports.The rectifier drives a bq25504-674 power management module(PMM)to achieve 1.21 V from the two-port connection.The rectifier has the ability to exploit both frequency domain through the multi-band operation with good impedance bandwidth and a spatial domain using dual-port configuration.Hence,it is a potential candidate for various applications in radio frequency energy harvesting(RFEH)system.
基金This research was supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2017R1D1A1B04035601).
文摘Bacterial endophytes are beneficial to their hosts as they can fix nitrogen in the soil and make it available to the host.Endophytic bacteria also secrete plant growth-promoting hormones to support their host plants under normal as well as stress conditions.The current study aimed to isolate endophytic bacteria from different parts of Calotropis procera,i.e.,roots,stem and leaves of Calotropis procera(Ait.)W.T.Aiton.Plants were collected from the Lundkhwar,district Mardan.A total of 12 bacterial strains,i.e.,six from roots,three from the stem and three from the leaves were isolated.The strains were screened for their growth-promoting activity in rice plants because rice shows a quick and easy response to the bioactive compounds present in the culture filtrate(CF)of the potent endophytic strains.The rice plants were cultivated in pots containing 30 mL of 0.8%w/v water-agar medium.The pots were placed in a growth chamber,operated at 28±0.3℃ for 14 h(day);and 25±0.3℃ for 10 h(night),at 70%relative-humidity.Among the isolated strains,R1,S1,S3,L1,R5 and R6 showed visible growth promotion in rice plants.The biochemical analysis revealed that the strains were able to produce indole acetic acid(IAA)and flavonoids in higher quantities.Moreover,the strains also produced bioactive compounds that inhibited the growth of Escherichia coli and Aspergillus flavus using the well diffusion method.From the results,it was concluded that these strains can secrete potent compounds that can promote the host plant growth and inhibit the growth of pathogenic microorganisms and,therefore,can be used as bio-fertilizer and bio-control agents.
基金This work was supported by TM R&D Malaysia under Project Number MMUE/190001.
文摘This paper proposed the design of a dual-port rectifier with multifrequency operations.The RF rectifier is achieved using a combination of L-section inductive impedance matching network(IMN)at Port-1 with a multiple stubs impedance transformer at Port-2.The fabricated prototype can harvest RF signal from GSM/900,GSM/1800,UMTS/2100,Wi-Fi/2.45 and LTE/2600 frequency bands at(0.94,1.80,2.10,2.46,and 2.63 GHz),respectively.The rectifier occupies a small portion of a PCB board at 0.20λg×0.15λg.The proposed circuit realized a measured peak RF-to-dc(radio frequency direct current)power conversion efficiency(PCE)of(21%,22.76%,25.33%,21.57%,and 22.14%)for an input power of−20 dBm.The RF harvester attains a measured peak RF-to-dc PCE of 72.70%and an output dc voltage of 154 mV for an input power of 3 dBm at 2.46 GHz.Measurement of the proposed rectifier in the ambiance gives a peak dc output voltage of 376.1 mV from the five signal tones.Similarly,a low-powered bq25504-674 evaluation module(EVM)is integrated with the rectifier.The module boost and drive the rectifier output dc voltage to 945 mV.The performance of the proposed rectifier in the ambiance environment makes it a suitable module for low-powered RF applications.
文摘Using a sample of 280 firms listed on the Pakistan Stock Exchange,we empirically investigate factors that determine corporate cash holdings in different periods from 2005 to 2014.We divide the sample into three sub-periods—pre-crisis,crisis,and post-crisis—and apply a panel data model to estimate the results.The results suggest that financial crises affect firms’cash holdings policies.Further,findings show that financial crisis has influenced the relationship of size and leverage with cash holdings.In particular,cash flow,liquidity,and tangibility are major determinants of cash holdings in the sub-periods.We present important implications for corporate managers,academicians,and policymakers.
