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Not asthma, but GERD: case report

WANG Zhonggao

《医学前沿（英文）》 2007年第1卷第1期页码 115-119 doi: 10.1007/s11684-007-0022-6

摘要： Asthma is a disorder of the lungs characterized by increased responsiveness of the airways, as manifested by episodes of wheezing and increased resistance to expiratory airflow because of varying degrees of smooth muscle contraction, edema of the mucosa, and mucus in the lumen of the bronchi and bronchioles. The stimuli vary widely and include antigens, infection, air pollutants, respiratory tract irritants, exercise, and emotional factors. This condition is completely different from distress breathing because of laryngotracheal spasm. One of its causes is the gastric content reflux through the pharynx to the larynx because of gastroesophageal reflux disease (GERD), in addition to the typical human avian flu that may cause immediate suffocation by laryngospasm owing to acute larygotrachitis. A patient suffered from GERD without esophageal symptoms, which was diagnosed and treated as bronchial asthma during his five emergency admissions. The admissions were because of episodic attacks of severe air hunger owing to an extreme throat tightening. The patient was being treated for as long as two years. After the correct diagnosis was made and treatment of laporascopic fundaplication was performed, the longstanding bronchial asthma , after all, completely disappeared. The concept of not asthma, but GERD seems undervalued, unappreciated, even misunderstood among patients with intractable asthma. Therefore, such a case is reported in detail, similar cases are mentioned briefly as well, and a mechanism responsible for GERD-originated larryngo- or laryngotracho-spasm is proposed.

关键词： resistance mechanism responsible unappreciated responsiveness different

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Lean Product Development—Faster, Better … Cleaner?

Geert Letens

《工程管理前沿（英文）》 2015年第2卷第1期页码 52-59 doi: 10.15302/J-FEM-2015007

摘要： To address this challenge, lean product development has emerged to become the leading improvement methodology for companies toward the creation of a competitive advantage on innovation and technology leadership. While lean product development has its origin in the best practice studies of Japanese car manufacturers such as Toyota, it has been further elaborated in defence and aerospace organizations over the last two decades, and recently empirical evidence has become available for successful introductions in sectors different from the traditionally-studied environments. The primary purpose of this work is to untangle the fuzziness that still surrounds lean product development and to ground the key aspects of lean product development based on insights from six studies published in a special issue of the on this topic. This demonstrates how better and faster product development can be achieved through the integration of lean principles with the best of more traditional new product development (NPD) practices, into a holistic system that can be characterised by value-focused and risk-based decision making, the socio-technical integration of people and process, improved project, pipeline and portfolio management, optimized knowledge management, and the creation of a learning organization. Unfortunately, while the increasing global competition offers the potential to improve the quality of life for many, the spirit of faster, better, and cheaper also threatens to endanger the future of our planet as a whole. As the majority of a product’s social and ecological impacts are committed in the design phase, it, therefore, seems imperative to investigate the integration of lean product development and eco-design principles. As a result, this work also explores the symbiosis of both approaches through the identification of tools and methods that can support the triple bottom-line goals for a sustainable future of life and business.

关键词： lean product development sustainability engineering responsible design

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Nano thermo-hydrodynamics method for investigating cell membrane fluidity

YANG Yang, LIU Jing

《能源前沿（英文）》 2008年第2卷第2期页码 121-128 doi: 10.1007/s11708-008-0033-2

摘要： As a barrier to compartmentalize cells, membranes form the interface between a cell and its surroundings. The essential function of a membrane is to maintain a relatively stable environment in the cell, exchange substances selectively and transfer energy and information continually from the outside. It is intriguing that above the phase transition temperature, the membrane lipid molecule will have three modes–lateral diffusion, rotational movement and flip-flop activity. These thermodynamic processes are vital to cell existence, growth, division, differentiation and are also responsible for hundreds of thousands of phenomena in life. Previously, species transport across the membrane was interpreted mainly from a phenomenological view using a lumped system model. Therefore, detailed flow processes occurred in the membrane domain and clues related to life mechanism were not sufficiently tackled. Such important issues can be clarified by modeling nano scale thermal hydrodynamics over the gap space of a cell membrane. Previously observed complex membrane behaviors will be shown in this paper and explained by the thermally induced fluidic convections inside the membrane. A correlation between nano scale hydrodynamics, non-equilibrium thermodynamics and cell membrane activities is set up. The disclosed mechanisms are expected to provide a new viewpoint on the interaction between intracellular and extracellular processes through the membrane.

关键词： responsible phenomenological phenomena modes–lateral diffusion differentiation

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Relationship between expression of hepatocyte grow factor and apoptosis of trophoblasts in hypertensive disorder complicating pregnancy

OUYANG Shan, ZHANG Qinghua, QIAO Fuyuan

《医学前沿（英文）》 2007年第1卷第4期页码 386-389 doi: 10.1007/s11684-007-0075-6

摘要： The aim of this study was to investigate the expression of hepatocyte growth factor (HGF) and Fas in placentas of uncomplicated pregnant women and those with hypertensive disorder complicating pregnancy (HDCP), and elucidate the possible relationship between HGF and apoptosis of trophoblasts. Reverse transcription-polymerase chain reaction (RT-PCR) was undertaken to examine the concentration of HGF mRNA and Fas mRNA obtained from 34 cases of HDCP and 30 cases of uncomplicated pregnancy. The expression of HGF mRNA in mild preeclampsia, severe preeclampsia and eclampsia cases was significantly lower than that in the uncomplicated cases (0.43±0.12, 0.38±0.09, 0.19±0.17 versus 0.67±0.19, <0.05), while the expression of Fas mRNA in mild preeclampsia, severe preeclampsia and eclampisa cases was significantly higher than that in the uncomplicated cases (1.58±0.26, 2.96±0.14, 5.98±1.17 versus 1.01±0.36, <0.05). For HGF mRNA and Fas mRNA, there was no difference between gestational hypertension cases and control cases. Decreased HGF mRNA or increased Fas mRNA was found along with the progress of HDCP. Negative correlation was found between the expressions of HGF and Fas. These results indicate that HGF inhibits the apoptosis mediated by Fas, and the reduced expression of HGF in HDCP may be responsible for the apoptosis of trophoblasts.

关键词： pregnancy concentration possible relationship responsible hepatocyte

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Construction engineering management culture shift: Is the lowest tender offer dead?

Eric SCHEEPBOUWER, Douglas D. GRANSBERG, Carla Lopez del PUERTO

《工程管理前沿（英文）》 2017年第4卷第1期页码 49-57 doi: 10.15302/J-FEM-2017014

摘要： The procurement of public construction projects must walk a fine line between the corruption of state officials and collusion of contractors. The method of awarding projects to the lowest responsible tenderer was originally implemented to guard against corruption of state officials. However, an investigation of the construction industry in the Canadian province of Quebec showed that lowest-tender-offer procurement gave rise to collusion of companies tendering for the contracts. Alternatively, best-value procurement has been used for decades, but here problems arise owing to the necessity of subjective judging of measures other than price to compare bids, giving rise to time- and money-consuming protests. The paper proposes a compelling argument that the construction engineering management (CEM) culture should refocus its efforts on enhancing project cost certainty rather than merely searching for means to design a project in a manner that produces the lowest initial cost, and awards the construction to the lowest tender offer that focuses on cost savings during the project development and delivery process. The difference in the two approaches is subtle but extremely important. To make the transition, the engineering management tools must be advanced to the next level. This means that all project control tools for managing cost, schedule, and technical scope must be transformed from working in the deterministic mode to the stochastic mode, thus making the probability of completing the project within or below its official budget the primary decision criterion. To do so, CEMs must accept that there is a benefit in paying more for an alternative that increases cost certainty for the entire project. The authors of this paper hope that it will provide the grist for a more general dialog across all industry sectors where engineering management is practiced.

关键词： cost certainty lowest responsible bid best value public procurement construction engineering management culture

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Theory and method of mechanism system design

Huijun ZOU, Qinghua LIANG, Qing ZHANG

《机械工程前沿（英文）》 2010年第5卷第4期页码 399-411 doi: 10.1007/s11465-010-0116-8

摘要： Conceptual design is the most critical and creative phase of design. Recently, increasing attention has been directed to supporting conceptual-level computer aided creative design and its theories and methodologies. Specifically, for conceptual design of mechanical products, this paper presents a novel function solving model for mechanical product design and highlights the importance of systematic synthesis to achieve creative design. Then it builds a framework as a function-effect-process-action- mechanisms (FEPAM) mapping process, which enables creative design on the basis of conceiving different action schemes. After that, several key points are elaborated including 1) representing and decomposition methods of functions and motion behaviors; 2) action scheme representing method based on network plan techniques; and 3) variation and creation methods based on action scheme transformations.

关键词： mechanism system creative design process model function solving model process action procedure mechanisms knowledge base principle of mechanism system composition

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Formation mechanism and modeling of surface waviness in incremental sheet forming

《机械工程前沿（英文）》 2022年第17卷第2期 doi: 10.1007/s11465-022-0679-1

摘要： Improving and controlling surface quality has always been a challenge for incremental sheet forming (ISF), whereas the generation mechanism of waviness surface is still unknown, which impedes the widely application of ISF in the industrial field. In this paper, the formation mechanism and the prediction of waviness are both investigated through experiments, numerical simulation, and theoretical analysis. Based on a verified finite element model, the waviness topography is predicted numerically for the first time, and its generation is attributed to the residual bending deformation through deformation history analysis. For more efficient engineering application, a theoretical model for waviness height is proposed based on the generation mechanism, using a modified strain function considering deformation modes. This work is favorable for the perfection of formation mechanism and control of surface quality in ISF.

关键词： surface waviness incremental sheet forming numerical simulation formation mechanism deformation history

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Autogenous healing mechanism of cement-based materials

《结构与土木工程前沿（英文）》页码 948-963 doi: 10.1007/s11709-023-0960-3

摘要： Autogenous self-healing is the innate and fundamental repair capability of cement-based materials for healing cracks. Many researchers have investigated factors that influence autogenous healing. However, systematic research on the autogenous healing mechanism of cement-based materials is lacking. The healing process mainly involves a chemical process, including further hydration of unhydrated cement and carbonation of calcium oxide and calcium hydroxide. Hence, the autogenous healing process is influenced by the material constituents of the cement composite and the ambient environment. In this study, different factors influencing the healing process of cement-based materials were investigated. Scanning electron microscopy and optical microscopy were used to examine the autogenous healing mechanism, and the maximum healing capacity was assessed. Furthermore, detailed theoretical analysis and quantitative detection of autogenous healing were conducted. This study provides a valuable reference for developing an improved healing technique for cement-based composites.

关键词： autogenous healing cement-based materials healing mechanism aggregation effect

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Optimal design of a linkage–cam mechanism-based redundantly actuated parallel manipulator

《机械工程前沿（英文）》 2021年第16卷第3期页码 451-467 doi: 10.1007/s11465-021-0634-6

摘要： A redundantly actuated parallel manipulator (RAPM) with mixed translational and rotational degrees of freedom (DOFs) is challenged for its dimensionally homogeneous Jacobian modeling and optimal design of architecture. In this paper, a means to achieve redundant actuation by adding kinematic constraints is introduced, which reduces the DOFs of the end-effector (EE). A generic dimensionally homogeneous Jacobian is developed for this type of RAPMs, which maps the generalized velocities of three points on the EE to the joint velocities. A new optimization algorithm derived from this dimensionally homogeneous Jacobian is proposed for the optimal design of this type of RAPMs. As an example, this paper presents a spatial RAPM involving linkages and cam mechanisms. This RAPM has 4 DOFs and 6 translational actuations. The linkage lengths and the position of the universal joints of the RAPM are optimized based on the dimensionally homogeneous Jacobian.

关键词： redundant actuation parallel manipulator linkage–cam mechanism Jacobian optimal design

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Cryogenic minimum quantity lubrication machining: from mechanism to application

《机械工程前沿（英文）》 2021年第16卷第4期页码 649-697 doi: 10.1007/s11465-021-0654-2

摘要： Cutting fluid plays a cooling–lubrication role in the cutting of metal materials. However, the substantial usage of cutting fluid in traditional flood machining seriously pollutes the environment and threatens the health of workers. Environmental machining technologies, such as dry cutting, minimum quantity lubrication (MQL), and cryogenic cooling technology, have been used as substitute for flood machining. However, the insufficient cooling capacity of MQL with normal-temperature compressed gas and the lack of lubricating performance of cryogenic cooling technology limit their industrial application. The technical bottleneck of mechanical–thermal damage of difficult-to-cut materials in aerospace and other fields can be solved by combining cryogenic medium and MQL. The latest progress of cryogenic minimum quantity lubrication (CMQL) technology is reviewed in this paper, and the key scientific issues in the research achievements of CMQL are clarified. First, the application forms and process characteristics of CMQL devices in turning, milling, and grinding are systematically summarized from traditional settings to innovative design. Second, the cooling–lubrication mechanism of CMQL and its influence mechanism on material hardness, cutting force, tool wear, and workpiece surface quality in cutting are extensively revealed. The effects of CMQL are systematically analyzed based on its mechanism and application form. Results show that the application effect of CMQL is better than that of cryogenic technology or MQL alone. Finally, the prospect, which provides basis and support for engineering application and development of CMQL technology, is introduced considering the limitations of CMQL.

关键词： cryogenic minimum quantity lubrication (CMQL) cryogenic medium processing mode device application mechanism application effect

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Review on mechanism and process of surface polishing using lasers

Arun KRISHNAN, Fengzhou FANG

《机械工程前沿（英文）》 2019年第14卷第3期页码 299-319 doi: 10.1007/s11465-019-0535-0

摘要： Laser polishing is a technology of smoothening the surface of various materials with highly intense laser beams. When these beams impact on the material surface to be polished, the surface starts to be melted due to the high temperature. The melted material is then relocated from the ‘peaks to valleys’ under the multidirectional action of surface tension. By varying the process parameters such as beam intensity, energy density, spot diameter, and feed rate, different rates of surface roughness can be achieved. High precision polishing of surfaces can be done using laser process. Currently, laser polishing has extended its applications from photonics to molds as well as bio-medical sectors. Conventional polishing techniques have many drawbacks such as less capability of polishing freeform surfaces, environmental pollution, long processing time, and health hazards for the operators. Laser polishing on the other hand eliminates all the mentioned drawbacks and comes as a promising technology that can be relied for smoothening of initial topography of the surfaces irrespective of the complexity of the surface. Majority of the researchers performed laser polishing on materials such as steel, titanium, and its alloys because of its low cost and reliability. This article gives a detailed overview of the laser polishing mechanism by explaining various process parameters briefly to get a better understanding about the entire polishing process. The advantages and applications are also explained clearly to have a good knowledge about the importance of laser polishing in the future.

关键词： laser polishing surface roughness process parameters mechanism

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Creation and integration mechanism of instrumentation flexible developing system

Xiaoli XU, Qiushuang LIU

《机械工程前沿（英文）》 2011年第6卷第2期页码 235-240 doi: 10.1007/s11465-011-0122-5

摘要：

To solve many key technical problems during the development of modern instrumentation system integration and provide a new mode and fundamental technical equipment for the research and development (R&D) of modern instrumentation products, based on the concept of an instrumentation flexible developing system (IFDS), this paper discusses the creation and open flexible integration mechanism, perfects the integrated supporting environment and integrated system of the flexible interconnection, and constructs the new flexible integrated system. Based on the operation mechanism of the modern instrumentation developing system and the research and optimization of the rapid integration design method, the paper emphasizes the dynamic integrating method of multiple types of knowledge in a modern instrument R&D system, to effectively utilize the rich integrated resource and achieve rapid integration of the system. Applications show that the new IFDS can improve the integration level and efficiency of R&D of the modern instrumentation system, enforce the reliability of the system, shorten the R&D period, and reduce the development costs.

关键词： modern instrumentation developing flexible interconnection flexible integration mechanism rapid integration system dynamic integrating method

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Mechanism and characterization of microplastic aging process: A review

《环境科学与工程前沿（英文）》 2023年第17卷第8期 doi: 10.1007/s11783-023-1700-6

摘要：

● Methods for estimating the aging of environmental micro-plastics were highlighted.

关键词： Microplastics Aging Degradation Characterization Mechanism

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Design of a novel side-mounted leg mechanism with high flexibility for a multi-mission quadruped earth

《机械工程前沿（英文）》 2023年第18卷第2期 doi: 10.1007/s11465-022-0740-0

摘要： Earth rover is a class of emerging wheeled-leg robots for nature exploration. At present, few methods for these robots’ leg design utilize a side-mounted spatial parallel mechanism. Thus, this paper presents a complete design process of a novel 5-degree-of-freedom (5-DOF) hybrid leg mechanism for our quadruped earth rover BJTUBOT. First, a general approach is proposed for constructing the novel leg mechanism. Subsequently, by evaluating the basic locomotion task (LT) of the rover based on screw theory, we determine the desired motion characteristic of the side-mounted leg and carry out its two feasible configurations. With regard to the synthesis method of the parallel mechanism, a family of concise hybrid leg mechanisms using the 6-DOF limbs and an L_1F1C limb (which can provide a constraint force and a couple) is designed. In verifying the motion characteristics of this kind of leg, we select a typical (3-UPRU&RRRR)&R mechanism and then analyze its kinematic model, singularities, velocity mapping, workspace, dexterity, statics, and kinetostatic performance. Furthermore, the virtual quadruped rover equipped with this innovative leg mechanism is built. Various basic and specific LTs of the rover are demonstrated by simulation, which indicates that the flexibility of the legs can help the rover achieve multitasking.

关键词： design synthesis parallel mechanism hybrid leg mechanism screw theory quadruped robot