可燃气体泄漏报警电路

使用石油天然气、液化气等作燃料给人们的日常生活带来许多方便,但这类气体一旦泄漏,往往会引起气体中毒、燃烧或爆炸,不但使财产造成巨大损失,而且会危及人们的生命安全。目前市售燃气器具(如燃气灶、燃气热水器等)质量有优有劣,部分生产厂家为了降低成本,对燃气泄漏未采取任何防范措施,导致因燃气泄漏造成的事故时有发生。为此,本文介绍一种可燃气体泄漏报警电路,可装在抽油烟机(如帅康CXW-128-78型)上,当发生燃气泄漏时,可通过声。

Pt-decorated NiWO_(4)/WO_(3) heterostructure nanotubes for highly selective sensing of acetone

The heterostructured NiWO_(4)/WO_(3) nanotubes(Ni/W NTs)were synthesized by using a facile self-assembly method on the sacrificial polystyrene(PS)nanofibers templates.Then,the Pt-decorated NiWO_(4)/WO_(3)(Pt@Ni/W)composite NTs were obtained through using an ultrasonic mixing method.The experimental results display that the order of gas-sensing performance is Pt@Ni/W>Ni/W>WO_(3).The 2wt.%Pt@Ni/W-5 NTs indicate the supreme acetone-sensing response(R_(air)/R_(gas)=58.4 at 100×10^(−6))at 375℃,which is 10.6 and 1.53 times that of the WO_(3) and NiWO_(4)/WO_(3) NTs,respectively.Additionally,the 2wt.%Pt@Ni/W-5 NTs also exhibit the dramatically high selectivity toward acetone against ethanol,methanal,methanol,NH_(3) and toluene.The Pt-decorated Ni/W NTs show the excellent responsivity and stability toward acetone,which is ascribed to the construction of heterostructured NiWO_(4)/WO_(3) and the spill-over effect of Pt nanoparticles.

Improving Refinery Profits via Fine Management of Hydrogen Networks

Hydrogen network management is important to refineries. Various systematic management techniques have been developed to improve the efficiency of refinery hydrogen networks. However, existing methods all treat the hydrogen network separately. The tradeoff between hydrogen network cost and oil processing network benefit has not been explored in the hydrogen network management yet. A novel sensitivity analysis scheme is presented to take oil processing network into consideration. Oil processing unit which is sensitive to both oil processing networks and hydrogen networks is identified first. Then, sensitivity analysis of the unit around the operating point of oil processing networks and hydrogen networks is carried out. Finally, the overall optimal operating condition is obtained. An example of a real Chinese refinery demonstrates the effectiveness of the proposed analysis method.

CLINICAL OBSERVATION ON TREATMENT OF ALLERGIC BRONCHIAL ASTHMA WITH ACUPOINT APPLICATION THERAPY

In the present paper, the therapeutic effect of acupoint application of Chinese Materia Medica in the treatment of allergic asthma was observed. The results revealed that topical application of drug paste [mixture of powder of Mahuang (Herba Ephedrae), Xixin (Herba Asari), Baijiezi (Semen Sinapis Albae), etc.] at the acupuncture points could improve symptoms and signs of allergic asthma patients, with the total effective rate being 69.57% (16/23) for the short term effect, and 52.17%(12/23) for the long term effect. In medication (Aminophylline) group, of the 25 cases of allergic asthma, 16 (64.0%) were effective after 4 weeks of treatment, while 6 (24.0%) were still effective that was shown by 6 months’ follow up. The therapeutic effect of acupoint application group was significantly better than that of medication group in the long term effect. Results also showed that no obvious interrelation between the short term therapeutic effect and the duration or the severity of the disease. Results also display that acupoint application therapy is an effective, safe and handy method with fewer side effects for asthma.

Effect of “three-acupoint and five-needling method” on the expression level of p-ERK 1/2 protein in lung tissue of rats with allergic bronchial asthma

Objective To explore the effect of ＂three-acupoint and five-needling method＂ on the expression level of p-ERK 1/2 protein in lung tissue of rats with allergic bronchial asthma.Methods Forty SPF-grade male SD rats were selected and randomly divided into four groups,including control group（group C）,model group（group M）,acupuncture group（group A） and blocker group（group PD）,with 10 rats in each group.After corresponding intervention was given,cell counting was conducted,and the expression level of p-ERK 1/2 protein in the lung tissue of rats was detected via immunohistochemical method and Western blot method.Results The number of leukocyte and eosinophil in the bronchoalveolar lavage fluid of rats in group A and group PD was smaller than that in group M,but larger than that in group C.It was shown based on the immunohistochemical test and Western blot test that the expression level of p-ERK1/2 protein in the lung tissue of rats in group M was higher than that in group C（P0.05）,while the expression level of p-ERK1/2 protein in group A and group PD was lower than that in group M（P0.05）.Conclusion ＂Threeacupoint and five-needling method＂ can effectively relieve the inflammatory response of rats with allergic bronchial asthma,and inhibit the expression level of p-ERK 1/2 protein in the lung tissue of rats with asthma.Acupuncture may alleviate the symptom of allergic bronchial asthma through inhibiting the expression level of p-ERK 1/2 protein.

Synthesis and acetone gas sensing properties of α-Fe_2O_3 nanotubes

α-Fe2O3 nanotubes was successfully prepared by single nozzle electrospinning method. Scanning electron microscope （SEM） was used to characterize the morphology of α-Fe2O3 nanotubes. The gas sensing properties of α-Fe2O3 nanotubes were investigated in detail. The results exhibit relatively good sensing properties to acetone at 240℃. The response and recovery times are about 3 and 5 s, respectively. The structure of nanotubes is beneficial to the gas sensing properties, which will enlarge the surface-to-volume ratio of α-Fe2O3 and then be available for the transfer of gas, and thus improved the sensor performance consequentially.

Fabrication of single-walled carbon nanotube-based highly sensitive gas sensors

A highly sensitive single-walled carbon nanotube(SWCNT)-based ammonia(NH3) gas detector is manufactured by orderly assembling SWCNT using the dielectrophoretical(DEP) technology.Atom force microscopy(AFM) and scanning electron microscopy(SEM) images revealed that SWCNTs were assembled between the microelectrodes.SWCNTs were affected by the electrophoretic force which was carried out by the related theoretical analysis in a nonuniform electric field.The SWCNT field effect transistors geometry was obtained.The electrical performance of NH3 gas sensor with the SWCNT field effect transistors geometry was tested before and after the adoption of NH3 at room temperature.Experimental results indicated that the efficient assembly of SWCNT was obtained by the applied alternating current voltage with frequency of 2 MHz and amplitude of 10 V.The SWCNTs-based gas sensor had high sensitivity to NH3,and the electrical conductance of NH3 gas sensor reduced two times after interaction with NH3.The SWCNTs surface gas molecules were removed by means of ultraviolet ray irradiation for 10 min.Hence,the fabricated NH3 gas sensor could be reversible.There is a clear evidence that the adsorption of NH3 on the SWCNT channel is easy to be realized.Our theoretical results are consistent with recent experiments.

The effect of MWCNTs on the performance of α-sexithiophene OTFT device and its gas-sensing property

In this paper,bottom contact organic thin-film transistor(OTFT)gas sensors were prepared.Silicon dioxide(SiO2)and titanium/aurum(Ti/Au)were used as the insulating layer and the electrode for the device,respectively.The multi-walled carbon nanotubes(MWCNTs)/α-sexithiophene(α-6T)bilayer films were used as the active layer,andα-6T single layer sensitive film was also prepared for comparison purpose.The electrical and trace NO2-sening properties of these two OTFT gas sensors were tested and analyzed.The results showed that,the OTFT device based on MWCNTs/α-6T bilayer had obviously better electrical properties,better stabilities and higher NO2-sening response values than the device withα-6T single layer,in which both the carrier mobility(μ)and on/off current ratio enhanced two order of magnitude.The improved performance of bilayer OTFT can be explained that MWCNTs acted as highly conducting bridges connecting the crystalline terraces in theα-6T film.Threshold voltage(VT),carrier mobility,on/off current ratio and grid current which showed extremely similar variation trend as source-drain current,were optional parameters to reveal the gas-sensing characteristic of OTFT gas sensors.Morphology analysis showed that the special feature of MWCNTs had certain influence on the gas-sensing properties.