Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC...Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC semiconductor device,an instrumentation amplifier(IA),two resistors,and a diode for disconnection detection.Based on the basic circuit,a multi-channel interface circuit was also implemented.The CJC was implemented using compensation semiconductor and IA,and disconnection detection was detected by using two resistors and a diode so that IA input voltage became-0.42 V.As a result of the experiment using R-type TC,the error of the designed circuit was reduced from 0.14 mV to 3μV after CJC in the temperature range of 0°C to 1400°C.In addition,it was confirmed that the output voltage of IA was saturated from 88 mV to-14.2 V when TC was disconnected from normal.The output voltage of the designed circuit was 0 V to 10 V in the temperature range of 0°C to 1400°C.The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel.The implemented multi-channel interface has a feature that can be applied equally to E,J,K,T,R,and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain.展开更多
A new method was proposed, in which a high-power CO2 laser modulated by high frequency was used as the driv- ing source to heat up a surface-temperature sensor. The continual beam and the pulsed beam sent out by the s...A new method was proposed, in which a high-power CO2 laser modulated by high frequency was used as the driv- ing source to heat up a surface-temperature sensor. The continual beam and the pulsed beam sent out by the same laser could be used in the same system to carry on the static calibration of the radiation thermometer and the dynamic calibration of the temperature sensor to be checked. The frequency-response characteristics of high-speed radiation thermometer surpassed that of the temperature sensor, therefore it could be used as the reference value to calibrate the latter and let system error be cor- rected. Differences in the environment of the sensor installing and the error caused by the change of thermo-physical proper- ty could be avoided. Thus, the difficult problem of traceable dynamic calibration of temperature was solved. In experiment, to obtain the frequency characteristics of the thermocouple and the dynamic performance of the K type thermocouple, which could compensate the dynamic characteristics of the sensor, the sensor was dynamically corrected by using the method, and then the mathematical model was established.展开更多
The theory for measuring the time constant of thermocouple was introduced, and the method for measuring the time constant of NANMAC thermocouple by using dynamic calibration system of transient surface temperature sen...The theory for measuring the time constant of thermocouple was introduced, and the method for measuring the time constant of NANMAC thermocouple by using dynamic calibration system of transient surface temperature sensor was proposed. In this system, static and dynamic calibrations were conducted for infrared detectors and thermocouples, and then both temperature-time curves were obtained. Since the frequency response of infrared detector is superior to that of calibrat- ed thermocouple, the values measured by infrared detectors are taken as true values. Through dividing the values measured with thermocouples by those with infrared detectors, a normalized curve was obtained, based on which the time constant of thermocouple was measured. With this method, the experiments were carried out with NANMAC thermocouple to obtain its time constant. The results show that the method for measuring the time constant is feasible and the dynamic calibration of thermocouples can be achieved at microsecond and millisecond level. This research has a certain reference value for research and application of NANMAC thermocouple temperature sensor.展开更多
In high-speed cutting, natural thermocouple, artificial thermocouple and infrared radiation temperature measurement are usually adopted for measuring cutting temperature, but these methods have difficulty in measuring...In high-speed cutting, natural thermocouple, artificial thermocouple and infrared radiation temperature measurement are usually adopted for measuring cutting temperature, but these methods have difficulty in measuring transient temperature accurately of cutting area on account of low response speed and limited cutting condition. In this paper, NiCr/NiSi thin-film thermocouples(TFTCs) are fabricated according to temperature characteristic of cutting area in high-speed cutting by means of advanced twinned microwave electro cyclotron resonance(MW-ECR) plasma source enhanced radio frequency(RF) reaction non-balance magnetron sputtering technique, and can be used for transient cutting temperature measurement. The time constants of the TFTCs with different thermo-junction film width are measured at four kinds of sampling frequency by using Ultra-CFR short pulsed laser system that established. One-dimensional unsteady heat conduction model is constructed and the dynamic performance is analyzed theoretically. It can be seen from the analysis results that the NiCr/NiSi TFTCs are suitable for measuring transient temperature which varies quickly, the response speed of TFTCs can be obviously improved by reducing the thickness of thin-film, and the area of thermo-junction has little influence on dynamic response time. The dynamic calibration experiments are made on the constructed dynamic calibration system, and the experimental results confirm that sampling frequency should be larger than 50 kHz in dynamic measurement for stable response time, and the shortest response time is 0.042 ms. Measurement methods and devices of cutting heat and cutting temperature measurement are developed and improved by this research, which provide practical methods and instruments in monitoring cutting heat and cutting temperature for research and production in high-speed machining.展开更多
For the manufacture of S-type thermocouple the so-called thermocouple wire of platinum and platinum-rhodium alloy is used.One of the main technical requirements for the quality of the wire,according to State Standard ...For the manufacture of S-type thermocouple the so-called thermocouple wire of platinum and platinum-rhodium alloy is used.One of the main technical requirements for the quality of the wire,according to State Standard of Russia(GOST 10821),is the uniformity of its largest thermoelectric force(Thermo-emf) in the length different sections.It was found that a determining impact on the uniformity of the wire thermo-emf is the distribution of rhodium along the length of the wire.The impact of platinum-rhodium melt crystallization conditions on the inhomogeneity of wire manufactured from it.It was suggested that the chemical inhomogeneity of the wire is related to the liquation phase of platinum-rhodium alloy.展开更多
The electromotive force (EMF) changes in type K heavy gauge sheathed thermocouple cables was investigated. To cope with this discrepancy owing to EMF steep reduction and understand the difference between type K heavy ...The electromotive force (EMF) changes in type K heavy gauge sheathed thermocouple cables was investigated. To cope with this discrepancy owing to EMF steep reduction and understand the difference between type K heavy gauge sheathed thermocouple cables and small ones, the affects of EMF from sheath pipe, drawing times, annealing temperature, annealing time and annealing way were mainly studied and appropriately analyzed. The results show the change in the thermal EMF is related with the residual stress and crystal defects, which are imparted by cold work during manufacture. The affects of cold work can be removed by annealing. Finally, a feasible way of fabricating heavy gauge sheathed thermocouples was suggested according to practical situation.展开更多
There are large errors of linear measurement when the thermocouple measure temperature as temperature sensor.In order to improve the measurement precision,the sensor cold junction compensation and nonlinear compensati...There are large errors of linear measurement when the thermocouple measure temperature as temperature sensor.In order to improve the measurement precision,the sensor cold junction compensation and nonlinear compensation are usually needed.For the circumstances that the cold junction’s temperature is determinate,there is biggish nonlinear between thermoelectric power and temperature signals of the thermocouple sensor’s output.In order to solve the problem,this paper proposed a practical method of linear compensation,introduced the principle of linear compensation and gave the corresponding compensation circuit and circuit analysis.This circuit has the characteristic of simpleness,high reliability,small linear error and so on.展开更多
Aiming at high requirements of temperature measurement system in high temperature,high pressure,highly corrosive and other special environments,a temperature acquisition system based on field-programmable gate array(F...Aiming at high requirements of temperature measurement system in high temperature,high pressure,highly corrosive and other special environments,a temperature acquisition system based on field-programmable gate array(FPGA) which is the controller of the system is designed.Also a Flash memory is used as the memory and an erosion thermocouple is used as sensor of the system.Compared with the traditional system using complex programmable logic device(CPLD)and microcontroller unit(MCU)as the main body,this system has some advantages,such as short response time,small volume,no loss of data once power is off,high precision,stability and reliability.And the sensor of the system can be reused.In this paper,boiling water experiment is used to verify accuracy of the system.The millisecond level signal from firecrackers is for verifying the stability and fast response characteristics of the system.The results of experiment indicate that the temperature measurement system is more suitable for the field of explosion and other environments which have high requirements for the system.展开更多
A new simultaneous measurement method for the measurement of the three thermoelectric properties with a film-type thermocouple probe was proposed. Seebeck coefficient was measured using the steady-state condi-tion of ...A new simultaneous measurement method for the measurement of the three thermoelectric properties with a film-type thermocouple probe was proposed. Seebeck coefficient was measured using the steady-state condi-tion of the differential method. The electrical resistivity was measured us-ing the four-probe method and the thermal diffusivity is measured using the periodic heating method. The effectiveness of the proposed method was verified using constantan as a reference material. After describing the effectiveness of the method, the measurement of three thermoelectric properties of Bi0.3Sb1.7Te3, which is a thermoelectric material, was per-formed.展开更多
BACKGROUND Heart failure(HF),a common cardiovascular condition,is characterized by significant morbidity and mortality.While traditional Chinese medicine(TCM)is often used as a complementary approach in HF management,...BACKGROUND Heart failure(HF),a common cardiovascular condition,is characterized by significant morbidity and mortality.While traditional Chinese medicine(TCM)is often used as a complementary approach in HF management,systematic evalua-tions of its impact on clinical outcomes,TCM syndrome scores,and B-type natriuretic peptide(BNP)levels are lacking.This study fills this gap through a comprehensive analysis of randomized controlled trials(RCTs)focusing on TCM for HF treatment.It encompasses an assessment of methodological quality,a meta-analysis,and an evaluation of evidence quality based on established standards.The results offer crucial insights into the potential advantages and constraints of TCM in HF management.RCTs on TCM for HF treatment published since the establishment of the database were searched in four Chinese and English databases,including China National Knowledge Infrastructure,Wanfang,VIP Information Chinese Science and Technology Journal,and PubMed.Methodological quality was assessed for the included studies with the Cochrane risk-of-bias assessment tool,and the meta-analysis and publication bias assessment was performed with the RevMan5.3 software.Finally,the quality of evidence was rated according to the GRADE criteria.RESULTS A total of 1098 RCTs were initially retrieved.After screening,16 RCTs were finally included in our study,which were published between 2020 and 2023.These RCTs involved 1660 HF patients,including 832 in the TCM group[TCM combined with conventional Western medicine(CMW)treatment]and 828 in the CWM group(CWM treatment).The course of treatments varied from 1 wk to 3 months.TCM syndrome differentiation was analyzed in 11 of the included RCTs.In all included RCTs,outcome indicators included comprehensive clinical outcomes,TCM syndrome scores,and BNP levels.The meta-analysis results showed significant differences between the TCM and CWM groups in terms of comprehensive clinical outcomes[risk ratio=-0.54;95%confidence interval(CI)=-0.61,-0.47;P<0.00001],TCM syndrome scores[weighted mean difference(WMD)=-142.07;95%CI=-147.56,-136.57;P<0.00001],and BNP levels(WMD=-142.07;95%CI=-147.56,-136.57;P<0.00001).According to the GRADE criteria,RCTs where"TCM improves clinical comprehensive outcomes"were rated as low-quality evidence,and RCTs where"TCM reduces TCM syndrome scores"or"TCM decreases BNP levels"were rated as medium-quality evidence.CONCLUSION TCM combined with CWM treatment effectively improves comprehensive clinical outcomes and diminishes TCM syndrome scores and BNP levels in HF patients.Given the low and medium quality of the included RCTs,the application of these results should be cautious.展开更多
Background Heart failure (HF) is a common disease with complex pathophysiological causes. The diagnosis of HF commonly relies on comprehensive analyses of medical history and symptoms, and results from echocardiogra...Background Heart failure (HF) is a common disease with complex pathophysiological causes. The diagnosis of HF commonly relies on comprehensive analyses of medical history and symptoms, and results from echocardiography and biochemical tests. Galectin-3, a rela-tively new biomarker in HF, was approved by the US Food and Drug Administration in 2010 as a marker in the stratification of risk for HF. We assessed galectin-3 as a biomarker for HF diagnosis in patients with preserved ejection fraction (pEF) and compared its performance with that of B-type natriuretic peptide (BNP). Methods Thirty-five pEF patients with HF (HFpEF group) and 43 pEF patients without HF (control group) were enrolled. Plasma levels of galectin-3 and BNP in HFpEF and control subjects were determined. Sensitivity, specificity, pre dictive values, and accuracy of galectin-3 and BNP as markers for HF diagnosis were calculated and compared. Results Levels of galec- tin-3 and BNP were 23.09 ±6.97 ng/mL and 270.46 ± 330.41 pg/mL in the HFpEF group, and 16.74 ± 2.75 ng/mL and 59.94 ± 29.93 pg/mL in the control group, respectively. Differences in levels of galectin-3 and BNP between the two groups were significant (P 〈 0.01). As a bio- marker for HF diagnosis in study subjects, galectin-3 showed sensitivity and specificity of 94.3% and 65.1%, respectively, at a cutoff value of 17.8 ug/mL. BNP showed sensitivity and specificity of 77.1% and 90.7%, respectively, at a cutoff value of 100 pg/mL. Galectin-3 was a significantly more sensitive (P 〈 0.05) but less specific (P 〈 0.01) biomarker compared with BNP. Differences in positive predictive value, negative predictive value, and accuracy between galectin-3 and BNP markers were not significant (P 〉 0.05). Areas under the receiver operating characteristic curve (95% confidence interval) were 0.891 (0.808-0.974) and 0.896 (0.809-0.984) for galectin-3 and BNP, respec- tively, with no significant difference between the two values (P 〉 0.05). Conclusions The level of galectin-3 is significantly elevated in patients with HF. Galectin-3 and BNP are useful biomarkers for the diagnosis of HF in patients with pEF.展开更多
Marked elevations of B-type natriuretic peptide (BNP) are not generally seen in patients with heart failure and preserved ejection fraction (HFpEF). The objective of this study was to examine the clinical and labo...Marked elevations of B-type natriuretic peptide (BNP) are not generally seen in patients with heart failure and preserved ejection fraction (HFpEF). The objective of this study was to examine the clinical and laboratory characteristics of a large cohort of patients with HFpEF and markedly elevated BNP. A retrospective examination of 421 inpatients at a university hospital admitted with a diagnosis of HFpEF was performed. Clinical and echocardiographic data in 4 groups of patients with levels of BNP ≤ 100 pg/mL, 100-400 pg/mL, 400-1,000 pg/mL and 〉 1,000 pg/mL were compared. Patients with HFpEF and BNP 〉 1,000 pg/mL (28% of the population) were characterized by impaired renal function and greater use of anti-hypertensive medications. A subset of these patients with BNP 〉 1,000 pg/mL had normal renal function (21%) and were significantly older, more frequently female, and tended to have lower ejection fractions. Conversely, patients with HFpEF and BNP ≤100 pg/mL were younger and had preserved renal function. BNP was inversely related to the likelihood of subsequent admission for heart failure, but not to myocardial infarction or death. In conclusion: BNP 〉 1,000 pg/mL is seen in almost 1/3 of patients hospitalized with HFpEF. This elevation of BNP often reflects impaired renal function, but can also be seen in patients with preserved renal function but relatively impaired systolic function.展开更多
BACKGROUND: Although pneumonia severity index(PSI) is widely used to evaluate the severity of community-acquired pneumonia(CAP), the calculation of PSI is very complicated. The present study aimed to evaluate the role...BACKGROUND: Although pneumonia severity index(PSI) is widely used to evaluate the severity of community-acquired pneumonia(CAP), the calculation of PSI is very complicated. The present study aimed to evaluate the role of B-type natriuretic peptide(BNP) in predicting the severity of CAP.METHODS: For 202 patients with CAP admitted to the emergency department, BNP levels, cardiac load indexes, inf lammatory indexes including C-reactive protein(CRP), white blood cell count(WBC), and PSI were detected. The correlation between the indexes and PSI was investigated. BNP levels for survivor and non-survivor groups were compared, and a receiver operating characteristic(ROC) curve analysis was performed on the BNP levels versus PSI.RESULTS: The BNP levels increased with CAP severity(r=0.782, P<0.001). The BNP levels of the high-risk group(PSI classes IV and V) were signifi cantly higher than those of the low-risk group(PSI classes I–III)(P<0.001). The BNP levels were signifi cantly higher in the non-survivor group than in the survivor group(P<0.001). In addition, there were positive correlations between BNP levels and PSI scores(r=0.782, P<0.001). The BNP level was highly accurate in predicting the severity of CAP(AUC=0.952). The optimal cut-off point of BNP level for distinguishing high-risk patients from low-risk ones was 125.0 pg/m L, with a sensitivity of 0.891 and a specifi city of 0.946. Moreover, BNP level was accurate in predicting mortality(AUC=0.823). Its optimal cut-off point for predicting death was 299.0 pg/m L, with a sensitivity of 0.675 and a specifi city of 0.816. Its negative predictive cut-off value was 0.926, and the positive predictive cut-off value was 0.426.CONCLUSION: BNP level is positively correlated with the severity of CAP, and may be used as a biomarker for evaluating the severity of CAP.展开更多
Wheat grain natural transverse sections of 12 periods were observed and analyzed using scanning electron micrographs technology and Bio-Quant system IV image analyzer in order to detect the developing process of A- an...Wheat grain natural transverse sections of 12 periods were observed and analyzed using scanning electron micrographs technology and Bio-Quant system IV image analyzer in order to detect the developing process of A- and B-type starch granules. In addition, the chemical composition and starch granule-bound proteins (SGPs) of A- and B-type starch granules were tested and analyzed. The results showed that A-type starch granules in wheat began from 3 d post anthesis (DPA) till grain maturing and B-type starch granules occured after 15 DPA till grain maturing. Approximately 98.5% of chemical compositions in both A- and B-type starch granules were amylose and amylopectin, and more than half of which were amylopectin. The amylopectin contents, average chain length, and chain length distribution (degree of polymerization〉 40) of amylopectin in A-type starch granules were significant higher than that of B-type starch granules. SGP-145, SGP-140, and SGP-26 kD were associated with A-type starch formation in wheat grain.展开更多
Environmental embrittlement in A3B-type intermetallics based on Ni3Al and Fe3Al has been studied in this paper. For the Ni3Al doped with 120 wt ppm B and Ni,(Al,Cr.Zr) doped with 80 wt ppm B,their elongation and ultim...Environmental embrittlement in A3B-type intermetallics based on Ni3Al and Fe3Al has been studied in this paper. For the Ni3Al doped with 120 wt ppm B and Ni,(Al,Cr.Zr) doped with 80 wt ppm B,their elongation and ultimate tensile strength decreased in the sequence:of vacuum > air >hydrogen. while for Ni,(Al,Mn) doped with 400 wt ppm B no envifonmental degradation was ob served, although a -Ni3(Al,Mn) alloy without B showed a decrease in ductility when tested in air in stead of oxygen. It is supposed that boron and hydrogen compete for the occupation of interstitial sites near grain boundaries. If boron content is sufficiently low, hydrogen embrittlement occurs ;however, if its content is sufficiently high. boron addition is capable of eliminating envjronmental ef fect in Ni3Al-based alloysi As to the micromechanism of hydrogen embrittlement in Ni3Al+B. S EM in situ observations showed that both grain boundary decohesion and a high stress concentration con tributed to hydrogen-assisted jntergranu lar cracking in this alloy. For the Fe3Al and Fe3 (Al.Cr) alloys.their mechanical properties depended strongly on grain size / grain shape and testing environment. A strain rate effect on ductiIity and fracture strength was also observed in the Fe3Al and Fe,(Al,Cr)+B aIloys. Preoxidation increased the ductility of the Fe,(Al,Cr)+B alloy. All these results can be rationalized from a hypothesis that surface reaction is the controlling process in embrittling Fe3Al-based alloys.展开更多
A 57-year-old man consulted a local hospital because of a persistent slight fever. At the age of 37 years he was diagnosed having B-type hepatitis, but left the liver dysfunction untreated. Twenty years later, he was ...A 57-year-old man consulted a local hospital because of a persistent slight fever. At the age of 37 years he was diagnosed having B-type hepatitis, but left the liver dysfunction untreated. Twenty years later, he was diagnosed having chronic hepatitis B, hepatocellular carcinoma (HCC) and macrocytic anemia, and referred to our hospital for further investigation. A HCC with a maximum diameter of 5.2 cm was detected in segment 8. Results of blood tests included 1.8 mg/dL serum total bilirubin, 0.9 mg/dL bilirubin, less than 10 mg/dL haptoglobin, 7.9 g/dL hemoglobin, 130 fL MCV, and 14.5% reticuloo/tes. A bone marrow sample showed erythroid hyperplasia. The direct Coombs test gave a positive result. We diagnosed the anemia as autoimmmune hemolytic anemia (AIHA), for which prednisolone could not be administered due to positivity for HBsAg and HBeAg. After preparation of washed blood cells for later transfusion, the patient underwent systematic resection of segment 8. The cut surface of the resected specimen demonstrated an encapsulated yellow-brownish tumor measuring 52 mmx 40 mm which was diagnosed pathologicaly as moderately differentiated HCC. On the 9th postoperative day, the patient's temperature rose to 38℃, and exacerbated hemolysis was observed. The maximum total bilirubin value was 5.8 mg/dL and minimum hemoglobin level was 4.6 g/dL. He tolerated this period without blood transfusion. Currently he is being followed up as an outpatient, and shows no signs of HCC recurrence or symptoms of anemia. AIHA associated with HBV infection has been described in only three previous cases, and the present case is the first in which surgery was performed for accompanying HCC.展开更多
Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultiva...Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultivars, and to compare structure and functionality of starches in four leading cultivars Zhongmai 175, CA12092, Lunxuan 987, and Zhongyou 206. A wide variation in volume percentages of A- and B-type starch granules among genotypes was observed. Volume percentages of A- and B-type granules had ranges of 68.4–88.9% and 9.7–27.9% in the first cropping seasons, 74.1–90.1% and 7.2–25.3% in the second. Wheat cultivars with higher volume percentages of A- and B-type granules could serve as parents in breeding program for selecting high and low amylose wheat cultivars, respectively. In comparison with the B-type starch granules, the A-type granules starch showed difference in three aspects:(1) higher amount of ordered short-range structure and a lower relative crystallinity,(2) higher gelatinization onset(To) temperatures and enthalpies(ΔH), and lower gelatinization conclusion temperatures(Tc),(3) greater peak, though, and final viscosity, and lower breakdown viscosity and pasting temperature. It provides important information for breeders to develop potentially useful cultivars with particular functional properties of their starches suited to specific applications.展开更多
Phase evolution and magnetic properties of (Nd_o.95La_0.05)9.5-11Febal.M_2B10.5. where M=Cr, Ti, Nb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons. except for(Nd_0....Phase evolution and magnetic properties of (Nd_o.95La_0.05)9.5-11Febal.M_2B10.5. where M=Cr, Ti, Nb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons. except for(Nd_0.95La_0.05)_9.5Fe_78M_2B_10.5(M=Mo and Mn),consist merely two magnetic phases, namely α-Fe and R_2Fe_14B, which display a better combination of _iH_c and magnetic energy product. Remanence (Br) and coercivity (i_H_c) values in the range of 8.0 to 9.1 kG and 9.5 to 18.9 kOe. respectively, can be achieved. Among compositions studied, the Ti and W-substitutions were found to be most effective in increasing the Br and i_H_c, respectively. For a fixed refractory metal substitution, namely, M=C_r, Ti or Nb, an increase in the total rare earth concentration resulted in nanocomposites of small grain sizes and a high volume fraction of the R_2Fe_14B phase, leading to an increase in the magnetic properties.展开更多
文摘Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC semiconductor device,an instrumentation amplifier(IA),two resistors,and a diode for disconnection detection.Based on the basic circuit,a multi-channel interface circuit was also implemented.The CJC was implemented using compensation semiconductor and IA,and disconnection detection was detected by using two resistors and a diode so that IA input voltage became-0.42 V.As a result of the experiment using R-type TC,the error of the designed circuit was reduced from 0.14 mV to 3μV after CJC in the temperature range of 0°C to 1400°C.In addition,it was confirmed that the output voltage of IA was saturated from 88 mV to-14.2 V when TC was disconnected from normal.The output voltage of the designed circuit was 0 V to 10 V in the temperature range of 0°C to 1400°C.The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel.The implemented multi-channel interface has a feature that can be applied equally to E,J,K,T,R,and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain.
基金Research Project Supported by Shanxi Scholarship Council of China(No.2012-068)Taiyuan Science and Technology Agency(No.120247-20)Surface-temperature Sensor Dynamic Measurement and Calibration Technology Research of National Defense Fundamental Scientific Research
文摘A new method was proposed, in which a high-power CO2 laser modulated by high frequency was used as the driv- ing source to heat up a surface-temperature sensor. The continual beam and the pulsed beam sent out by the same laser could be used in the same system to carry on the static calibration of the radiation thermometer and the dynamic calibration of the temperature sensor to be checked. The frequency-response characteristics of high-speed radiation thermometer surpassed that of the temperature sensor, therefore it could be used as the reference value to calibrate the latter and let system error be cor- rected. Differences in the environment of the sensor installing and the error caused by the change of thermo-physical proper- ty could be avoided. Thus, the difficult problem of traceable dynamic calibration of temperature was solved. In experiment, to obtain the frequency characteristics of the thermocouple and the dynamic performance of the K type thermocouple, which could compensate the dynamic characteristics of the sensor, the sensor was dynamically corrected by using the method, and then the mathematical model was established.
文摘The theory for measuring the time constant of thermocouple was introduced, and the method for measuring the time constant of NANMAC thermocouple by using dynamic calibration system of transient surface temperature sensor was proposed. In this system, static and dynamic calibrations were conducted for infrared detectors and thermocouples, and then both temperature-time curves were obtained. Since the frequency response of infrared detector is superior to that of calibrat- ed thermocouple, the values measured by infrared detectors are taken as true values. Through dividing the values measured with thermocouples by those with infrared detectors, a normalized curve was obtained, based on which the time constant of thermocouple was measured. With this method, the experiments were carried out with NANMAC thermocouple to obtain its time constant. The results show that the method for measuring the time constant is feasible and the dynamic calibration of thermocouples can be achieved at microsecond and millisecond level. This research has a certain reference value for research and application of NANMAC thermocouple temperature sensor.
基金supported by National Natural Science Foundation of China(Grant No.50775210)Liaoning Provincial Natural Science Foundation of China(Grant No.20062143)Liaoning Provincial Universities Science and Technology Program of China(Grant No.05L023)
文摘In high-speed cutting, natural thermocouple, artificial thermocouple and infrared radiation temperature measurement are usually adopted for measuring cutting temperature, but these methods have difficulty in measuring transient temperature accurately of cutting area on account of low response speed and limited cutting condition. In this paper, NiCr/NiSi thin-film thermocouples(TFTCs) are fabricated according to temperature characteristic of cutting area in high-speed cutting by means of advanced twinned microwave electro cyclotron resonance(MW-ECR) plasma source enhanced radio frequency(RF) reaction non-balance magnetron sputtering technique, and can be used for transient cutting temperature measurement. The time constants of the TFTCs with different thermo-junction film width are measured at four kinds of sampling frequency by using Ultra-CFR short pulsed laser system that established. One-dimensional unsteady heat conduction model is constructed and the dynamic performance is analyzed theoretically. It can be seen from the analysis results that the NiCr/NiSi TFTCs are suitable for measuring transient temperature which varies quickly, the response speed of TFTCs can be obviously improved by reducing the thickness of thin-film, and the area of thermo-junction has little influence on dynamic response time. The dynamic calibration experiments are made on the constructed dynamic calibration system, and the experimental results confirm that sampling frequency should be larger than 50 kHz in dynamic measurement for stable response time, and the shortest response time is 0.042 ms. Measurement methods and devices of cutting heat and cutting temperature measurement are developed and improved by this research, which provide practical methods and instruments in monitoring cutting heat and cutting temperature for research and production in high-speed machining.
文摘For the manufacture of S-type thermocouple the so-called thermocouple wire of platinum and platinum-rhodium alloy is used.One of the main technical requirements for the quality of the wire,according to State Standard of Russia(GOST 10821),is the uniformity of its largest thermoelectric force(Thermo-emf) in the length different sections.It was found that a determining impact on the uniformity of the wire thermo-emf is the distribution of rhodium along the length of the wire.The impact of platinum-rhodium melt crystallization conditions on the inhomogeneity of wire manufactured from it.It was suggested that the chemical inhomogeneity of the wire is related to the liquation phase of platinum-rhodium alloy.
文摘The electromotive force (EMF) changes in type K heavy gauge sheathed thermocouple cables was investigated. To cope with this discrepancy owing to EMF steep reduction and understand the difference between type K heavy gauge sheathed thermocouple cables and small ones, the affects of EMF from sheath pipe, drawing times, annealing temperature, annealing time and annealing way were mainly studied and appropriately analyzed. The results show the change in the thermal EMF is related with the residual stress and crystal defects, which are imparted by cold work during manufacture. The affects of cold work can be removed by annealing. Finally, a feasible way of fabricating heavy gauge sheathed thermocouples was suggested according to practical situation.
文摘There are large errors of linear measurement when the thermocouple measure temperature as temperature sensor.In order to improve the measurement precision,the sensor cold junction compensation and nonlinear compensation are usually needed.For the circumstances that the cold junction’s temperature is determinate,there is biggish nonlinear between thermoelectric power and temperature signals of the thermocouple sensor’s output.In order to solve the problem,this paper proposed a practical method of linear compensation,introduced the principle of linear compensation and gave the corresponding compensation circuit and circuit analysis.This circuit has the characteristic of simpleness,high reliability,small linear error and so on.
基金Natural Science Foundation of Shanxi Province(No. 2009011023)
文摘Aiming at high requirements of temperature measurement system in high temperature,high pressure,highly corrosive and other special environments,a temperature acquisition system based on field-programmable gate array(FPGA) which is the controller of the system is designed.Also a Flash memory is used as the memory and an erosion thermocouple is used as sensor of the system.Compared with the traditional system using complex programmable logic device(CPLD)and microcontroller unit(MCU)as the main body,this system has some advantages,such as short response time,small volume,no loss of data once power is off,high precision,stability and reliability.And the sensor of the system can be reused.In this paper,boiling water experiment is used to verify accuracy of the system.The millisecond level signal from firecrackers is for verifying the stability and fast response characteristics of the system.The results of experiment indicate that the temperature measurement system is more suitable for the field of explosion and other environments which have high requirements for the system.
文摘A new simultaneous measurement method for the measurement of the three thermoelectric properties with a film-type thermocouple probe was proposed. Seebeck coefficient was measured using the steady-state condi-tion of the differential method. The electrical resistivity was measured us-ing the four-probe method and the thermal diffusivity is measured using the periodic heating method. The effectiveness of the proposed method was verified using constantan as a reference material. After describing the effectiveness of the method, the measurement of three thermoelectric properties of Bi0.3Sb1.7Te3, which is a thermoelectric material, was per-formed.
文摘BACKGROUND Heart failure(HF),a common cardiovascular condition,is characterized by significant morbidity and mortality.While traditional Chinese medicine(TCM)is often used as a complementary approach in HF management,systematic evalua-tions of its impact on clinical outcomes,TCM syndrome scores,and B-type natriuretic peptide(BNP)levels are lacking.This study fills this gap through a comprehensive analysis of randomized controlled trials(RCTs)focusing on TCM for HF treatment.It encompasses an assessment of methodological quality,a meta-analysis,and an evaluation of evidence quality based on established standards.The results offer crucial insights into the potential advantages and constraints of TCM in HF management.RCTs on TCM for HF treatment published since the establishment of the database were searched in four Chinese and English databases,including China National Knowledge Infrastructure,Wanfang,VIP Information Chinese Science and Technology Journal,and PubMed.Methodological quality was assessed for the included studies with the Cochrane risk-of-bias assessment tool,and the meta-analysis and publication bias assessment was performed with the RevMan5.3 software.Finally,the quality of evidence was rated according to the GRADE criteria.RESULTS A total of 1098 RCTs were initially retrieved.After screening,16 RCTs were finally included in our study,which were published between 2020 and 2023.These RCTs involved 1660 HF patients,including 832 in the TCM group[TCM combined with conventional Western medicine(CMW)treatment]and 828 in the CWM group(CWM treatment).The course of treatments varied from 1 wk to 3 months.TCM syndrome differentiation was analyzed in 11 of the included RCTs.In all included RCTs,outcome indicators included comprehensive clinical outcomes,TCM syndrome scores,and BNP levels.The meta-analysis results showed significant differences between the TCM and CWM groups in terms of comprehensive clinical outcomes[risk ratio=-0.54;95%confidence interval(CI)=-0.61,-0.47;P<0.00001],TCM syndrome scores[weighted mean difference(WMD)=-142.07;95%CI=-147.56,-136.57;P<0.00001],and BNP levels(WMD=-142.07;95%CI=-147.56,-136.57;P<0.00001).According to the GRADE criteria,RCTs where"TCM improves clinical comprehensive outcomes"were rated as low-quality evidence,and RCTs where"TCM reduces TCM syndrome scores"or"TCM decreases BNP levels"were rated as medium-quality evidence.CONCLUSION TCM combined with CWM treatment effectively improves comprehensive clinical outcomes and diminishes TCM syndrome scores and BNP levels in HF patients.Given the low and medium quality of the included RCTs,the application of these results should be cautious.
文摘Background Heart failure (HF) is a common disease with complex pathophysiological causes. The diagnosis of HF commonly relies on comprehensive analyses of medical history and symptoms, and results from echocardiography and biochemical tests. Galectin-3, a rela-tively new biomarker in HF, was approved by the US Food and Drug Administration in 2010 as a marker in the stratification of risk for HF. We assessed galectin-3 as a biomarker for HF diagnosis in patients with preserved ejection fraction (pEF) and compared its performance with that of B-type natriuretic peptide (BNP). Methods Thirty-five pEF patients with HF (HFpEF group) and 43 pEF patients without HF (control group) were enrolled. Plasma levels of galectin-3 and BNP in HFpEF and control subjects were determined. Sensitivity, specificity, pre dictive values, and accuracy of galectin-3 and BNP as markers for HF diagnosis were calculated and compared. Results Levels of galec- tin-3 and BNP were 23.09 ±6.97 ng/mL and 270.46 ± 330.41 pg/mL in the HFpEF group, and 16.74 ± 2.75 ng/mL and 59.94 ± 29.93 pg/mL in the control group, respectively. Differences in levels of galectin-3 and BNP between the two groups were significant (P 〈 0.01). As a bio- marker for HF diagnosis in study subjects, galectin-3 showed sensitivity and specificity of 94.3% and 65.1%, respectively, at a cutoff value of 17.8 ug/mL. BNP showed sensitivity and specificity of 77.1% and 90.7%, respectively, at a cutoff value of 100 pg/mL. Galectin-3 was a significantly more sensitive (P 〈 0.05) but less specific (P 〈 0.01) biomarker compared with BNP. Differences in positive predictive value, negative predictive value, and accuracy between galectin-3 and BNP markers were not significant (P 〉 0.05). Areas under the receiver operating characteristic curve (95% confidence interval) were 0.891 (0.808-0.974) and 0.896 (0.809-0.984) for galectin-3 and BNP, respec- tively, with no significant difference between the two values (P 〉 0.05). Conclusions The level of galectin-3 is significantly elevated in patients with HF. Galectin-3 and BNP are useful biomarkers for the diagnosis of HF in patients with pEF.
基金supported by the National Center for Advancing Translational Sciences (NCATS),National Institutes of Health(NIH),through grant #UL1 TR000002
文摘Marked elevations of B-type natriuretic peptide (BNP) are not generally seen in patients with heart failure and preserved ejection fraction (HFpEF). The objective of this study was to examine the clinical and laboratory characteristics of a large cohort of patients with HFpEF and markedly elevated BNP. A retrospective examination of 421 inpatients at a university hospital admitted with a diagnosis of HFpEF was performed. Clinical and echocardiographic data in 4 groups of patients with levels of BNP ≤ 100 pg/mL, 100-400 pg/mL, 400-1,000 pg/mL and 〉 1,000 pg/mL were compared. Patients with HFpEF and BNP 〉 1,000 pg/mL (28% of the population) were characterized by impaired renal function and greater use of anti-hypertensive medications. A subset of these patients with BNP 〉 1,000 pg/mL had normal renal function (21%) and were significantly older, more frequently female, and tended to have lower ejection fractions. Conversely, patients with HFpEF and BNP ≤100 pg/mL were younger and had preserved renal function. BNP was inversely related to the likelihood of subsequent admission for heart failure, but not to myocardial infarction or death. In conclusion: BNP 〉 1,000 pg/mL is seen in almost 1/3 of patients hospitalized with HFpEF. This elevation of BNP often reflects impaired renal function, but can also be seen in patients with preserved renal function but relatively impaired systolic function.
基金supported by a grant from the Excellent Talent Training Special Fund,Xicheng District of Beijing(20110046)
文摘BACKGROUND: Although pneumonia severity index(PSI) is widely used to evaluate the severity of community-acquired pneumonia(CAP), the calculation of PSI is very complicated. The present study aimed to evaluate the role of B-type natriuretic peptide(BNP) in predicting the severity of CAP.METHODS: For 202 patients with CAP admitted to the emergency department, BNP levels, cardiac load indexes, inf lammatory indexes including C-reactive protein(CRP), white blood cell count(WBC), and PSI were detected. The correlation between the indexes and PSI was investigated. BNP levels for survivor and non-survivor groups were compared, and a receiver operating characteristic(ROC) curve analysis was performed on the BNP levels versus PSI.RESULTS: The BNP levels increased with CAP severity(r=0.782, P<0.001). The BNP levels of the high-risk group(PSI classes IV and V) were signifi cantly higher than those of the low-risk group(PSI classes I–III)(P<0.001). The BNP levels were signifi cantly higher in the non-survivor group than in the survivor group(P<0.001). In addition, there were positive correlations between BNP levels and PSI scores(r=0.782, P<0.001). The BNP level was highly accurate in predicting the severity of CAP(AUC=0.952). The optimal cut-off point of BNP level for distinguishing high-risk patients from low-risk ones was 125.0 pg/m L, with a sensitivity of 0.891 and a specifi city of 0.946. Moreover, BNP level was accurate in predicting mortality(AUC=0.823). Its optimal cut-off point for predicting death was 299.0 pg/m L, with a sensitivity of 0.675 and a specifi city of 0.816. Its negative predictive cut-off value was 0.926, and the positive predictive cut-off value was 0.426.CONCLUSION: BNP level is positively correlated with the severity of CAP, and may be used as a biomarker for evaluating the severity of CAP.
基金supported by the National Natural Science Foundation of China (30860145)
文摘Wheat grain natural transverse sections of 12 periods were observed and analyzed using scanning electron micrographs technology and Bio-Quant system IV image analyzer in order to detect the developing process of A- and B-type starch granules. In addition, the chemical composition and starch granule-bound proteins (SGPs) of A- and B-type starch granules were tested and analyzed. The results showed that A-type starch granules in wheat began from 3 d post anthesis (DPA) till grain maturing and B-type starch granules occured after 15 DPA till grain maturing. Approximately 98.5% of chemical compositions in both A- and B-type starch granules were amylose and amylopectin, and more than half of which were amylopectin. The amylopectin contents, average chain length, and chain length distribution (degree of polymerization〉 40) of amylopectin in A-type starch granules were significant higher than that of B-type starch granules. SGP-145, SGP-140, and SGP-26 kD were associated with A-type starch formation in wheat grain.
文摘Environmental embrittlement in A3B-type intermetallics based on Ni3Al and Fe3Al has been studied in this paper. For the Ni3Al doped with 120 wt ppm B and Ni,(Al,Cr.Zr) doped with 80 wt ppm B,their elongation and ultimate tensile strength decreased in the sequence:of vacuum > air >hydrogen. while for Ni,(Al,Mn) doped with 400 wt ppm B no envifonmental degradation was ob served, although a -Ni3(Al,Mn) alloy without B showed a decrease in ductility when tested in air in stead of oxygen. It is supposed that boron and hydrogen compete for the occupation of interstitial sites near grain boundaries. If boron content is sufficiently low, hydrogen embrittlement occurs ;however, if its content is sufficiently high. boron addition is capable of eliminating envjronmental ef fect in Ni3Al-based alloysi As to the micromechanism of hydrogen embrittlement in Ni3Al+B. S EM in situ observations showed that both grain boundary decohesion and a high stress concentration con tributed to hydrogen-assisted jntergranu lar cracking in this alloy. For the Fe3Al and Fe3 (Al.Cr) alloys.their mechanical properties depended strongly on grain size / grain shape and testing environment. A strain rate effect on ductiIity and fracture strength was also observed in the Fe3Al and Fe,(Al,Cr)+B aIloys. Preoxidation increased the ductility of the Fe,(Al,Cr)+B alloy. All these results can be rationalized from a hypothesis that surface reaction is the controlling process in embrittling Fe3Al-based alloys.
文摘A 57-year-old man consulted a local hospital because of a persistent slight fever. At the age of 37 years he was diagnosed having B-type hepatitis, but left the liver dysfunction untreated. Twenty years later, he was diagnosed having chronic hepatitis B, hepatocellular carcinoma (HCC) and macrocytic anemia, and referred to our hospital for further investigation. A HCC with a maximum diameter of 5.2 cm was detected in segment 8. Results of blood tests included 1.8 mg/dL serum total bilirubin, 0.9 mg/dL bilirubin, less than 10 mg/dL haptoglobin, 7.9 g/dL hemoglobin, 130 fL MCV, and 14.5% reticuloo/tes. A bone marrow sample showed erythroid hyperplasia. The direct Coombs test gave a positive result. We diagnosed the anemia as autoimmmune hemolytic anemia (AIHA), for which prednisolone could not be administered due to positivity for HBsAg and HBeAg. After preparation of washed blood cells for later transfusion, the patient underwent systematic resection of segment 8. The cut surface of the resected specimen demonstrated an encapsulated yellow-brownish tumor measuring 52 mmx 40 mm which was diagnosed pathologicaly as moderately differentiated HCC. On the 9th postoperative day, the patient's temperature rose to 38℃, and exacerbated hemolysis was observed. The maximum total bilirubin value was 5.8 mg/dL and minimum hemoglobin level was 4.6 g/dL. He tolerated this period without blood transfusion. Currently he is being followed up as an outpatient, and shows no signs of HCC recurrence or symptoms of anemia. AIHA associated with HBV infection has been described in only three previous cases, and the present case is the first in which surgery was performed for accompanying HCC.
基金financial support from the National Natural Science Foundation of China (31171547,31401651)
文摘Starch is the major component of wheat flour and serves as a multifunctional ingredient in food industry. The objective of the present study was to investigate starch granule size distribution of Chinese wheat cultivars, and to compare structure and functionality of starches in four leading cultivars Zhongmai 175, CA12092, Lunxuan 987, and Zhongyou 206. A wide variation in volume percentages of A- and B-type starch granules among genotypes was observed. Volume percentages of A- and B-type granules had ranges of 68.4–88.9% and 9.7–27.9% in the first cropping seasons, 74.1–90.1% and 7.2–25.3% in the second. Wheat cultivars with higher volume percentages of A- and B-type granules could serve as parents in breeding program for selecting high and low amylose wheat cultivars, respectively. In comparison with the B-type starch granules, the A-type granules starch showed difference in three aspects:(1) higher amount of ordered short-range structure and a lower relative crystallinity,(2) higher gelatinization onset(To) temperatures and enthalpies(ΔH), and lower gelatinization conclusion temperatures(Tc),(3) greater peak, though, and final viscosity, and lower breakdown viscosity and pasting temperature. It provides important information for breeders to develop potentially useful cultivars with particular functional properties of their starches suited to specific applications.
基金National Science Council, Taiwan! under grant !No. NSC-87-2112-M194-005.
文摘Phase evolution and magnetic properties of (Nd_o.95La_0.05)9.5-11Febal.M_2B10.5. where M=Cr, Ti, Nb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons. except for(Nd_0.95La_0.05)_9.5Fe_78M_2B_10.5(M=Mo and Mn),consist merely two magnetic phases, namely α-Fe and R_2Fe_14B, which display a better combination of _iH_c and magnetic energy product. Remanence (Br) and coercivity (i_H_c) values in the range of 8.0 to 9.1 kG and 9.5 to 18.9 kOe. respectively, can be achieved. Among compositions studied, the Ti and W-substitutions were found to be most effective in increasing the Br and i_H_c, respectively. For a fixed refractory metal substitution, namely, M=C_r, Ti or Nb, an increase in the total rare earth concentration resulted in nanocomposites of small grain sizes and a high volume fraction of the R_2Fe_14B phase, leading to an increase in the magnetic properties.