Catalytic oxidation at room temperature is recognized as the most promising method for formaldehyde(HCHO)removal.Pt‐based catalysts are the optimal catalyst for HCHO decomposition at room temperature.Herein,flower‐l...Catalytic oxidation at room temperature is recognized as the most promising method for formaldehyde(HCHO)removal.Pt‐based catalysts are the optimal catalyst for HCHO decomposition at room temperature.Herein,flower‐like hierarchical Pt/NiAl‐LDHs catalysts with different[Ni2+]/[Al3+]molar ratios were synthesized via hydrothermal method followed by NaBH4 reduction of Pt precursor at room temperature.The flower‐like hierarchical Pt/NiAl‐LDHs were composed of interlaced nanoplates and metallic Pt nanoparticles(NPs)approximately 3–4 nm in diameter were loaded on the surface of the Pt/NiAl‐LDHs with high dispersion.The as‐prepared Pt/NiAl21 nanocomposite was highly efficient in catalyzing oxidation of HCHO into CO2 at room temperature.The high activity of the hierarchical Pt/NiAl21 nanocomposite was maintained after seven recycle tests,suggesting the high stability of the catalyst.Based on in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)studies,a reaction mechanism was put forward about HCHO decomposition at room temperature.This work provides new insights into designing and fabricating high‐performance catalysts for efficient indoor air purification.展开更多
MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap el...MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap electric field is superposed at the trigger gap to let the electrons in its spark channel also become initial electrons, is proposed and tested. The design idea is: as electrons in the spark channel of the trigger gap always exist after its breakdown, the injection time of pre-ionization should have a more negligible effect on reducing the switch jitter. The experiment results under pulses with a rise time of ~100 ns support the above assumptions.When the operating voltage is from ~300 to ~800 kV and the self-triggering time is ~45% to~75% of the peak time, the breakdown time delay jitter is less than 2 ns, and the breakdown voltage jitter is smaller than 1.25%. Under specific self-triggering time, the breakdown time delay jitter is less than 1.5 ns, and the breakdown voltage jitter is smaller than 0.8%.展开更多
Male-biased sexual dimorphism in hind limb muscles is widespread in anuran species where scramble competition is common among males. Such sexual difference is thought to result from sexual selection. In this view, we ...Male-biased sexual dimorphism in hind limb muscles is widespread in anuran species where scramble competition is common among males. Such sexual difference is thought to result from sexual selection. In this view, we tested the differences in muscle mass between the sexes and between amplectant and non-amplectant males by quantifying the mass of four hindlimb muscles （triceps femoris, sartorius, gracilis and plantaris longus） of females and males of Odorrana schmackeri. The results showed that females significantly exceeded males for muscle triceps femoris, gracilis, plantaris longus and total mass when controlled for body size. There are no significant differences between amplectant and non-amplectant males. It is probable that the maintenance of the amplectant position in O. schmackeri may depend on the strength of hindlimb muscles in females to support the pair.展开更多
In this paper we consider the problem of state estimation over a communication network. Using estimation quality as a metric, two communication schemes are studied and compared. In scheme one, each sensor node communi...In this paper we consider the problem of state estimation over a communication network. Using estimation quality as a metric, two communication schemes are studied and compared. In scheme one, each sensor node communicates its measurement data to the remote estimator, while in scheme two, each sensor node communicates its local state estimate to the remote estimator. We show that with perfect communication link, if the sensor has unlimited computation capability, the two schemes produce the same estimate at the estimator, and if the sensor has limited computation capability, scheme one is always better than scheme two. On the other hand, when data packet drops occur over the communication link, we show that if the sensor has unlimited computation capability, scheme two always outperforms scheme one, and if the sensor has limited computation capability, we show that in general there exists a critical packet arrival rate, above which scheme one outperforms scheme two. Simulations are provided to demonstrate the two schemes under various circumstances.展开更多
This paper analyses security mechanism and authentication, key agreement protocol of 3G system amply, puts forward a amelioration scheme. This scheme assures security communications without credible VLR. This paper an...This paper analyses security mechanism and authentication, key agreement protocol of 3G system amply, puts forward a amelioration scheme. This scheme assures security communications without credible VLR. This paper analyses ameliorative protocol and resolves the security communications problem between MS and HLR.展开更多
Objective:Moxibustion,a common therapy in traditional Chinese medicine,has potential benefits for treating decreased ovarian reserve(DOR).The present study investigates the protective effect of moxibustion in a rat mo...Objective:Moxibustion,a common therapy in traditional Chinese medicine,has potential benefits for treating decreased ovarian reserve(DOR).The present study investigates the protective effect of moxibustion in a rat model of DOR and explores the possible mechanisms.Methods:Sixty-four female Sprague-Dawley rats were randomly divided into four groups:control,DOR,moxibustion(MOX),and hormone replacement therapy(HRT).The DOR rat model was established by intragastric administration of 50 mg/kg Tripterygium glycoside suspension(TGS),once daily for 14 days.MOX and HRT treatments were given from the day TGS administration was initiated.The ovarian reserve function was evaluated by monitoring the estrus cycle,morphological changes in ovaries,levels of serum estradiol(E2),follicle-stimulating hormone(FSH),luteinizing hormone(LH),and anti-Mullerian hormone(AMH),pregnancy rate and embryo numbers.Terminal-deoxynucleotidyl transferase-mediated nickend-labeling staining was used to identify ovarian granulosa cell apoptosis,while the protein and m RNA expressions of Bax,B-cell lymphoma-2(Bcl-2),phosphatidylinositol 3-kinase(PI3 K)and protein kinase B(AKT)in ovarian tissues were examined by immunohistochemistry,Western blot and quantitative reverse transcription-polymerase chain reaction.Results:Compared with the DOR group,MOX improved the disordered estrous cycle,promoted follicular growth,reduced the number of atresia follicles,increased the concentrations of serum E2 and AMH,and decreased serum FSH and LH concentrations.More importantly,the pregnancy rate and embryo numbers in DOR rats were both upregulated in the MOX treatment group,compared to the untreated DOR model.Further,we found that the MOX group had reduced apoptosis of ovarian granulosa cells,increased Bcl-2 expression and reduced expression of Bax.Furthermore,the PI3 K/AKT signaling pathway was triggered by the moxibustion treatment.Conclusion:Moxibustion improved ovarian function and suppressed apoptosis of ovarian granulosa cells in a rat model of DOR induced by TGS,and the mechanism may involve the PI3 K/AKT signaling pathway.展开更多
The dual active bridge(DAB) converters are widely used in the energy storage equipment and the distributed power systems. However, the existence of switching nonlinearity and control delay can cause serious stability ...The dual active bridge(DAB) converters are widely used in the energy storage equipment and the distributed power systems. However, the existence of switching nonlinearity and control delay can cause serious stability problem to the DAB converters. Thus, this paper,studies the stability of a digitally controlled DAB converter with an output voltage closed loop controller. Firstly, to accurately study the stability in a DAB converter, a discrete-time model established in a whole switching period is obtained. The model considers the output capacitor ESR,the digital control delay, and sample-and-hold process. By using this model, the stabilities of the DAB converter versus the proportional controller parameter and the output capacitor ESR are analyzed and the critical values are predicted accurately. Moreover, the stability boundary ofthe proportional controller parameter and the output capacitor ESR is also obtained. The result shows that the value of the output capacitor ESR can have a great effect on the stability region of the proportional controller parameter. Finally, the theoretical analyses are verified by the simulation and experimental results.展开更多
Cyber-physical systems （CPSs） are new emerging systems that seamlessly integrate physical systems, communication systems and computation systems. Their wide use has been witnessed in the past decades in many crossdi...Cyber-physical systems （CPSs） are new emerging systems that seamlessly integrate physical systems, communication systems and computation systems. Their wide use has been witnessed in the past decades in many crossdiscipline fields such as smart energy systems, industrial process control, aerospace and automobile engineering, health-care and assisted living, to just name a few. For many of these systems, secure operations are of key con- cerns. In particular, for some safety-critical applications, security is of paramount importance. Diverse motivations and strong incentives exist everywhere and at any time for launching malicious attacks on the CPSs, for example, economic reasons （e.g., by reducing or even not paying electricity charge） and terrorism the purpose of which is apparent.展开更多
基金supported by the National Natural Science Foundation of China (21577046, 21307038)Wuhan Morning Light Plan of Youth Science and Technology (2017050304010327)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University (JDGD-201813)~~
文摘Catalytic oxidation at room temperature is recognized as the most promising method for formaldehyde(HCHO)removal.Pt‐based catalysts are the optimal catalyst for HCHO decomposition at room temperature.Herein,flower‐like hierarchical Pt/NiAl‐LDHs catalysts with different[Ni2+]/[Al3+]molar ratios were synthesized via hydrothermal method followed by NaBH4 reduction of Pt precursor at room temperature.The flower‐like hierarchical Pt/NiAl‐LDHs were composed of interlaced nanoplates and metallic Pt nanoparticles(NPs)approximately 3–4 nm in diameter were loaded on the surface of the Pt/NiAl‐LDHs with high dispersion.The as‐prepared Pt/NiAl21 nanocomposite was highly efficient in catalyzing oxidation of HCHO into CO2 at room temperature.The high activity of the hierarchical Pt/NiAl21 nanocomposite was maintained after seven recycle tests,suggesting the high stability of the catalyst.Based on in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)studies,a reaction mechanism was put forward about HCHO decomposition at room temperature.This work provides new insights into designing and fabricating high‐performance catalysts for efficient indoor air purification.
文摘MV pulsed switch plays a key role as the transfer switch in large electromagnetic pulse simulators. To broaden the range of self-triggering time, a novel spark-discharge pre-ionization switch, in which the main gap electric field is superposed at the trigger gap to let the electrons in its spark channel also become initial electrons, is proposed and tested. The design idea is: as electrons in the spark channel of the trigger gap always exist after its breakdown, the injection time of pre-ionization should have a more negligible effect on reducing the switch jitter. The experiment results under pulses with a rise time of ~100 ns support the above assumptions.When the operating voltage is from ~300 to ~800 kV and the self-triggering time is ~45% to~75% of the peak time, the breakdown time delay jitter is less than 2 ns, and the breakdown voltage jitter is smaller than 1.25%. Under specific self-triggering time, the breakdown time delay jitter is less than 1.5 ns, and the breakdown voltage jitter is smaller than 0.8%.
基金the National Natural Science Foundation of China，the 'Chun Hui' Plan of Chinese Ministry Education，the Scientific Research Foundation of Education Department of Yunnan Province，the Youth Program of Yunnan Province，the Chemistry of Key Construction Disciplines for Master Degree Program in Yunnan，the Educational Reform Program of Honghe University，the General Program of Yunnan Provincial Education Departmen
基金supported by National Sciences Foundation of China (No. 31372164, 30870277)the Scientific Research Foundation of Henan Normal University (No. 01046500145)+1 种基金Joint Funds for Fostering Talents of NSFC the People’s Government of Henan Province (Grant No. U1304309)
文摘Male-biased sexual dimorphism in hind limb muscles is widespread in anuran species where scramble competition is common among males. Such sexual difference is thought to result from sexual selection. In this view, we tested the differences in muscle mass between the sexes and between amplectant and non-amplectant males by quantifying the mass of four hindlimb muscles （triceps femoris, sartorius, gracilis and plantaris longus） of females and males of Odorrana schmackeri. The results showed that females significantly exceeded males for muscle triceps femoris, gracilis, plantaris longus and total mass when controlled for body size. There are no significant differences between amplectant and non-amplectant males. It is probable that the maintenance of the amplectant position in O. schmackeri may depend on the strength of hindlimb muscles in females to support the pair.
基金supported by the Hong Kong University of Science and Technology Direct Allocation Grant(DAG08/09.EG06)
文摘In this paper we consider the problem of state estimation over a communication network. Using estimation quality as a metric, two communication schemes are studied and compared. In scheme one, each sensor node communicates its measurement data to the remote estimator, while in scheme two, each sensor node communicates its local state estimate to the remote estimator. We show that with perfect communication link, if the sensor has unlimited computation capability, the two schemes produce the same estimate at the estimator, and if the sensor has limited computation capability, scheme one is always better than scheme two. On the other hand, when data packet drops occur over the communication link, we show that if the sensor has unlimited computation capability, scheme two always outperforms scheme one, and if the sensor has limited computation capability, we show that in general there exists a critical packet arrival rate, above which scheme one outperforms scheme two. Simulations are provided to demonstrate the two schemes under various circumstances.
文摘This paper analyses security mechanism and authentication, key agreement protocol of 3G system amply, puts forward a amelioration scheme. This scheme assures security communications without credible VLR. This paper analyses ameliorative protocol and resolves the security communications problem between MS and HLR.
基金supported by the National Natural Science Foundation of China(No.81774408,No.81973957)the Youth Science Fund Project(No.81804179)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.KYCX21_1653)。
文摘Objective:Moxibustion,a common therapy in traditional Chinese medicine,has potential benefits for treating decreased ovarian reserve(DOR).The present study investigates the protective effect of moxibustion in a rat model of DOR and explores the possible mechanisms.Methods:Sixty-four female Sprague-Dawley rats were randomly divided into four groups:control,DOR,moxibustion(MOX),and hormone replacement therapy(HRT).The DOR rat model was established by intragastric administration of 50 mg/kg Tripterygium glycoside suspension(TGS),once daily for 14 days.MOX and HRT treatments were given from the day TGS administration was initiated.The ovarian reserve function was evaluated by monitoring the estrus cycle,morphological changes in ovaries,levels of serum estradiol(E2),follicle-stimulating hormone(FSH),luteinizing hormone(LH),and anti-Mullerian hormone(AMH),pregnancy rate and embryo numbers.Terminal-deoxynucleotidyl transferase-mediated nickend-labeling staining was used to identify ovarian granulosa cell apoptosis,while the protein and m RNA expressions of Bax,B-cell lymphoma-2(Bcl-2),phosphatidylinositol 3-kinase(PI3 K)and protein kinase B(AKT)in ovarian tissues were examined by immunohistochemistry,Western blot and quantitative reverse transcription-polymerase chain reaction.Results:Compared with the DOR group,MOX improved the disordered estrous cycle,promoted follicular growth,reduced the number of atresia follicles,increased the concentrations of serum E2 and AMH,and decreased serum FSH and LH concentrations.More importantly,the pregnancy rate and embryo numbers in DOR rats were both upregulated in the MOX treatment group,compared to the untreated DOR model.Further,we found that the MOX group had reduced apoptosis of ovarian granulosa cells,increased Bcl-2 expression and reduced expression of Bax.Furthermore,the PI3 K/AKT signaling pathway was triggered by the moxibustion treatment.Conclusion:Moxibustion improved ovarian function and suppressed apoptosis of ovarian granulosa cells in a rat model of DOR induced by TGS,and the mechanism may involve the PI3 K/AKT signaling pathway.
基金supported by National Natural Science Foundation of China(NSFC)(No.51207126)
文摘The dual active bridge(DAB) converters are widely used in the energy storage equipment and the distributed power systems. However, the existence of switching nonlinearity and control delay can cause serious stability problem to the DAB converters. Thus, this paper,studies the stability of a digitally controlled DAB converter with an output voltage closed loop controller. Firstly, to accurately study the stability in a DAB converter, a discrete-time model established in a whole switching period is obtained. The model considers the output capacitor ESR,the digital control delay, and sample-and-hold process. By using this model, the stabilities of the DAB converter versus the proportional controller parameter and the output capacitor ESR are analyzed and the critical values are predicted accurately. Moreover, the stability boundary ofthe proportional controller parameter and the output capacitor ESR is also obtained. The result shows that the value of the output capacitor ESR can have a great effect on the stability region of the proportional controller parameter. Finally, the theoretical analyses are verified by the simulation and experimental results.
文摘Cyber-physical systems （CPSs） are new emerging systems that seamlessly integrate physical systems, communication systems and computation systems. Their wide use has been witnessed in the past decades in many crossdiscipline fields such as smart energy systems, industrial process control, aerospace and automobile engineering, health-care and assisted living, to just name a few. For many of these systems, secure operations are of key con- cerns. In particular, for some safety-critical applications, security is of paramount importance. Diverse motivations and strong incentives exist everywhere and at any time for launching malicious attacks on the CPSs, for example, economic reasons （e.g., by reducing or even not paying electricity charge） and terrorism the purpose of which is apparent.
