1. An oxygen sensor comprising:
a base body portion; and
a plurality of function layers laminated on a surface of the base body portion, the function layers including
a solid electrolyte layer adapted to conduct oxygen ions,
a reference electrode layer located on a base body portion side of the solid electrolyte layer,
a sensing electrode layer located on the opposite side of the solid electrolyte layer to the reference electrode layer,
a heater portion adapted to activate the solid electrolyte layer by heating, and
a gas diffusion layer formed between the reference electrode layer and the base body portion, and adapted to diffuse a reference gas within the gas diffusion layer,
the gas diffusion layer being formed to have a porosity indicating a limit current value ranging between 60 \u03bcA and 200 \u03bcA, the limit current value being a value of a current flowing between the reference electrode layer and the sensing electrode layer when the current flowing therebetween becomes substantially constant during the process of bringing higher a voltage applied between the reference electrode layer and the sensing electrode layer.
2. The oxygen sensor as claimed in claim 1, wherein
the gas diffusion layer is formed of a ceramic material and a vacancy forming material having an amount accounting for a ratio between 10% and 60% of a total amount of the ceramic material and the vacancy forming material in weight;
an average particle diameter of the vacancy forming material ranges from 1 \u03bcm to 20 \u03bcm; and
the vacancy forming material is adapted to disappear when undergoing a sintering to form the gas diffusion layer as a porous ceramic layer.
3. The oxygen sensor as claimed in claim 2, wherein the ratio is defined by a content of the vacancy forming material relative to the ceramic material before undergoing the sintering.
4. The oxygen sensor as claimed in claim 2, wherein the gas diffusion layer is formed of the ceramic material and the vacancy forming material having an amount accounting for a ratio between 30% and 50% of the total amount of the ceramic material and the vacancy forming material in weight.
5. The oxygen sensor as claimed in claim 1, wherein
the gas diffusion layer is formed of a ceramic material and a vacancy forming material having an amount accounting for a ratio between 20% and 80% of a total amount of the ceramic material and the vacancy forming material in volume;
an average particle diameter of the vacancy forming material ranges from 1 \u03bcm to 20 \u03bcm; and
the vacancy forming material is adapted to disappear when undergoing a sintering to form the gas diffusion layer as a porous ceramic layer.
6. The oxygen sensor as claimed in claim 1, wherein the solid electrolyte layer includes a plurality of laminated sublayers.
7. The oxygen sensor as claimed in claim 5, wherein the gas diffusion layer is formed of the ceramic material and the vacancy forming material having an amount accounting for a ratio between 50% and 70% of the total amount of the ceramic material and the vacancy forming material in volume.
8. An oxygen sensor comprising:
a base body portion; and
a plurality of function layers laminated on a surface of the base body portion, the function layers including
a solid electrolyte layer adapted to conduct oxygen ions,
a reference electrode layer located on a base body portion side of the solid electrolyte layer,
a sensing electrode layer located on the opposite side of the solid electrolyte layer to the reference electrode layer,
a heater portion adapted to activate the solid electrolyte layer by heating, and
a gas diffusion layer formed between the reference electrode layer and the base body portion, and adapted to diffuse a reference gas within the gas diffusion layer,
the gas diffusion layer being formed of a ceramic material and a vacancy forming material having an amount accounting for a ratio between 10% and 60% of a total amount of the ceramic material and the vacancy forming material in weight, the vacancy forming material being adapted to disappear when undergoing a sintering to form the gas diffusion layer as a porous ceramic layer.
9. The oxygen sensor as claimed in claim 8, wherein
the gas diffusion layer is formed of the ceramic material and the vacancy forming material having an amount accounting for a ratio between 30% and 50% of the total amount of the ceramic material and the vacancy forming material in weight under a state before the sintering.
10. The oxygen sensor as claimed in claim 8, wherein an average particle diameter of the vacancy forming material ranges from 1 \u03bcm to 20 \u03bcm.
11. An oxygen sensor comprising:
a base body portion; and
a plurality of function layers laminated on a surface of the base body portion, the function layers including
a solid electrolyte layer adapted to conduct oxygen ions,
a reference electrode layer located on a base body portion side of the solid electrolyte layer,
a sensing electrode layer located on the opposite side of the solid electrolyte layer to the reference electrode layer,
a heater portion adapted to activate the solid electrolyte layer by heating, and
a gas diffusion layer formed between the reference electrode layer and the base body portion, and adapted to diffuse a reference gas within the gas diffusion layer,
the gas diffusion layer being formed of a ceramic material and a vacancy forming material having an amount accounting for a ratio between 20% and 80% of a total amount of the ceramic material and the vacancy forming material in volume, the vacancy forming material being adapted to disappear when undergoing a sintering to form the gas diffusion layer as a porous ceramic layer.
12. The oxygen sensor as claimed in claim 11, wherein the gas diffusion layer is formed of the ceramic material and the vacancy forming material having an amount accounting for a ratio between 50% and 70% of the total amount of the ceramic material and the vacancy forming material in volume under a state before the sintering.
13. The oxygen sensor as claimed in claim 11, wherein an average particle diameter of the vacancy forming material ranges from 1 \u03bcm to 20 \u03bcm.
14. A manufacturing method for an oxygen sensor including
a base body portion; and
a plurality of function layers laminated on a surface of the base body portion, the function layers including
a solid electrolyte layer adapted to conduct oxygen ions,
a reference electrode layer located on a base body portion-side of the solid electrolyte layer,
a sensing electrode layer located on the opposite side of the solid electrolyte layer to the reference electrode layer,
a heater portion adapted to activate the solid electrolyte layer by heating, and
a gas diffusion layer formed between the reference electrode layer and the base body portion, and adapted to diffuse a reference gas within the gas diffusion layer,
the manufacturing method comprising:
a first step of mixing a ceramic material with a vacancy forming material having an amount accounting for a ratio between 10% and 60% in weight or between 20% and 80% in volume relative to a total amount of ceramic material and vacancy forming material; and
a second step of sintering the mixture to cause the vacancy forming material to disappear, thereby to form the gas diffusion layer as a porous ceramic layer.
15. The manufacturing method as claimed in claim 14, wherein in the first step,
a ceramic material is mixed with the vacancy forming material having an amount accounting for a ratio between 30% and 50% in weight or between 50% and 70% in volume relative to the total amount of ceramic material and vacancy forming material.
16. The manufacturing method as claimed in claim 14, wherein in the first step,
an average particle diameter of the vacancy forming material ranges from 1 \u03bcm to 20 \u03bcm.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An elongate wooden post for embedment in the ground comprising:
a first portion for embedment into the ground, said first portion having a longitudinal axis and a solid cross-sectional shape having a first cross-sectional area oriented perpendicular to said longitudinal axis;
a second portion integrally formed with and extending from said first portion for extending along said longitudinal axis upwardly above the ground;
at least one notch cut into said first at a predetermined location portion, said at least one notch comprising a predetermined concave arcuate shape extending radially inward a predetermined radial depth into said first portion to define a minimum cross-sectional area of said area of first portion, said minimum cross-sectional area being oriented perpendicular to said longitudinal axis and substantially smaller than said first cross-sectional area, interaction between said at least one notch and the ground creating a compressive interaction, variation in said predetermined radial depth enabling a post pull-out force to be selectively increased to a desired value resulting from increasing the compressive force interaction between said at least one notch and the ground wherein said desired value exceeds a pull-out force resulting from a shear force interaction between the post and the ground; and
a protective cover formed from a non-perforated plastic heat-shrunk material covering the entirety of said first portion and an adjacent portion of said second portion to prevent deterioration of said wooden post, said material having a shrink ratio wherein said shrink ratio is equal to or greater than a ratio of said first cross-sectional area to said minimum cross-sectional area thereby enabling said cover to fully conform to the surface of said post and said at least one notch.
2. The post of claim 1, wherein said post has a generally rectangular cross section and said at least one notch is formed on an apex of two adjacent sides of said post.