Theoretical and Experimental Investigation of Laser Drilling in a Partially Transparent Medium

1992 ◽  
Vol 114 (1) ◽  
pp. 71-80 ◽  
Author(s):  
T. Nowak ◽  
R. J. Pryputniewicz
Keyword(s):  
Laser Beam ◽  
Three Dimensional ◽  
Laser Drilling ◽  
Drilling Process ◽  
Transparent Medium ◽  
Finite Sample ◽  
Cross Sectional ◽  
Quantitative Correlation ◽  
Study Results ◽  
Successful Prediction

An investigation of pulsed, laser drilling in a partially transparent medium was conducted. The study included both theoretical and experimental analyses. The theoretical analysis included development of a computer simulation to model the laser drilling process—a three-dimensional finite difference solution with temperature-dependent thermal properties, finite sample geometry, and experimentally determined laser beam characteristics. Both qualitative and quantitative correlation of the theoretical and experimental results was good with successful prediction of hole shapes and minimum error in the theoretically predicted cross-sectional areas of the laser-drilled holes ranging approximately ± three percent over the range of energies per laser pulse considered in this study. Results of calculations and experiments demonstrated the importance of the shape and irradiance distribution of the incident laser beam on the quality of laser-drilled holes in Al2O3 samples.

Three-dimensional transient numerical simulation of laser drilling process

2012 ◽  
Vol 42 (8) ◽  
pp. 869-876 ◽  
Author(s):  
ZhiFu GE ◽  
ShaoXia LI ◽  
Gang YU ◽  
XiuLi HE ◽  
GuoQuan LU
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Laser Drilling ◽  
Drilling Process ◽  
Transient Numerical Simulation

CO2 Laser Drilling of Microvias Using Diffractive Optics Techniques: I — Mathematical Modeling

2005 ◽  
Author(s):  
Chong Zhang ◽  
Sachin Bet ◽  
Islam A. Salama ◽  
Nathaniel R. Quick ◽  
Aravinda Kar
Keyword(s):  
Mathematical Modeling ◽  
Laser Beam ◽  
Co2 Laser ◽  
Thermal Energy ◽  
Laser System ◽  
Damage Threshold ◽  
Laser Drilling ◽  
Diffractive Optics ◽  
Prototype System ◽  
Drilling Process

This paper is the first of three parts summarizing the research to use diffractive optics at the CO2 laser wavelength to drill microvias in the 40–50 μm range for organic packaging applications. This first part mainly focuses on mathematical modeling of the drilling process, which is used to define the characteristics of the laser beam necessary to achieve the required geometry of the microvias. These laser characteristics and the properties of the incoming laser beam of the CO2 laser system are then used to provide a deterministic approach for obtaining performance data for the diffractive optics design. The targeted optics are designed based on the modeling result and are then integrated into a prototype system to execute the drilling operation. The model is based on the conversion of optical energy into thermal energy due to laser-substrate interaction, propagation of thermal energy in the substrate, thermal as well as radiation damage threshold of the substrate and other important laser drilling parameters (e.g., fluence, temporal and spatial characteristics of the beam, residue at the via bottom).

scholarly journals Effects of Beam Size and Pulse Duration on the Laser Drilling Process

2016 ◽  
Author(s):  
Nazia Afrin ◽  
Pengfei Ji ◽  
J. K. Chen ◽  
Yuwen Zhang
Keyword(s):  
Laser Beam ◽  
Pulse Duration ◽  
Material Removal ◽  
Convection Heat Transfer ◽  
Laser Drilling ◽  
Drilling Process ◽  
Beam Diameter ◽  
Beam Size ◽  
Laser Beam Diameter ◽  
Ablation Efficiency

A two-dimensional axisymmetric transient laser drilling model is used to analyze the effects of laser beam diameter and laser pulse duration on the laser drilling process. The model includes conduction and convection heat transfer, melting, solidification and vaporization, as well as material removal resulting from the vaporization and melt ejection. The validated model is applied to study the effects of laser beam size and pulse duration on the geometry of the drilled hole. It is found that the ablation effect decrease with the increasing beam diameter due to the effect of increased vaporization rate, and deeper hole is observed for the larger pulse width due to the higher thermal ablation efficiency.

ASSESSMENT OF SKILLED BIRTH ATTENDANTS REGARDING HELPING BABIES BREATH INTERVENTION TO IMPROVE NEWBORN CARE IN RURAL DISTRICT OF SINDH

1970 ◽  
Vol 7 (1) ◽  
pp. 48-53
Author(s):  
Sheh Mureed ◽  
Muhammad Hassan Gandro ◽  
Walid Hassan
Keyword(s):  
Newborn Care ◽  
Cross Sectional Study ◽  
Vital Role ◽  
Skilled Birth Attendants ◽  
Cross Sectional ◽  
Neonatal Deaths ◽  
Birth Attendants ◽  
Study Results ◽  
Knowledge And Practice ◽  
Labour Room

Background: Globally, 3.1 million newborn deaths occur every year out of these estimated 400,000 neonatal deaths occur in Pakistan. All neonatal deaths 99% take place in poorest region and countries of the world, usually within hours of birth; mostly the cause of neonatal deaths is hypoxia. To access knowledge and practice of SBAs regarding HBB and to access the availability of equipments required for HBB. Methods: Descriptive Cross-Sectional Study on SBAs as trained in HBB. All 46 SBAs trained on HBB working in Labour room eight rural Health centers, four Taluka, One district Head Quarter Health Facilities and thirteen Mlbcs of the district, were included in the sample for study. All 41 SBAs were trained on HBB participated in the study. Results: Mean age of 30 years. Out of total 41 participants 25 were working in B-EmoNC (61%), 3in C-EmoNC (7.3%) and 13 in mid wife laid birth Centre (MLBC) or birth station (31.7%). About 92.7% of participants said that main purpose of HBB training is to decrease the NMR by improving newborn care. Drying of newborn is 82.7%, hand washing is 95.12% and 85.3% of the study participants said that they gave 30-40 breaths per minutes. Cord clamp and pair of ties was accessible to 85% of participants versus 14.3% who reported it's not accessible. Almost one quarter (34.1%) participants have low knowledge and practice. Knowledge and training had significant effect on the overall practices of the skilled birth attendants for skilled birth deliveries and reduce the neonatal deaths (P <0.001). Conclusion: Tools play a vital role for the implication of the knowledge into practices and tools were available almost to every participant. Although few barriers also identified for the less application of the helping hand babies trainings in the community.

COMPARISION OF DENTAL SCORING SYSTEM WITH RADIOGRAPHIC SKELETAL SYSTEM IN AGE ESTIMATION

JKCD ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 9-11
Author(s):  
Sadaf Ambreen
Keyword(s):  
Age Estimation ◽  
Scoring System ◽  
Skeletal Age ◽  
Chronological Age ◽  
Age Group ◽  
Dental Age ◽  
Scoring Method ◽  
Cross Sectional ◽  
Study Results ◽  
Male Subjects

Objectives: To compare Demirjian Dental scoring method with Greulich-Pyle (GP) Skeletal method of age estimation in pubertal children. Materials and Methods: Sample of the study included 267 male healthy subjects of 11-16 years of age group.. Demirjian Scoring system was utilized to evaluate the orthopantomograms to assess their Dental age and the Hand-Wrist radiographs were analyzed to calculate the skeletal age by utilizing GP atlas. Chronological age was obtained from the date of birth of the subject .Both methods were compared with one another and with the chronological age. It was a cross-sectional study and only healthy male subjects without any clinical abnormalities were included in the study. Results: A total of 267 male subjects of 11-16 years of age group were assessed by Demirjian and Greulich Pyle Methods. Both were compared with Chronological Age. Data obtained was statistically analyzed and the Student “t” test was applied in the study population. The mean difference between Chronolgical age and dental age was 0.69years and that of chronological age and skeletal age was 0.87 years. It was observed from dental age assessment that it does not differ much from the skeletal age. Conclusion: It was concluded that Demirjian method of Age Estimation is more precise than Greulich Pyle method of Age Estimation. Furthermore both methods can be used selectively in Medicolegal cases to access bone age which can be easily correlated to chronological age.

Blood Analysis Requests of Patients’ and Clinical Reflections in Primary Care

2020 ◽  
Vol 9 (2) ◽  
pp. 96-102
Author(s):  
Zerrin Gamsizkan ◽  
Mehmet Ali Sungur ◽  
Yasemin Çayır
Keyword(s):  
Chronic Disease ◽  
Blood Test ◽  
Family Health ◽  
Cross Sectional Study ◽  
Blood Analysis ◽  
Primary Role ◽  
Cross Sectional ◽  
High Expectations ◽  
Blood Tests ◽  
Study Results

Aim: The aim of the study is to determine the factors that may affect the demands of patients who come with the request to have a blood test without any chronic disease or a planned examination check. Methods: The data of this descriptive, cross-sectional study, were collected with a questionnaire that was prepared to examine the opinions of the patients who claim to have a blood test by coming to the family health center without any complaints. Patients over 18 years of age, who did not have any chronic disease and had no scheduled examination appointments were included in the study. Results: A total of 278 patients who wanted to have a blood test within the 6-months period were included in the study. Female patients who wanted to have a blood test were significantly more than male patients. When we look at the causes of patients who wanted to have a blood test; 61.2% (n=170) patients stated that they are concerned about their health and 6.1% (n=17) stated that they were affected by media warnings. There was no significant relationship between the frequency of blood test requests of patients and their age, gender, education, and general health status. Conclusion: Patients with high expectations and anxiety may be more willing to perform blood tests at inappropriate intervals. Family physicians, whose primary role is preventive medicine, have consultancy and information duties in order to protect their patients from the risk of over-examination and diagnosis. Keywords: blood tests, patient, screening, routine diagnostic tests

Laser Failure Isolation Techniques Demonstrated On Test Structures

2008 ◽  
Author(s):  
Frank S. Arnold
Keyword(s):  
Integrated Circuits ◽  
Laser Beam ◽  
Case Studies ◽  
Induced Resistance ◽  
Simple Test ◽  
Resistance Change ◽  
Cross Sectional ◽  
Beam Focusing ◽  
Isolation Techniques ◽  
Heating Effects

Abstract To be better prepared to use laser based failure isolation techniques on field failures of complex integrated circuits, simple test structures without any failures can be used to study Optical Beam Induced Resistance Change (OBIRCH) results. In this article, four case studies are presented on the following test structures: metal strap, contact string, VIA string, and comb test structure. Several experiments were done to investigate why an OBIRCH image was seen in certain areas of a VIA string and not in others. One experiment showed the OBRICH variation was not related to the cooling and heating effects of the topology, or laser beam focusing. A 4 point probe resistance measurement and cross-sectional views correlated with the OBIRCH results and proved OBIRCH was able to detect a variation in VIA fabrication.

HIV INFECTION AND SOME RELATED FACTORS IN FEMALE MASSAGE THERAPISTS IN QUANG NGAI PROVINCE

2015 ◽  
pp. 57-60
Author(s):  
Xuan Chuong Tran ◽  
Thi Thanh Hoa Le ◽  
Ngoc Van Nguyen ◽  
Thanh Nguyen
Keyword(s):  
Hiv Infection ◽  
Urban Areas ◽  
Risk Groups ◽  
Sexual Contact ◽  
Related Factor ◽  
Related Factors ◽  
Cross Sectional ◽  
Keywords Hiv ◽  
Study Results ◽  
Massage Therapists

Background: HIV/AIDS is still a dangerous infection in Vietnam and in the world. Studying of HIV infection and related factors in high risk groups, including female massage therapists is therefore very important. Aims: 1. To study the HIV infection in female massage therapists in Quang Ngai province. 2. To fine some related factors to HIV infection. Patients and methods: Female massage therapists working in Quang Ngai province. Cross-sectional, descriptive study. Results: The rate of HIV infection was 0.99%. Group older than 22 years old had higher rate of infection than group under 22 years old (1.80% vs 0.69%). The girls from urban areas or not using condom had higher rate of infection than group from rural or not using condom (1.57% vs 0.47% and 7.32% vs. 0.57%). Most of HIV infected belong to single or divorce groups. Conclusions: The rate of HIV infection in female massage therapists in Quang Ngai province was 0.99%. The HIV infection related factor was not using condom in sexual contact. Keywords: HIV, female massage therapists, Quang Ngai

STUDYING OF CHILDREN WITH MENTAL RETARDATION IN HUE CITY IN 2011

2012 ◽  
pp. 83-87
Author(s):  
Thi Minh Xuan Doan ◽  
Xuan Chuong Tran
Keyword(s):  
Mental Retardation ◽  
Cross Sectional Study ◽  
Learning Ability ◽  
Daily Activities ◽  
Sectional Study ◽  
Cross Sectional ◽  
Slow Development ◽  
Study Results

Children with mental retardation have low intelligence, slow thinking, low learning ability in comparison with the same age children. Objectives: 1. To determine the prevalence of children with mental retardation in Hue City. 2. To study some characteristics of children with mental retardation. Materials and methodes: All children with mental retardation in Hue city. Cross sectional study. Results: The prevalence of children with mental retardation (CMR) among children under 15 yrs is 0.23%, among disable children 38.16%. The highest prevalences ware in Phu Binh, Xuan Phu quarters (0.79 and 0.66%), lowest in Thuan Loc, Thuan Thanh quarters (0.03 and 0.06%). Children over 5 yrs old were 75.95%. Most of children have slow development in movement and daily activities. More than 78% have late walking, 84% have late speaking. Conclusions: The prevalence of children with mental retardation among children under 15 yrs is 0.23%, among disable children 38.16%. Most of children have slow development in movement and daily activities.

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