资源类型

期刊论文 484

会议视频 7

年份

2024 1

2023 30

2022 42

2021 38

2020 32

2019 24

2018 32

2017 23

2016 21

2015 27

2014 31

2013 23

2012 30

2011 17

2010 24

2009 16

2008 14

2007 19

2006 7

2005 7

展开 ︾

关键词

影响因素 7

评价指标 6

制造强国 4

指标体系 4

评价 4

可持续发展 3

能源 3

COVID-19 2

制造业 2

制造大国 2

双目标渐进法 2

效果评估 2

模糊综合评判 2

环境 2

目标识别 2

评价体系 2

评估 2

驱动因素 2

21世纪海上丝绸之路 1

展开 ︾

检索范围：

排序： 展示方式：

Numerical modeling and performance evaluation of passive convergence-permeable reactive barrier (PC-PRB

《环境科学与工程前沿（英文）》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1731-z

摘要：

● A 2D finite-element solute transport model, PRB-Trans, is developed.

关键词： Passive convergence-permeable reactive barrier     Numerical modeling     Hydraulic behavior assessment     Pollutant treatment performance evaluation     Influential factors analysis    

HTML PDF 收藏

页岩气主要富集因素与核心区选择及评价

王社教,杨涛,张国生,李登华,陈晓明

《中国工程科学》 2012年 第14卷 第6期   页码 94-100

摘要：

影响页岩气规模开发的因素很多，最核心的因素是首先要通过建立地质评价标准，选出页岩气核心区。核心区的确定关系到在页岩气勘探初期，是否能找准页岩气最富集的目标，选择最有利地区进行勘探，突破出气关，进而实现大规模经济开发。从页岩气成藏特征、页岩气富集因素分析入手，重点探讨我国富有机质页岩的丰度、成熟度、脆性矿物含量、含气性以及盖层等关键参数及其作用。借鉴北美页岩气勘探开发和研究成果，结合我国页岩气勘探开发和研究新进展，初步建立我国页岩气核心区地质评价标准，并优选出我国南方海相页岩气的核心区，指出四川盆地南部是我国最现实的页岩气开发区。

关键词： 核心区     选区与评价     富集因素     海相页岩     页岩气    

HTML PDF 收藏

A Fast Evaluation and Research Method for Exploration Potential of Oversea Basins

Hong-quan Kang,Yun-hua Deng,Huai-cun Jia,Tao Cheng,Bo Bai

《工程管理前沿（英文）》 2016年 第3卷 第4期   页码 338-342 doi: 10.15302/J-FEM-2016052

摘要： Oversea hydrocarbon exploration always faces some problems, such as multiple basin types, different exploration prospects, various exploration degrees, diverse data quantities and geological recognitions. This paper focuses on overseas basins with different exploration degrees and offers a new evaluation system and research method for fast evaluation and risk analysis on hydrocarbon potential. Based on the theory of probability, this new evaluation system evaluates each parameter and core accumulation factor with comprehensive and quantitative assignment, to accelerate geological evaluation. In addition, this paper suggests that source rock evaluation should be the core criterion in screening evaluation of poor-explored basins, and also proposes that both the exploration potential and geological recognition should drive the evaluation for basins with high exploration degrees. This new system and method, which is an effective system for fast basin evaluation, is suggested to be used in oversea evaluation and decision-making objectively, scientifically and efficiently.

关键词： geological risk analysis     probability model     evaluation factors     oversea exploration     hydrocarbon exploration    

HTML PDF 收藏

Evaluation of factors influencing soluble microbial product in submerged MBR through hybrid ASM model

Fangyue LI, Joachim BEHRENDT, Knut WICHMANN, Ralf OTTERPOHL

《环境科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 226-235 doi: 10.1007/s11783-009-0008-5

摘要： In this study, a mathematical model was established to predict the formation of the soluble microbial product (SMP) in a submerged membrane bioreactor. The developed model was calibrated under the reference condition. Simulation results were in good agreement with the measured results under the reference condition. The calibrated model was then used in the scenario studies to evaluate the effect of three chosen operating parameters: hydraulic retention time (HRT), dissolved oxygen concentration, and sludge retention time (SRT). Simulation results revealed that the SMP dominated the soluble organic substances in the supernatant. The scenario studies also revealed that the HRT can be decreased to 1 h without deteriorating the effluent quality; dissolved oxygen concentration in the reactor can be kept at 2-3 mg/L to maintain the effluent quality, reduce the content of SMP, and minimize operating costs; the optimal SRT can be controlled to 10-15 d to achieve complete nitrification process, less membrane fouling potential, and acceptable organic removal efficiency.

关键词： hybrid activated sludge model (ASM)     membrane bioreactor (MBR)     soluble microbial product (SMP)    

HTML PDF 收藏

数控机床精度评价新方法

赵万华,张 俊,刘 辉,杨晓君

《中国工程科学》 2013年 第15卷 第1期   页码 93-98

摘要：

传统的定位精度与重复定位精度等指标是在准静态下评价数控机床（CNC）性能的，无法反映数控机床在运动和加工过程中的精度。首先从数控机床的数控、伺服、机械等环节在服役态下所表现出来的性能出发，提出一种对数控机床更有针对性的，以运动精度为指标的机床精度评价新方法，通过数控指令与运动轴实际位移的符合程度即运动精度来评价机床精度，然后给出了具体的评价指标，并提出了评价指标的测量方法。分析表明，这种新的机床运动精度描述评价方法能够系统、全面地评价数控机床关键性能的优劣。最后从数控、伺服和机械角度分别阐述了影响运动精度的因素。

关键词： 数控机床     运动精度     评价指标     影响因素    

HTML PDF 收藏

Meta-analysis of the risk factors of breast cancer concerning reproductive factors and oral contraceptive

Qiong DAI MD, Bei LIU MD, Yukai DU MM,

《医学前沿（英文）》 2009年 第3卷 第4期   页码 452-458 doi: 10.1007/s11684-009-0080-z

摘要： The authors performed a meta-analysis of case-control studies that addressed whether reproductive factors and oral contraceptive use were associated with breast cancer by searching the MEDLINE, PubMed, Proquest, Embase, ScienceDirect, African Healthline, BMJ Health Intelligence and Chinese Periodical net databases for all English-language and Chinese-language papers published from January 1, 1997 to December 31, 2007. A total of 15 studies calculating pool ORs indicated that menopausal age >50yr [odds ratio (OR), 1.39; 95% confidence interval (CI), 1.22―1.57] and oral contraceptive use (OR, 2.12*, “*”: summary OR was adjusted; 95% CI, 1.24―3.62) were correlated with the increase in breast cancer risk while the summary OR based on number of full-term pregnancies ≥1 (OR, 0.63*; 95% CI, 0.60―0.68) and breast-feeding (OR, 0.76; 95% CI, 0.64―0.90) indicated no association with breast cancer risk. The correlation was statistically significant. Menopausal age >50yr and oral contraceptive use are positively correlated with an increase in breast cancer risk while breast-feeding and number of full-term pregnancies ≥1 are protective factors.

关键词： meta-analysis     breast cancer     risk factors     reproductive factors     oral contraceptive use    

HTML PDF 收藏

我国铁路工程勘察设计质量指标和因素统计分析

谢洪涛,陈帆

《中国工程科学》 2011年 第13卷 第4期   页码 96-100

摘要：

为深入了解我国铁路勘察设计质量的现状，开展了较大范围的问卷调查工作。调查的内容主要包括两个部分：铁路勘察设计质量的现状以及影响铁路勘察设计质量的主要因素。在问卷调查的基础上，利用SPSS软件对统计数据进行了频数分析、描述性统计分析、相关性分析、因子分析等。通过对调查问卷的统计计算，分析了我国铁路勘察设计质量的现状及存在的主要问题，分析了影响我国铁路勘察设计质量的主要因素，并提出了相应的对策。

关键词： 勘察设计     质量评价     竞争机制     主成分     相关性分析    

HTML PDF 收藏

Risk factors of prognosis after acute kidney injury in hospitalized patients

null

《医学前沿（英文）》 2017年 第11卷 第3期   页码 393-402 doi: 10.1007/s11684-017-0532-9

摘要：

The risk factors, especially laboratory indicators, of prognosis after acute kidney injury (AKI) remain unclear. We conducted a retrospective survey of Chinese People’s Liberation Army General Hospital from January 1, 2012 to December 31, 2012 according to the AKI diagnosis standard issued by Kidney Disease Improving Global Outcomes. The epidemiological features and factors influencing hospital mortality and renal function recovery were evaluated through logistic regression analysis. Among 77 662 cases of hospitalized patients, 1387 suffered from AKI. The incidence rate and mortality of AKI were 1.79% and 14.56%, respectively. Multivariate logistic regression analysis revealed that high AKI stage, age greater than 80 years, neoplastic disease, low cardiac output, increased white blood cell count, and decreased platelet count and serum albumin levels were the risk factors affecting the mortality of AKI patients. Conversely, body mass index between 28 and 34.9 was a protective factor. Increased AKI stage, tumor disease, post-cardiopulmonary resuscitation, and RRT were the risk factors of renal function recovery upon discharge. In addition to traditional risk factors, white blood cell count, platelet count, albumin, and BMI were the predictors of the mortality of AKI patients. No laboratory indicators were found to be the risk factors of renal function recovery in AKI patients.

关键词： acute kidney injury     risk factors     prognosis    

HTML PDF 收藏

Factors affecting the distribution of microplastics in soils of China

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1710-4

摘要：

● Microplastic (MP) abundance in soil of China was highly heterogeneous.

关键词： Microplastic distribution     Microplastic heterogeneity     Effecting factors     Agriculture     Socio-economic factors    

HTML PDF 收藏

Epidemic obesity in children and adolescents: risk factors and prevention

Eun Young Lee, Kun-Ho Yoon

《医学前沿（英文）》 2018年 第12卷 第6期   页码 658-666 doi: 10.1007/s11684-018-0640-1

摘要： The prevalence of obesity among children and adolescents (aged 2–18 years) has increased rapidly, with more than 100 million affected in 2015. Moreover, the epidemic of obesity in this population has been an important public health problem in developed and developing countries for the following reasons. Childhood and adolescent obesity tracks adulthood obesity and has been implicated in many chronic diseases, including type 2 diabetes, hypertension, and cardiovascular disease. Furthermore, childhood and adolescent obesity is linked to adulthood mortality and premature death. Although an imbalance between caloric intake and physical activity is a principal cause of childhood and adolescent obesity, environmental factors are exclusively important for development of obesity among children and adolescents. In addition to genetic and biological factors, socioenvironmental factors, including family, school, community, and national policies, can play a crucial role. The complexity of risk factors for developing obesity among children and adolescents leads to difficulty in treatment for this population. Many interventional trials for childhood and adolescent obesity have been proven ineffective. Therefore, early identification and prevention is the key to control the global epidemic of obesity. Given that the proportion of overweight children and adolescents is far greater than that of obesity, an effective prevention strategy is to focus on overweight youth, who are at high risk for developing obesity. Multifaceted, comprehensive strategies involving behavioral, psychological, and environmental risk factors must also be developed to prevent obesity among children and adolescents.

关键词： obesity     children     adolescents     epidemiology     risk factor     prevention    

HTML PDF 收藏

CRITICAL PROCESSES AND MAJOR FACTORS THAT DRIVE NITROGEN TRANSPORT FROM FARMLAND TO SURFACE WATER BODIES

《农业科学与工程前沿（英文）》 2023年 第10卷 第4期   页码 541-552 doi: 10.15302/J-FASE-2023518

摘要：

Agricultural non-point source pollution is increasingly an important issue affecting surface water quality. Currently, the majority of the studies on nitrogen loss have focused on the agricultural field scale, however, the response of surface water quality at the watershed scale into the nitrogen loss at the field scale is poorly understood. The present study systematically reviewed the critical processes and major factors that nitrogen transport from farm fields to surface water bodies. The critical processes of farmland nitrogen entering surface water bodies involve the processes of nitrogen transport from farmland to ditches and the transformation processes of nitrogen during migration in ditches/rivers. Nitrogen transport from farmland to ditches is one of the prerequisites and critical processes for farmland nitrogen transport to surface water bodies. The transformation of nitrogen forms in ditches/rivers is an intermediate process in the migration of nitrogen from farmland to surface water bodies. Nitrogen loss from farmland is related to soil storage and exogenous inputs. Therefore, nitrogen input management should not only consider the current input, but also the contribution of soil storage due to the historical surpluses. Ditches/rivers have a strong retention capacity for nitrogen, which will significantly affect the process of farmland nitrogen entering surface water bodies. The factors affecting nitrogen transformation in river/ditches can be placed in four categories: (1) factors affecting hydraulic retention time, (2) factors affecting contact area, (3) factors affecting biological activity, and (4) forms and amount of nitrogen loading to river/ditches. Ditch systems are more biologically (including plants and microbes) active than rivers with biological factors having a greater influence on nitrogen transformation. When developing pollution prevention and control strategies, ecological ditches can be constructed to increase biological activity and reduce the amount of surplus nitrogen entering the water body. The present research should be valuable for the evaluation of environment impacts of nitrogen loss and the non-point source pollution control.

关键词： nitrogen     loss from soil     transformation     farm field scale     watershed scale    

HTML PDF 收藏

Oocyte-associated transcription factors in reprogramming after somatic cell nuclear transfer: a review

Fengxia YIN,Hui LIU,Shorgan BOU,Guangpeng LI

《农业科学与工程前沿（英文）》 2014年 第1卷 第2期   页码 104-113 doi: 10.15302/J-FASE-2014003

摘要： Oocytes are unique cells with the inherent capability to reprogram nuclei. The reprogramming of the somatic nucleus from its original cellular state to a totipotent state is essential for term development after somatic cell nuclear transfer. The nuclear-associated factors contained within oocytes are critical for normal fertilization by sperm or for somatic cell nuclear reprogramming. The chromatin of somatic nuclei can be reprogrammed by factors in the egg cytoplasm whose natural function is to reprogram sperm chromatin. The oocyte first obtains its reprogramming capability in the early fetal follicle, and then its capacity is enriched in the late growth phase and reaches its highest capability for reprogramming as fully-grown germinal vesicle oocytes. The cytoplasmic milieu most likely contains all of the specific transcription and/or reprogramming factors necessary for cellular reprogramming. Certain transcription factors in the cytoplast may be critical as has been demonstrated for induced pluripotent stem cells. The maternal pronucleus exerts a predominant, transcription-dependent effect on embryo cytofragmentation, with a lesser effect imposed by the ooplasm and the paternal pronucleus. With deep analysis of transcriptomics in oocytes and early developmental stage embryos more maternal transcription factors inducing cellular reprogramming will be identified.

关键词： nuclear reprogramming     somatic cell     transcription factors     transcriptomics    

HTML PDF 收藏

Understanding coupled factors that affect the modelling accuracy of typical planar compliant mechanisms

Guangbo HAO,Haiyang LI,Suzen KEMALCAN,Guimin CHEN,Jingjun YU

《机械工程前沿（英文）》 2016年 第11卷 第2期   页码 129-134 doi: 10.1007/s11465-016-0392-z

摘要：

In order to accurately model compliant mechanism utilizing plate flexures, qualitative planar stress (Young’s modulus) and planar strain (plate modulus) assumptions are not feasible. This paper investigates a quantitative equivalent modulus using nonlinear finite element analysis (FEA) to reflect coupled factors in affecting the modelling accuracy of two typical distributed-compliance mechanisms. It has been shown that all parameters have influences on the equivalent modulus with different degrees; that the presence of large load-stiffening effect makes the equivalent modulus significantly deviate from the planar assumptions in two ideal scenarios; and that a plate modulus assumption is more reasonable for a very large out-of-plane thickness if the beam length is large.

关键词： coupling factors     modelling accuracy     compliant mechanisms     equivalent modulus    

HTML PDF 收藏

Changes in major factors affecting the ecosystem health of the Weihe River in Shaanxi Province, China

Qi LI, Jinxi SONG, Anlei WEI, Bo ZHANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第6期   页码 875-885 doi: 10.1007/s11783-013-0568-2

摘要： Maintenance of the ecosystem health of a river is of great importance for local sustainable development. On the basis of both qualitative and quantitative analysis of the influence of natural variations and human activities on the ecosystem function of the Weihe River, the changes in major factors affecting its ecosystem health are determined, which include: 1) Deficiency of environment flow: since the 1960s, the incoming stream flow shows an obvious decreasing tendency. Even in the low flow period, 80% of the water in the stream is impounded by dams for agriculture irrigation in the Baoji district. As a result, the water flow maintained in the stream for environmental use is very limited. 2) Deterioration of water quality: the concentrations of typical pollutants like Chemical Oxygen Demand (COD) and NH -N are higher than their maximum values of the Chinese environmental quality standard. Very few fish species can survive in the River. 3) Deformation of water channels: the continuous channel sedimentation has resulted in the decrease in stream gradient, shrinkage of riverbed and the decline in the capability for flood discharge. 4) Loss of riparian vegetation: most riparian land has been occupied by urban construction activities, which have caused the loss of riparian vegetation and biodiversity and further weakened flood control and water purification functions.

关键词： influencing factors     ecosystem health     ecological and environmental functions     the Weihe River     Shaanxi Province    

HTML PDF 收藏

Clinical outcomes and prognostic factors of patients with epithelial ovarian cancer subjected to first-line

null

《医学前沿（英文）》 2014年 第8卷 第1期   页码 91-95 doi: 10.1007/s11684-014-0305-7

摘要：

A total of 251 patients with epithelial ovarian cancer (EOC) treated between 2002 and 2008 was retrospectively analyzed to investigate the long-term outcomes and prognostic factors of these patients, particularly those who underwent primary debulking surgery followed by platinum-based chemotherapy. Clinico-pathological parameters, including progression-free survival (PFS) and overall survival (OS), were also analyzed. The median follow-up period from the end of initial treatment to June 2010 was 58 months. The three-year PFS rate was 61.7% for International Federation of Gynecology and Obstetrics (FIGO) I–II, 19.9% for FIGO III–IV, and 33.9% for all stages. By comparison, the five-year PFS rate was 44.6% for FIGO I–II, 17.7% for FIGO III–IV, and 28.3% for all stages. The three-year OS rate was 67.9% for FIGO I–II, 41.7% for FIGO III–IV, and 50.2% for all stages. The five-year OS rate was 52.7% for FIGO I–II, 30.8% for FIGO III–IV, and 39.2% for all stages. Univariate analysis revealed that advanced FIGO stage, serum CA125, and suboptimal debulking were significant factors affecting PFS and OS. In multivariate analysis, PFS was significantly influenced by FIGO stage and suboptimal debulking. However, OS was significantly influenced by advanced FIGO stage only. Our study confirms the efficacy of surgery followed by platinum-based chemotherapy for EOC. FIGO stage is considered as one of the most reliable predictors of the prognosis of patients with EOC.

关键词： ovarian carcinoma     prognostic factors     surgery     chemotherapy     survival    

HTML PDF 收藏

标题 作者 时间 类型 操作

Numerical modeling and performance evaluation of passive convergence-permeable reactive barrier (PC-PRB

期刊论文

页岩气主要富集因素与核心区选择及评价

王社教,杨涛,张国生,李登华,陈晓明

期刊论文

A Fast Evaluation and Research Method for Exploration Potential of Oversea Basins

Hong-quan Kang,Yun-hua Deng,Huai-cun Jia,Tao Cheng,Bo Bai

期刊论文

Evaluation of factors influencing soluble microbial product in submerged MBR through hybrid ASM model

Fangyue LI, Joachim BEHRENDT, Knut WICHMANN, Ralf OTTERPOHL

期刊论文

数控机床精度评价新方法

赵万华,张 俊,刘 辉,杨晓君

期刊论文

Meta-analysis of the risk factors of breast cancer concerning reproductive factors and oral contraceptive

Qiong DAI MD, Bei LIU MD, Yukai DU MM,

期刊论文

我国铁路工程勘察设计质量指标和因素统计分析

谢洪涛,陈帆

期刊论文

Risk factors of prognosis after acute kidney injury in hospitalized patients

null

期刊论文

Factors affecting the distribution of microplastics in soils of China

期刊论文

Epidemic obesity in children and adolescents: risk factors and prevention

Eun Young Lee, Kun-Ho Yoon

期刊论文

CRITICAL PROCESSES AND MAJOR FACTORS THAT DRIVE NITROGEN TRANSPORT FROM FARMLAND TO SURFACE WATER BODIES

期刊论文

Oocyte-associated transcription factors in reprogramming after somatic cell nuclear transfer: a review

Fengxia YIN,Hui LIU,Shorgan BOU,Guangpeng LI

期刊论文

Understanding coupled factors that affect the modelling accuracy of typical planar compliant mechanisms

Guangbo HAO,Haiyang LI,Suzen KEMALCAN,Guimin CHEN,Jingjun YU

期刊论文

Changes in major factors affecting the ecosystem health of the Weihe River in Shaanxi Province, China

Qi LI, Jinxi SONG, Anlei WEI, Bo ZHANG

期刊论文

Clinical outcomes and prognostic factors of patients with epithelial ovarian cancer subjected to first-line

null

期刊论文