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Polystyrene microplastics (mic-PS) have become harmful pollutants that attracted substantial attention about their potential toxicity. Hydrogen sulfide (H2S) is the third reported endogenous gas transmitter with protective functions on numerous physiologic responses. Nevertheless, the roles for mic-PS on skeletal systems in mammals and the protective effects of exogenous H2S are still indistinct. Here, the proliferation of MC3T3-E1 cell was analyzed by CCK8. Gene changes between the control and mic-PS treatment groups were analyzed by RNA-seq. The mRNA expression of bone morphogenetic protein 4 (Bmp4), alpha cardiac muscle 1 (Actc1), and myosin heavy polypeptide 6 (Myh6) was analyzed by QPCR. ROS level was analyzed by 2 ′ ,7 ′ -dichlorofluorescein (DCFH-DA). The mitochondrial membrane potential (MMP) was analyzed by Rh123. Our results indicated after exposure for 24 h, 100 mg/L mic-PS induced considerable cytotoxicity in the osteoblastic cells of mice. There were 147 differentially expressed genes (DEGs) including 103 downregulated genes and 44 upregulated genes in the mic-PS-treated group versus the control. The related signaling pathways were oxidative stress, energy metabolism, bone formation, and osteoblast differentiation. The results indicate that exogenous H2S may relieve mic-PS toxicity by altering Bmp4, Actc1, and Myh6 mRNA expressions associated with mitochondrial oxidative stress. Taken together, this study demonstrated that the bone toxicity effects of mic-PS along with exogenous H2S have protective function in mic-PS-mediated oxidative damage and mitochondrial dysfunction in osteoblastic cells of mice.

The frame is an integral part of the corn harvester and is the mounting carrier for all components, so a high strength frame structure is a basic requirement for a high level corn harvester. Corn harvesters often operate in harsh conditions on farmland and have a high intensity of concentrated operating hours. This often leads to fatigue cracks in the frame, which can affect the operational life of the harvester seriously and even result in accidents. Therefore the vibration characteristics of the frame structure of corn harvesters with cracks need to be investigated. Firstly, the typical experimental platform of the frame structure of the corn harvester with cracks is established, according to the structural characteristics and force situation of the frame of the corn harvester during operation. Then, the vibration characteristics of the frame with cracks in the longitudinal beam and the frame with cracks in the crossbeam were subject to different excitation frequencies and excitation amplitudes. Finally, the effects of crack location, excitation frequency and excitation amplitude on the vibration characteristics of the harvester frame structure were investigated by analyzing the time domain and frequency domain plots of the experimental results of the frame vibration characteristics under various conditions. The results of the study can provide reference for frame structure fault diagnosis and fault localization.

Background The prevalence of drug-related problems in patients hospitalized at respiratory care units is unknown in mainland China. Objective To identify and categorize drug-related problems in a respiratory care unit in China. Setting Respiratory care unit in a tertiary university hospital in China. Methods Clinical pharmacy services were introduced and documented during an 18-months study period. The problems were categorized using the Pharmaceutical Care Network Europe DRP classification tool V8.02. Main outcome measures Problems and causes of drug-related problems, interventions proposed, and outcome of pharmacy recommendations. Results A total of 474 patients were reviewed, 164 patients had DRPs (34.6%). Total 410 problems were identified, an average of 2.5 per patient. Treatment effectiveness was the major type of problem detected (219; 53.4%) followed by treatment safety (140; 34.1%). The most common causes of the problems were patient-related (25.8%), drug selection (24.0%), and drug use process (23.4%). Pharmacist made 773 interventions; average 1.9 per drug-related problem. A total of 96.2% of these interventions were accepted leading to solving 81.9% of the identified problems. Conclusion There is a high prevalence of drug-related problems in patients hospitalized at the respiratory unit of this clinic. Clinical pharmacists should focus on improving prescribing practice and patient counseling.

OBJECTIVE: To assess the clinical value of individualized pharmaceutical services for patients receiving vancomycin for severe infections and establish clinical monitoring procedures during vancomycin treatment. METHODS: Data were collected from patients with severe infections who received vancomycin treatment with individualized pharmacy services (test group, 144 cases) or without such services (control group, 884 cases) between January, 2017 and December, 2018. Using propensity score matching, the patients in the two groups with comparable baseline data were selected for inclusion in the study (62 in each group), and the efficacy, safety and economic indicators were compared between the two groups. RESULTS: The curative effects of the treatment did not differ significantly between the two groups, with the overall response rates of 95.16% in the test group and 91.94% in the control group (P > 0.05). The percentage of neutrophils before vancomycin treatment and calcitonin level after the treatment differed significantly between the two groups (P < 0.05). No significant difference was found in the incidence of adverse events associated with the treatment between the test and control groups (8.06% vs 9.68%, P > 0.05); a significant difference in creatinine level was noted between the two groups after vancomycin treatment (P < 0.05). The number of days of medication, the cost of vancomycin and its proportion in the total expenses differed significantly between the two groups (P < 0.05). Cost-effectiveness analysis showed a better cost-effectiveness in the test group than in the control group (50052.78 vs 57601.23). The intensity of vancomycin use was also lower in the test group than in the control group (0.11 vs 0.36). CONCLUSION: The participation of clinical pharmacists during the treatment can improve the clinical benefits of vancomycin in patients with severe infections.

Instructions for Salvia miltiorrhiza polyphenol injections indicate abnormal liver function as an occasional adverse reaction, but the incidence of this adverse drug reaction (ADR) has increased in recent years. We assessed S. miltiorrhiza polyphenol ADRs by performing a nested case-control study(NCCS) and meta-analysis. In the NCCS, 2633 patients receiving this treatment in the First Affiliated Hospital of Bengbu Medical College were enrolled. Logistic regression models found that in 58 (2.2%) patients experiencing abnormal liver function, the risk for liver dysfunction was associated with sulfa drug allergy (OR = 7.874, 95%CI (1.280, 48.447), P = 0.026), payment methods (OR = 0.106, 95%CI (0.012, 0.934), P = 0.043), duration of administration (OR = 0.922, 95%CI (0.862, 0.986), P = 0.017), cefathiamidine (OR = 0.441, 95%CI (0.216, 0.900), P = 0.025), human serum albumin (OR = 1.958, 95%CI (1.011, 3.789), P = 0.046), Dazhu Rhodiola injection (OR = 2.599, 95%CI (1.112, 6.070), P = 0.027), or reduced glutathione (OR = 0.394, 95%CI (0.188, 0.826), P = 0.014). Meta-analysis of reports on S. miltiorrhiza polyphenol ADRs in controlled trials and other observational studies included 676 patients, of which 17 (2.17%; 95%CI (0.0105, 0.0358)) presented with liver dysfunction; associated ADR risk factors included co-administration of other drugs. Our NCCS and meta-analysis had similar ADR incidence rates, which were higher than the rate in the drug instructions. This study provides guidance for assessing liver dysfunction risks associated with S. miltiorrhiza polyphenol injections.

OBJECTIVE To analyze the correlation between VKORC1 gene polymorphisms and warfarin maintenance dosage, as well as the correlation of dosage of warfarin with age and ethnicity. METHODS We retrieved related studies published between January 2000 and March 2016 from PubMed, Embase, the Cochrane Library, Web of Science, VIP, CNKI, and Wan Fang data. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data and crosscheck data. Then, RevMan5.3 software was used to perform a meta-analysis. RESULTS 53 studies were included in the meta-analysis. The most prevalent genotypes were -1639 AA, 1173 TT, and 3730 GG in both Asian and Caucasians, but the distribution frequencies of all three were higher in Asians than in Caucasians. The meta-analysis showed that compared with homozygous VKORC1-1639 AA carriers, carriers of type GA, GG, and G (GA + GG) required 45% (95% confidence interval (CI) 42 - 49), 77% (95% CI 70 - 84), and 51% (95% CI 47 - 55) higher warfarin doses, respectively. Carriers of type CC, TC, and C (CC + TC) required 83% (95% CI 73 - 92), 26% (95% CI 23 - 29), and 53% (95% CI 44 - 62) higher warfarin doses, respectively, compared to homozygous VKORC1 1173 TT carriers. Carriers of type AA, GA, and A (AA + GA) required 40% (95% CI 29 - 51), 25% (95% CI 17 - 33), and 33% (95% CI 21 - 45) higher warfarin doses, respectively, compared to carriers of the homozygous VKORC1 3730 GG polymorphism (all p 60 years. Caucasian patients aged > 60 years carrying -1639 GA, GG and G genotypes needed 24%, 39%, and 37% lower warfarin doses, respectively, compared with patients aged ≤ 60 years. These differences were statistically significant (p VKORC1 gene polymorphisms and warfarin maintenance dose differs between individuals, and that individuals with different ages and ethnicities require different doses of warfarin. Caucasians carriers of genotype -1639 GG, G and 1173 CC, TC, C required a higher mean daily warfarin doses compared with Asian patients. Therefore, in order to achieve optimal treatment and lowest risk, VKORC1 gene polymorphism detection is suggested. .

Background The predictive value of adiposity indices and the newly developed index for cardiometabolic risk factors and cardiovascular diseases ( CVD s) remains unclear in the Chinese population. This study aimed to compare the predictive value of A Body Shape Index with other 5 conventional obesity‐related anthropometric indices (body mass index, waist circumference, hip circumference, waist‐to‐hip ratio, waist‐to‐height ratio) in Chinese population. Methods and Results A total of 44 048 participants in the study were derived from the baseline data of the PURE ‐China (Prospective Urban and Rural Epidemiology) study in China. All participants’ anthropometric parameters, CVD s, and risk factors (dyslipidemia, abnormal blood pressure, and hyperglycemia) were collected by standard procedures. Multivariable logistic regression models and receiver operator characteristic curve analysis were used to evaluate the predictive values of obesity‐related anthropometric indices to the cardiometabolic risk factors and CVD s. A positive association was observed between each anthropometric index and cardiometabolic risk factors and CVD s in all models ( P AUC s) for predicting dyslipidemia ( AUC s: 0.646, sensitivity: 65%, specificity: 44%), hyperglycemia ( AUC s: 0.595, sensitivity: 60%, specificity: 45%), and CVD s ( AUC s: 0.619, sensitivity: 59%, specificity: 41%). Waist circumference showed the best prediction for abnormal blood pressure ( AUC s: 0.671, sensitivity: 66%, specificity: 40%) compared with other anthropometric indices. However, the new body shape index did not show a better prediction to either cardiometabolic risk factors or CVD s than that of any other traditional obesity‐related indices. Conclusions Waist‐to‐height ratio appeared to be the best indicator for dyslipidemia, hyperglycemia, and CVD s, while waist circumference had a better prediction for abnormal blood pressure.

Launch vehicle network as an extremely important national defense information system, is faced with the threat of information security because of the dynamic detection limitation of the traditional firewall, virus detection software and so on. In this paper, we choose evaluation index and establish the entropy weight combination model based on the exponentially weighted moving-average (EWMA) model and the echo state network (ESN) model, Finally, we select the actual traffic data of the network, verify the effectiveness of the sequential dynamic security detection model, and study the influence of different time window observation scale on anomaly detection.

Massive machine type communication (mMTC) is one key scenario in 5G deployment. Reducing the signaling overhead and enhancing the coverage are two important targets. To reduce the signaling overhead, UL grant free transmission is considered, where one user equipment (UE) transmits data directly on one resource unit within the preconflgured resource set without eNB's scheduling. Repetition is the baseline method for coverage enhancement. To achieve efficient transmission, different repetition levels are configured for one UE and UE selects the repetition level for the transmission based on its measurement results. On the eNB side, eNB blindly decode the incoming data by assuming different repetition levels. In this case, eNB may successfully decode the data in earlier time before the repetition ends due to the inaccurately under-estimated channel estimation on the UE side and then performs the HARQ-ACK feedback earlier than the UE's expectation. In this case, unnecessary retransmissions happen at UE side due to the miss detection of the HARQ-ACK. Unnecessary retransmissions lower the spectral efficiency and consume more power on the UE side. To avoid the early termination on the eNB side, we propose to use repetition-level specific sequence to scramble the data. Simulation results show by using the proposed method, the unnecessary retransmissions are totally eliminated and the spectral efficiency is improved by around 30% and the power saving is improved by around 35%.

Lycopene is widely used as a dietary supplement. However, the effects of lycopene on cytochrome P450 (CYP) enzymes or P-glycoprotein (P-gp) are not comprehensive. The present study was performed to investigate the effects of lycopene on the CYP enzymes and P-gp activity. A cocktail method was used to evaluate the activities of CYP3A4, CYP2C9, CYP2C19, CYP2D6 and CYP2E1. Caco-2 cell monolayer model was carried out to assay lycopene on P-gp activity. The results indicated that lycopene had a moderate inhibitory effect on CYP2E1, with IC50 value of 43.65 μM, whereas no inhibitory effects on CYP3A4, CYP2C19, CYP2D6 and CYP2E1, with IC50 values all over 100 μM. In addition, lycopene showed almost no inhibitory effect on rhodamine-123 efflux and uptake (p .05), indicated no effects on P-gp activity. In conclusion, there should be required attention when lycopene are coadministered with other drugs that are metabolised by CYP2E1.

Efficient and accurate analysis of the traffic data contained in the network is the key measure to detect the abnormal behavior, resist the invasion and protect the information security. In this paper, we make a comprehensive utilization of the characteristics of port mapping identification, payload identification, statistical analysis and SVM machine learning, and propose the dynamic hybrid strategy. Firstly, the machine learning training samples are obtained through port mapping and load feature recognition. Then, on the basis of information gain feature selection, the SVM machine learning model is built and trained. Finally, through the voting mechanism, we achieve comprehensive analysis of the traffic data. The experimental results show that the accuracy of the proposed algorithm is as high as 99.1%, and the number of manual decision analysis is greatly reduced at the same time.

Background: Nosocomial pneumonia (NP) is a frequent complication among patients with intracerebral hemorrhage (ICH). However, there are currently no pharmacokinetic (PK) and pharmacodynamic (PD) data to guide meropenem dosing in these patients. Objective: To investigate the PK/PD properties of meropenem in these patients and whether the usual dosing regimens of meropenem (2-hour infusion, 1 g, every 8 hours) was suitable. Methods: A total of 11 patients with a diagnosis of ICH complicated with NP were selected in the emergency internal medicine and treated with a 1-g/2-hours extended infusion model. The plasma concentrations of meropenem were determined by high-performance liquid chromatography. PK parameters were estimated by plasma concentration versus time profile using WinNonlin software. The probability of target attainments (PTAs) of meropenem at different minimum inhibitory concentrations (MICs) based on percentage time that concentrations were above the minimum inhibitory concentration (%T>MIC) value were performed by Monte Carlo simulation. Results: The volume of distribution and total body clearance of meropenem were 55.55 L/kg and 22.89 L/h, respectively. Using 40%T>MIC, PTA was >90% at MICs ≤4 µg/mL. Using 80% or 100%T>MIC, PTA was >90% only at MICs ≤1 µg/mL. Conclusions: The PK/PD profile of dosing regimens tested will assist in selecting the appropriate meropenem regimens for these patients. At a target of 40%T>MIC, the usual dosing regimens can provide good coverage for pathogens with MICs of ≤4 µg/mL. However, when a higher target (80% or 100%) is desired for difficult-to-treat infections, larger doses, prolonged infusions, shorter intervals, and/or combination therapy may be required.

Cross domain data such as numerical or categorical types are ubiquitous in practical network. Network anomaly detection based on cluster analysis exist some difficulties, for example, the initial center of cluster analysis is sensitive and easy to fall into the local optimal solution. Cross domain data involved great information, but can't be effectively used, which will influence the performance of detection. In this paper, we proposed the dynamic hierarchical clustering method. Firstly, the feature selection based on information gain was used to reduce the feature dimension. Next, to measure the cross domain data, we defined the generalized Euclidean distance to extend the traditional Euclidean distance. Thirdly, dynamic clustering accuracy was set to guide the dynamic hierarchical clustering, guaranteeing the clustering accuracy as well as the convergence of clustering. Finally, Anomaly detection and classification model was constructed by using the training sample data. Simulation results show that the proposed algorithm can achieve higher detection rate and lower false detection rate.

The existing network platform can not meet the new launch vehicle launch costs, and there is the need for high reliability storage and application of massive data. A scheme of measuring and controlling network system based on cloud platform is put forward. The centralized management of system resources is realized. Enhanced resource utilization and system scalability, and reduced the development cost of the system. Through the centralized storage and management of rocket data, as well as the powerful computing and storage capacity of cloud computing, promote the gathering, integration and sharing of data resources. Enhance the security of the network system.

Background Most cardiovascular diseases occur in low‐ and middle‐income regions of the world, but the socioeconomic distribution within China remains unclear. Our study aims to investigate whether the prevalence of cardiovascular diseases differs among high‐, middle‐, and low‐income regions of China and to explore the reasons for the disparities. Methods and Results We enrolled 46 285 individuals from 115 urban and rural communities in 12 provinces across China between 2005 and 2009. We recorded their medical histories of cardiovascular diseases and calculated the INTERHEART Risk Score for the assessment of cardiovascular risk‐factor burden, with higher scores indicating greater burden. The mean INTERHEART Risk Score was higher in high‐ and middle‐income regions than in low‐income regions (9.47, 9.48, and 8.58, respectively, P P trend =0.0064). In high‐ and middle‐income regions, urban communities have higher INTERHEART Risk Score and higher prevalent rate than rural communities. In low‐income regions, however, the prevalence of total cardiovascular disease was similar between urban and rural areas despite the significantly higher INTERHEART Risk Score for urban settings. Conclusions We detected an inverse trend between risk‐factor burden and cardiovascular disease prevalence in urban and rural communities in high‐, middle‐, and low‐income regions of China. Such asymmetry may be attributed to the interregional differences in residents’ awareness, quality of healthcare, and availability and affordability of medical services.

Objective: Previous research has shown a high rate and a unique pattern of suicide in China. We aim to present the current suicide rates and patterns in the Yunnan province, a multi-ethnic region in Southwestern China. Methods: This is a descriptive study based on the 3rd Chinese national mortality survey. We reported the suicide rates by sex, 5-year age group, region (urban or rural), and minority group from 2004 to 2005 in the Yunnan province. Results: We estimated a mean annual suicide rate of 19.82 per 100,000 and a total of 8751 suicide deaths per year. Sex-specific rate estimates were 21.09 per 100,000 and 18.46 per 100,000 for males and females, respectively. The male/female ratio was 1.14. Region-specific rate estimates were 20.60 per 100,000 and 19.18 per 100,000 for rural and urban regions, respectively. The rural-to-urban ratio was 1.07. Suicide accounted for 4.83% of all deaths in the Yunnan province and represented the fifth leading cause of death. In minority groups, the highest suicide rates were found in the Li su minority (50.75 per 100,000), the Jing po minority (36.38 per 100,000), the Meng gu minority (32.65 per 100,000) and the Miao minority (30.75 per 100,000). The lowest rates were found in the Hui minority (0.96 per 100,000) and the Ha ni minority (1.64 per 100,000). Conclusions: The suicide characteristics of this multi-ethnic region of China are different from those of the rest of China and the world, which indicates that the development of a special intervention strategy in multi-ethnic areas for suicide prevention is needed.

Osteoporosis is a most frequent systemic skeletal disease characterized as low bone mineral density and microarchitectural deterioration of bone tissue, resulting in increased bone fragility and fracture risk. Although several drugs such as bisphosphonates, estrogen replacement treatment, and selective estrogen receptor modulators have been used to treat osteoporosis, all these are not the ideal drugs because of insufficient curative ability and adverse side effects. Recently, atorvastatin has ordinarily been prescribed as an anti-hyperlipidemia drug, not as an anti-osteoporosis drug. However, its clinical outcome and potential treatment mechanism are still unclear. In this study, the bilateral ovariectomy of rabbits was duplicated to develop osteoporosis animal model. The effect of atorvastatin on in vivo was determined, and the functional mechanism was studied in vitro after the curative effect was explored. Atorvastatin was observed to significantly increase the mechanical parameters such as maximum load, stiffness, and energy-absorbing capacity, and it improved the microarchitecture. The anti-osteoporosis activity of atorvastatin may be the result of the promotion of differentiation of osteoblasts by inducing synthesis of vascular endothelial growth factor, bone morphogenetic protein 2 (BMP2), core-binding factor alpha 1 (CBFα1), and inhibition of osteoclast formation through the osteoprotegerin (OPG)-receptor activator for the nuclear factor κB ligand (RANKL) system. Our study observations give reliable experimental evidence for clinical application of atorvastatin to treat the disorder of osteoporosis.

A method is presented for generating multiple-channel color-entangled photon pairs simultaneously based on type I quasi-phase-matched spontaneous parametric downconversion pumped in a single periodically poled lithium niobate (PPLN) crystal. It is predicted that one-, and two-channel color-entangled photon pairs can be simultaneously generated just by suitably choosing the PPLN grating period and the pump frequency. We point out that the full width at half maximum (FWHM) of idler and signal light are broadened dramatically due to spontaneous parametric downconversion in case of a pulsed pump. Then this method is applied for generating multiple-channel polarization-entangled photon pairs simultaneously based on type II quasiphase- matched spontaneous parametric downconversion.

To investigate the cystathione beta synthase (CBS) gene T833C, G919A, 844ins68 polymorphisms and plasma homocysteine (Hcy) levels in ethnic Uyghur and Han patients with essential hypertension (EH) in Xinjiang.Four hundred twenty nine cases including 211 Uyghur and 218 Han EH patients were recruited, whilst 410 healthy individuals including 210 Uyghurs and 200 Hans were used as the controls. Amplification refractory mutation system (ARMS) was adopted to analyze the CBS gene polymorphisms including T833C, G919A and 844ins68. Enzymoimmunoassay was applied to determine the plasma level of Hcy. Chemiluminescence was applied to determine the plasma folic acid and vitamin B12.Compared with the controls, the plasma Hcy level was significantly higher in the EH group in both ethnic Uyghurs and Hans (P0.05). Plasma levels of Hcy in T833C, G919A genotypes (for both heterozygotes and homozygotes) were statistically higher than wild types (P0.05). A significant difference was detected in G919A polymorphism between the EH patients and controls in both Uyghur and [CM(144.5mm] Han ethnics (Uyghur: x² = 10.264, P0.01; Han: x² = 23.075, P0.01), and in T833C between the EH patients and controls in ethnic Uyghurs (x² = 40.254, P0.01). Logistic regression analysis indicated that age (OR=1.151, P=0.047, 95% CI = 1.002-1.323), T833C (CC) (OR = 1.078, P = 0.003, 95% CI = 1.043-1.114), obesity (OR = 1.284, P = 0.021, 95% CI = 1.038-1.590), hyperhomocysteine (OR = 3.296, P = 0.016, 95% CI = 1.244-8.733) were independent risk factors for EH among ethnic Uygurs, while age (OR = 1.162, P = 0.007, 95% CI = 1.042-1.297), obesity (OR = 3.501, P = 0.003, 95% CI = 1.521-8.060), hyperhomocysteine (OR = 1.046, P = 0.031, 95% CI = 1.011-1.459) were independent risk factors for EH in ethnic Hans after adjusting for confounding factors.Plasma level of Hcy is associated with ethnic Uyghur and Han patients with EH in Xinjiang. CBS gene T833C CC genotype may be associated with the EH among Uyghur ethnics.

Objective Drug use evaluation (DUE) criteria were established to assess the rational use of antibiotic prophylaxis (RUAP) in Type I incision operations (TOIO) during peri-operation period and to enhance pharmacists' responsibilities for antibiotic stewardship. Methods The criteria were set with a threshold based on a literature review and discussions with multidisciplinary experts. Patients who received TOIO from July 2008 to June 2012 were enrolled in the study. The percentage of prescriptions adhering to all items of criteria was 10% at baseline. Results According to DUEs and interviews by pharmacists, the percentages of prescriptions adhering to all items of criteria of DUE-1, DUE-3, DUE-5, and DUE-8 were 13.3, 20.0, 50.0 and 66.7%, respectively. The study showed that the most common inappropriate therapies were no indications for prophylaxis antibiotic use and inappropriate choices of antibiotics. Pharmacists finally disseminated DUE criteria and reports to prescribe and improve RUAP in TOIO at the hospital through the Drug and Therapeutics Committee (DTC). Conclusion The study demonstrated that application of pharmacist- directed DUE is a useful strategy to detect, supervise and help correct challenges encountered during antibiotic prophylaxis in TOIO.

The recent introduction of Fortran 90, along with constant increases in the speed of desktop personal computers, makes direct integration an extremely viable means of computing radiation view factors. Using the new intrinsic functions and simplified array operations which are part of the Fortran 90 standard, an algorithm based on discretization of the two surfaces can be implemented in fewer than a hundred lines of code and run in only a few seconds on a typical personal computer. The basics of such an algorithm for arbitrarily oriented flat parallelograms will be reviewed in this brief note.

The phase generated carrier (PGC) arctangent algorithm needs to be compensated when the carrier modulation depth C deviates from 2.63 rad. Parameters measurement error can induce an incomplete compensation in the arctangent algorithm. The demodulation distortion due to parameters esti mation error is analyzed quantitatively in this paper. The relative amplitude error (RAE) and harmonic suppression ratio (HSR) are considered, which indicate a linear distortion and a nonlinear one separately. Theoretical analysis shows that the fluctuation ra nge of RAE has a linear relation with an absolute value of / C which is the estimation error of the modulation depth C . The fluctuation range of RAE also has a square relation with / o1 , / o2 which are the estimation error of the phase delay ' o 1 ' o 2 of fundamental and second harmonic carriers respectively. Similarly, minimum HSR decr eases by 6dB along with a doubled absolute value of / C and by 12dB with that of / o1 . Experimental results are presented to corroborate the theory. Keywords: optical fiber hydrophone, phase generated carrier(PGC), arctangent demodulation algorithm , relative amplitude error(RAE), harmonic suppression ratio(HSR),modulation depth, carrier phase delay, parameter estimation

An integrated demodulation system of optical fiber hydrophone array is designed in the paper for the application of oceanic oil exploration. The ch aracteristic of artificial seismic signal, sens ed and collected by pi ezoelectric hydrophone sensor used in the actual situation, is analyzed by joint ti me-frequency analysis. Based on this, parameters of the optical fiber hydrophone sensitivity and modulation frequency are designed with re dundancy , ensuring that the upper limit of dynamic range of fiber optic hydrophone demodulation system can meet the requirements in the same operating conditions of sea trials, as those of piezoelectric sensor system. Key Words: optical fiber hydrophone array , phase generated carrier, time-frequency analysis, dynamic range 1. INTRODUCTION With the development of modern acoustic technology, some performance indexes of an underwater acoustic detection system, such as wide bandwidth, large dynamic range, low noise and high sensitivity, tend to be simultaneously improved

This paper presents the development of a parabolic numerical procedure for rotating flows and its applications to three-dimensional viscous rotating flows. The formulation is based on the Navier–Stokes equations in general co-ordinates fixed on a rotating frame, so that the rotation effect is included in the guess-correct process. The use of body-fitted curvilinear co-ordinates makes it easier to handle the complex geometries of turbomachinery components. In the present work a k–ϵ turbulence model was used for the three-dimensional numerical tests. The algorithm is equally applicable to incompressible and compressible flows. Comparisons of the predicted results with the experimental data were reasonably good, and the solutions were stable to rotational speeds up to at least 14 000 rpm.

Phase Generated Carrier (PGC) with directly Frequency Modulation (FM) is one of the most important demodulation methods for optical fiber interferometric sensor system. Previous research has confirmed that system performance using Orthogonal Demodulation Type PGC (ODT-PGC) method is determined by many parameters, such as signal phase delay, FM depth, laser intensity accompanying modulation. This article proposes a new PGC demodulation method based on Fixed Phase Delay (FPD-PGC) by 3x2 directional coupler, using second-harmonic components of two interferometric signals to demodulate. The demodulation principle of the new method is described in detail and its performances have been studied. Theoretical analysis and experimental results show that the new method combines main advantages of directional coupler method and ODT-PGC method, and eliminates, to a great extent, the impacts of FM depth, signal phase delay, intensity modulation. Signal-to-total-Harmonic Ratio (SHR) of new method increases more than 30dB compare with ODT-PGC method under the condition of intensity modulation coefficient is 0.4. Besides that, Signal to Noise Ratio (SNR) also improves significantly.

Studying on the law of heat generation and transmission of the mini-automobile clutch friction, it is found that a single junction temperature rise of clutch friction plate is related to the friction power and characteristics of the friction pairs. Thus the assumption condition that appropriates to calculate the mini-automobile clutch friction plate surface temperature is proposed. A single bonding formula for calculating the average temperature of friction surface is built through the theoretical analysis of friction. The mathematical model is applied to a single engagement temperature calculation of the specific micro-clutch engagement. At the same time, a single engagement temperature is obtained by the bench test. The results show that the calculating value is good fit with the bench testing value. Thus it is proved that average surface temperature of the calculation method and mathematical model is indeed feasible.

Automatic control of the clutch is the key technology in the development of electronic control and mechanical automatic transmission. A control system of Automatic clutch is studied which is Based on the dynamic behavior of the process of clutch engagement and performance evaluation index of integrated analysis. The control strategy of the clutch engagement process is determined and it is also applied to mini-cars. The hardware and software of a micro-clutch automatic control system are designed and implemented. The system reduces the driver's labor intensity effectively and improves the car's quality of power starting and shifting.

This paper describes the development and application of a parabolic finite-volume procedure for the computation of viscous rotating flows having complex geometries. A parabolic numerical scheme has been developed to include the influence of the Coriolis force on pressure corrections. Two-equation turbulence models were employed to account for the effect of turbulence on the flows. Numerical tests for 2-D flows have been conducted, and the results show that computation with the new pressure-based method gives reasonably good agreement with the experiments.

We present a new Phase Generated Carrier (PGC) demodulating system for optical seismometer and discuss its stability and consistency which is improved by modifying and compensating key parameters. A simple and easy approach to measure key parameters is presented and realized and its measure error and consistency can satisfy practical system's requirement. Several factors affecting the stability and consistency are analyzed theoretically and experimentally. The results prove that laser drive current of Direct Current (DC) bias would severely affect the stability of key parameters, and it fluctuates seriously the Signal-to-Noise-And-Distortion (SINAD) and Total-Harmonic-Distortion (THD) of demodulating result. Besides, different sensors would deteriorate the stability and consistency at a large degree which must be considered. The demodulating results have been compared between respectively modifications and unified. Other factors such as circuit gain and light attenuation also impact on system's stability and consistency, and it could be neglected at a certain extent. In this work, our system's SINAD is better than 45dB and THD is better than 50dB with the maximum fluctuation is ±1.5dB, the noise background is near -100dB/ √Hz and dynamic range has reached 130dB@100Hz.

We proposed a kind of fiber-optic gradient hydrophone based on interferometer. Two arms of the interferometer are sensing fibers, each of which can be regard as a scalar pressure sensing element, and then the phase gradient between the two elements is transformed into the light intensity modulated output by the coupler. In this paper, a suit of analytical models for researching the sensor performance are developed. The theoretical and experimental research was carried out to demonstrate this kind of gradient hydrophone's phase sensitivity as the function of the measure frequency and the "8" directivity response.

Optical Kerr effect in the passive ring-resonator optical fiber gyroscope (PORG) made from hollow-core photonic band-gap (PBG) fiber is analyzed theoretically using a simple optical field overlap method, comparing it with the passive ring-resonator optical fiber gyroscope made from conventional single mode fiber (SMF). The theoretical evidence show that optical Kerr effect induced rotation rate shift in PORG made from hollow-core PBG fiber should be reduced by 1~2 orders at different ring resonator length when the optical source spectral width is fixed.

An improved demodulation method for the phase-generated carrier (PGC) system by eliminating laser-intensity modulation (LIM) is proposed. The influence of LIM is analyzed theoretically and experimentally. Two parameters are used to describe the effect of LIM: the LIM coefficient (LIMC) and the LIM phase delay (LIMPD). Good stability of the LIMC and LIMPD is confirmed by experimentation with an actual system. The demodulation signal using the traditional method has a much greater higher harmonic component than the improved method due to LIM. The increase of the signal-to-total-harmonic ratio (SHR) using the improved method is >23 dB, and there is a corresponding improvement of 19 dB to the signal to noise and distortion (SINAD) and signal-to-noise ratio (SNR). A new prototype system using the improved PGC method for marine seismic sensing capable of demodulating multiple channels in parallel, simultaneously, is demonstrated. The SHR is stable at 56 dB when the LIMC is