Study of the key factors affecting the triple grid lifetime of the LIPS-300 ion thruster

In order to ascertain the key factors affecting the lifetime of the triple grids in the LIPS-300 ion thruster,the thermal deformation,upstream ion density and component lifetime of the grids are simulated with finite element analysis,fluid simulation and charged-particle tracing simulation methods on the basis of a 1500 h short lifetime test.The key factor affecting the lifetime of the triple grids in the LIPS-300 ion thruster is obtained and analyzed through the test results.The results show that ion sputtering erosion of the grids in 5 kW operation mode is greater than in the case of 3 kW.In 5 kW mode,the decelerator grid shows the most serious corrosion,the accelerator grid shows moderate corrosion,and the screen grid shows the least amount of corrosion.With the serious corrosion of the grids in 5 kW operation mode,the intercept current of the acceleration and deceleration grids increases substantially.Meanwhile,the cold gap between the accelerator grid and the screen grid decreases from 1 mm to 0.7 mm,while the cold gap between the accelerator grid and the decelerator grid increases from 1 mm to 1.25 mm after 1500 h of thruster operation.At equilibrium temperature with 5 k W power,the finite element method（FEM）simulation results show that the hot gap between the screen grid and the accelerator grid reduces to 0.2 mm.Accordingly,the hot gap between the accelerator grid and the decelerator grid increases to 1.5 mm.According to the fluid method,the plasma density simulated in most regions of the discharge chamber is 1?×?10;-8?×?10;m;.The upstream plasma density of the screen grid is in the range 6?×?10;-6?×?10;m;and displays a parabolic characteristic.The charged particle tracing simulation method results show that the ion beam current without the thermal deformation of triple grids has optimal perveance status.The ion sputtering rates of the accelerator grid hole and the decelerator hole are 5.5?×?10;kg s;and 4.28?×?10;kg s;,respectively,while after the thermal deformation of the triple grids,the ion beam current has over-perveance status.The ion sputtering rates of the accelerator grid hole and the decelerator hole are 1.41?×?10;kg s;and 4.1?×?10;kg s;,respectively.The anode current is a key factor for the triple grid lifetime in situations where the structural strength of the grids does not change with temperature variation.The average sputtering rates of the accelerator grid and the decelerator grid,which were measured during the 1500 h lifetime test in5 k W operating conditions,are 2.2?×?10;kg s;and 7.3?×?10;kg s;,respectively.These results are in accordance with the simulation,and the error comes mainly from the calculation distribution of the upstream plasma density of the grids.

Optimization on Production Key Factors of Microbial Fermented Feed and Analysis on Composition Variation During Fermentation

[ Objective] In order to study the production key factors of microbial fermented feed and the composition variation during fermentation. [ Methods ] Water, temperature, energy and protein were selected to study the effects on microbial fermented feed. And the fermentation conditions were optimized. Changes on nutrient composition during fermentation were determined and analyzed. [ Result ] Test results showed that feed formula with high sugar content, low protein, 34% - 36% water content, high fermentation temperature was more conducive to the production and actual production needs of fermentation strains. During the fermentation, strains showed interactions, test tended to be completed at the 144^th h after the fermentation, and number of lactic acid bacteria reached the peak of 1.86×10^9 strain/g, contents of lactic acid could even reach 0.89%. As time prolonged, contents of total energy, fiber and isothiocyanate gradually reduced, while contents of water and protein increased slightly. Contents of vitamin were stable, which in an order of VB〉 VE 〉 Vx 〉 VA 〉 VD. Composition of amino acids showed an better change, contents of glutamic acid and proline decreased slowly, while contents of glycine and phenylalanine increased slowly. [ Conclusion] High quality microbial fermentation feed could improve the palatability and safety of feed and keep the intestinal balance of livestock and poultry, which had broad application prospect.

Spatial distribution and potential poverty-returning factors of former poverty-stricken villages in the Liangshan Mountains,China

Remote mountainous villages are at risk of falling back into poverty,despite having been lifted out of extreme poverty.However,there has been a lack of focus on the factors contributing to povertyreturn in these villages,which making it difficult to understand the risks and their underlying causes.This study investigates the spatial distribution of 546 key assistance villages(KAVs)in the Liangshan mountainous region,a former poverty-stricken area,using the average nearest neighbor(ANN)and kernel density estimation(KDE)methods.Linear regression and geographically weighted regression(GWR)models are then employed to analyze the relationship between the KAVs'economy and potential povertyreturning factors.The results show that KAVs are primarily located in elevation ranges of 1800-2500 m(31.87%),with slopes of 6°-15°(42.67%)and 2-3 km from the township(28.94%).The distribution of KAVs exhibits distinct spatial clustering,forming four gathering areas.Several factors impact the KAVs'economy positively,including the normalized difference vegetation index(NDVI),built-up area,grassland,and education facilities,while elevation has a negative effect.The built-up area has the most critical impact on the rural economy,followed by NDVI and elevation.Additionally,education facilities and grassland areas also have significant effects.The study suggests promoting the Ex-situ Poverty Alleviation Relocation Program(ESPARP)and increasing rural built-up areas,grasslands,and educational facilities as practical measures for preventing poverty return and promoting economic development promotion in remote mountain villages.

Key Human Factors of Vehicle Interior Occupant Packaging in SAE Standard

Fourteen SAE standards related to accommodation and occupant＇ packaging for vehicle interior are studied. The influencing factors, key reference accommodation points and major design dimensions and their relationships of occupant packaging and ergonomics during the vehicle interior layout design and development are analyzed. Prototypes are presented to verify the results and how to achieve the packaging is shown. Auto- mobile designers can achieve significant practical guidance for human safety, efficiency accommodation and occupant packaging of all passengers during the vehicle design process.

Study on the Key Influence Factors of Environmental Mass Incidents by Delphi-PCA-Frequency Analysis Composite Method

In order to prevent and control environmental mass incidents,by comprehensively using literature research,case analysis and logical reasoning method,27 factors influencing environmental mass incidents were selected. Among them,15 key influencing factors were screened by Delphi-PCA-frequency analysis composite method. The key influencing factors were analyzed,and corresponding countermeasures were put forward.

Risk Factors of Cervical Carcinoma and Countermeasures against Them in Mountainous Area of Wufeng County, China

Cases (n=44) with squamous cell cervical cancer (SCCA) and age-matched healthy controls (n=176) were analyzed. Significant difference due to human papillomavirus (HPV) infection, ages at the first marriage, ages at the first sexual intercourse, ages at the first birth given to baby, number of gravidities, number of deliveries, Body Mass Index (BMI), education level of women and their husbands (p<0.05) was observed. According to multivariate logistic regression analysis, four factors have entered the model (p<0.05), including HPV infection [OR (odds ratio)=26.13, 95%CI (confidence interval)=9.40?72.60], education level of women (OR=0.41, 95%CI=0.21?0.79), education level of spouses (OR=0.45, 95%CI=0.22?0.94), BMI (OR=0.73, 95%CI=0.57?0.93). Moreover, HPV infection is relative to education level of women (r=?0.14), and their spouses (r=?0.21), age at the first marriage (r=?0.20), age at the first birth given to baby (r=?0.20) and BMI (r=?0.15).

R & D A Key Driving Factor of the Pipeline Industry

Kalamay-Dushanzioilpipelinebuiltin1958isthefirstlongdistanceoilpipelineofChina.Since1960s,withthedevelopmentofDaqing,Shengli,HuabeiandZhongyuanoilfields,oilpipelinenetworkscoveringnortheast,eastChina,andnorthChinahavebeensetup.Withthedevelopmentofnat...

A Review of the Research on the Influencing Factors of Enterprise Key Core Technology Breakthrough

The breakthrough of key core technology is a theoretical and practical strategic issue to realize the rise of the country.This paper analyzes the concept of key core technology and its breakthrough and analyzes its characteristics.Based on the perspective of participants,this paper summarizes the influencing factors of key core technology breakthroughs in enterprises:internal and external enterprises,universities and scientific research institutions,and government.This paper expands the relevant research on key core technology breakthroughs and provides inspiration for enterprises to carry out key core technology research and breakthrough practices.

从社会幸福感到积极心理健康模型—Keyes介评

继主观幸福感、心理幸福感后,Keyes提出了社会幸福感理论,构成幸福感理论第三阵营。其主要贡献涉及社会幸福感理论与测量、心理健康双因素理念,倡导积极心理健康模型,深化了幸福感的理解,拓展了幸福感的应用,架构了从幸福感到积极心理健康的桥梁。

Future Drought Changes in China Projected by the CMIP6 Models:Contributions from Key Factors

Model simulations show that drought may become more severe and widespread in the 21st century due to humaninduced global warming. However, the contributions from the key factors to the model-projected drought changes in China have not yet been examined in detail. We used the self-calibrated Palmer Drought Severity Index with Penman–Monteith potential evapotranspiration(scPDSIpm) based on 10 model simulations selected from the Coupled Model Intercomparison Project Phase 6(CMIP6). We investigated the contributions from precipitation(P), near-surface air temperature and specific humidity [Δ(T + q)], net surface longwave radiation(LW), net surface shortwave radiation(SW), and wind speed(WS) to the future changes in scPDSIpm, including the long-term mean, drying area,probability distribution function(PDF), drought frequency, and drought duration based on the scPDSIpm over China.Our results show that model-projected drying mainly occurs over southern China, whereas the dry areas under drought conditions increase from 20% to about 23%/30% under the two scenarios of the shared socioeconomic pathway(SSP2-4.5/SSP5-8.5) from 1985 to 2100, despite large uncertainties in individual projections partly due to internal variability. Drought frequency is projected to increases by about 10%–54%(15%–88%) under the SSP2-4.5(SSP5-8.5) scenario by the late 21st century, along with increases in drought duration. These changes are accompanied by a decrease in the mean scPDSIpm and flattening of the PDFs. The changes in drying over southern China are mainly attributed to surface warming and the increased surface vapor pressure deficit(VPD), with small contributions from changes in the surface net radiation. The changes in wetting over northern China mostly result from increased precipitation along with a small wetting effect from the changes in wind speed.

New Weak Keys in RSA

The security of the RSA system with the prime pairs of some special form is investigated. A new special-purpose algorithm for factoring RSA numbers is proposed. The basic idea of the method is to factor RSA numbers by factoring a well-chosen quadratic polynomial with integral coefficients. When viewed as a general-purpose algorithm, the new algorithm has a high computational complexity. It is shown thai the RSA number n = pq can be easily factored if p and q have the special form of p = as＋b, q=cs＋d, where a, b, c, d are relatively small numbers. Such prime pairs （p, q） are the weak keys of RSA, so when we generate RSA modulus, we should avoid using such prime pairs （p, q）.

Analysis on the key factors of allergic rhinitis treated with acupuncture and moxibustion

Allergic rhinitis(AR)is the frequently-encountered disease and commonly seen in clinic.Acupuncturemoxibustion therapy brings the significant therapeutic effects on it.In order to achieve the significant effects on AR,the relevant key factors should be determined definitely in treatment with acupuncturemoxibustion therapy.In the combination of the theoretic study with clinical practice,the authors expounded the key factors in acupuncture-moxibustion treatment for AR,including the identification of disease and syndrome of traditional Chinese medicine(TCM),the differentiation of meridians,acupoint selection,manipulation key factors and timing.Moreover,the authors proposed a new pointcut for the future clinical research,aiming to further optimize the therapeutic regimen of acupuncture and moxibusiton for AR.

Writing strategies for improving the access of medical literature

When conducting a literature review,medical authors typically search for relevant keywords in bibliographic databases or on search engines like Google.After selecting the most pertinent article based on the title’s relevance and the abstract’s content,they download or purchase the article and cite it in their manuscript.Three major elements influence whether an article will be cited in future manuscripts:the keywords,the title,and the abstract.This indicates that these elements are the“key dissemination tools”for research papers.If these three elements are not determined judiciously by authors,it may adversely affect the manuscript’s retrievability,readability,and citation index,which can negatively impact both the author and the journal.In this article,we share our informed perspective on writing strategies to enhance the searchability and citation of medical articles.These strategies are adopted from the principles of search engine optimization,but they do not aim to cheat or manipulate the search engine.Instead,they adopt a reader-centric content writing methodology that targets well-researched keywords to the readers who are searching for them.Reputable journals,such as Nature and the British Medical Journal,emphasize“online searchability”in their author guidelines.We hope that this article will encourage medical authors to approach manuscript drafting from the perspective of“looking inside-out.”In other words,they should not only draft manuscripts around what they want to convey to fellow researchers but also integrate what the readers want to discover.It is a call-to-action to better understand and engage search engine algorithms,so they yield information in a desired and self-learning manner because the“Cloud”is the new stakeholder.

Key influence factors and mechanism of public digital culture service effectiveness

Public digital culture service refers to the public digital culture facility,culture product,culture activity or any other related service provided by the government and participated by social forces.Its main purpose is to meet the basic digital culture needs of the public.

Epidemiological study of elderly constipation in Beijing

AIM: To investigate the present situation of elderly constipation in urban and rural areas of the Beijing region.METHODS: A total of 1942 cases(≥ 60 years) were selected in the Beijing region for investigation. Constipation-related data collection was carried out via hierarchical status, segmentation, and random cluster sampling. Patient data concerning constipation-related demographic indicators, education level, occupation, economic status, and history of gastrointestinal disease was obtained via questionnaires and surveys. Constipation was defined according to the Rome Ⅲ criteria, with the following constipation judgment indicators: defecation less than 3 times per week, stool weight less than 35 g/d, dry and hard stool, and difficulty in defecating during more than 25% of evacuation attempts.RESULTS: Of the 1942 cases, 634 were diagnosed with constipation, and the total prevalence rate was 32.6%, which increased with age. There was a statistically insignificantly higher prevalence of constipation in females(compared to males) and urban areas(compared to rural areas). There was a statistically insignificantly higher prevalence in the illiterate group compared to the literacy group. Those engaged in mental work suffered from statistically significantly higher constipation prevalence than those engaged in physical labor. A total of 1847 cases did not suffer from gastritis, of which 595 cases were constipated; although the prevalence rate was 32.2%, showing a higher incidence of constipation in patients with gastritis, no significant statistical difference between the two groups was found. A total of 59 cases with a past history of biliary tract disease were found, of which 26 had constipation; constipation prevalence was 44.1%(far higher than other groups), which was a statistically significant difference.CONCLUSION: The prevalence of elderly constipation in the B eijing region closely resembles Western countries, and is significantly affected by region, age, and past history of other related illnesses.

A hydrocarbon enrichment model and prediction of favorable accumulation areas in complicated superimposed basins in China

The geologic conditions of superimposed basins in China are very complicated. This is mainly shown by multi-phase structural evolution, multiple sets of source-reservoir-cap rock combinations, multiple stages of hydrocarbon generation and expulsion from source rocks, multi-cycle hydrocarbon enrichment and accumulation, and multi-phase reservoir adjustment and reconstruction. The enrichment, accumulation and distribution of hydrocarbon is mainly controlled by the source rock kitchen, paleo- anticline, regional cap rock and intensity of tectonic movement. In this paper, the T-BCMS model has been developed to predict favorable areas of hydrocarbon accumulation in complicated superimposed basins according to time and spatial relationships among five key factors. The five factors include unconformity surface representing tectonic balancing （B）, regional cap rock representing hydrocarbon protection （C）, paleo-anticline representing hydrocarbon migration and accumulation （M）, source rock kitchen representing hydrocarbon generation and expulsion （S） and geological time （T）. There are three necessary conditions to form favorable areas of hydrocarbon accumulation. First, four key factors BCMS should be strictly in the order of BCMS from top to bottom. Second, superimposition of four key factors BCMS in the same area is the most favorable for hydrocarbon accumulation. Third, vertically ordered combination and superimposition in the same area of BCMS should occur at the same geological time. The model has been used to predict the most favorable exploration areas in Ordovician in the Tarim Basin in the main hydrocarbon accumulation periods. The result shows that 95% of the discovered Ordovician hydrocarbon reservoirs are located in the predicted areas, which indicates the feasibility and reliability of the key factor matching T-BCMS model for hydrocarbon accumulation and enrichment.

Removal of a type of endocrine disruptors—di-n-butyl phthalate from water by ozonation

Ozonation of synthetic water containing a type of endocrine disruptor-di-n-butyl phthalate （DBP） was examined. Key impact factors such as pH, temperature, ionic strength, ozone dosage and initial DBP concentration were investigated. In addition, the activities of radicals on uncatalysed and catalysed ozonation were studied. The degradation intermediate products were followed and the kinetic of the ozonation were assessed as well. Results revealed that ozonation of DBP followed two mechanisms. Firstly, the reaction rate of direct ozonation was slower at lower pH, temperature, and ionic strength. Secondly, when these factors were increased for indirect radical reaction, higher percentage of DBP was removed with the increase of the initial ozone dosage and the decrease of the initial DBP concentration. In addition, tea-butanol, humic substances and Fe（Ⅱ） affected DBP ozonation through the radical pathway. It was determined that ozonation was restrained by adding tea-butanol for its radical inhibition effect. Furthermore, humic substances enhanced the reaction to some extent, but a slight negative effect would be encountered if the optimum dosage was exceeded. As a matter of fact, Mn（Ⅱ） affected the ozonation by ＂active sites＂ mechanism. In the experiment, three different kinds of intermediate products were produced during ozonation, but the amount of products for each one of them decreased as pH, temperature, ionic strength and initial ozone dosage increased. A kinetic equation of the reaction between ozone and DBP was obtained.

Welding of 2205 duplex stainless steel natural gas pipeline

There are abundant natural gas resources in western China, but many oil and gas fields are rich in chloridion, sulfureted hydrogen, carbon dioxide and other corrosive medium, which have strong corrosivity to pipeline. One gas field possesses abundant natural gas with great pressure, and the chloridion concentration in the water separated from gas is about 10% , so the medium has great corrosivity. In order to ensure the safety of the pipeline, about 13 km length pipeline and the internal pipes of a gas treatment plant that purifies gas about 12 billion cubic meter a year are made of 2205 duplex stainless steel （2205 DSS ） . 2205 DSS has many characteristics in welding with complex welding process; and because of high quality requirements for the construction of natural gas pipeline and restriction of on-site conditions, the site welding is very difficult. Around the engineering application, a large number of experimental researches have been carried out on the material microstructure, properties and weldability. Finally welded joints which conform to the requirements of standard are obtained, contributing to the first large-scale application of this material in the field of oil and gas pipelines. Considering the engineering application and the latest research development, the welding and key factors affecting the joint properties of 2205 DSS pipes are summarized and analyzed.

ANOTHER NEW METHOD FOR SUPPORTING ENTERPRISE IN THE FORMULATION OF ITS MERGER STRATEGIES

This paper discusses the key factors about industrial attractiveness and enterprise strength which influence the formulation of enterprise merger strategies. A new method for supporting an enterprise to analyze and evaluate its merger strategies is developed when the enterprise is making the decision of its merger strategies the method can be used to provide scientific support.

Cardiovascular surgery in the elderly: an update

The aging of the population and improvements in outcomes after cardiovascular surgery have resulted in a worldwide growing demand of complex surgical intervention for elderly patients. We briefly review the up-to-date English-language literature with particular focus on cardiovascular surgery in elderly patients. With earlier referral, careful preoperative evaluation, strategic planning, and the continuing efforts in optimizing surgical techniques, operative mortality and morbidity following primary or reoperative coronary artery bypass grafting and valvular interventions are expected to fall in this high-risk patient subset. Importantly,accumulating evidence indicates that elderly patients may benefit from improved functional status and quality of life after cardiovascular surgical